Taxonomic composition of zoopsammon in fresh and brackish waters of Estonia, a Baltic province ecoregion of Europe

Abstract

Zoopsammon communities, i.e. fauna dwelling in the interstitial sandy habitat at the water's edge, are largely understudied. The aim of the present study was to provide an overview of the taxonomic structure of zoopsammon in Estonian waters. The study is based on samples collected from four lakes across Estonia and from three sandy beaches on the Estonian coast of the Gulf of Finland, Baltic Sea, in 2008-2014. Animals from 12 phyla were found, of which the majority of rotifers and testate amoebae were identified to species level. A total of 156 taxa were determined, including 84 rotifer species and 39 testate amoebae species. In addition to the 46 new taxa for the Estonian fauna already registered in our previous works, the present study reports further 11 new rotifer, 19 testate amoebae, and 6 nematode taxa. The psammic communities in lake beaches had higher species richness than in coastal beaches, and the communities were more similar in coastal beaches than in lake beaches. The mesotrophic Lake Saadjärv had the highest taxon richness with 80 taxa from 10 phyla. Similarly, the number of testate amoebae species was higher in lake beaches than in coastal beaches. The number of taxa, especially the number of rotifer species, was lower in sampling sites with an elevated trophic state and/or human population density. The number of testate amoebae species was the highest in the hypertrophic Lake Verevi. As compared to testate amoebae, rotifer communities had a higher taxonomic richness at landscape scale characterized by variable communities both in time and space.

Species diversity of rotifers (rotifera: monogononta) in freshwater psammon with three new records to Vietnam

“…Bielańska-Grajner reported a higher number of psammonic rotifer species and a higher Shannon index value in lakes with lower trophic levels [2]. This was supported by findings of Lokko in her study on Estonian lakes, which found that the zoopsammic community in mesotrophic lake Saadjärv was more diverse than that in eutrophic lake Võrtsjärv [28]. Our results showed a different pattern as higher numbers of rotifer species were recorded in sampling sites that were typically richer in total nitrogen and phosphorus concentrations (S3, S4, S6, S7).…”

“…Furthermore, Lecane rotifers have some advantages over other microfaunal groups to dominate the interstitial habitat. With their malleate trophi, Lecanids are classified as microphagous sedimentation that feeds on minute particles or microorganisms [28]. Besides, the typical hard shell potentially allows Lecanids to tolerate collision and friction with sand grains better.…”

Erugomicula, a new genus of Arcellinida (testate lobose amoebae)

“…Erugomicula bidens has been observed in lakes across Canada, including eastern Canada (Medioli and Scott, 1983;McCarthy et al, 2012;Patterson et al, 2012;Macumber et al, 2014), western Canada (Torigai et al, 2000;Neville et al, 2010), and the Northwest Territories (Nasser et al, 2016(Nasser et al, , 2020. It has also been found in Europe in Bulgaria (Serafimov et al, 1995;Golemansky et al, 2003), Estonia (Lokko et al, 2014), Finland (Kauppila et al, 2006;Kihlman and Kauppila, 2012), France (Thomas, 1954), Lithuania (Šatkauskienė, 2014), Portugal (Camacho et al, 2015), and of course Switzerland (Penard, 1902;Golemansky et al, 2003), where the species was first described. Based on the similarly compressed test we also tentatively place Difflugia biconcava Ertl, 1965 and the possible junior synonym of that species Difflugia balcanica Zivovich, 1983 in Erugomicula.…”

Lacustrine Arcellinida (Testate Lobose Amoebae) as Bioindicators of Arsenic Contamination: A new tool for Environmental Risk Assessment

“…Following these key studies, Arcellinida research output saw a significant increase in the number of studies investigating the distribution, diversity, and ecology of Arcellinida in lakes from North America (e.g., Escobar et al, 2008;Segala et al, 2017), Europe (e.g., Lokko et al, 2014;Sakauskiene et al, 2014;Varol et al, 2015), Asia (Chung andChoi, 1989, 1995;Yang et al, 2005Yang et al, , 2009Ju et al, 2014;Yu and Tahirova, 2018), and South America (e.g., Escobar et al, 2005;Alves et al, 2010;Cauffau et al, 2015) -to date, there have been no Arcellinida studies from African lakes (Schwind et al, 2013). This line of research further evolved to include studies aiming to assess the use of Arcellinida as bioindicators of land-use impact.…”