REC-ERC-82-21 COMMON PLANKTON OF TWIN LAKES, COLORADO February 1983 Engineering and Research Center U. S. Department of the Interior Bureau of Reclamation 7-2090 ( 4-81) Water and Power TECHNICAL REPORT STANDARD TITLE PAGE 1. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENT'S CATALOG NO. REC-ERC-82-21 4. TITLE AND SUBTITLE 5. REPORT DATE February 1983 Common Plankton of Twin Lakes, Colorado 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S■ 8 , PERFORMING ORGANIZATION REPORT NO. Davine M. Lieberman REC-ERC-82-21 9. PERFORMING ORGANIZATION NAME AND ADDRESS 1 0. WORK UNIT NO. Engineering and Research Center 11. CONTRACT OR GRANT NO Bureau of Reclamation Denver, Colorado 80225 1 3. TYPE OF REPORT AND PERIOD COVERED 12. SPONSORING AGENCY NAME AND ADDRESS Engineering and Research Center Bureau of Reclamation Denver, Colorado 80225 1 4. SPONSORING AGENCY CODE DIBR 1 5. SUPPLEMENTARY NOTES Microfiche or hard copy available at the Engineering and Research Center, Denver, Colo. Ed:REC 1 6. ABSTRACT ABSTRACT - A series of studies is being performed to evaluate the effects of the Mt. Elbert Pumped-Storage Powerplant on the ecology of Twin Lakes. Twin Lakes are a pair of connected dimictic lakes, formed as the result of glacial action on alluvial deposits. This report presents a taxonomic species study of the common plankton collected since 1974 from Twin Lakes. A total of 11 zooplankters and 14 phytoplankters were identified from the limnetic zone of Twin Lakes and the associated Mt. Elbert Forebay. The four divisions of zooplankton included four species of Rotifera (rotifer), three species of Copepoda (copepod), three species of Cladocera (cladoceran), and one species of Mysidacea (opossum shrimp). The dominant zooplankters were the rotifers and copepods. The nocturnal opossum shrimp, Mysis relicta are abundant in Twin Lakes but were not collected in plankton samples. Cladocerans were rarely collected and made up less than 1 percent of the zooplankton population. The lower lake has a greater density of zooplankton than the upper lake. For example, in July 1981, average zooplankton densities in the lower lake reached a maximum of 116 individuals/L, as compared to 53 individuals/L in the upper lake. The four divisions of phytoplankton included three species of Chrysophyta (blue-green algae), three species of Chlorophyta (green algae), six species of Bacillariophyta (diatom), and two species of Cyanophyta (yellow-brown algae). The phytoplankton was dominated by the yellow-brown algae, Dinobryon, and by the diatoms, Aster/one//a and Synedra. During 1981, average density of phytoplankton reached a maximum of 4870 organisms/L during September in the upper lake; the average density in the lower lake peaked during March at 18,042 organisms/L. 1 7. KEY WORDS AND DOCUMENT ANALYSIS a. DESCRIPTORS-- /*phytoplankton/* zooplankton/* taxonomy/ limnology/ lakes/ shrimp/ cladocera/ copepods/ rotifers/ blue-green algae/ green algae/ diatoms/ yellow-brown algae/ algae/ power plants/ aquatic environment/ pumped storage/ fauna/ flora/ systematics b. IDENTIFIERS-- / Twin Lakes, Colo./ Mt. Elbert Pumped-Storage Powerplant, Colorado c. COSATI Field/Group 06H coviR R : 0606 SRIM 1 8. DISTRIBUTION STATEMENT 1 9. SECURITY C LASS 21. NO. OF PAGES (THIS REPORT) Available from the National Technical Information Service, Operations UNCLASSIFIED 17 Division, 5285 Rood, Springfield, Virginia 22/61. Port Royal 20. SECURITY CLASS 22. PRICE THIS PAGE/ UNCLASSIFIED REC-ERC-82-21 COMMON PLANKTON OF TWIN LAKES, COLORADO by Davine M. Lieberman February 1983 Applied Sciences Branch Div ision of Research Engineering and Research Center Denver, Colorado SI METRIC UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF RECLAMATION ACKNOWLEDGMENTS This study is a part of the Twin Lakes Ecological study (DR-331). Twin Lakes studies are being performed under the supervision of N.E. Otto, Environmental Sciences Section; and L.O. Timblin, Jr., Applied Sciences Branch. Contributions to both the field and laboratory portions of this study by the Aquatic Ecology Group are gratefully acknowledged. Special thanks to Richard Roline, biologist, for his assistance and hours spent in species identi- fication of plankton. The research covered by this report was funded by the Frying- pan-Arkansas Project DR331, Lower Missouri Region, Division of Research, Bureau of Reclamation. As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources. This includes fostering the wisest use of our land and water resources, protecting our fish and wildlife, preser- ving the environmental and cultural values of our national parks and historical places, and providing for the enjoyment of life through out- door recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also has a major respon- sibility for American Indian reservation communities and for people who live in Island Territories under U.S. Administration. The information contained in this report regarding commercial products or firms may not be used for advertising or promotional purposes and is not to be construed as an endorsement of any product or firm by the Bureau of Reclamation. CONTENTS Page Introduction ......... 