algas lagos salinos

7/27/2019 Algas Lagos Salinos

http://slidepdf.com/reader/full/algas-lagos-salinos 1/28

LIMNOLOGYAND

OCEANOGRAPHY

January, 1960

VOLUME V

NUMBER 1

SEASONAL CHANGES IN THE ATTACHED ALGAE OF

FRESHWATER AND SALINE LAKES IN THE

LOWER GRAND COULEE, WASHINGTON1

Richard W. Castenholx

Department of Biology, University of Oregon, Eugene

ABSTRACT

A two year investigation of two freshwater alkaline lakes and two saline lakes in the

Lower Grand Coulee has provided a quantitative and qualitative record of many of theseasonal changes occurring in the non-planktonic algae. A glass plate method satisfactorilyrecorded quantitative changes in the attached algae. The plates (28 by 28 cm) were sub-

merged for 2 to 4 weeks at various depths. Dry weight and ash-free dry weight of thepredominantly algal attachment materials on plates were determined, and the ash-free weight

was expressed as a production rate. The ash from freshwater lakes was composed normallyof intact diatom frustules. The ash from saline lakes was also diatomaceous, but the weakly

silicified frustules were deformed during ashing. Proportional counts of the various species

in freshwater lakes were made using the ash. The evaluation of relative dominance wasbased on the mathematical product of the cell count and a calculated volume factor for each

species. The glass-plate production technique was examined at some length and it wasconcluded that a e-week submergence period was most satisfactory, that glass was not unduly

selective, that a horizontal position was satisfactory, and that the method was best suited to

the freshwater lakes.

In freshwater lakes ( 200450 ppm T.D.S. ) results clearly show a bimodal production curvewith the peak generally higher in the spring than in the fall. Lowest production invariably

occurred in late summer. High production values in the spring were commonly near or above

500 mg/m”/day. Comparison of the results of two years shows sizable differences in total

production at comparable times of year, but the seasonal distribution of species followed

the same general pattern both years. Cymbella affinis, C. cistula, C. mexicana, Diatomaelongatum, Fragiluria uaucheriae, Gomphonema eriense, Nitxchia spp., Synedra acus, and

S. ulna were characteristic spring dominants in the freshwater lakes. These diatoms werereplaced in summer mainly by Epithemia sorex, E. turgida, and Rhopalodia gibba. A few

“spring” species were common in one lake in summer but only at greater depths. The

1 This study is a revision of part of a thesis sub- chemical data. Dr. Vernon W. Proctor read criti-

mitted to the Department of Botany, the State

College of Washington in partial fulfillment of the

tally a large part of the manuscript. The author

wishes to thank these people.

requirements for the Ph.D. degree.The author is grateful to Dr. Noe Higinbotham

The study was assisted in part by a grant from the

for aid and encouragement through the course of the

Jessup Fund of The Academy of Natural Sciences

of Philadelphia to which the author is indebted.investigation. Dr. Ruth Patrick and associates of the Voucher specimens of almost all algae collected

Academy of Natural Sciences of Philadelphia, have are preserved in the author’s personal collection.given valuable aid in the identification of diatoms. Permanent slides of most of the diatoms collected

Dr. Francis Drouet has been very helpful in the will be deposited soon in the collection of Theidentification of blue-green algae. Mr. ROSSNel-

son, formerly superintendent of Sun Lakes State

Academy of Natural Sciences of Philadelphia.

Park, has been helpful in many aspects of field

With the exception of Alkali, Alcove, and Talus,

transportation. Various staff members of the

the lake names are those used by Bretz ( 1932).

Alkali, a recently formed lake, is the name used on

Columbia Basin Project, Bureau of Reclamation, Bureau of Reclamation maps. Alcove Lake and

U.S.D.I. have supplied maps and physical and Talus Lake have previously borne no names (Fig. I).



RICHARD W. CA STENIIOLZ

summer period was also characterized by a great abundance of Cludophora, Spirogyq

OsciZZuto~ia, and mcmbcrs of the Chlorococcalcs. The dominant summer diatoms usuallyremained through the fall and were joined at that time by scvcral of the “spring” ’ *.In winter diatom production was generally low, but Uloth~ix clothed rocks in l?al~~?~~

even under an ice cover.

Nine per cent of the 275 algal taxa collected in the Lower Grand Coulec occurred in bothfreshwater and saline lakes. Although the saline lakes were not rich in numbers of species,

production rates were similar to and even higher than production rates in the freshwater

lakes. In the two saline lakes ( Lake Lcnorc-10,000 ppm and Soap Lake-25,000 ppm )

there was a pronounced diatom pulse in the fall. Production rate values as high as 550

mg/mz/day were achieved during this season. In Soap Lake a winter pulse reached a vaIucof 1000 mg/mz/day which was followed by a distinct spring pulse, both absent in Lake

Lcnore. The dominants on glass plates in both lakes were species of Nitzschia and Amphora.

Blue-green algae were also common and were conspicuous for their lack of seasonality.

INTRODUCTION

The description of freshwater algal peri-

odicity and the study of the causes of

bimodal, unimodal, or apparently erraticseasonal production curves have had a longhistory, yet no entirely convincing solutions

have been proposed. Most studies havebeen on phytoplankton, and relatively little

effort has been expended in analyzing theperiodicities of the vastly more numerousspecies of the non-planktonic algal asscm-

blages, freshwater or marine. Nor has thecontribution of the non-planktonic algae to

the total primary production of a lake orpond been satisfactorily evaluated.

The present invcs tigation has attempted to

develop a satisfactory quantitative method

for measuring the changes in attachedalgae. For a period from December, 1954,

to November, 1956, submerged glass wasused as a rcmovablc substrate for measuring

attachment and growth of normally epilithicand epiphytic algae. This was a part of a

general floristic and ecological survey of

certain freshwater and salinc lakes in theLower Grand Coulee of central Washing-

ton.The algae of lakes in the northwestern

United States have rarely been investigated.Previous published research on algae in theColumbia Basin of Washington is limitedto studies of the seasonal periodicity ofphytoplankton in two of the saline lakes in

the Lower Grand Coulee (Anderson 1958,and Anderson et al. 1955).

The Grand Coulee runs in a northeast tosouthwest direction for about 80 km,

extending from Grand Coulee Dam on the

Columbia River to the city of Soap Lake.tt is the most spectacular part of the wide-

spread channeled scablands formed duringthe Pleistocene by outwash rivers from ice-dammed lakes. A detailed and interpreta-tive geological description of the GrandCo&e is given by Bretz ( 1932).

The Lower Grand Coulee is a deep gorgewith vertical walls 120 to 300 m in height

and with a maximum width of almost 2 km( Fig. 1) . The trench, extending about 27km from Coulee City to Soap Lake, was cut

by the recession of a cataract. The walls

and floor consist of basalt with small num-bers of granitic boulders.

The Lower Grand Coulee lies in a semi-desert belt in which the Artemisia trident-ata/Agropyron spicatum association is pre-

dominant ( Daubenmire 1942). The annualprecipitation is about 8 inches, most ofwhich occurs in fall, winter, and spring.

The annual snowfall is about 18 inches.Summer is characterized by clear warm

days. The mean temperatures for January

and July are about -3°C and 25”C, respec-tively.

The series of natural lakes in the LowerGrand Coulee is of particular interest inthat it shows a considerable salinity gradi-ent, increasing from north to south. Thelakes originated in late Pleistocene after theColumbia River regained its present course

and the flow of water through the Grand

Coulee ceased. Falls, Castle, Deep, Perch,

Park, Blue, and Alkali lakes ( Fig. 1) may

be classified as freshwater, although thetotal dissolved solid content ( T.D.S.) ranged

from 200 to over 400 ppm. According to



SEASONAL CHANGES IN AlTACIIED ALGAE 3

FIG. 1. Sketch map of Lower Grand Coulee +a based on Reclamation Scrvicc map Rz-4045-3.

Rawson and Moore (1944) such waters bonate are the most abundant ions of the

could be classified as saline. However, freshwater lakes (Table 1). The predom-these lakes stand in contrast to the closed inant ions of the saline lakes are sodium,waters of Lake Lenore, Talus Lake, and bicarbonate, and carbonate with lesser

Soap Lake (Fig. 1) in which the T.D.S. amounts of potassium, magnesium, sulfate,content of surface waters ranged from about and chloride (Table 1) .8,000 to over 25,000 ppm. In these highly Recent changes include a rather rapidsaline lakes the metazoan fauna is limited dilution of the saline waters. This is caused

to a few species of rotifers, microcrusta- principally by a pumping out of excess

ceans, and insects. Whittaker and Fair- water from Lake Lenore and Soap Lake tobanks (1958) d scuss the copepod fauna of counteract the rising water level. A rising

these and other Columbia Basin lakes. water table is a widespread phenomenon in

Sodium, magnesium, calcium, and bicar- the region of the Columbia Basin Project.



4 RICHARD W. CRSTENHOLZ

TABLE 1. Conductivity, pH, and concentration of dissolved solids of Lower Grand Coulee surface waters;

data in italics from present study, other data from U. S. Dept. of the Interior

Water Year PII

Conductivity,micromhos @

Parts per million

25°C T.D.S. Cs Mg Na K CO3 HC03 so4 Cl

FalIs 1954 - 398 244 24 17 33 6 12 185 24 9Lake 1956 - 415 300 22 19 33 7 0 203 30 11

55-56 8.0-9.1 370-407 - - -

Alkali 1955 - 678 440 13 24 105 12 0 367 34 20Lake 1956

8.p9.4556 356 18 22 71 13 0 291 30 15

55-56 674-539 - - - - -

Lenore

Lake

1949 9.7

1954 9.8

1955 9.5-9.6

1956 9.7

1956 9.5-9.7

Soap

Lake

1949 9.8

1954 10.0

1955 9.5-9.7

1956 10.0

1956 9.7-9.8

23,206 18600 9 20 6969 508 3990 4636 2923 1856

14,158 11040 8 20 3887 321 1746 3221 1627 1093

11,528-l 2,3880,640 7500 i li 262; 23; - - - -36 2885 1378 724lO,OOO-11,227 - - - - - - -

43,000 38954 5 17 14260 739 7440 6893 6960 5183

30,087 25440 8 20 8763 774 4050 5020 4560 344427,666 - - -

24,980 20600 5 16 7291 602 336; 3788 3782 257024,774-26,774 - - - - - - - - -

The sixteen or more lakes and ponds in 1950). Newcombe ( 1950), working for athe Lower Grand Coulce are not polluted few months in a Michigan lake, used

to any extent at this time, but it is likely 18 standard microscope slides horizontally

that some forms of pollution will occur with placed in wooden racks and suspended at

a constantly increasing recreational usage. various depths from buoys.

MATERIALS AND METHODS

The regular collection of non-plank tonicalgae included both a quantitative collec-tion of attached algae on glass plates anda more or less random sampling of algaefrom all lake habitats. The present report

is restricted almost entirely to a considera-tion of the quantitative data and will not

give a detailed account of the algal flora.A full account is available in typescript at

the Science Division, Holland Library, StateCollege of Washington ( Castenholz 1957).

The measurement of production rate

A quantitative sampling method whichemployed submerged glass plates was usedfor a two-year period. The method involved

submergence of the plates in a horizontalposition for a fixed period of time, removalof attachment materials by scraping, anddetermination of dry weight followed by a

determination of weight lost on ignition.This method is essentially a modification ofthe technique used by Newcombe (1949,

A glass slide or plate technique was alsoused in freshwater by Abdin ( 1949), Butch-er ( 1932a, 193213 , Cholodny ( 1930)) God-ward ( 1937)) Ivlev ( 1933)) Patrick et aZ.

( 1954), Thomasson ( 1925 ) , Yount ( 1956 ) ,and others. Bissonnctte ( 1930), Cot andAllen ( 1937), Hentschel ( 1916, 1925),Scheer ( 1945) and scvcral others have used

glass to study attachment, growth, and suc-cession in marine situations. The generalmethods are reviewed by Cooke ( 1956).Many of the workers have utilized direct

microscope counts of organisms attached toslides. Such a method fails when growthbecomes so heavy that it cannot be frac-tionated in situ under the microscope. Thiswas generally the case with the submcrg-cnce period of two weeks used in the presentstudy. Newcombe, on the other hand, con-sidercd only the production of total organicmatter and gave no consideration to thespecies composition. The present study hassought to combine a method of estimating

production rate in terms of ash-free weightwith a method of estimating the spccics

composition of the attachment materials.



