seasonal succession of phytoplankton in roosevelt lake, arizona

Arizona-Nevada Academy of Science

Seasonal Succession of Phytoplankton in Roosevelt Lake, ArizonaAuthor(s): Rose Mary Cisneros, Richard D. Olsen and Milton R. SommerfeldSource: Journal of the Arizona-Nevada Academy of Science, Vol. 14, No. 1 (Feb., 1979), pp. 7-12Published by: Arizona-Nevada Academy of ScienceStable URL: http://www.jstor.org/stable/40024465 .

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SEASONAL SUCCESSION OF PHYTOPLANKTON IN ROOSEVELT LAKE, ARIZONA1

ROSE MARY CISNEROS, RICHARD D. OLSEN2 and MILTON R. SOMMERFELD

[226]

Department of Botany and Microbiology Arizona State University Tempe, Arizona 85281

INTRODUCTION. - Of the four storage reservoirs impounding the Salt River of Arizona, the upper and largest is Roosevelt Lake. The reservoir, impounded by Theodore Roosevelt Dam constructed in 1905-191 1, is located ca. 126 km ENE of Phoenix in southwest Gila County. The reservoir has a maximum surface area of 72.2 km2 (17,315 acres), a capacity of 170.4 x 107 m3 (1,381,580 acre-feet) and a high water elevation of 651 m (2136ft). Water storage for irriga- tion, hydroelectric generation and recreation (fishing, boating, skiing, and camping) are the primary uses of the reservoir. The reservoir is subject to severe seasonal fluctuations in water level because of down- stream water demands and the maintenance of the lower reservoirs at near capacity for pumped-storage operation.

This study was performed to determine the composition and seasonal pattern of phytoplankton succession in Roosevelt Lake. Data on phytoplankton abundance and their seasonal dynamics in south- western lakes remain relatively sparse although there are several recent investigations on the phytoplankton of Arizona lakes (Olscn and Somerfeld, 1970, 1976; Sommerfeld, Cisneros and Olsen, 1975; Staker, Hoshaw and Everett, 1974; Steward and Blinn, 1974). The data that are available indicate that the lakes studied are diverse in species and rich in abundance with relatively little overlap in species from lake to lake. This may be due to the major chemical and physical differences among the lakes of Arizona (Cole, 1966; Kessler and Stull, 1978; Stull and Kessler, 1978).

MATERIALS AND METHODS. - This investigation was performed from February, 1971 through August, 1974. Although four sampling sites were established to represent differences in reservoir morphometry (Fig. 1) and phytoplankton were collected from the surface, 2, 5, 10 and 20 m, the data presented in this paper are primarily from the 2 m samples collected at site R-2 during the period February, 1971 - February, 1972. The site, depth and time period selected was generally representative of species richness, abundance and succession in the euphotic zone of Roosevelt Lake.

Two-liter water samples were collected monthly between 1000- 1400 hr with a Kemmerer sampler. In the laboratory 500 ml of the natural water sample was concentrated to 25 ml by centrifugation at 3200 rpm for 20 min at 5 C using a refrigerated centrifuge (Inter- national Model PR-2). Possible errors in phytoplankton estimates arising from loss of buoyant forms were assumed negligible since re- centrifugation and observation revealed no phytoplankton. Plating out of the supernatant on Bristol's agar and Bristol's plus soilwater extract agar media also revealed little or no loss of phytoplankton in the centrifugation process.

The 25-ml concentrate was thoroughly mixed and one ml aliquots were removed with a Hensen-Stempel pipet and introduced into a standard Sedgewick-Rafter counting cell. A cover slip was placed over the cell, the cell inverted and the material allowed to settle for 20 min. A net micrometer was used to delimit the area and fields within the counting cell. Forty fields, which included 10 micrometer fields on each of four cell mounts, were enumerated for noni-diatom phytoplankton (Kutkuhn, 1958). The diatoms were identified and enum-

erated separately by placing 0.5 ml of the phytoplankton concentrate evenly over the surface of a 22 mm square cover glass. The sample was dried, incinerated on a hot plate and mounted on a microscope slide using a drop of Hyrax. Using a 1.0 mm net micrometer, diatoms from five random scans across the length of the coverslip were counted at a magnification of 300X.