1 Methods ......... 2 Results and discussion ......... 2 Zooplankton ............ 2 Zooplankton abundance ......... 3 Phytoplankton ............7 Phytoplankton abundance ......... 7 Summary ......................................................................................12 Glossary of terms ........13 Bibliography ........14 Appendix ........15 TABLES 1 Zooplankton collected from Twin Lakes 1974-82 ............3 2 Phytoplankton collected and identified at Twin Lakes ......... 7 3 Twin Lakes Phytoplankton ..........16 FIGURES 1 General location map of Twin Lakes, Colo. ......... 1 2 Twin Lakes and Mt. Elbert Forebay ............ 1 3a Structure of Daphnia ......... 4 3b Claw of D. pulex ......... 4 3c Claw of D. rosea ......... 4 4 Daphnia pulex. Teeth of pecten of postabdominal claw ......... 5 5 Structure of Bosmina ......... 5 6a Structure of Cyclops ......... 6 6b Leg 4 ............6 7 Cyclops bicuspidatus thomasi: Leg 5 ............ 6 8 Cyclops bicuspidatus thomasi. Caudal ramus ............6 9 Cyclops bicuspidatus thomasi Leg 4 ............7 10a Structure of Diaptomus ......... 8 10b Antepenultimate segment ......... 8 10c Leg 5 of D. judayi ......... 8 10d Leg 5 of D. connexus ......... 8 11 Diaptomus judayi Right antenna ......... 9 12 Diaptomus judayi Right Leg 5 ............9 13a Structure of Kellicottia ......... 9 13b Structure of Keratella ......... 9 14 Species composition of zooplankton population in Twin Lakes during 1981 ..........10 15 Species composition of phytoplankton population in Twin Lakes during 1981 ..........11 INTRODUCTION Mt. Elbert Pumped-Storage Powerplant located on the northwest shore of the lower lake has been operating sporadically since mid-1981. A newly Twin Lakes are a pair of connected dimictic lakes constructed dam on the shallow eastern end of located on Lake Creek, a tributary to the Arkansas the lower lake, which will raise the water level River, on the eastern slope of the Continental and allow mixing of the two lakes to increase, will Divide (figs. 1 and 2). The lakes are natural and begin to be used in 1984. Detailed information on formed as the result of glacial action on alluvial the limnology and ecology of Twin Lakes is in deposits (Buckles, 1973) [2].1 The lower lake is the LaBounty and Sartoris (1981) [8], LaBounty, et al. largest natural mountain lake in Colorado (Pennak, (1980) [9]; Sartoris, et al. (1977) [15]; and La- 1 966) [13]. Bounty and Sartoris (1980) [7]. In 1901, the Twin Lakes Reservoir Company built a dam on the Lake Creek outlet. The dam and the dredging of the connecting channel allowed for water level fluctuations of 7.8 m in the lower lake and about 5.8 m in the upper. The lakes' water surface elevation is 2802 m above mean sea level. The maximum depth in the lower lake is about 27 m, and about 28 m in the upper lake. The lakes are currently operated as a reservoir. The present studies of the ecology of Twin Lakes began in 1971. The overall purpose of these studies is to identify the effects of operating the pumped-storage powerplant on Twin Lakes. The Figure 1.—General location map of Twin Lakes, 1 Numbers in brackets refer to entries in the Bibliography. Colorado. Mt. Elbert Conduit (buried) u_ from Turquoise Reservoir Mt. Elbert Forebay Dam Forebay Inlet-Outlet Dike LEGEND Inlet-Outlet Structure — Preproject shoreline Penstocks (buried) New shoreline Mt. Elbert Pumped-Storage Powerplant Research sampling station Flow ICO 0 1000 Twin Lakes SCALE OF METERS Dam (new) Cie °44 4 March 13. 1982 Figure 2.—Twin Lakes and Mt. Elbert Forebay. Previous to this study, both phytoplankton and Identification was done at this step. The following zooplankton from Twin Lakes had been enu- references were used in the identification of Twin merated and identified to genus. In 1976, the first Lakes plankton: Palmer (1959) [11]; Needham and comprehensive species list of the phytoplankton Needham (1962) [10]; Ward and Whipple (1966) was prepared by Claire Norton, a botanist formerly [16]; Pennak (1978) [12]; Dumont and Green of Colorado State University, Fort Collins. Little (1980) [4]; and Dodson (1981) [3]. recent work on the identification of zooplankton to species