SEASONAL CHANGES IN ATTA4CHED ALGAE 5

Square plates (28 by 28 cm) of doublestrength glass were placed in the lakes. Inmost locations the plates were placed di-

rectly on the rock substrate. Such plates

had a single drilled hole and were attachedto an object on shore by means of a wire

line. Other plates in regions of unstable

bottom material or of heavy wave action

were fitted with 3 holes and mounted on 3rubber cups of a standard automobile top-

rack type. Thus, the plate was above thesubstrate by a few centimeters and break-age or heavy silting was usually prevented.

The motive in placing plates directly on the

substrate, instead of suspending them from

buoys in open water, was to have the arti-ficial substrate as close as possible to theorigin of the “seed” of the epilithic algae.

Whether a measurable lag in “seeding-

” would occur offshore has not beenDetermined.

At the stations in all lakes, plates were

located at approximately 0.4 m depth. InFalls Lake plates were also located veryclose to the surface, and during the summer

at depths of 1, 2, and 3 m. The deeper

plates were placed and retrieved by diving.The depth of plates was kept fairly cons-

tant by adjustment at every visit. Through-

out the study, plates were exposed for eithera 2-week or a 4-week period. The attachment

material was removed from the plates with

a steel carpenter’s scraper with a straightedge. Both sides of the plates were scrapedbut generally only material from the top

side was collected except when tripod

mounts were used. The material from each

plate was collected in a wide mouth jarand preserved with a small amount of for-

malin immediately after collection. In mostcases the scraped plates were replaced in

position after washing in lake water. Gen-

erally only a few minutes elapsed between

scraping and washing and thus the plateswere seldom dried. In some cases unused

plates were used as replicates.

The collected material was then examined

microscopically in the laboratory and an

estimate of the relative abundance of eachspecies was made. It was then oven-dried

at 105°C for 24 hours in tared porcelain

crucibles and allowed to come to equili-

brium in a desiccator. Following the dry

weight determination the material wasashed at 650°C for one hour in a muffle

furnace. The ash-free dry weight (loss on

ignition) was taken as an approximatemeasure of the organic weight. Ash-free

dry weight is a practical quantity whichrepresents mostly organic matter. Carbon

dioxide is also lost from alkaline earth car-bonates and from some alkali bicarbonates,

but generally at higher temperatures only.

Carbonates probably occur on glass platesmainly as inorganic sediments which werepresent usually in small amounts. In anycase essentially inorganic sediments of

Lower Grand Coulee lakes were ashed withless than 5% loss of weight.

The results are expressed as mg of ash-

free dry weight produced/m2/day (Figs. 2-

10 and Tables 4-5). The date chosen for

plotting is the mid-date of the submergenceperiod.

The species composition

Almost all of the ash from the freshwater

attachment material was composed of in-

tact diatom frustules. This ash was sus-pended uniformly in water by vigorousshaking, pipetted onto slides, and dried to

a uniform film. Permanent mounts were

made with hyrax medium. The additionof hyrax did not appear to alter the uni-

formity of the diatom spot.The ash from saline lakes was also com-

posed primarily of diatom wall material.However, the walls of these diatoms were

weakly silicified and were greatly deformed

during ashing. The ash developed a glazedcrust and uniform suspensions and counts

could not be made.Proportional counts of the freshwater ma-

terial were then made under a ~100 oilimmersion lens with x10 oculars, using a

Whipple ocular micrometer grid. Random

grid fields were counted until the total num-

ber of cells amounted to 300 usually. Bymaking several counts of 1,000 cells or more

for different samples it was found that 300

gave reasonable statistical accuracy in mostcases. In some instances only 100 cellswere needed, and occasionally 600 were

necessary.



6 RICHARD W. CASTENHOLZ

The number of cells of each species wastabulated. All species that occurred more

than once were included in subsequentcalculations.

Since the production rate of the total at-tachment material was expressed in weight,it is obvious that the number of cells ofspecies which differ considerably in volumewould not lead to an accurate expressionof dominance in biomass. For this reasonthe relative cell volumes were calculated.Even though the ratio of silica wall weight

to organic weight would undoubtedlychange with increasing or decreasing vol-ume, relative volume appears to be the only

practical factor to combine with cell num-bers of species to approximate a quantityof the biomass collected.

Volume calculations wcrc made by mak-ing camera lucida drawings of the largestand smallest cells encountered of each spe-cies. Valve views and girdle views of thesame length were drawn. The relativeareas of valve views of different specieswere determined by using a Keuffel and

Esscr planimetcr. The areas of girdle viewswere similarly determined and divided bylength to arrive at the third dimension withwhich to calculate volume. The problem of

length in girdle view is not difficult to solve,since the ends are usually truncate. Thus,the value area was multiplied by the meanwidth of girdle view, this for both minimumand maximum sizes. The mid-volume valuewas used on a relative scale for the various

species. The species with the smallest vol-ume was given a value of one; all otherspecies were given values relative to this( Table 2). It may be seen that the volumeof the largest species ( CymatopZeura solea)

was SO4 times the volume of one of thesmallest (Acnanthes minutissima) (Table 2).

The cell count for each species wasmultiplied by the respective volume factor.The products obtained in this manner weretotaled, and percentages of the total weredetermined for each species. The percent-

ages thus obtained were plotted as a fractionof the ash-free dry weight expressed as aproduction rate for each plate sample (Figs.

TABLE 2. Relative cell volumes of diatom taxa occurring on glass plates in fresh-water lakes

Tnxon Volume Taxon Volume

Acnades minutissima _.___-_--_-__---____------_ 1

Amphora ovnlis . _-- ______ 2

A. ovnlis v. pecliculus ___----_-_---__-__-___-----___

A. sp. “A” _ ---.._ -__----_--____________.__._.-_-_ _ 1

Cocconeis pediculus ._.__..._._..._.._..______________C. placentula ___-..__..__.----- ___.___------ ____---- 8

Cyclotella meneghiniann __.------- _______-----__ 6

Cymatopleurn solea _._.._._______..._..________________04

Cymhella affinis ___-____._____._.__.___.______...._5

c. cistulu ..__.______-___.____------__-----_-- ____-----_ 79

C. mexicana __._..-_---____.__..__-_______.._.____._.._88

C. microcephala - .__. _.----- ...___--_---- _______ 1

C. turgicln __.__._____ ._______---_.--------_- _____---___ 67

C. ventricosa ._...____._______- _____._-_-----____-_-__

L>iutoma elongntum ___________.___._.__- ____________

;

Epithemia sorex -- _.______________.-- __________________._6

I?. turgicla -----__ ..-__-- ____.__________..________________49l?. xebrn ._ _._.____---.________--__-_-----_______________ 36

Frugilaria brevistriata ___------___--- ____________-_ 1

F. capucinn ----- ___.--_-_____..._____._.___________.._____F. construens ____._...__......___.----___-----_--__-_

T

F. vaucherine ----__.-- ______._..___..___________________ 3

Gomphoncma constrictum .------ _________----___ 14

G. eriense . ._ --__ -----_--____.--- ___._.___._._..._ 22G. intricatum .__ -- ._________- ._.- _______.__..._ _.__ 2

G. olivaceum .__.___....._._..-----. ---------_-__________G. parvulum . _...___.------__ .._ -__--. ____ 3

Gomphonema sp. “A” ----------_----- -.-__-- _______ 6

Melosira itnlicn --_---__.___--_----_.--___.____.______.

Navicula cryptocephaln .---__ --___--_____._.___._

TV. cuspiclata .---------_-_-__.__^--.-.- __-_-_------- 52

N. gregaria ._ . .____---------__.._____---_---______--.

N. lanceolatn . .____------ _......___ ____--_- _____.__3N. oblonga . ._ .____----- ._.._._..___------_-_----___ 92N. racliosa ._.. . .._--__--- .__._.____-------___--__ 16

Neiclium iridis . ._.__...-- ___---....._._._..____ 69Nitzschia amphibia __.._-- ____..._._...____________N. ungustata .._._.__------ . ._.___ _---------_________4N. dissipata ._...__.--------... ._____.______----___ _ 4N. frustulum . __-.--- _____..___._________---- ____- 3

N. gracilis ____-------- ___________------__________________

N. linearis .___. _____------ ____.__._______-__---___-__ 6

N. palea .______...._._.__...____________________---------..--Rhoicosphenia curvata _.______________-----_-______16Rhopnlodia gibba ----_-__________------------ _________35Stauroneis phoenicenteron _-----_----_-______..__6Stephanodiscus astraea __-_--------_______._.._._._.

S. niagarae ------__-_--_________-__--______.__._...___._..30Surirelln ovatn __________- __.______--_---------____-__ 43

Synedra ucus -._-____....__._____________.__....._______ 8

S. mnxamaensis ----_---________-----___-_-_____________S. rumpens _-------.-______._.__--------- ___.._____.___..._S. ulna .--- ____.....__________....____________-____________ 7



SEASONAL CHANGES IN ATTACHED ALGAE 7

I

O(-) 20-- F-I (0.4M)

I --I--

I - ICE -

g IO “’

?/’

0 o___d’

i

- CYMBELLA TURGIDA

-we C. AFFINIS

ZE-ok!- FRAGILARIA VAUCHERIAEI=

28 - RHOPALODIA GIBBA

E _SYNEDRA ACUS

E -

-500

-400

-300

-200

-100

JOJ F M A M J J A S 0 N D

MONTH - 1955

FIG. 2. Falls Lake F-I (0 .4 m) 1955 : production rate on glass as ash-free dry weight, the diatom

species composition, and tcmpcraturc and ice data. Mid-dates of submcrgencc periods arc used.

2-S). This technique cvaluatcs the contri-bution in biomass of different species to thewhole production of organic matter. Un-fortunately, with the scale used in thegraphical representation it was impracticalto take into account many of the smallercelled species whose calculated contrihu-tions do not exceed 5 mg of ash-free dryweight/m2/day. Thus, the technique as herepracticed does not succeed in comparing thegrowth rates of species of all cell sizes. An-other difficulty is the fact that in the fresh-water lakes many of the important epilithicdiatoms are attached by elongate “gela-tinous” stalks (e.g., Cymbelln, Gomphonemn)

while others are attached by short “gela-tinous” pads or by an entire side of thefrustule (e.g., Synedra, Epithemia, Acnan-thes). The presence of the extracellular or-ganic matter in a mixed sample would causean underestimate of the contribution ofstalked species and an overestimate for non-stalked species.

Physical ancl chemical measurements

Conductivity measurements were made

regularly. A conductiometric device uti-lizing an electronic bridge as described byWithrow and Withrow (1953) was used.

A 1 cm2 platinum elcctrodc coated withblack platinum was used. The calibrationof the cell constant was made with standard

KC1 salutions. All conductivity measure-

ments ‘were calculated to the micromhosconductance of a standard cell at 25°C.Measurements of conductivity, total dis-

solved solids, and ions were made biannual-ly by the Design and Construction Divisionof the Bureau of Reclamation, United States

Department of the Interior (Table 1) . Mea-suremcnts of pH were made in the labora-tory with a model “N” Beckman pH meterwith standard electrodes. During warmweather water samples were refrigerated

while being transported to the laboratory.In general, about 24 hours elapsed fromsampling time to the time of laboratoryreadings. Temperatures of surface waterswere measured with a calibrated thermom-eter. Temperatures of deeper waters weremeasured with a calibrated Taylor maxi-mum-minimum thermometer.

