Meiofauna and nematode dispersal selectivity in the Whittard Canyon, NE Atlantic

Benthic marine nematodes are often resuspended in the water column by strong currents and turbidity events, after which they may resettle as particles. To achieve dispersal, such dislodgement is important for organisms like nematodes, which have no pelagic life stage. The Whittard Canyon along the Irish continental margin is a physically heavily disturbed environment that receives high amounts of sediments and organic material coming from the shelf or surface waters. Biological sampling in the upper reaches of this canyon has shown that meiofauna communities are highly diverse and characterised by the occurrence of chemosynthetic nematodes feeding on sulphidic compounds through endosymbiotic micro-organisms. To test whether meiofauna are able to actively choose the substrate where they settle after resuspension events, an ex situ experiment was performed whereby three different substrates were offered to a resuspended community (bacteria, green micro-algae, sulphide-enriched substrate). The main aim of this study is to assess the ability of canyon meiofauna, particularly nematodes, to disperse actively towards different food sources, a strategy that would enhance the survival of these organisms in this highly dynamic environment. Results are discussed on the level of higher meiofauna taxa, but also nematode genus level to distinguish between genus selective responses.Benthic marine nematodes are often resuspended in the water column by strong currents and turbidity events, after which they may resettle as particles. To achieve dispersal, such dislodgement is important for organisms like nematodes, which have no pelagic life stage. The Whittard Canyon along the Irish continental margin is a physically heavily disturbed environment that receives high amounts of sediments and organic material coming from the shelf or surface waters. Biological sampling in the upper reaches of this canyon has shown that meiofauna communities are highly diverse and characterised by the occurrence of chemosynthetic nematodes feeding on sulphidic compounds through endosymbiotic micro-organisms. To test whether meiofauna are able to actively choose the substrate where they settle after resuspension events, an ex situ experiment was performed whereby three different substrates were offered to a resuspended community (bacteria, green micro-algae, sulphide-enriched substrate). The main aim of this study is to assess the ability of canyon meiofauna, particularly nematodes, to disperse actively towards different food sources, a strategy that would enhance the survival of these organisms in this highly dynamic environment. Results are discussed on the level of higher meiofauna taxa, but also nematode genus level to distinguish between genus selective responses.C