The structure of psammic rotifer communities in two boreal lakes with different trophic conditions: Lake Võrtsjärv and Lake Saadjärv (Estonia)

Abstract

Psammon communities are still poorly studied worldwide. The aim of the present study was to establish the structure of psammic rotifer communities including their diversity and quantitative parameters. A total of 41 rotifer taxa were found in hydro-, hygro-, and euarenal zones of eutrophic Lake Võrtsjärv and mesotrophic Lake Saadjärv during the study carried out in Estonia in 2008, including 11 rotifer species new to Estonia. In L. Võrtsjärv, the predominant rotifer taxa were Bdelloidea and Lecane psammophila. L. psammophila dominated in July and August and bdelloids prevailed in the rest of the year. In L. Saadjärv, the most abundant taxa were Lepadella ovalis, Keratella hiemalis, and Cephalodella megalocephala. The psammic rotifer community of L. Saadjärv proved to be more diverse than that of L. Võrtsjärv. Microphagous rotifers were dominant in L. Võrtsjärv. Raptorial feeders dominated in L. Saadjärv in summer and autumn and were more abundant at sites with coarser sand and low plant density.

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“…Rotifers were identified according to Emir, (1994), Koste, (1978), Ruttner-Kolisko, (1974), Segers, (1995), Nogrady & Paurriot, (1995), De Smet, (1996), De Smet & Pourriot, (1997), De Smet (1998). Zooplankton taxa were divided into different functional groups into feeding guilds (Barnett, Finlay, & Beisner, 2007, Obertegger & Manca, 2011Bertani, Ferrari, & Rosetti, 2012;Lokko & Virro, 2014. The Guild Ratio was calculated as GR=(biomass raptorial-biomass microphagous)/(total rotifer biomass), and values range from -1 to +1.…”

Diversity, Composition and Environmental Relations of Periphytic Rotifer Assemblages in Lentic Freshwater Bodies (Flanders, Lower Belgium)

“…Yet, the assemblage composition of periphyton-inhabiting rotifers in surface waters remains underexplored and it is unclear whether changes in periphytic communities due to eutrophication mirror those occurring in the plankton, for instance in the prevalence of feeding guilds, or differ widely. Although some studies suggest that feeding guilds also reflect food availability in psammon communities [30,31], this is less straightforward for periphyton growths where predator-prey interactions may be alleviated by the relative shelter provided by plant architecture and microstructures. Additionally, food abundance and quality may be less constraining in more organically rich biofilms, allowing development of communities that are less dominance-oriented.…”