Van Gaever, S.; Moodley, L.; De Beer, D.; Vanreusel, A. (2006). Meiobenthos at the Arctic Håkon Mosby Mud Volcano, with a parental-caring nematode thriving in sulphide-rich sediments. Marine Ecology Progress Series. 321: 143-155.
Van Gaever, S.; Moodley, L.; De Beer, D.; Vanreusel, A.
2006
Meiobenthos at the Arctic Håkon Mosby Mud Volcano, with a parental-caring nematode thriving in sulphide-rich sediments
Marine Ecology Progress Series
321: 143-155
Publication
NeMys doc_id: 18010
Available for editors
Håkon Mosby Mud Volcano (HMMV, SW Barents Sea slope, 1280 m) is one of the
numerous cold methane-venting seeps existing along the continental margins. Analyses of videoguided
core samples revealed extreme differences in the diversity and density of the metazoan
meiobenthic communities associated with the different sub-habitats (centre, microbial mats,
Pogonophora field, outer rim) of this mud volcano. Diversity was lowest in the sulphidic, microbial
mat sediments that supported the highest standing stock, with unusually high densities (11 000 ind.
10 cm–2) of 1 nematode species related to Geomonhystera disjuncta. Stable carbon isotope analyses
revealed that this nematode species was thriving on chemosynthetically derived food sources in these
sediments. Ovoviviparous reproduction has been identified as an important adaptation of parents
securing the survival and development of their brood in this toxic environment. The proliferation of
this single species in exclusive association with free-living, sulphide-oxidising bacteria (Beggiatoa)
indicates that its dominance is strongly related to trophic specialisation, evidently uncommon among
the meiofauna. This chemoautotrophic association was replaced by copepods in the bare, sulphidefree
sediments of the volcano’s centre, dominated by aerobic methane oxidation as the chemosynthetic
process. Copepods and nauplii reached maximum densities and dominance in the volcano’s
centre (500 ind. 10 cm–2). Their strongly depleted carbon isotope signatures indicated a trophic link
with methane-derived carbon. This proliferation of only selected meiobenthic species supported by
chemosynthetically derived carbon suggests that, in addition to the sediment geochemistry, the associated
reduced meiobenthic diversity may equally be related to the trophic resource specificity in
HMMV sub-habitats.
