Cryptophyta Flagellates of Meromictic Lakes Shira and Shunet (Khakassia, Russia): Mechanisms of Vertical Distribution and Trophic Role

1 Introduction Many of the stratified lakes are characterized by the presence of large populations of cryptomonads in their chemocline zones(Reynolds,1992;Gervais et al,2003;Pedro’s-Alio’et al.,1995).These populations are adapted to low light intensity and high sulfide concentration;they have a mixotrophic ability and form the so-called'deep chlorophyll maxima'(Gervais,1998;Marsha'and Laybourn-Parry,2002).A similar Cryptomonas sp.