FALLS LAKE

General description

Falls Lake (Fig. 1 ), referred to on some

maps as Fall Lake or Dry Falls Lake, is a



RICHARD W. CASTENHOLZ

AMPtlORA OVALIS - - -CYMBELLA TURG. w

FIG, 3. Falls Lake F-V (surf) 1955: production rate on glass as ash-free dry weight, the diatom

species composition, and tcmperaturc data. No ice was present. Mid-dates of submergence periods are

used.

plunge pool lake located in the westernmostalcove below Dry Falls (Sec. 6, T.24N.,

R.28E., Grant County). The lake has a sur-face area of 40.2 ha and a perimeter of6.2 km. Indentations and promontories arcnumerous. Vertical basalt cliffs and steeptalus slopes border about 30% of the lake;gradual slopes of predominantly inorganicsediments border about 12%; gradual slopesof organic detritus border the marshes andcomprise about 58% of the total periphery.

A continuous vertical wall, 90 to 125 m inheight, rises above Falls Lake on the east,

north, and west. The lake bottom is coveredentirely with a soft brownish-grcy gyttjawhich includes a large amount of diato-maceous material. Submerged anchored

macrophytes form an open to dense coveron the bottom to a depth of about 6 m.

Nearly half of the total surface area con-sists of a Typlaa latifolia-Scirpus validus

marsh rarely more than 1 m deep. Thelargest marsh area occupies the south-western end of the lake in the gradually

narrowing effluent which leads to RainbowLake to the south. During low water, theopen water portion of the lake has a maxi-mum depth of 10 m and an average depth

of 5.4 m. The range of water level wasusually about 0.3 m from high mark in

March to low in September. The cal-culated volume of the open portion is about1,150,OOOm3. The lake is spring-fed.

Sodium, calcium, and magnesium are theprincipal cations in that order of abundance

(Table 1). &carbonate is the principalanion, with sulfate and chloride of second-ary importance. The concentration of total

dissolved solids ranged from 244 to 300ppm. (Table 1) , The pH of surface watersranged from 8.0 in winter to 9.1 in late

summer.During the winters of 1954-55 and 1955-

56, Falls Lake was ice covered with theexception of two narrow crescents of openwater bordering the two northerly bays.These remained open apparently becauseof continuous subterranean inflow of warm-er water and a subsequent upwelling. Sur-face water temperatures were as high as7°C in these crescents through portions ofboth winters (Figs. 3 and 6). The lake andmarsh surface froze in mid-December, 1954,and mid-November, 1955. The thaw tookplace in early March and late March in 1955and 1956, respectively (Figs. 2 and 5). Ice




I.-

F-Y(3 Ml

700-_ F-Y(04M)

600-

200-

lob-

0 I

J F M A M J J A S 0 N D

MONTH - 1955

FIG. 4. Falls Lake F-V (0.4 m) and F-V (3.0 m) 1955: production rate on glass as ash-free dry

weight and the diatom spccics composition. Mid-dates of submergence periods are used.

thickness reached a maximum of 35 cm dur-ing January and February of 1955 and 1956.Snow, ranging from 2-10 cm in depth, cov-ered the ice through most of both winters.

A surface water temperature of 20°C wasreached or approached by late May in 1954,1955, and 1956 ( Figs. 2 and 5). Tcmpera-

tures ranging from 20°C to 25°C existed

until mid-September. Nearly homothcrmal

conditions lasted until mid-May when a

thermocline developed between 5 and 6 m.

At this time the surface temperature was

rising above 15”C, and the bottom tcmpcra-

ture was near 9°C. Stratification generally

remained until the surface temperature

dropped to about 14°C in mid-October. By

that time the thermocline had descended

to below 6 m. During the warmest periods

the bottom temperature (g-10 m ) rarely

exceeded 12.5”C.

Glass plate stations

Station F-I was a rocky ledge cxtcnding

from 0.2 to 0.6 m depth. It was directly

below a southerly facing cliff. Full light

was received except during late afternoon.The station was within 15 m of the mainmarsh. The station was ice-covered in win-

tcr. The size of the ledge allowed the regu-lar use of three glass plates.

Station F-V was a large gradually sloping

rock at the base of a high south-westerly

facing talus slope in one of the northerlybays. It was shaded during the early morn-ing hours, The station was at least 150 mdistant from the nearest marsh arca. F-Vwas ice free during the winters. Four glass

plates were generally used at a depth of0.1 m and again at 0.4 m. Single plates weresubmerged at 1, 2, and 3 m depths during

the summers.Several other glass plate stations were es-

tablishcd in other sectors of the lake. Re-

sults obtained at these stations will not bepresented. A number of disturbances prc-vented a continuous collection of materials

at these stations. Among these were de-struction of plates by vandals and frequentpiling up of vegetation over the plates,

Production and composition of theepilithic algae

Production rates on glass plates expressedas ash-f rce dry weight are shown graphically

in Figures 2-7. The data from 2-week sub-mergence periods were used except whenonly 4-week data were available,



10 RICHARD W. CASTENIIOLZ

CYMBELLA AFF. -

C. CISTULA B

C. MEXICANA

EPITHEMIA TURG.

E. SOREX

RHOPALODIA GIBBA w------z

ss‘(t-f,E;; ACUS-2

I I I I I I I I I I I I ---JO

J F M A M J J A s 0 N DMONTH - 1956

FIG. 5. Falls Lake F-I (0.4 al) 1956: production rate on glass as ash-fret dry weight, the diatom

species composition, and tcrnpcrature and ice data. Mid-dates of submergence periods are used.

The attachment material was composedprimarily of living diatoms, The undis-turbed material was examined periodically

in the living state when pieces of brokenglass were returned to the laboratory, Manyof the common species were attached bymeans of gelatinous stalks (e.g., Cymbella,Gomphonema) while others were sessile( e.g., Syncdra, Epithemia).

The diatom species composition on plates

was similar to that occurring on the shallowrock substrate and, for that matter, on sub-merged macrophytes as well. In general,however, a thicker cover of diatoms was

present on the permanent substrate. Per-manently submerged rocks were never bareat any season. There was invariably a thincrust of blue-green algae, (e.g., Calothrix

pnrietina, Amphithrix ianthinn) on whichthe attachment of diatoms and other forms

took place. Only glass plates submergedfor six weeks or longer showed a develop-ment of these encrusting forms. During thesummer Gongrosirn and Entophysalis wereadded to the crust.

Cladophoru fracta was luxuriant on rocksand macrophytes during summer but didnot occur on glass plates. The summer pc-riod was also characterized by an abund-

ante of bcnthal Oscillatoria, Phormidium,and Spirogyra but these were seldom com-mon on plates. During fall and winter

Ulothrix aequaZis was a common epilithicalga at the water-air interface but again sel-dom occurred on plates.

The species composition of the glass platematerial was analyzed (see Materials andMethods ) for stations F-I ( 0.4 m ) and F-V( surface and 3 m ) only. Those species rep-

resented graphically were dominant by vol-

ume, but many species of smaller cell size,

possibly representing equal or greater divi-

sion rates, could not be shown ( Figs. 2-7).

Following are certain rather prominentfeatures of plate results in Falls Lake:

1. The highest production rate gcncrally

occurred in spring or early summer.

(a) Several species combined high

production rates to form the

spring pulse.

(b ) The pattern of occurrence of

spring species was rather similar

in 1955 and 1956.

( c ) Total production rate was lower

in the spring of 1956.2. The lowest production rate generally

occurred in late summer.



SEASONAL CHANGES IN ATTACIIED ALGAE 11

I

a0 20-I -

F -Y(SURF.)

“r IO-

?O

J F M ‘A M JMONTH - It56

A S 0 N D

FIG 6. Falls Lake F-V (surf) 1956: production rate on glass as ash-fret dry weight, the diatom

species composition, and tcmpcraturc data. No ice was present. Mid-dates of submergence periods are

ascd.

( a) Only a few species showed great-est production in the summers.

(b) The dominant species of springand summer were usually not the

same.( c ) A few of the spring dominants

remained abundant through thesummer at lower depths.

3. A second but generally smaller pulseoccurred in the fall. The fall pulsewas composed of summer dominantsplus a few of the spring dominants.

4. The production rate was fairly low inwinter, particularly under ice andsnow cover.

1955. Highest production rates were ob-tained at all stations in April ( Figs. 2-4))although high production was evident asearly as February at F-V ( Fig. 4)) whichwas ice-free. Production under the ice andsnow apparently made a steady ascent froman extremely low rate in January to thepulse in April, which occurred soon afterthe thaw (Fig. 2). Acnanthes minutissimavar. cryptocephala, CymbeZZa affinis, C. cis-

tula, C. mexicana, Fragilaria vaucheriae,Gomphonema eriense, Synedra ncus, andS. ulna were the commonest winter diatoms

( Fig, 2). Very little qualitative difference

existed between the ice-covered and ice-free

areas.The spring pulse was in effect a periodof increasing production rates for Amphoraovalis, Cymbella affinis, C. cistula, C. mexi-

cnnn, C. turgida, Frngilaria vaucherine,Gomphonemn eriense, Synedra acus, and

S. ulnn ( Figs. 2 and 3). An increase inabundance was also observed in Acnanthes

minutissima, Cocconeis placentuk, Cymbel-la ventricosa, Fragilaria brevistriatn, Nitx-schia amphibia, N. dissipata, N. frustulum,N. gracilis, N. linearis, N. palea, and Synedrnrumpens.

At F-V there was a prominent secondmaximum in May. This was primarily dom-inated by Synedra acus, C ymbella mexicnna,and Gomphonema eriense (Fig. 3). Al-though a second spring pulse was not ex-hibited at F-I the decline that followed thefirst peak was, nevertheless, a maximal pe-riod for Synedra acus ( Fig. 2 ) . This species

was conspicuously dominant on all platesand rocks during this period and in the

plankton as well.The spring diatom communities formed

thick greyish-brown to yellowish-brown



12

FIG. 7. Falls Lake F-V (0.4 m) and F-V (3.0 m) .Z956: production rate on glass as ash-free

weight and the diatom species composition. Mid-dates of submcrgencc periods are used.

RICHARD W. CASTENHOLZ

1-1-I--‘--7- -- I-- -- -T -I--- 1 __

F-P(3M) ,--e/y,-

CYMBELLA MEXICANA

x -

EPITHEMIA TURGIDA

= SYNEDRA ULNA

300

0 LL

0

0

I- III


MONTH - 1956

coatings on rocks and plates. The coatingon rocks often reached a thickness of over1 cm. There was a gradual lessening of thediatom cover with increasing depth, at leasthclow 1 m. Species of Cymbelln at firstformed distinct tufts, but when growth ofthis genus and others became widespreadthe tufts were consolidated into a contin-uous mat. By mid-April the mat had

reached such a thickness that gas becametrapped and sections or fragments wouldconsequently rise to the surface. On somedays the entire surface of the lake wouldbe charged with clots of detached diatoms.

By early or mid-June there was a general

decline in production rate at both stations.A minimum was reached in August in allcases ( Figs. 2-4). It should be noted, how-ever, that summer was the period of great-est abundance of Epithemia turgida (Figs.2-4). This was also true for Epithemiasorex and Rhopalodia gibba. The .summcrdiatoms formed a thin, tightly-held crust onrocks and glass plates. Acnanthes minutissi-ma, Cocconeis pediculus, C. placentula, andFragilaria brevistriata were also common.

The highest production rate during mid-summer occurred at 3 m-depth at F-V ( Fig.4). Slightly lower but similar curves were

produced at 2 m and 1 m. The results at3 m arc interesting in that C ymbella m,exi-cana was abundant at that depth on bothglass and rocks, while it had been reducedto rarity in water shallower than about I.5 m.Cymbella cistula and Synedra ulna followedthe same pattern to some extent.

-4 small increase in production rate wasevident at F-V ( and possibly at F-I ) during

September and October (Figs. 24). Thiswas primarily a result of a continued abund-ancc of Epithemia turgida, but it may alsobe seen that Cymbella mexicana and Syne-dra ulna had returned in some abundancein shallow water by late October (Figs. 2

and 3). Other common diatoms of thefall were Acnanthes minutissima, Amphoraovalis, Cocconeis placentula, Cymbella af-finis, C. cistula, C. turgida, C. ventricosa,Epithemia sorex, Gomphonema parvulum,and Synedra acus.