RESULTS AND DISCUSSION. - One hundred and nine species were represented in the phytoplankton of Roosevelt Lake during the study period (Table 1). Of the species identified, 50 were Chloro- phyceae, 33 Bacillariophyceae, 8 Cyanophyceae, 8 Chrysophyceae, 8 Euglenophyceae and 2 Dinophyceae.

Total phytoplankton numbers were found to be relatively similar throughout the year. The total population ranged only from 2 x 103 organisms/ml to approximately 8 x 103 organisms/ml, without major declines or increases. Whereas total phytoplankton numbers showed comparatively little variability, there was a distinct successional pattern of phytoplankton species on an annual basis.

Members of the Chlorophyceae were common in the plankton of Roosevelt Lake throughout the year, but became the dominant organisms in early spring (March) and early fall (October) (Fig. 2). Although the chlorophycean algae comprised more than half of the total population in March, only one species, Crucigenia tetrapedia, occurred in great abundance. In October, only one species, Cruci- genia apiculata, was found in appreciable numbers. During the period June - September, the chlorophycean algae were no longer the dominant organisms even though their actual concentrations were higher than during the period they dominated the flora. A few other species were present at levels of 103 organisms/ml or greater. They included Kirchneriella obesa var. major, Chlamydomonas angulosa, Carteria klebsii and Selenastrum minutum. Many other species were found at subdominant levels. From November through January, the population of green algae remained significant, but large numbers of specific taxa were not observed.

Although chlorophycean algae are rarely the predominating organisms in the phytoplankton population of temperate lakes, the number of species in the freshwater plankton can be very large. Generally the chlorophycean algae are most abundant during late spring and fall. This periodicity is not sharply marked since they can be found at all times (Hutchinson, 1967; Smith, 1950). Roosevelt Lake varied slightly from these patterns in that as a group they were dominant in spring, but were actually more abundant in summer. A similar phytoplankton study in another reservoir on the Salt River, Canyon Lake, Arizona during the same period showed a more distinct chlorophycean periodicity with two peaks occurring in early spring and late summer (Cisneros, 1975).

The Bacillariophyceae were represented in the phytoplankton throughout the year in numbers exceeding 103 organisms/ml except in March and July when the numbers dipped to less than 102 organisms/ml. Diatoms were the dominant organisms in Roosevelt Lake during several months (Fig. 2). In February, when the phytoplankton population was almost exclusively diatoms, one genus, Cyclotella, was dominant. The numbers of diatoms declined in March and April, but these were still the dominant plankters in April with Cyclotella spp. the most common.

'The authors gratefully acknowledge the support of the Salt River Project for this investigation.

2Current address of the second author is Division of Environmental Impact Studies, Argonne National Laboratory, Argonne, Illinois 60439.

7



8 JOURNAL OF THE ARIZONA-NEVADA ACADEMY OF SCIENCE Vol. 14

Figure 1 . Map of Roosevelt Lake, Arizona showing approximate location of sampling sites.

During the summer and early fall (June - October) the diatoms were

replaced as dominants, although their numbers were still significant. During this period there was a diverse assemblage of diatom species, but only a few were found in any abundance. They included three

species of Cyclotella (C. meneghiniana, C. atomus, C. striata), Synedra ulna, Nitzschia acicularis, Nitzschia fonticola and Melosira

fennoscandia. In the late fall and winter period (November - January) the diatoms were once again the dominant phytoplankters. The major contributors to the flora during this period were Nitzschia fonticola, Melosira fennoscandia, Cyclotella spp. and Stephanodiscus sp.

The Cyclotella spp. were major contributors to the phytoplankton community throughout the 12-month investigation (with the excep- tion of September). Two genera, Cocconeis and Cymbella, generally considered benthic or littoral forms were observed in the plankton of Roosevelt Lake. Benthic and planktonic forms of Nitzschia have also been recognized. Benthic forms typically occur in temperate lakes, whereas planktonic forms are more common in tropical lakes (Richardson, 1968; Ruttner, 1937).

