Factors Controlling Phytoplankton Production in Lake Vanda (77°S)

Abstract

At least three floristically distinct communities of algae were distributed down the permanently ice-capped water column of Lake Vanda. Phytoplankton at each depth were highly specialized towards specific conditions of light and temperature. Maximum photosynthesis and algal biomass was at the bottom of the euphotic zone (55–57.5 m) immediately above a region of nutrient-rich anoxic water. This Phormidium-dominated community was adapted towards warm temperatures (18–20 °C) but a dim light regime. Dissolved inorganic N to P ratios in this region were extreme (> 5000:1) and the plankton demonstrated strong cellular P deficiency. A much smaller photosynthetic maximum was recorded in the middle of a large thermohaline convection cell at 25–30 m where P deficiency was less severe, but detectable. A microflagellate community immediately under the ice demonstrated the least response to phosphorus enrichment, but photosynthetic characteristics appeared to be more attuned to the low irradiances which prevail early in the growing season rather than to the relatively bright light regime during midsummer sampling. Algal biomass levels at most depths declined over 4 wk of sampling, further indicating that population maxima are timed early in the season. The low input of phosphorus relative to nitrogen exerts an overall control on phytoplankton biomass in Lake Vanda, but low production rates per unit biomass characterize the shade-adapted populations at all depths.Key words: phytoplankton, photosynthesis, algal biomass, N to P ratios, ice cap

Autotrophic Picoplankton: Community Composition, Abundance and Distribution across a Gradient of Oligotrophic British Columbia and Yukon Territory Lakes

“…At this time Jojo Lake was isothermal (4.0 "C), suggesting that winter ice had only recently left the lake. From these data we conclude that a large picoplankton population built up under ice, confirming what others have noted in permanently ice-covered Antarctic lakes (Vincent and Vincent 1982), and in Arctic and Antarctic marine waters (SMITH el a [. 1985;PROBYN and PAINTING 1985).…”

Ace Lake: three decades of research on a meromictic, Antarctic lake

“…For example, over annual cycles in Highway Lake and Pendant Lake rates ranged from 0 to 437 and 26.5 to 149 lg C L -1 day -1 , respectively , 2007. These levels of production are higher than rates reported for saline lakes in the McMurdo Dry Valleys, for example, in Lake Fryxell where rates varied between undetectable to 73 lg C L -1 day -1 (Vincent 1981;Priscu et al 1987), Lake Bonney where the maximum rate was 10 lg C L -1 day -1 (Priscu 1995) and Lake Vanda where the range was 0.1-1.6 lg C L -1 day -1 (Vincent and Vincent 1982). Thus, Ace Lake and other saline lakes in the Vestfold Hills are more productive than their more southerly counterparts in the Dry Valleys.…”

“…and Synechococcus sp. are also major components of the plankton in the meromictic lakes of the McMurdo Dry Valleys (Vincent and Vincent 1982;Spaulding et al 1994;Roberts et al 2000;Bielewicz et al 2011). Cryptophytes and P. gelidicola are mixotrophic in Ace Lake, other Vestfold Hills saline lakes and in Lakes Fryxell, Hoare and Bonney in the Dry Valleys, ingesting bacteria and/or taking up dissolved organic carbon (Marshall and Laybourn-Parry 2002;Laybourn-Parry et al 2005;Thurman et al 2012).…”

Phytoplankton dynamics in the stratified water column of Lake Bonney, Antarctica

“…Goldman et al 1967;Vincent 1981;Vincent and Vincent 1982;Priscu 1989;Priscu et al 1989;Priscu 1992a, 1994). However, there have been few time series studies on the seasonal development of these phytoplankton populations.…”