There was a visible change in the appear-ance of the diatom coating on rocks duringthis period. The crusty summer coating con-sisting mainly of Epithemia became a softeryellowish-brown mat similar in appearance

to that of early spring but of less thickness.The late fall period was attended by a

gradual decline in production rate with




MONTH

FIG. 8. Alkali Lake A-I ( 0.4 m ) 1955 and 1956: production rate on glass as ash-free dry weight, the

diatom species composition, and temperature and ice data. Mid-dates of submcrgencc periods are used.

minimum values attained in December(Figs. 2-4). The decline was a reflectionof the decreased abundance of most species

with the exception of Cyrnbelln affinis andC. mexicnna ( Fig. 3).

1956. The spring production rates of1956 were generally lower than those of

1955 ( Figs, 5-7). A spring pulse was evi-dent at F-I (0.4 m) and F-V (surface) butwas conspicuously absent at F-V (0.4 m)( Fig. 7). This stems incongruous with re-sults obtained in 1955 when the surface and0.4 m-depths exhibited values and curves

that wcrc quite similar (Figs. 3 and 4).

Both F-I and F-V 0.4 m-stations of 1956were similar in that spring values were lowrelative to values at the surface station. Atthe surface station increasing productionwas evident as early as February, and therewas a continuous increase until late Mayat which time the spring pulse ended (Fig,6). It should bc remembered that stationF-V was ice-free and with higher tcmpera-

turcs in February and March ( Fig. 6). Thespccics composition on the plates and on

the shallow rocks at F-V was comparableto that of 1955. Howeves, Cymbella affinisand Gomphonema eriense peaks appear to

have been earlier in 1956, and Synedra acus

and S. ulna peaks, were not so well de-

vcloped (Fig. 6).An examination of the species composi-

tion at F-I leads to a partial explanation ofthe relatively low production rate in spring.A very low production rate was recordedunder the ice and snow cover. After the

late thaw there was only a short flourish ofspring spccics which were soon replaced by

the summer dominants, namely Epithemiaturgida, E. sorex, and Rhopolodia gibba( Fig. 5 ) . During the spring pulse Cynz-bella mexicana and Gomphonema eriensenever reached any sizable proportions ( Fig.

5). This statement also applies to the 0.4 m-depth at F-V although the species com-position was not completely analyzed.

A conspicuous feature of summer produc-tion at the surface at F-V was the veryheavy growth of Epithemin. turgida duringlate June and July (Fig. 6). This was trueto a lesser cxtcnt at F-I (0.4 m) where mid-summer production by E. turgida was onlya little less than production in May (Fig. 5).At F-V (0.4 m ) summer production figureswcrc quite low, although this was an in-explicable feature at this station through allthe seasons ( Fig. 7). At 3 m- and 2m-

depths, however, mid-summer production



RICIIARD W. CASTENZIOLZ

\\z 2 100

:;I

0I I

---^1-“. :

I I I I I I I I I


MONTH

FIG. 9. Lake Lenore L-III (0.4 m) 1955 and 1956: production rate on glass as ash-free

and tcmpcrature and ice data. Mid-dates of submergence periods are used.dry weight

was even higher than in 1955, and, as be-

fort, the characteristic spring species Cym-bella mexicana and Synedra ulna were quitecommon (Fig. 7).

At all stations a summer minimum wasreached in August which agrees with theresults of 1955. A rise in production ratein September was significant only at F-I

( 0.4 m ) . The characteristic summer specieswere again dominant ( Fig. 5). However, asin 1955, several spring species reappearedat all stations by October. At about thistime there was a general decline in produc-tion at all stations (Figs. 5-7).

With the various exceptions noted, the

seasonal distribution of species followed thesame general pattern as in 1955.

ALKALI LAKE

General description

Alkali Lake, located about 11 km south-

west of Falls Lake ( Fig. 1 ), is the southern-most lake of the freshwater chain. Themajor portion of the lake is located in Sec.31, T.24N., R.27E., Grant County. The lakehas a surface arca of approximately 95 haand a perimeter of 7.3 km. A large part ofthe perimeter consists of gently sloping

shores of compact inorganic sediments. A

smaller part consists of fairly steep talus andvertical basalt cliffs. The canyon wall closeto the southeasterly shore rises to 150 m

above the lake surface. It is a shallow lake

with a maximum depth of about 4 m and anaverage depth of about 2 m. The large

southernmost bay is very shallow, rarelyover 1 m in depth. No marshes have yetdeveloped in Alkali Lake. The entire lakeb asin, however, is covered by submergedanchored macrophytes. The benthal sub-

strate is a soft dark gyttja.The lake was originally a part of Lake

Lenore to the south and was isolated bythe road fill of the present highway about

1936. Lake Lenore was then and remainsa saline lake. The total dissolved solid con-tent of Alkali Lake ranged from 356 to 440ppm (Table 1). A freshwater influcntpasses from Blue Lake to Alkali Lake. Theeffluent from Alkali Lake to Lake Lcnorc

consists of a flow through the coarse rocksof the road fill during high water. Sodiumand magnesium are the principal cations,while bicarbonate is the dominant anion(Table 1) . The pH of Alkali Lake surfacewaters ranged from 8.4 in the colder months

to 9.4 in late summer.The lake became ice and snow covered

in mid-December 1954, and mid-November



SEASONAL CIIANGES IN ATTACHED ALGAE 15

e3t-a

MONTH

FIG. 10. Soap Lake S-II (0.4 m) 1955 and 1956: production rate on glass as ash-free dry weight

and temperature data. No ice was present. Mid-dates of submergcncc periods arc used.

1955. The thaw occurred in early March

1955, and late March 1956 ( Fig. 8). Theannual temperature curves of surface waterswere similar to those of Falls Lake ( Fig. 8).Essentially homothermal conditions existed

throughout the year in Alkali Lake.The water level fluctuated greatly. In the

spring of 1955 the level fell about 1.5 m.The water was lost through the road fillinto Lake Lcnore, which had been loweredartificially. The rapid water drop in AlkaliLake caused a great amount of turbidity andsedimentation throughout the spring period.In 1956 the spring level dropped gradually

1.0 m by fall; retention dikes had beenconstructed.


Station A-I (0.4 m) was located off agradually sloping rocky point in the south-eastern corner of the main (northern) sec-tion of the lake. Rubber cups were used onthe plates because of the rough nature ofthe bottom rock. The station was not shadedduring any part of the day, The rock shelfof the station was located within a fewmeters of dense Myriophyllum-Potamogeton

beds. Three plates were generally used.

A few other glass plate stations were usedtemporarily during the spring and early

summer of 1955. Because of heavy sedi-mentation and continuous breakage onlyscattered results were obtained.

Production and composition of the

epilithic algaeProduction rates on glass plates are shown

in Figure 8. The species composition wasnot completely analyzed as in Falls Lake.The glass plate attachment material wascomposed of a large percentage of green

algae together with diatoms except for briefalmost pure diatom blooms in spring. Thus,except for this short period it was impossibleto plot diatom volumes as percentages ofthe total ash-free dry weight.

In general the attachment material onglass plates was quite similar to that on therock substrate. Exceptions were the greatabundance of the epiphytic Gloeotrichiapisum on the lower surface of plants duringsummer and the abscncc of some cpilithicgreen algae on plates (i.e., Ulothrix aequalisand Claclophora fracta).

At the time of the thaw in 1955 and 1956

( Fig. 8) a brief bloom composed mainlyof Fragilaria vaucheriae and Synedra acusformed a thin brownish coating on rocks

and vascular plants.A large spring diatom pulse occurred in



16 RICIIARD W. CASTl3NHOLZ

early May 1955, and late April 1956. In

both years the pulse was initiated after sur-face water temperature had risen to about13°C. Because of particularly heavy sedi-

mcntation and frequent breakage of glassplates in the spring of 1955 the recording ofquantitative data at A-I (0.4 m) began in

June. In 1955 the pulse was composedprimarily of Diatoma elongatum, D. uul-

gare, Fragilaria vaucheriae, Gomphonema

eriense, G. olivaceum, Rhoicosphenia cur-vata, and the green alga Stigeoclonium sp.In 1956 the main species were as follows:Cymbella cistula, Diato,ma elongatum, D.v&are, Fragilaria vaucheriae, Gomphone-

ma eriense, G. olivaceum, Nitzschia clis-sipata, N. gracilis, Synedra acus, Synedraulna, and Stigeoclonium sp. Other common

though not abundant spring diatoms in 1955

and 1956 wcrc Acnanthes minutissima, Am-phora ovalis, Cymbella mexicana, C. tur-

&la, C. ventricosa, Nitzschia amphibia, N.angustata, N. frustulum, and N. linearis.

At the peak of spring production platesand rocks were covered with satiny yellow-

ish-brown diatom tufts usually consolidatedinto a continuous mat, which was nearly 1

cm thick in 1956. Bright green tufts ofStigeoclonium were dispcrscd through the

diatom mat. Below 1 m there was a striking

reduction in the amount of diatom cover.Shallow macrophytes were also covered byheavy coatings of the same diatoms. How-

cvcr, by early or late June plates and othersubstrates appeared almost bare, and pro-

duction had decreased considerably.In 1955 extremely high production values

were obtained early in June. This was due

primarily to a heavy growth of Epithemiaturgida, E. sorex, Cymbella turgida, C. ven-

tricosa, and Sceneclesmus spp. The produc-tion rate during the remainder of thesummer was fairly high with a minimumreached in September. Dominant plate andepilithic algae throughout the summer were

those mentioned above plus Closterium sp.,Cosmarium spp., Tetraedron minimum, andCocconeis placentula. Shaded surfaces ofrock were well covered with a nodular green

crust of Gongrosira sp. Most rocks in Alkali

Lake had a crust of blue-green algae thin-

ner but similar to that in Falls Lake.

Amphithrix janthina and Calothrix parie-

tina were present.

In 1956 the decline in production contin-

ued from late May to early August. The

species composition was, nevertheless, simi-lar to that of the previous summer. Thediatoms Cymbella turgida, C. ventricosa,Epithemia sorex, and E. turgida dominatedthe glass plate material until mid-Junewhen the various green algae became moreabundant.

During summer months macrophyteswere covered by spherical colonies of Glo-eotrichia pisum. The heaviest infestationoccurred in August or September of 1954,

1955, and 1956. The undersides of glassplates also showed an abundance of thisalga, but it was rare on the topsides andon rocks.

A distinct fall production peak was re-alized in October 1955, when water tem-

perature had dropped to 15°C. A fall in-

crease comparable to that of 1955 was notevident in 1956. Most of the important dia-

toms and green algae of summer remainedplentiful through the fall. Conspicuous inthat respect were Closterium sp., Scenedes-

mus spp., Tetraedron minimum, Cocconeisplacentula, Cymbella turgida, C. ventricosa,and Epithemia sorex. Amphora ovalis, Cym-bella cistula, Fragilaria vaucheriae, Nitx-schia amphibia, N. dissipata, Synedra acus,and S. ulna were common spring diatomsthat returned in some abundance at least

during one fall period.The great thickness of ice on Alkali Lake

prevented much sampling during mid-winter. The curve in Figure 8 would sug-

gest that production was very low duringthat period.

LAKE LENORE

General description

Lake Lenore, located immediately southof Alkali Lake, is the largest of the LowerGrand Coulec lakes and is saline (Fig. 1 ),It falls primarily in Sections 11, 12, 14, 23,

24, and 35, T.23N., R.26E., Grant County.

The surface area is about 556 ha, the length

is 9.2 km, and the maximum width is 0.9 km.The perimeter is 21.5 km.




A large part of the periphery is intersected

by steep bedrock and talus slopes from the

western wall of the canyon. The easternside possesses a great proportion of gradual-

ly sloping shores which consist of predom-inantly mineral sediments and boulders. Thehigh water mark of the latter type of shore-line is marked by a belt of DistichZis stricta

and S&pus nevadensis. No submerged

macrophytes were found in Lake Lenorcwith the exception of a few patches ofPotamogeton pectinatus near the seepage

from Alkali Lake at the northern end.The maximum depth is 11 m, and the

mean depth 6.5 m (Anderson 1958). LakeLenore occupies a long narrow troughwhich is divided into basins. The bottomis mostly rocky, but extensive areas arccomposed of gyttja. The calculated water

volume in 1950-51 &as 36,042,OOOm3 (An-derson 1958). The lake is holomictic andstratified only temporarily in late spring.During the summer and winter homothcr-ma1 conditions existed. In the winter of1954-55 the northern and southern ends ofLake Lenorc were ice-covered from earlyJanuary to early March. The main glass

plate station was entirely ice-free. In thefollowing winter the entire lake had an iceand snow cover from early December tolate March ( Fig. 9). The temperaturecurves of surface water were similar to thoseof Alkali Lake and Falls Lake ( Fig. 9).

