Vanreusel, A.; Fonseca, G.; Danovaro, R.; Da Silva, M. C.; Esteves, A. M.; Ferrero, T.; Gad, G.; Galtsova, V.; Gambi, C.; Da Fonsêca Genevois, V.; Ingels, J.; Ingole, B.; Lampadariou, N.; Merckx, B.; Miljutin, D.; Miljutina, M.; Muthumbi, A.; Netto, S.; Portnova, D.; Radziejewska, T.; Raes, M.; Tchesunov, A.; Vanaverbeke, J.; Van Gaever, S.; Venekey, V.; Bezerra, T. N.; Flint, H.; Copley, J.; Pape, E.; Zeppilli, D.; Martinez, P. A.; Galeron, J.
2010
The contribution of deep-sea macrohabitat heterogeneity to global nematode diversity
Marine Ecology
31(1): 6-20
Publication
NeMys doc_id: 17985
Available for editors
The great variety of geological and hydrological conditions in the deep sea generates
many different habitats. Some are only recently explored, although their
true extent and geographical coverage are still not fully established. Both continental
margins and mid-oceanic seafloors are much more complex ecologically,
geologically, chemically and hydrodynamically than originally thought. As a
result, fundamental patterns of species distribution first observed and explained
in the context of relatively monotonous slopes and abyssal plains must now be
re-evaluated in the light of this newly recognized habitat heterogeneity. Based
on a global database of nematode genus composition, collected as part of the
Census of Marine Life, we show that macrohabitat heterogeneity contributes
significantly to total deep-sea nematode diversity on a global scale. Different
deep-sea settings harbour specific nematode assemblages. Some of them, like
coral rubble zones or nodule areas, are very diverse habitats. Factors such as
increased substrate complexity in the case of nodules and corals seem to facilitate
the co-existence of a large number of genera with different modes of life,
ranging from sediment dwelling to epifaunal. Furthermore, strong biochemical
gradients in the case of vents or seeps are responsible for the success of particular
genera, which are not prominent in more typical soft sediments. Many nematode deep-sea genera are cosmopolitan, inhabiting a variety of deep-sea
habitats and oceans, whereas only 21% of all deep-sea genera recorded are
restricted to a single habitat. In addition to habitat heterogeneity, regional differences
are important in structuring nematode assemblages. For instance, seeps
from different regions yield different genera that thrive on the sulphidic sediments.
This study also shows that many areas and habitats remain highly
under-sampled, affecting our ability to understand fully the contribution of
habitat heterogeneity versus regional differences to global nematode diversity.
