Spatial distribution of nematode assemblages in Cienfuegos Bay (Caribbean Sea), and their relationships with sedimentary environment
2009
Pérez-GarcÃa, J.A. | Armenteros, M. | DÃaz-Asencio, L. | DÃaz-Asencio, M. | Ruiz-Abierno, A. | Fernández-Garcés, R. | Bolaños-Alvarez, Y. | Alonso-Hernández, C.
Spatial distribution of nematode assemblages was studied at six subtidal stations in Cienfuegos Bay, Cuba on September, 2005 The processes of re-suspension of 'sediment and transport of water masses would explain homogeneity of salinity and temperature across stations; as well the relative high levels of some heavy metals at stations far from the main pollution sources (power station, city). Density and diversity of nematode assemblages were negatively correlated with the concentration of Co and Zn in sediments, but the influence of hydrodynamic regime prevent to separate natural and anthropogenic causes of this pattern. The high recorded levels of Ni did not have apparent effects on nematodes; possible explanations were presence of tolerant assemblages and/or low bioavailability of the metal. The structure of assemblages was typical from soft bottoms around the world and dominant genera were Terschellingi and Sabatieria. The fine grain size and high organic content in sediments enhanced the dominance of deposit feeder nematodes. The presence of dense mats of benthic microalgae at one station, as result of eutrophication, possibly caused the observed increase in the percentage of epistrate feeders. Vertical distribution of nematodes showed a general decrease of density and diversity along depth within sediment; thiobiotic species occurred in all strata. The complex spatial pattern in the vertical distribution suggests migration inside sediment due to physical disturbance and/or predation.
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