The concentration of total dissolved solidsranged from 7,500 to 11,040 ppm duringthe course of the study (Table 1) . The pre-dominant ions were sodium, carbonate, sul-fate, and chloride (Table 1). The pH

ranged from 9.5 to 9.7. A more detailed ac-count of chemical and physical variables is

to be found in Anderson ( 1958). DuringAnderson’s study, phosphate was high in

early spring ( 195pg/L ) , fluctuated throughthe summer and remained at about 20Pg/Lduring the rest of the year.

Since the beginning of this study therehas been a considerable lowering of the

water level by means of pumps to ahcviatethe problem of a rising water table. Conse-

quently there was a heavy inflow of fresh-

water from Alkali Lake through the separat-

ing road fill. This occurred mainly during

the high water period of late winter andspring. The result was a considerable fresh-ening of the northern reaches of Lake Le-norc in 1955. The conductivity of northern

water was reduced from about 12,000 mi-cromhos to values as low as 1,000 micromhosa few hundred meters away from the road

fill. Values varying from 4,000 to 9,000micromhos existed in the northern waters

throughout the summer after the seepagehad been reduced considerably. Freshwaterseepage was reduced in 1956, and the con-ductivity of northern waters not immediate-

ly adjacent to the road fill was seldom lowerthan 10,000 micromhos.


The main station, L-III (0.4 m ), was lo-cated midway on the cast shore. The littoralregion is gradually sloping and consists of

fine and coarse sediments with scattered

boulders. A tripod mount was used on thethree plates. The plates were unshaded

throughout the day. Stations L-I and L-IIwere located in the northern bays near theroad fills. Generally qualitative data onlywere obtained from these plates since heavy

sedimentation occurred through most of theyear.

Production and composition of theepilithic algae

The epilithic vegetation of Lake Lenoremay bc divided into the following three

types: ( 1) the slowly growing green crustof Gongrosira sp. which was tightly adhesive

to rocks and most prominent on shadedsides, ( 2) the perennial tough coating of

blue-green algae, primarily Calothrix parie-tina, Amphithrix janthina, and Plectonema

nostocorum, and (3) the rapidly growingyellowish-brown film of diatoms. The dia-tom film covered the “bare” rocks and the

other algal rock coatings during most of theyear, and it was the dominant algal assem-blage on glass plates.

Diatoms frustules were weakly silicifiedin Lake Lcnore and were greatly deformedduring ashing. The ash developed a glazedcrust, and uniform suspensions and countscould not be made ( see below).

The curves of production rates of ash-



18 RICIIARD W. CASTENIIOLZ

fret material at station L-III (0.4 m ) werequite similar in 1955 and 1956 (Fig, 9).

Production rates were low in the spring andsummer until September. Nitzschia frus-

&urn var. minutuln Grun., N. frustulum var.tenella Grun., and N. palea var. Kuetxing-iann Hilse were essentially the sole dom-inants during early spring (March andApril ) , while Amphora salinn W . Sm. ( var. )and, to a lesser extent, Amphora coffeae-formis ( Ag. ) Kuetz. ( var. ) were also veryimportant in May, The species of these two

genera continued as dominants throughthe summer period, but Anncystis marina(Hansg. ) Dr. & Daily, Pkectonema nostoco-

rum, 0o”cystis sp., and Gloeocystis sp. wereoccasionally important on plates. Duringthe entire summer of 1956 Stigeocloniumsp. was one of the dominant algae on plates,particularly on the underside.

Stigeoclonium first became established inLake Lenore in May of 1955 following thefirst significant freshening of northern bays.It appeared only on rocks and plates adja-cent to the Alkali Lake road fills. It wascommon at this time in Alkali Lake. Soon

it spread to nearly all shores of the northend of Lake Lenore. It remained abundantin this area through the summer and fall. Inlate spring of 1956, it reappeared, first in

the north end as before, but by June itoccupied the littoral regions of the entirelake. According to G. C. Anderson (per-sonal communication) it was not observedin Lake Lenore before 1955.

A steep increase in production occurredin September or October of both years (Fig.

9). A high rate continued in the fall of 1955

probably until the time of ice formation.One winter reading gave a relatively lowrate during late December. Nitxschin spp.

and Amphora spp. were the dominant ele-ments of the fall pulse, although Anacystismarina, Stigeoclonium, and Gloeocystis

were also important in 1956. During theseperiods of high production rocks of theshallow littoral became covered with soft

yellowish-brown diatom mats which often

loosened and peeled.

The high diatom production corrcspond-ed approximately to periods of cooler tcm-peratures (l5”-5°C) and of low light in-

tensity and duration. Anderson described

phytoplankton volume and chlorophyll con-tent curves which were somewhat similarto the attached algal production curves of

the present study, although he found a dis-tinct spring pulse as well as one in the fall.The spring phytoplankton pulse consistedprimarily of Amphora sp. ( almost certainlyA. salinn var.), while Chaetoceros elmoreidominated the fall pulse.

Besides the rather distinctive assemblagesof cpilithic algae, there was a conspicuousloose and continuously shifting bentho-plankton composed of blue-green algae inthe form of crumbly gelatinous aggregates.

The primary constituents were Anncystismarina and Plectonemn nostocorum. Thebenthal algae which covered a major part ofthe basin of Lake Lenore arc describedmore extensively by Castenholz ( 1957).

SOAP LAKE

General description

Soap Lake, the southernmost of the Grand

Coulce lakes, is also the most saline. It islocated in Sections 12, 13, and 24, T.22N.,

R.26E., and Sections 18 and 19, T.22N.,R.27E., Grant County (Fig. 1). The surfacearea is about 360 ha. The length is 3.6 kmand the maximum width is 1.3 km. Thepcrimetcr is about IO km. The shape ismore or less rectangular and quite regular.The major portion is bordered by bedrockintersecting the water at a rather gradualangle. Much of the southern and northernends consists of gradually sIoping mineralsediments. In certain areas there is a shal-low shelf-like crust of precipitated carbo-

nates, As in Lake Lenore, part of the shorc-line is bordered by a narrow belt of Dis-tichlis stricta and Scirpus nevndensis. Thereare no submerged macrophytes.

The maximum depth is about 27 m andthe mean depth is about 10 m. Black or-ganic deposits cover most of the lake bot-tom. The lake is meromictic. Summerthermal stratification occurs in the mixo-limnion. The chemoclinc was found below14 m ( Anderson 1958), The calculated vol-

ume is about 36,500,OOO ms.The water is capable of forming a froth

and is generally quite clear. There is no




surface influent or effluent, although a sub-terranean inflow from Lake Lenore has been

suggested (Anderson 1958). The conccn-tration of total dissolved solids in surface

waters ranged from 25,440 ppm in 1954to 20,600 ppm in 1956 (Table 1). Accord-ing to Anderson the maximum concentration

in the monimolimnion has remained atabout 144,000 ppm. There has been overa 40% reduction in salinity of surface waters

since 1949 at which time 35,000 ppm wasan average value ( Anderson 1958). Thepredominant ions were sodium, carbonate,sulfate, and chloride as in Lake Lenore(Table 1). The pH ranged from 9.5 to 9.8.

A more complete discussion of physical-chemical properties of Soap Lake is to befound in Anderson ( 1958).

During the winter of 1954-55 Soap Lake

was completely ice-free (the freezing pointof surface was about -1.4”C). During thefollowing winter ice and snow covered mostof the lake from January to mid-March. Theperipheral waters, including the site of theplate station, were generally open however.The temperature curves of surface water

show a relatively slow warming in springand a slow cooling in fall ( Fig. 10).


Several stations were used at various times

in Soap Lake. Breakage of plates was sofrequent, however, that ultimately only onestation was maintained through the courseof the study. Breakage was due not only tovandalism but also to the frequently heavywave action, High winds were most com-con in winter and spring, Stations S-II

( 0.4 m ) was located in the northeasterncorner of the lake and was fairly well pro-tected from heavy wave action by a fewsmall promontories to the south, The littoralregion is a gradually sloping shelf rock with

coarse gravel and some small boulders. Theshelf drops off rather suddenly to 5 m depthabout 14 m from shore. Three plates mount-

ed on a tripod were generally used. S-II wasice-free through the entire course of study.

Production and composition of the

epilithkc algae

The flora of Soap Lake was fairly similarto that of Lake Lenore. The epilithic diatom

assemblages were quite similar. Gongrosira

formed an epilithic crust in both lakes. A

characteristic “crumbly” type of bentho-

plankton composed of blue-green algae COV-

ered much of the bottom in both lakes, buta prominent thick epilithic coating of blue-

green algae was absent in Soap Lake.As in Lake Lenore several difficulties pre-

vented an analysis of the species composi-

tion on glass plates ( see below ) .Production rate curves in 1955 and 1956

were similar (Fig. IO). The same wastrue in Lake Lenore. Reduction increasedgreatly in fall, but unlike the situation in

Lake Lenore a large winter and spring pulse

was evident in Soap Lake (Fig. 10). Theprincipal glass plate constituents were thediatoms Nitzschia frustulum var. minutuln,N. frustulum var. tenella, IV. palea var. kuetx-

ingiana, Amphora s&n var., and the blue-green alga Anncystis marina. These taxawere dominant during blooms and during

low production as well. However, for a few

weeks in June 1955 and May 1956 06cystissp. was also a dominant. Plectonema nosto-corum was common on plates throughout

the summer. The high production of falland winter in 1955 consisted predominantlyof the diatoms mentioned above, althoughChlamydomonas sp. was important on platesand as inshore plankton. The extremelyhigh winter rate observed in December 1955

in Soap Lake, when compared to the low

rate at the same time in Lake Lenore, maybe explained by the presence of an ice andsnow cover over the station in Lake Lcnore

at that time ( Fig. 9). The study was notfollowed through late fall and winter of1956, but the production curve showed a

steady ascent through late October (Fig. IO).Anderson ( 1958) studied the phytoplank

ton of Soap Lake in 1950 and 1951. Al-though he did not determine the volumeof phytoplankton, his curves representing

chlorophyll content of the water in themixolimnion correspond well with the pro-duction rate curves of attached algae in the

present study. Amphora sp. (presumablyA. snlina var.) was the dominant phyto@-

lankter during Anderson’s study. The ex-

planation proposed by Anderson for the

low chlorophyll content in summer <was hat



20 RICHARD W. CASTENE-IOLZ

phytoplankton was reduced mainly by ex-tensive zooplankton grazing. Using sus-pended bottles he demonstrated that graz-

ing was effective in reducing the size of

the phytoplankton population in Soap Lake.Using the same technique he was unable todemonstrate the same effect with regard toorganisms in Lake Lenore. It was suggested(Anderson et al. 1955) that production rateremained high during the periods of chloro-phyll decline, The epilithic and plate dia-toms, including a large proportion of Am-phora salina, were not significantly affected

by zooplankton grazing. The cladoceranand rotifer zooplankters of Soap Lake were

most abundant in open water; concentra-tions along the shore seldom occurred. In-sect larvae, although sometimes common,never appeared abundant enough duringlate spring and summer to influence theapparent low production values. It is sug-gestcd, then, that the decline in productionrate was real as far as the epilithic diatoms

are concerned. Probably there was a realdecline in production rate of the phyto-plankton as well, since Amphora was com-

mon to both situations, and it is likely thatthe same’ factors would apply. It should beremembered, however, that the two studieswere not carried on concurrently.

