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Free-living Marine Nematode Communities from Patagonian Coastal
Lagoons
Pastor, C.T. & R. Warwick
Centro Nacional Patagónico Boulevard Brown 2825 U 9120 Puerto Madryn, Chubut, Argentina
This paper describes a baseline study on nematode biodiversity from three different latitudes
(Península Valdes, 43ºS; San Julián, 49ºS and Río Gallegos, 51ºS in Chubut and Santa Cruz
provinces) contrasting coastal upper littoral marine areas with saline coastal lagoons in
Patagonia. The lagoons vary in salinity from hypersaline to almost fresh water. The
objective of the study was to give the first inventory of the fauna of these habitats, in
particular a detailed study of the dominant taxa the free-living marine nematodes.
Fitfteen lagoons and three upper littoral coastal areas have been sampled at the three
latitudes. The samples have been fixed in 5% formalin with rose Bengal in the field. The
geographical position (GPS), salinity and granulometry, have been taken. Nematodes were
extracted using the elutriation/decantation/LUDOX TM method and specimens mounted on
slides.
The Nematodes found were identified up to the lowest taxonomy level possible, and
photographs were taken using a Photomicroscope. For nematode identifications, the keys of
Platt & Warwick and Warwick et al. were used. The differences in nematode species
composition between latitudes and environments were analysed by multivariate methods.
The results indicate that salinity and elevation above sea level seem to be the main
environmental variables that explain the complex distribution found. Lagoons near the sea
have similar nematode fauna to coastal littoral sites, and inland lagoons have a particularly
extreme nematode fauna associated with the salinity regimes. Detailed information about
species found plus dominant genera at each latitude will be presented.
This project was supported by Royal Society of London, UK and CONICET, Argentina.
5 th International Congress of Nematology, 2008 160