Diversity of meiofauna at deep-sea hydrothermal vents and cold seeps with particular reference to nematodes

Deep-sea hydrothermal vents and cold seeps are remarkable for their spectacular megaand<br/>macrofauna, many of which appear to have a high level of endemism to these chemosynthetic<br/>environments. It is not clear whether the patterns of biodiversity, faunal zonation<br/>and biogeography documented in these size categories, are also present in the meiofauna.<br/>This thesis examines the diversity and density patterns of the meiofauna (with particular<br/>reference to nematodes) in quantitative samples collected from: Bathymodiolus mussel beds<br/>in a deep-sea hydrothermal vent field on the East Pacific Rise; Bathymodiolus mussel beds<br/>at an Atlantic methane seep site; an Atlantic hydrothermal vent sediment mound and a<br/>reference non-chemosynthetic sediment site on the Mid-Atlantic Ridge. Results suggested<br/>that deep-water chemosynthetic substrata will generally harbour assemblages exhibiting<br/>lower diversity and elevated dominance. The densities of meiobenthos appeared to vary<br/>in accordance with the presence of macrofauna. From the study of the meiobenthos of<br/>hydrothermal vent mussel beds spanning 27 degrees of latitude on the EPR, the nematodes<br/>share the same, if not a larger biogeographical province as the macrofauna. From<br/>comparison of data collected from the vent mussel beds and the Atlantic methane seep<br/>mussel bed, it was evident that the species composition of the nematode assemblage was<br/>completely different. Density levels and major taxa composition were very similar as a<br/>result of similar local factors acting within the mussel beds. Based on a comparison of<br/>data collected from all mussel bed samples and the hydrothermal sediment core, it was<br/>evident that the nematode assemblages were significantly different. Factors determining<br/>all the observed differences are discussed.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2007

Author dc:creator

• Flint, Hannah Christina