A FLORISTIC COMPARISON

The lakes of the Lower Grand Couleefall easily into two classes-freshwater andsaline. Alcove Lake ( Fig. 1) is the onlybody of water approaching intermediateconditions. During high water salinities as

low as 3,000 ppm T.D.S. were reached;salinities rose as high as 8,000 ppm T.D.S.

during low water. It was not surprising to

find both characteristic freshwater and sa-line species of algae in Alcove Lake togetherwith several taxa scemingIy restricted to this

lake.The truly freshwater lakes of the Lower

Grand Coulee were found to have about 234species and varieties compared to 65 for thesaline lakes (including Alcove and TalusLakes). In both classes of lakes diatomsand blue-green algae were well representedin numbers of species; green algae were wellrepresented in the freshwater lakes only

TAIKE 3. The number of taxu occurring in four

lakes of the Lower Grand Coulee

Class Falls Alkali Lenorc Soap

Chlorophyccac __-__. 74 45 8 7Charophyceae ______ 1 1 0 0Euglcnophyceae __ 2 1 2 1Xanthophyceac __-- 9 0 0 1Chrysophyccae ._-- 3 1 0 0Bacillariophyceae __ 86 70 15 11Dinophyceae ._.___-- 4 1 0 0Cryptophyceae ____-- 1 0 0 0Cyanophyceae --._.. 39 17 12 10

Total __-_-_-_-_--___ 19 136 37 30

( Table 3). There were 25 algal taxa com-mon to freshwater and constantly saline

lakes (Lenore and Soap). These include,Botryococcus braunii, Gongrosira sp., Sti-

geoclonium sp., Anomoeoneis sphnerophora,Campylodiscus clypeus, Nitxschiu frustul-um, Amphithrix janthina, Anacystis marina,Cakothrix parietina, Plectonema nostocorum,and others. All of the blue-green algae

mentioned play dominant roles in the salinelakes and occasionally in freshwater lakes

as well. Stigeoclonium and Gongrosirz wereimportant in both classes of lakes. Nitx-schia frustulum was an abundant epilithicand glass plate diatom in the saline lakesonly. Since no single taxon represents adominant attachment form on glass in bothclasses of lakes, no comparison of specificproduction rates in the two habitats couldbe made. It should also be borne in mindthat the taxa shared by both classes of lakesmay not bc the same genetically.

Although Falls Lake and Alkali Lake areboth freshwater a sizeable floristic diffcr-ence existed between the two (Table 3).Falls and Alkali Lakes shared about 106taxa. Falls Lake, however, had 105 taxanot found in Alkali Lake. Many of thesewere spccics restricted to the marsh habitat.Twenty-three taxa found in Alkali Lakewere not collected in Falls Lake, but almostall occurred in other freshwater lakes in thearea. It is impossible with the informationat hand to speculate on factors influencingthe floristic differences and similarities be-tween these two lakes. They are similar ingross chemistry (Table 1) although Alkali



Stations Stations

(Ozl)F-V F-V F-V A-I

Date ( surf. ) (0.4m) (3m) ( 0.4m )1955 - - - - ___

mg % mg % mg % mg % mg %

l-l 7243--------l-27 45 48 - - - - - - - -2-28 287 38 - - 284 41 - - - -3-12 200 40 - - - - - - - -3-25 248 35 75 52 171 38 - - - -4-2 603 38 - - - - - - - -4-8 452 33 - - - - - - - -4-15 856 40 - - - - - - - -4-22 535 40 458 40 748 43 - - - -4-29 4033521129 38136 - - - -

5-6 171 32 161 20 204 38 - - - -5-13 144 36 250 31 513 38 - - - -5-20 123 37 554 30 428 41 - - - -5-27 95 31 575 33 231 38 - - - -6-3 149 33 363 44 259 44 - - - -6-10 153 34 357 31 - - - - - -6-17 159 33 233 33 103 42 84 43 916 216-24 99 40 151 29 89 38 - - - -7-l 100 43 36 36 96 42 94 34 116 397-l - - 85 33 197 64 - - 181 377-8 35 37 46 30 36 36 - - -7-15 31 41 16 30 13 37 71 38 2i9 437-15 - - 51 24 19 36 - - 286 467-21 67 32 127 18 84 29 - - 318 377-28 56 29 81 28 38 35 167 48 253 477-28 - - 118 17 42 33 - - 380 467-28 - - 126 20 64 39 - - - -8-7 3530 - - - - - - - -8-13 25 30 - - - _ _ _ - _8-18 26 34 30 33 16 26 105 43 266 378-18 - - 39 35 21 34 - - - -8-18 - - 44 26 27 38 - - - -8-18 - - 52 20 32 36 - - - -8-28 29 33 - - - _ _ _ - -9-4 49 39 - -9-9 53 41 30 25 22 4; 39 40 29 4i9-9 - - 45 22 24 34 - -

9-17 47 38 127 18 65 41 - - 108 4;9-17 - - 131 28 80 30 - - - -9-24 51 40 139 18 80 36 22 46 81 49

10-l 93 42 126 25 83 44 - -10-8 61 40 151 35 133 50 - - li9 iilo-15 78 35 110 21 - - - - 158 4110-15 - - 113 25 - - - -lo-22 74 31 53 22 86 33 - - 253 4011-13 26 27 89 19 88 24 - - - -11-13 35 30 - - - - - - - -12-4 4 14 20 41 30 30 - - - -12-4 11 50 35 43 42 32 - - - -12-25 - - 47 36 39 37 - - - -12-25 - - 65 39 46 40 - - - -


TABLE 4. Ash-free dry weight o f attached materials from. freshwater lakes expressed as milligrams persquare meter per clay and as percentage of total dry weight; two week results are in roman type,

four week results are in italics; mid-dates of submergence periods are used

Date (OZl)F-V F-V F-V

(surf. ) (0.4m) (3m) (Of&,1956 ~ ____ ____ - -

mg % mg % mg % m g % mg %

l-24 - - 67 34 41 41 - - - -l-24 - - 83 38 54 36 - - - -2-24 - - 186 35 131 38 - - - -2-24 - - 187 35 - - - - - -3-17 - - 172 13 30 20 - - .- -3-24 47 27 203 16 30 23 - - - -3-24 64 29 - - 60 20 - - - -3-24 101 31 - - - - - - - -3-31 - - 252 13 69 22 - - - -4-7 - - 301 22 31 36 - - - -

4-14 76 28 199 21 43 39 - - 38 94-14 88 32 296 20 50 29 - - 52 104-21 275 29 354 22 138 35 - - 585 234-28 243 27 329 20 81 32 - - 508 334-28 - - 373 18 119 25 - - - -5-5 186 30 - - - - - - 322 265-12 245 33 307 22 125 31 - - 232 255-19 173 30 - - - - - - 78 175-26 196 27 416 22 61 30 - -. 192 156-2 245 31 - - - - - - 152 266-9 205 31 204 25 75 33 145 33 100 256-9 - - 90 41 - -6-16 126 29 379 16 153 27 - - s2 2i

6-23 129 25 449 13 118 21 207 31 88 26G-30 138 29 340 25 120 26 - -7-7 147 33 536 21 106 24 400 30 74 277-14 105 37 101 18 27 37 - - 23 36 .7-21 137 32 175 17 54 30 291 29 3 187-28 74 32 79 21 49 44 - - 6 188-4 75 39 92 21 49 42 181 24 24 298-4 - - 98 20 - - - -8-25 128 36 60 12 31 27 - - 107 ii08-25 134 34 74 9 52 32 - - 148 309-22 248 29 90 14 89 28 - - 56 299-22 274 30 117 20 148 27 - - 61 29

lo-20 160 40 31 30 21 32 - - 74 36lo-20 166 45 34 29 21 34 - - 100 37

lo-20 172 40 39 31 - - - - loo 39lo-20 184 40 40 32 - - - - 106 3410-20 - - 4225 - - - - _ _



22 RICHARD W. CA!XENHOLZ

Lake contains more sodium. They are quite

different in morphometry. The shallow andunstratified Alkali Lake also lacks the marshhabitat so abundant in Falls Lake. The k

relatively brief freshwater history of AlkaliLake and the great fluctuations of waterlevel may well explain the absence of the

Typhn-S&pus marshes.Floristically Lake Lenorc and Soap Lake

arc quite similar, although the fresher LakeLenore has the greater complement (Table

3). Twenty-three taxa were common to

both lakes. Fourteen taxa in Lake Lenore

never occurred in Soap Lake but many ofthese were found regularly in freshwater or

semi-saline lakes in the Grand Coulee. Sev-

en taxa in Soap Lake did not occur in LakeLenore. Only one of these was typical offresher water, however. The majority of thealgae occurring in these saline lakes areknown the world over in waters of similarsalinities. A more detailed discussion of thesaline flora may be found in Castenholz

(1957).

TABLE 5. Ash-free dry weight of attached materials from saline lakes expressed as milligrams per square

meter per day and as percentage of total dry weight; two week results are in roman type,

four week results are in italics; mid-dates of submergence periods are used

Stations Stations

L-III Under- S-II Uncler- L-T11 Under- S-II Undcr-Date 0.4m top side 0.4m top side Date 0.4m top sick 0.4m top side1955 ~ ~ ~ ~ 1956 ___ - _____ ____

mg % mg % mg % mg % mg % mg % mg % mg %

3-25

4-2

4-15

4-22

4-29

5-13

5-20

6-3B-10

6-17

6-24

7-l

7-l

7-8

7-15

7-21

7-28

7-28

8-18

8-18

9-99-17

9-24

10-B

10-15

10-22

11-13

11-13

12-4

12-4

12-25

12-25

24 30

52 55

21 25

26 25

33 28

63 33

24 3947 27

82 25

150 19

35 30- -

26 42

53 45- -

49 32

62 40

11 27

18 25

226 4399 48

171 47

246 46

203 43

650 43- -- -

- -- -- -- -35 6165 60

71 61

34 5986 58

42 57

106 64

81 62- -

- -

24 52- -- -- -35 55

44 53

101 5135 56

21 49- -

126 5184 47- -- -- -

- -39 23

122 37

245 36- -- -- -

219 42- -

74 33

24 32

49 32

74 20- -

42 30

61 3886 34- -

27 34

31 38

96 3944 38

101 34

533 35

144 27490 26

183 19- -

221 23

282 26

987 32

1043 32

- -- -- -- -- -- -- -

- -- -- -17 45- -

- -

- -

- -

11 33- -- --- -- -

35 3835 45

51 41

26 40

47 50

74 47

52 43

76 45- -

- -

- -

- -

2-24

2-24

3-17

3-24

3-31

4-14

4-14

4-214-28

5-5

5-12

5-12

5-19

5-26

6-2

6-9

6-16

6-23

6-23

6-30

7-77-7

7-14

7-21

7-21

7-28

8-4

8-4

8-25

8-25

9-22

9-22

10-20

10-20

10-2010-20

10-20

- -

?4 i

15 3144 36

61 37

64 36

22 3243 38

21 3628 29

39 36

20 1869 3943 36

92 41

33 30

66 35- -

98 16

136 26- -

26 2174 23- -

23 34

101 27

111 23

44 30

44 34

84 1796 16

323 40

340 45

375 39423 40

- -

- - 127 41- - 178 41- - 183 3368 58 120 20- - - -

- - 441 31- - - -

61 67 118 28- - 208 33

25 56 79 34

- - 193 32- - - -

25 58 125 32- - 192 33- - 49 23

- - 113 26

33 60 25 19- - 80 25- - 92 29

74 60 26 31

--

33 20- - 54 31

46 57 50 33- - 91 31

- - 98 3248 57 46 40

- - 154 35

36

- -

47 100 34- - 123 34

116 16 122 42127 69 148 40

63 52 170 3676 55 188 33

82 58 200 36- - 214 35- - 231 31

- -- -- -- -- -- -- -

- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -48 48

49 48

127 45131 45

170 46203 53

- -



SEASONAL CHANGES IN ATTACIIED ALGAE 23

DISCUSSION OF THE GLASS PLATE

TECHNIQUE

Submergence time

Results obtained from 2- and 4-weekplates were usually comparable during sum-mer periods of low production in both

classes of lakes (Tables 4 and 5). Duringgreater spring production in freshwaterlakes somewhat higher rates were generallyobtained with 4-week plates (Table 4).

