Productivity of Epipelic Algae in Tundra Ponds and a Lake near Barrow, Alaska

Stanley, Donald

The biomass and productivity (14C) of epipelic benthic algae were measured in several tundra ponds and in a lake near Point Barrow, Alaska. In the ponds (50 m diam x 20 cm deep) the epipelic algae (mostly Chlorophyta and Cyanophyta) are most abundant in that upper 2 cm of sediment but their total biomass is low (0.5-1.5 g C╖m-▓) and no surface mat of cells forms, largely because of the continuous mixing of the flocculent surface sediments by a variety of benthic invertebrates. Epipelic photosynthesis is limited to a 3-mo thaw period (June through August) and has a single broad peak in mid-July of _ 200 mg C.m-2╖day-1. Epipelic production ranged from 10-4 C.m-2.yr-1 (1971-1973), compared to l g C.m-2╖yr-1 for the pond phytoplankton. In contrast, epipelic production in nearby Ikroavik Lake (12 km2 X 2 m deep) was only 2.3 g C.m-2╖yr-1 because of lower light intensities at the sediment surface, lower water temperatures, a shorter ice-free period than in the ponds.

Productivity of Epipelic Algae in Tundra Ponds and a Lake near Barrow, Alaska

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