The occurrence of two annual diatom peaks (spring and fall) in

temperate lakes is typical (Fogg, 1965; Hutchinson, 1967). Roosevelt Lake differs in that diatoms were dominant in two periods, early spring (February - April) and late fall and winter (November January), but not in distinct peaks since there was relatively little

change in total diatom numbers throughout the year. The Cyanophyceae were represented in the phytoplankton only

during the late summer and fall (July through October) with maximum numbers slightly over 3 x 103 organisms/ml (Fig. 2). Merismopedia tenuissma and Spirulina laxissma were the dominant

species in August. During October the blue-greens were no longer the

predominating group, but several species were still found in significant concentrations. These included M. tenuissma, S. laxissma and

Gloeocapsa sp.

The Cyanophyceae are usually the dominant organisms during late summer and early fall (Moss, 1972; Seenayya, 1972; Smith, 1950). Not infrequently, there is a development of one or two species of blue-

green algae to bloom proportions (Smith, 1950). While this was not the case for Roosevelt Lake, a blue-green bloom in which S. laxissma

comprised over 90% of the total phytoplankton has been observed in another Arizona Lake (Canyon Lake). There have been few reports of the genus Spirulina producing dense growths in temperate waters, but its presence in tropical waters, especially Spirulina platensis, appears to be common. The genus Lyngbya is common in the more

productive lakes of temperate regions in the summer as well as in

many shallow tropical lakes (Hutchinson, 1967; Prowse and Tailing, 1958; Ruttner, 1937; Seenayya, 1972). Anabaenopsis raciborskii, a

relatively rare cyanophyte, occurred in noticeable numbers during July in Roosevelt Lake. This alga, when found in abundance, appears to be restricted to tropical water (Prowse and Tailing, 1958; Ross, 1955; Ruttner, 1937; Seenayya, 1972). It has been reported in this country in

Canyon Lake, Arizona (Cisneros, 1975) and in Lake Minnetonka, Minnesota, during the late summer months (Megard, 1972).

The chrysophycean phytoplankton reached its highest numbers in

March-July with June the month of maximum concentration during which numbers exceeded 3 x 103 organisms/ml. The chrysophycean algae achieved the greatest abundance during this period (Fig. 2). Important chrysophycean contributors were Kephyrion ovale, Dino-

bryon sertularia and D. divergens. In June, D. sertularia comprised 99.6% of the chrysophycean population and in July, D. divergens was the only chrysophycean observed. Chrysococcus biporus, which was a

significant contributor (subdominant-dominant) to the chrysophycean population at sites R-l and R-4 during April and July, never reached these proportions at site R-2. The occurrence of Chrysophyceae during the early summer months is common (Hutchinson, 1944; Pearsall, 1932;Pennak, 1949).



February, 1 979 SEASONAL SUCCESSION OF PH YTOPLANKTON IN ROOSEVELT LAKE 9

Table 1. Phytoplankton species of Roosevelt Lake, Arizona.

Month of

Species Maximum Occurrence Abundance*

CHLOROPHYCEAE Ankistrodesmus convolutus Corda Sept S A. falcatus var. mirabilis (West & West) G.S. West Aug S Carteria klebsii (Dang.) Dill Aug D C. sphaerica Huber-Pestal. Aug S Chlamydomonas angulosa Dill Aug D C. globosa Snow July F C. minimum Playf . Aug S Closteriospsis longissima Lemm. June S Coelastrum sphaericum Naeg. July F

Crucigenia apiculata (Lemm.) Schmidle Oct S C. tetrapedia (Kirch.) West & West Mar S Dactylothece confluens (Kiitz.) Lagerh. Feb, July S Dysmorphococcus variabilis Takeda Apr S Elakothrix americana Wille Aug S Franceia ovalis (France) Lemm. Apr S Gyromitus sp. Apr F Kirchneriella obesa (W. West) Schmidle July S K. obesa var. major (Bernard) G.M. Smith June, Sept D K. subsolitoria G.S. West Aug S Lagerheimia ciliata (Lag.) Chodat. July F L. quadrisetae Lemm. Mar, Apr R L. sub salsa Lemm. Apr, Sept F