However, during high production in salinelakes &week plates definitely showed higherproduction ( Table 5).

In general a 2-week submergence period

is empirically more satisfactory since ashorter period records more fluctuations ofproduction rate and more accurately pin-points the time. A period of less than 2weeks would be perhaps even more desir-able. However, if the period were shortenedto only a few days it is probable that thenumber of algal cells settling on the plateswould exaggerate the production rate orgrowth increment values.

Patrick and co-workers (Patrick et nt.1954) found that the number of diatom spe-

cies occurring on l-week slides was similarto that on 2-week slides. A significantlysmaller number occurred on 4-week slides.The greater accumulation of debris andother organisms and the crowding out ofsome forms by fast growing diatom spccicswere given as possible explanations for the4-week results. Patrick concluded that two

weeks seemed to be the optimum period ofsubmergence in the rivers studied to date.

It has been pointed out, however, that sub-

mergence time should probably vary some-what according to the type of lake or river,water temperature, season, and purpose of

the experiment (Patrick et al. 1954, andNewcombe 1949, 1950). Patrick’s group

was not studying production but floras in-dicative of river conditions. Newcombe,studying production, suggested that duringperiods of low production either largerslides or longer periods of submergence beused in order to obtain at least 3-5 mg ofash-free dry weight per slide. The glass

plates used in the present study obtainedweights well in excess of this after two

weeks of submergence even during lowestproduction.

One would expect production rate resultsto dccrcase with loss from mineralization,

with peeling and rising because of trappedgases, with sloughing off of dead and loose

cells by wave movements, and with grazingby animals, These factors would distort pro-

duction rate values more with longer sub-mergence periods. Peeling was observedonly on plates that had been submergedlonger than four weeks in freshwater. Gas-tropods were present in the freshwater lakes

only but were not common, at least in the

upper 2 m. Grazing of attachment materials

on plates by gastropods was rarely observed.Since higher production rate values in fresh-

water lakes were obtained from 4-weekplates than from 2-week plates during pc-riods of high production, it might be as-sumed that real production rates were evenhigher and that the reduction factors were

probably very slight. Therefore, four weeks

is probably not too long a period of sub-

mcrgence but it is certainly less sensitivethan a 2-week period. In saline lakes, how-ever, the low values of 4-week plates indi-

cate a large amount of reduction. Here itappeared that loss by wave action was themain factor after the thickness of attach-ment materials had increased beyond a pe-

riod of 1.5 to 3 weeks. Many of the algae,particularly the blue-green, in the saline

lakes were loosely attached to the substrate.

The scraping of glass plates

As mentioned earlier (see Materials and

Methods) it was the usual practice to re-turn scraped plates to the water. Sometimes

unused plates wcrc used as replicates. Insuch cases no significant differences in re2

sults were found. It might be supposed thatgreater quantities of attachment materialsshould be obtained from used plates thanfrom unused ones after a 2- or 4-week sub-

mergence period. The washed plates sel-dom dried completely before resubmer-gcncc. It is also questionable whether ashort period of desiccation would affect theviability of most diatoms (Evans 1958).Scraping cannot be 100% efficient, and the

diatoms remaining on used plates wouldhave some start. Since results indicate




otherwise, it would seem that the “sceding-

on” of diatom cells must be rapid enoughto colonize the plate surface uniformly in ashort time. Perhaps, if both types of plates

had been examined after only a few daysa significant difference would have beenfound.

Glass sezectivity

Most of the epilithic algae became at-tached to glass as well as to rocks. Therapidly growing green alga UZothrix aequal-is in Falls Lake did not attach to glass ex-

ccpt when the plates were located at thewater-air interface, This, however, was the

only region of attachment on rocks as well.The positive phototaxis of zoosporcs was theprobable factor involved. Cladophora fractain freshwater lakes did not attach to glass.

This was probably due to the perennial na-ture of Cladophora filaments and the prob-

ably infrequent production of swarmers( Castenholz 1957). Many of the slowlygrowing, rock encrusting blue-green algae(e.g., Amphithrix, Calothrix, Entophysalis)did not occur commonly on 2- or -I-week

plates. This was apparently due to the timefactor, since plates exposed for much longerperiods showed a development of these

genera. The rock encrusting green algaGongrosira also falls into this category.

The results of Patrick et al. ( 1954) alsoshow that glass is not selective as far asdiatoms are concerned. The species col-lected by their apparatus . . . . “arc from75 to 85% the same as those taken by

thorough collecting of the region by a di-atomist at the time the slide is rcmovcd from

the apparatus. Those diatoms not common

to the slide and to the collections made bythe diatomist were mostly represented byless than four specimens; 95% of those rep-resented by 8 or more specimens were com-

mon to both.” In all the lakes of the LowerGrand Coulee no epilithic or epiphytic di-atom species were excluded from glass

plates. It was also apparent that the rela-tive abundance of the various species onthe glass plates was similar to that on the

rock substrate in the immediate vicinity.Although the ordinary window glass used

in this investigation appeared non-selective,

it is possible that a rougher surface wouldbe rcquircd for permanent settling and firmattachment of some species of algae. Inrather crude preliminary experiments sand-

blasted (frosted) and normal glass micro-scope slides were submerged horizontallyin metal staining racks. After both two and

four weeks of submergence no differencein quantity and composition of attachedalgae was apparent. If a bacterial film isformed very quickly on a .glass surface, at-tachment of small forms, such as diatoms,may not be much affected by the natureof the glass surface itself.

It is recommended that in future studies

of this sort a direct comparison be madebetween production rate on glass plates andon submerged sterile rocks of the type foundin the lake studied. Finding rocks of suffi-cient size to present a flattened side large

enough in area to be usable is apt to bcdifficult. A further difficulty is removingthe attachment material from an irregularand pitted rock surface in a quantitativemanner.

Comparison of horizontal and

vertical surfaces

In the present study it was found thatthe weight of material from vertically andhorizontally placed plates in Falls Lake wasin a ratio of 1: 12.4 during the spring and1:6.2 in the summer. The results of New-

combe ( 1950) were somewhat similar, 1:6.6in late summer and early fall and 1:3 in latefall. Newcombe also noted that the lossduring removal of vertical slides from the

water may exceed the amount that re-

mained. Horizontal slides could bc removedwith a minimum of surface disturbance. It

is obvious, however, that horizontal surfaceswill collect more of the organic detritus thatsettles out from suspension. This seemed anegligible factor in the fresh-water lakes ofthe Grand Coulec. Undisturbed living ma-tcrial was examined periodically under themicroscope. During high production in thespring nearly all of the material was com-posed OF attached diatoms. In the saline

lakes, however, a considerable amount oforganic detritus was collected by the hori-

zontally placed plates.



SEASONAL CHANGES 1

The attachment material produced on theunderside of glass plates was also collectedregularly from plates mounted on tripods.

The ash-free dry weight of underside ma-

terial sometimes equaled or even exceededthe weight of upperside material during lowproduction periods in both the freshwaterand saline lakes (Table 5). During high

production, however, upperside productionpredominated, as would be expected be-cause of greater light absorption. In mostcases the species composition was similar onboth surfaces. Ncwcombc (1950) found

that the amount of attachment material onthe underside of slides was generally small.

Sedimentation of inorganic particulatematter on horizontal glass plates was ofsome importance in all the lakes, but wasconsidered of major importance only during

the turbid period in Alkali Lake in spring1955, and occasionally in the saline lakes.Of the materials collected from the uppcr-side of glass plates, the ash varied usuallyfrom 50% to about 85% of the dry weight

(Tables 4 and 5). Thcsc figures were com-pared with the percentages of ash on theundersides where inorganic sediment wouldbc nearly absent. The underside ash per-

centages of nearly pure diatom materialwere fairly constant for each lake through-out the year and were thus considered the

“ideal” ash percentages. They amounted toabout 47% in Falls Lake, 48% in Alkali Lake,42% in Lake Lenore, and 55% in Soap Lake.This compares fairly well with percentagesof ash from pure diatom material: Amphi-pleura rutilnns-46%, Navicula torquntum-35% ( Burlcw 1953). By subtracting the

“ideal” ash pcrccntages from those obtainedfrom the uppcrsides, estimates of the inor-ganic sediment deposited on top were made.The sediment thus varied from practically0% to 40% of the dry weight of the material.The percentage ash from the uppcrsidc wasnever less than that obtained from the un-derside of the same plate. It was often

found that greater sedimentation occurredon shallower plates than on deeper ones

( Table 4). Greater sedimentation occurred

in freshwater lakes during high water pe-riods of spring than during low water

periods of summer and early fall ( Table 4).

[N ATTACHED ALGAE 25

TXRLE 6. Ash-free dry weights as milligrams peg

square meter per day from replicateglass plates

No. ofStation plates ?I S c as %

Falls-V ( surface ) 5 37.2 -t- 9.4 25.3

Falls-I (0.4 m) 4 170.5 217.3 10.1

Alkali-I ( 0.4 m ) 4 95.0 k24.2 25.5

Lenorc-III (0.4 m) 4 365.3 -177.9 21.3

Soap-II ( 0.4 m > 5 200.6 zb43.8 21.8

Replicate plates

At most stations, at least three plates were

used at each depth in order to collect 2- and4-week plate material at bi-weekly intervals.At some stations extra plates were used peri-

odically as replicates (Table 4 and 5 andFigs. 2-10). Fewer than four replicateswere used at most times, but four or five

replicates of 4-week plates were used atthe main stations in all lakes for the collec-

tion on November 3, 1956. The mean ash-free dry weights expressed in mg/m2/day,the standard deviations (s), and coefficientsof variation ( C ) are given in Table 6. Asexpected, variations are numerically greater

with higher weights, but percentage varia-

tions arc rather similar. Although 25% initself represents a rather large degree of

variation, it may be seen that it would notdistract much from the major trends shownby the curves (Figs. 2-10). Wheneverduplicate or replicate plates were used at

other dates the results are usually wellgrouped. It is the author’s opinion thatsingle plate results may be considered re-liable within *25% of the value obtained,

particularly if no disturbances are noted onthe plates in the field.

A more widespread use of many plates ata single station was prevented by insuffi-cient space on the rock ledges and also bybarely adequate time to sample all stationsin the four lakes. Some attempts at settingup many replicates were spoiled by vandalswho destroyed entire sets.

Suitability of the method in the saline lakes

The glass plate method was not so welladapted to use in the saline lakes. In the

freshwater lakes the epilithic vegetation wasdominated by diatoms which readily at-tached to glass. Diatoms were important




plate organisms in the saline lakes as well,

but there were also very important epilithicspecies of blue-green algae that commonlyattached to glass in the 2- or 4-weeks. Some

blue-green algal species were only slightlyadhesive to plates and rocks. Generallythese were species more characteristic ofthe benthoplankton, such as Anacystis ma-rina and Plectonema nostocorum. It wasdifficult to remove plates from the waterwithout losing some of this material. Chi-ronomid larvae were frequently found en-cased on the surface of plates. In Lake

Lenore these organisms never amounted tomore than 5% of the ash-fret dry weight.

However, in Soap Lake, chironomids somc-times accounted for as much as SO%, par-ticularly in the spring.

Another complication encountered in the

saline lakes was the weakly silicified nature

of the diatom frustules. The walls of mostspccics were completely deformed duringashing. Consequently the counting methodcould not be used. This difficulty was com-pensated for by the fact that only a fewspecies of diatoms occurred commonly, and

these were of approximately the same cellsize. Thus, rough estimates of dominancewere made before ashing.

The two saline lakes had a larger surface

area than the two freshwater lakes. Thesignificantly greater wave action in largerlakes probably has a greater reducing effecton attachment materials on glass plates. Itwas also noted in the larger freshwater lakes,such as Hue Lake and Park Lake, that thespring diatom carpet was not so heavy as

in Falls Lake and that epilithic Cladophorawas not so luxuriant in the summer. It maybe surmised that the greater wave action in

the larger lakes has a modifying influenceon such features. Jorgensen (1948) foundsimilar differences between large and smalllakes in Denmark.

