Original paper
Limnology of a caldera lake influenced by hydrothermal processes
Cameron, William A.; Larson, Gary L.
Archiv für Hydrobiologie Volume 128 Number 1 (1993), p. 13 - 38
10 references
published: Aug 31, 1993
published online: Jun 2, 2021
DOI: 10.1127/archiv-hydrobiol/128/1993/13
ArtNo. ESP141012801001, Price: 29.00 €
Abstract
Surprise Lake is located in the hydrothermally active Aniakchak caldera on the Alaska Peninsula. The lake is at an elevation of 322 m with a surface area of 275 ha and a maximum depth of 19.8 m. Many of the inlet streams and springs are influenced by hydrothermal fluids. In the vicinity of inlet streams and springs influenced by hydrothermal fluids, the near lake surface increased in temperature, conductivity, trace elements, and periphyton biomass, and decreased in pH and dissolved oxygen. For the whole lake, water quality and trace element concentrations were influenced to a lesser degree by the hydrothermal inputs. Bright orange precipitates deposited in the lake at the mouths of hydrothermal springs during winter were periodically suspended by easterly winds greater than 25 km/hr between ice-out and late July, changing the lake color to olive green. The precipitates settled slowly during calm periods. The supply of precipitates for suspension diminished by the end of July. By mid-August, Secchi disk clarity increased to a summer maximum, and the color of the lake turned blue-green. The phytoplankton community included 22 taxa dominated numerically by cyanobacteria. Chlorophyll was low in concentration. The maximum concentration of chlorophyll was associated with a decrease of Secchi disk clarity in late August. The zooplankton community included three crustacean species and nine rotifer species. Polyarthra and Bosmina were the most abundant zooplankters, reaching their peak densities in mid-summer when Secchi disk clarity and chlorophyll concentrations were increasing. All other zooplankton taxa were at their highest densities in either early or late summer. The bottom fauna was dominated by oligochaetes near the mouths of the hydrothermally influenced streams and springs, while Stictochironomus and oligochaetes dominated littoral areas near cold springs. A mid-depth group was dominated by Sphaeriids and oligochaetes. Sphaeriids and chironomid pupae dominated the deep lake.
Keywords
Limnology • hydrothermal • phytoplankton • cyanobacteria