Mesostigma grande (Karsch.) Apr S Micractinium pusillum Fres. July F Pandorina sp. Sept F Padiastrum duplex Meyen - R P. duplex var. clathratum (A. Braun) Lagerh. Sept R P. simplex (Meyen) Lemm. Apr R P. tetras var. tetraedon (Corda.) Rabenh: - R Phacotus lenticularis (Ehr.) Lemm. July, Aug. S Oocystis parva West & West Aug, Sept S Pteromonas angulosa (Carter) Lemm. Mar, Apr R P. cordiformis Lemm. em. Fott Feb R Pteromonas sp. June S Scenedesmus abundans (Kirch.) Chodat. Sept S S. abundans var. asymetrica (Schroed.) G. M. Smith Apr, Nov R S. acuminatus (Lag.) Chodat. June, July R S. armatus (Chod.) G.M. Smith June F S. dimorphus (Turp.) Kiitz. June, July R S. longus Meyen Jan F S. quadricauda var. longispina (Chod.) G.M. Smith July F S. quadricauda var. parvus G.M. Smith Apr. July F S. serratus (Corda) Bahlin Sept, Oct F Scendesmus sp. June S Shroederia setigera (Schroed.) Lemm. Sept F Selenastrum minutum (Naeg.) Collins Sept D Treubaria setigerum (Archer) G.M. Smith June, Aug F Tetraedron minimum (A. Braun) Hansg. June, Aug S T. trigonum (Naeg.) Hansg. Sept F Tetrastrum staurogeniaformae (Schroed.) Lemm. June F

BACILLARIOPHYCEAE

Amphipleura pellucida Kiitz. - R

Amphora delicatissima Rreasske Feb R Chaetoceros sp. - R Cocconeis placentula var. lineata (Ehr.) V.H. June R

Cyclotella spp. • * Feb, Nov D

Cymbella mexicanum Ehr. July, Aug R

Diploneis smithii (Breb.) C. - R

Fragillaria construens var. venter (Ehr.) Grun. Sept R F. vaucheriae (Kiitz.) Peters July R



10 JOURNAL OF THE ARIZONA-NEVADA ACADEMY OF SCIENCE Vol. 14

Gyrosigma spencerii (Quek.) Griff and Henfr. Mar, Oct R Hantzschia amphioxys (Ehr.) Muell. Jan R Melosira fennoscandia H. Cl. Sept S M. granulata (Ehr.) Ralfs June R Navicula cryptocephala Kiitz. - R N. mutica Kiitz. July R Navicula sp. Feb R N. pelliculosa (Breb.) Hilse - R N. pupula Kiitz. June, Nov R Nitzschia acicularis (Kiitz.) Wm. Smith Aug S Nitzschia sp. Feb R N. closterium (Ehr.) Wm. Smith Oct, Nov R N. dissipata (Kiitz.) Grun. _ R N.fonticola Grun. Oct, Dec S N. palea (Kutz.) Wm. Smith - R N. subtilis (Kutz.) Grun. - R N. tryblionella var. debilis (Arnott) A. Mayer Feb, Mar R Rhizosolenia eriensis H.L. Smith July, Sept R Stauroneis sp. - R Stephanodiscus sp. Jan S Surirella angusta Kiitz. Feb R Synedra acus Kiitz. Apr R S. rumpens var. fragilarioides Grun. Feb, June R S. u/na (Nitz.) Ehr. June, Aug, Sept D

CYANOPHYCEAE Anabaena sp. July S Anabaenopsis raciborskii Wol. July S Chroococcus limneticus Lemm. Aug S Gloeocapsa sp. Sept D Lyngbya limnetica Lemm. Aug D Merismopedia tenuissma Lemm. July, Sept D Spirulina laxissma G.S. West July, Sept D S. okensis (C.Meyer) Geitl. July S

EUGLENOPHYCEAE Euglena proxima Dang. - R Phacus acuminatus Stokes - R P. longicauda (Ehr.) Dujard. July F P. megalopsis Pochm. - R Strombomonas sp. Jan R Trachelomonas crebea (Kell.) Defl. Apr S T. intermedia Dang. Apr S Trachelomonas sp. Mar, Apr R

CHRYSOPHYCEAE Chrysococcus biporus Skuja Apr R Dinobryon divergent Imhof . July S D. sertularia Ehr. June D Hymenomonas roseola Stein Mar F Kephyrion ovale Pasch. Mar S Mallomonas allorgei (Defl.) Conrad Apr F M. producta (Zach.) Iwanoff - R

DINOPHYCEAE Glenodinium sp. Mar, Apr F Peridinium sp. Aug F

*R - rare occurrence, ^ 15 organisms/ml F - frequent occurrence, 16-99 organisms/ml S - subdominant, 100-999 organisms/ml D - dominant, 1000 organisms/ml

**Consists of C. meneghiniana Kiitz., C. atomus Hust., and C. striata (Kutz.) Grun. These species were grouped because of the difficulty in

distinguishing them during enumeration process.