General application

Although there are several limitations tothe glass plate production technique, the

author believes that it may be applied sue-ccssfully to a large number of lake andstream types, as well as to marine situations.IIowever, the present type of quantitative

procedure in analyzing species composition

is practical only where diatoms predom-inate, since it is very difficult to mix

thoroughly the mass of attachment ma-

terials before ashing at a high temperature.It is possible that glass production results

may be of some value in characterizing thewhole primary production of a lake, al-though many members of the phytoplankton

do not attach readily to a firm substrate.Simultaneous studies of planktonic and at-

tached algal production would be of inter-est. Certainly the attached algae should notbe ignored in studies of primary production,particularly in smaller bodies of water

where their contribution may be great.

DISCUSSION OF SEASONAL CHANGES

A comparison of diatom production inFalls Lake and Alkali Lake brings outseveral quantitative and qualitative diffcr-ences. From the results of the one stationin Alkali Lake it would appear, however,that total annual production of organic mat-ter per unit area in the upper meter wassimilar to that of Falls Lake. The seasonal

similarities were such that a bimodal pro-duction curve with a higher maximum inspring was evident in both lakes (Figs. 2-6and 8). It may be seen that the spring di-atom outburst was usually initiated at alower temperature (5”-12°C) than the falloutburst ( 15”-17°C). It is also true thatlight intensity and length of day are greaterin April and May than in October or No-vember. There exist, then, widely differenttemperature-light values at the initiation

time of the two main diatom pulses althoughsome of the same species are involved. Asimilar situation appears to be common inlakes throughout the temperate world (Pat-rick 1948). This pattern is by no means aconsistent feature of all types of lakes, how-ever. Pennak ( 1946,1949) pointed out thatbimodal planktonic diatom curves are mostcharacteristic of medium to large deep lakes.In several stuclies of small to medium size

lakes in Colorado hc noted no characteristic

spring or fall pulse. Instead, one, two, orthree pulses occurred at various times of

year.It may be seen that the seasonal fluctua-




tion of overall diatom production curves isgenerally a function of the combined indc-pendent variations of several species. ‘Theseasonal pcriodicities of only a few of the

diatom taxa occurring in the Lower GrandCoulce have been noted in other temperatewaters. In making comparisons one must

bear in mind that there is always a possi-bility or probability that two or more eco-types or genetic types are involved.

The role of certain species during highproduction periods differed somewhat inFalls Lake and Alkali Lake. Cymbellaaffinis, C. cistula, and C. mexicana were

abundant species of fall, winter, and spring

on shallow rocks in Falls Lake. All werepresent in Alkali Lake but never in anygreat abundance. Blum ( 1957)) on theother hand, noted that C. affinis was pre-dominantly a “summer” form in a Michiganstream. C. cistula is widespread throughoutthe world, but little has been said about

its seasonal periodicity. C. mexicana, how-ever, is apparently rcstrictcd to westernNorth America, and no other seasonal infor-mation is available. C. mexicana was the

most conspicuous “spring” diatom of FallsLake, but it also occurred in some abun-dance during the summer in deeper habitats.A similar distribution of certain diatomswas noted by Godward (1937) and Rohdc

(1948).Cymhella turgida and C. ventricosa were

common during the spring pulse in FallsLake but occurred abundantly in the sum-mer only in Alkali Lake, Similarly, God-ward (1937) and Butcher (1932a) foundC. ventricosa as a spring form in Englishlakes and streams, while in a Michiganstream it was most abundant in summer( Blum 1957).

Synedra ucus and S. ulna were character-istic “spring” forms of both freshwater lakes.Reports of Butcher ( 1932a) and others con-

firm this pattern. Blum ( 1957), however,found both species most abundant in

summer.

Diatoma elongatum, D. w&are, and

Gomphonema olivaceum were “spring” spe-cies abundant in Alkali Lake only. The re-ports of several workers confirm that thesespecies are restricted to cold water periods

(e.g., Blum 1957, Butcher 1932a, Godward

1937 ) .The rather dramatic replacement of

“spring” diatom species on shallow rocks

by Epithemia turgida and E. sorex in sum-mcr has (to this author’s knowledge) notbeen discussed elsewhere. There is little

information on the seasonal cycles of otherspecies of diatoms common in the Grand

Coulcc. Bock (1953), Budde (1928), Butch-er ( 1946)) Jiirgcnsen ( 1935)) and Niesscn( 1956) present some additional information

from studies in Europe.Since only a small portion of the environ-

mental complex has been studied it is im-

possible to offer a positive statement rcgard-ing the factors causing the initiation, main-

tenance, and depletion of algal pulses inthcsc lakes. It would seldom be possible todesignate a single factor as the sole agent

involved, and it is probable that an intcr-play of many factors is involved. Probably

different combinations of chemico-physicalfactors are effective from one type of water

to another, from one season to the next, andfrom one species or ecotype to another.

The seasonal cycles of production in thesalinc lakes were conspicuous for the largefall pulse which was initiated at rather hightemperatures (15”-20°C) in both lakes. Alarge winter pulse followed by a spring

pulse was characteristic of Soap Lake only.

Yet, the pulses of all three seasons in SoapLake were dominated by the same speciesand varieties of Nitzschia and Amphora.The same taxa (plus Amphora coffeaeform-is) were involved in the fall pulse in LakeLcnore. The absence of a winter peak inLake Lenore can probably be ascribed tothe prcscnce of an ice and snow cover. Theabsence of a spring peak in Lake Lenorc isunusual, particularly since Anderson ( 1958)noted a spring phytoplankton pulse.

An extensive literature on the salinity and

pH tolerances of diatom species exists.Rather strict halobicn and pII spectra have

been established ( Patrick 1948). The floris-tic composition of Lake Lcnorc and Soap

Lake agree well with the established order.However, thcrc is practically no informationavailable on the seasonal periodicity of the

saline diatoms in other regions.




REFERENCES

ADDIN, G. 1949. Benthic algal flora of Aswan

Reservoir ( Egypt ) . Hydrobiol., 2 : 118-133.ANDERSON, G. C. 1958. Seasonal characteristics

of two saline lakes in Washington. Limnol.Oceanogr., 3 : 51-68.

ANDERSON, G. C., G. W. COMITA, AND VERNA ENG-

STROM-HEG. 1955. A note on the phyto-

plankton-zooplankton relationships in two

lakes in Washington. Ecol., 36: 757-759.BISSONNETTE, T. H. 1930. A method of securing

marine invertebrates. Scicncc, 71: 464-465.

BLUM, J. L. 1957. An ecological study of the

algae of the Saline River, Michigan. Hydro-

biol., 9: 361-408.

BOCK, W. 1953. Floristisch-akologische Unter-

suchung der Algenvegctation periodischcr

Gewjisser im siidlichen Teil dcs Maindrcicckcs.

Arch. Hydrobiol., 47: 9-74.BRETZ, J. II. 1932. The Grand Coulec. Am.

Geogr. Sot., Spcc. Publ. No. 15. 89 pages.BUDDE, H. 1928. Die Algcnflora des Sauerlsncl-

ischcn Gcbirgsbaches. Arch. Hydrobiol., 19 :433-520.

BURLEW, J. S. ( ed. ) 1953. Algal culture: from

laboratory to pilot plant. Carncgic Inst. ofWash. Publ. 600, p. 286.

BUTCIIEH, R. W. 1932a. Studies on the ecology

of rivers. II. The microflora of rivers with

special reference to the algae on the river bed.

Ann. Bot., 46: 813-861.

-. 193213. An apparatus for studying thegrowth of cpiphytic algae with special refer-

ence to the River Tees. Trans. North. Natur-

alist’s Union, 1: l-15.-. 1946. Studies in the ecology of rivers.

VI. Algal growth in certain highly calcareous

streams. J. Ecol., 33: 268-283.

CASTENI-IOLZ, R. W. 1957. Seasonal changes in

the algae of freshwater and saline lakes in the

Lower Grand Coulce, Washington. Ph.D.Thesis, State Collcgc of Washington.

CIIOLODNY, N. 1930. Wber eine neue Mcthode

zur Untcrsuchung dcr Bodenmikroflora. Arch.

f. Mikrobiol., 1: 620-652.

COE, W. R., AND W. E. ALLEN. 1937. Growthof sedentary marinc organisms on expcrimcntalblocks and plates for nine succcssivc years at

the pier of the Scripps Institution of Occan-

ography. Bull, Scripps Inst. Oceanogr. Tech.

Ser., 4: 101-136.COOKE, W. B. 1956. Colonization of artificial

bare areas by microorganisms. Bot. Rev., 22:

613-638.

DAUBENMIRE, R. F. 1942. An ecological study

of the vegetation of southeastern Washington

and adjacent Idaho. Ecol. Monogr., 12: 53-

79.EVANS, J. H. 1958. The survival of freshwater

algae during dry periods. Part I. An investi-gation of the algae of five small ponds. J.

Ecol., 46: 148-167.

nomic investigation of the littoral algal flora ofLake Windermere. J. Ecol., 25: 496-568.

HENTSCHEL, E. 1916. Biologische Untersuch-ungcn iiber den tierischcn und pflanzlichenBewuchs im Hamburger Hafen. Mitt. Zool.

Mus. Hamburg, 33: 1-172.-. 1925. Abwasserbiologie. Abderhalden’s

IIandb. Biol. Arbeitsmcthod., 9 ( 2) : 233-280.

IVLEV, v. S. 1933. Ein Versuch zur cxperimcnt-

ellcn Erforschung der Ukologie dcr Wasscrbio-cijnoscn. Arch. Hydrobiol., 25 : 177-191.

JORGENSEN, E. G. 1948. Diatom communities insome Danish lakes and ponds. K. DanskeVidensk. Sclsk. Biol. Skr., 5 ( 2 ) : l-140.

J~~RGENSEN, CI-IARLOTTE. 1935. Die Mainalgcnbci Wiirzburg. Arch. IIydrobiol., 28: 361-414.

NEWCOMBE, C. L. 1949. Attachment materials

in relation to water productivity. Trans. Am.

Micros. Sot., 68: 355-361.

-. 1950. A quantitative study of attach-ment materials in Sodon Lake, Michigan.Ecology, 31: 204-215.

NIESSEN, HERTA. 1956. Bkologische Untersuch-

ungen iiber die Diatomccn und Desmidiaccen

cles Murnauer Moorcs. Arch. Hydrobiol., 51:281-375.

PATRICK, RUTII. 1948. Factors effecting the dis-

tribution of diatoms. Bot. Rev., 14: 473-524.

-, M. H. HOIIN, AND J. H. WALLACE. 1954.

A new method for detclmining the pattern of

the diatom flora. Notulac Naturac, No. 259,

12 PP.

PENNAK, R. W. 1946. The dynamics of frcsh-water plankton populations. Ecol. Monogr.,

16: 339-391.

-. 1949. Annual limnological cycles in

some Colorado reservoir lakes. Ecol. Monogr.,

19: 233-267.RAWSON, D. S., AND J. E. MOORE. 1944. The

salinc lakes of Saskatchewan. Can. J. Res.,

Sec. D, 22: 141-201.ROHDE, W. 1948. Environmental requircmcnts

of fresh-water plankton algae. Experimental

studies in the ecology of phytoplankton.

Symbolac Bot. Upsalicnscs, 10 ( 1) : 1-149.

SCI-IEER, B. T. 1945. The development of marinc

fouling communities. Biol. Bull., 89: 103-121.

TIIOMASSON, H. 1925. Methoden zur Untcrsuch-

lmg der Mikrophyten der limnischcn Litoral-lmd Profundalzone. Abdcrhalclcn’s IIandb.

Biol. Arbcitsmethod., 9( 2) : 681-712.

WIIITTAKKR, R. H., AND C. W. FAIRBANKS. 1958.

A study of plankton copepod communities in

the Columbia Basin, Southeastern Washing-

ton. Ecol., 39: 46-65.

WITIIROW, R. B., AND ALICE P. WITIIIlow. 19%.

A linear recording AC conductance bridge for

measuring salt exchange in plants. Physiol.

Plan tarum, 6 : 444-450.YOUNT, J. L. 1956. Factors that control spe-

cies numbers in Silver Springs, Florida.

Limnol. Oceanogr., 1: 286-295.

algas lagos salinos

Documents