Nutrient Recycling by Fish and Zooplankton in Arctic Alaskan Lakes

Lakes in Arctic Alaska are typically ultra-oligotrophic, and as such quantifying sources of inorganic nutrients algal growth. Fish can impact internal nutrient cycles either directly, by translocating nutrients from benthic to pelagic habitats, or indirectly through predation control of nutrient recycling by lower trophic levels. We looked at the direct and indirect effects of the presence of fish communities on lake consumer nutrient recycling. Fish populations were low in all of our lakes, and direct nutrient translocation was also found to be minimal. Fish had a much larger impact on consumer nutrient recycling by lower trophic levels. Zooplankton communities in lakes with fish were dominated by smaller individuals, which recycle nutrients at a higher mass specific rate. Consequently, zooplankton recycling rates were much higher in lakes with resident fish populations, and supplied a greater proportion of nutrients required for primary productivity compared to lakes without fish