February, 1 979 SEASONAL SUCCESSION OF PH YTOPLANKTON IN ROOSEVELT LAKE 1 1

Figure 2. Monthly percent composition of the phytoplankton of Roosevelt Lake from January, 1971, through February, 1 972. Bac = Bacillariophyceae; Chi = Chlorophyceae; Chry = Chrysophyceae; Cyan = Cyanophyceae; Eug = Euglenophv ceae.



1 2 JOURNAL OF THE ARIZONA-NEVADA ACADEMY OF SCIENCE Vol. 1 4

Although the Euglenophyceae were represented throughout most of the months their concentrations were too small to be expressed in

Figure 2. A rise in the euglenophycean population was observed in

April when two species were present. These were Trachelomonas crebea and T. intermedia. Elsewhere in the lake the euglenophycean population was observed in more significant concentrations with one species, Euglena proxima, being fairly common during April and July.

Two members of the Dinophyceae were represented in the phytoplankton. Although numbers were not appreciable, there was an increase in numbers during early spring (March - April) and summer (August). Glenodinium sp. contributed to the spring increase and Peridinium sp. was responsible for the summer increase. The other Roosevelt Lake sites were considerably more productive in the dinoflagellate population. Although reports of freshwater dinoflagellate blooms are relatively rare, the same Glenodinium sp. has been observed to produce a mild "red tide" in Canyon Lake, Arizona. During our study period on Roosevelt Lake, such a bloom was not observed.

Although most of the phytoplankton species encountered in Roose- velt Lake are rather common, they have been described from diverse geographical areas including temperate and subtropical regions (Huber-Pestolozzi, 1941, 1955, 1961, 1968; Lind, 1968; Meyer, 1971; Prescott, 1967; Reynolds, 1973; Ruttner, 1937; Seenayya, 1971, 1972; Smith, 1950). The presence in Roosevelt Lake of significant populations of species common to the tropics makes this phytoplankton community rather unique in North America.

SUMMARY. - One hundred and nine species of algae occurred

annually in the plankton of Roosevelt Lake, with the majority of the species chlorophycean and bacillariophycean forms. Community size of the total phytoplankton assemblage was relatively constant throughout the year, although a noticeable succession of algal classes and species occurred. Diatoms dominated the winter flora, whereas

blue-green algae were the summer dominants. Chlorophycean and

chrysophycean algae were dominants briefly during the fall and

spring periods. The algal flora was primarily temperate in nature with some tropical tendencies.

LITERATURE CITED

CISNEROS, R. M. 1975. Temporal and Spatial Distribution of Phy- toplankton and Chlorophyll a in Canyon Lake. M.S. Thesis. Arizona State Univ., Tempe.

COLE, G. A. 1966. The American Southwest and Middle America, p. 393-434. In D.C. Frey (ed.) Limnology in North America. Univ. Wisconsin Press, Madison.

FOGG, G. E. 1965. Algal Cultures and Phytoplankton Ecology. Univ. Wisconsin Press, Madison.

HUBER-PESTOLOZZI, G.I 941. Das Phytoplankton des Susswassers, Band XVI. Tiel 2. 1 . Halfte. Chrysophyceen. Stuttgart.

. 1955. Das Phytoplankton des Susswassers. Band CVI. Tiel 4. Euglenophyceen. Stuttgart.

. 1961. Das Phytoplankton des Susswassers. Band XVI. Tiel 5. Chlorophyceae. Stuttgart.

1968. Das Phytoplankton des Susswassers. Band XVI. Tiel 3. Auglage 2. Cryptophyceae, Chloromonadophyceae, Dino-

phyceae. Stuttgart. HUTCHINSON, G. E. 1944. Limnological studies in Connecticut.

