Inter-Research > AME > v18 > n2 > p157-164  
Aquatic Microbial Ecology

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AME 18:157-164 (1999)  -  doi:10.3354/ame018157

Anoxic thermomineral cave waters and bacterial mats as habitat for freshwater nematodes

Wolfgang Riess1,*, Olav Giere2, Oliver Kohls1, Serban M. Sarbu3

1Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany
2Zoological Institute and Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
3Department of Biological Sciences, University of Cincinnati, 821-A Rieveschl Hall, Cincinnati, Ohio 45221-0006, USA

ABSTRACT: A unique chemoautotrophic system of floating microbial mats was examined in a subterranean cave in southern Romania. Oxygen measurements were made with a recently developed technique applying micro-optodes. The oxygen uptake rate of the anoxic and sulfidic cave waters over the atmosphere/water interface was as high as 103.3 ± 9.1 mmol O2 m-2 d-1. Floating microbial mats consisting primarily of sulfide oxidizers and fungal mycelia were found to be adapted to reduced oxygen supply and thrived even under strict anoxia. These 2 mm thick mats were inhabited by 5 different species of nematodes, reaching densities of 9.8 x 106 ind. m-2. Possible alternative pathways for growth of the mats and also for the persistence and reproduction of nematodes under strict anoxic conditions are discussed.

KEY WORDS: Microbial mat · Chemoautotrophic · Cave · Nematodes · Anoxia · Optode

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