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The Fauna of Floating Cyanobacterial Mats in the Oligohaline Eulittoral Zone off Hiddensee (South‐west Coast of the Baltic Sea)
Author(s) -
Vopel K.,
Arlt G.
Publication year - 1995
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/j.1439-0485.1995.tb00407.x
Subject(s) - meiobenthos , microfauna , fauna , benthic zone , biology , ecology , microbial mat , biotope , brackish water , sediment , abundance (ecology) , cyanobacteria , paleontology , habitat , salinity , bacteria
. The fauna — including macrofauna, meiofauna, and large ciliates — of floating cyanobacterial mats in a brackish shallow‐water area was studied by analysing six 20 cm 2 pieces of mat. Although these microbial aggregations were scarcely 1 cm thick, their total meiofauna abundance was about five times as high as in the uppermost 4 cm of the adjacent sediment. The mat fauna was dominated by harpacticoids, although large ciliates, rotifers, nematodes, and oligochaetes were also markedly more abundant than in the sediment. All species occurring in the mats were members of the surrounding sediment fauna. Out of the 47 species found, only a few, among them predominantly the harpacticoid, Mesochra lilljeborgi B oeck , 1864, and the nematode Daptonema setosum ( bütschli , 1874), accounted for the majority of the individual abundance in the mats. Both are regularly found in sulphidic biotopes near Hiddensee. As SEM micrographs revealed, the oligochaete Paranais litoralis (O. F. M üller , 1788) and the harpacticoid Cletocamptus confluens (Schmeil, 1894) were apparently optimal substrates for dense lawns of cyanobacteria. This indicates possible close interactions between the meiofauna and these microbiota. The frequent predation of histophagous ciliates on nematodes and harpacticoids, which were probably weakened by oxygen deficiency and/or high sulphide concentrations, were not only a sign of a generally neglected pathway in the food chain, but also impressively emphasized the huge variety of interactions taking place between meio‐ and microfauna within this specific benthic microcosm. Because of their floating character, the mats can play an important role in the dispersal of benthic fauna.