VII. A critical examination of the supposed relationship between

phytoplankton periodicity and chemical changes in lake waters.

Ecology 25:3-26. . 1967. A Treatise on Limnology. Vol. I. John Wiley

and Sons, Inc., New York. KESSLER, S. J. and E. A. STULL. 1978. Regional similarities of

Arizona lakes. J. Ariz.-Nev. Acad. Sci., Proc. Suppl. 13:22.

KUTKUHN, J. H. 1958. Notes on the precision and volumetric

plankton estimates from small-sample concentrates. Limnol. Oceanogr. 3:69-83.

LIND, E. M. 1968. Notes on the distribution of phytoplankton in some Kenya waters. Br. Phycol. Bull. 3:481-493.

MEGARD, R. O. 1972. Phytoplankton, photosynthesis, and phos- phorus in Lake Minnetonka, Minnesota. Limnol. Oceanogr. 17: 68-87.

MEYER, R. L. 1971. A study of phytoplankton dynamics in Lake

Fayetteville as a means of assessing water quality. Arkansas Water Resources Res. Ctr. Public. No. 10, Univ. of Arkansas, Fayetteville.

MOSS, B. 1972. Studies in Gull Lake, Michigan I. Seasonal and

depth distribution of phytoplankton. Freshwater Biol. 2:289-307. OLSEN, R. D. and M. R. SOMMERFELD. 1970. A preliminary

study of planktonic diatoms of central Arizona. J. Ariz. Acad. Sci. 6:135-138.

. 1976. Thermal ecology of phytoplankton in a desert reservoir p. 195-201. In G. W. Esch and R.W. McFarlane (eds.) Ther- mal Ecology II, Proceedings of a Symposium. Nat. Tech. Inf. Serv., Springfield, Va.

PEARSALL, W. H. 1932. Phytoplankton in the English lakes II. The

composition of the phytoplankton in relation to dissolved sub- stances. J. Ecol. 20:241-262.

PENNAK, R. W. 1949. Annual limnological cycles in some Colorado reservoir lakes. Ecol. Monogr. 19:233-367.

PRESCOTT, G. W. 1967. Algae of the Western Great Lakes. Wm. C. Brown Co., Inc., Dubuque, Iowa.

PROWSE, G. A. and J. F. TALLING. 1958. The seasonal growth and succession of plankton algae in the White Nile. Limnol.

Oceanogr. 3:222-238. REYNOLDS, C. S. 1973. The phytoplankton of Crose Mere, Schrop-

shire. Br. Phycol. J. 8:153-162. RICHARDSON, J. L. 1968. Diatoms and lake typology in east and

central Africa. Inter. Revue ges. Hydrobiol. 54:175-176. ROSS, R. 1955. Algae of east African Great Lakes. Verh. Int. Ver.

Limnol. 12:320-326. RUTTNER, F. 1937. Limnologischen studien an einigen Seen der

Ostalpen. Arch. Hydrobiol. 32:167-319. SEENAYYA, G. 1971. Ecological studies in the plankton of certain

freshwater ponds of Hyderabad-India II. Phytoplankton- 1. Hydro- biologia 38:55-82.

. 1972. Ecological studies in the plankton of certain freshwater ponds of Hyderabad-India II. Phytoplankton-2. Hydro- biologia 39:247-271.

SMITH, G. M. 1950. Freshwater Algae of the United States. 2nd Ed. McGraw-Hill Book Co., New York.

SOMMERFELD, M. R., R. M. CISNEROS and R. D. OLSEN. 1975. The phytoplankton of Canyon Lake, Arizona. Southwest. Nat. 20:45-53.

STAKER, R. D., R. W. HOSHAW and L. G. EVERETT. 1974.

Phytoplankton distribution and water quality indices for Lake Mead (Colorado River). J. Phycol. 10:323-33 1 .

STEWARD, A. J. and D. W. BLINN. 1974. Phytoplankton population dynamics in Warm Creek Bay, Lake Powell. J. Phycol. (Proc. Suppl.) 10:11.

STULL, E.A. and S.J. KESSLER. 1978. Major chemical constituents of Arizona lakes. J. Ariz.-Nev. Acad. Sci. 13:57-6 1 .



seasonal succession of phytoplankton in roosevelt lake, arizona

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