Gut content analysis of Gammarus lacustris from a Siberian lake using biochemical and biophysical methods

We studied the gut contents of Gammarus lacustris from the littoral of Shira lake, a Siberian salt lake, by microscopic analysis in conjunction with measuring of fluorescence of chlorophyll and composition of fatty acids. Gammarus ingested primarily fresh seston, probably settled on the bottom. Additionally, the amphipods obtained essential polyunsaturated fatty acids of omega 3 family by selectively consuming bottom sediment particles. A considerable part of the ingested seston comprised cells of Botryococcus sp., which passed the intestinal tract in living form and their photosynthetic activity increased. This viable gut passage was likely one of the causes of bloom of Botryococcus in the littoral. Unlike a number of literature data, there was no selective digestion of any fatty acid species, including polyunsaturated acids, in the intestinal tract.