Análisis espaciales de la biodiversidad bentónica del Golfo San Jorge (Spatial analyses of benthic biodiversity in San Jorge Gulf).

KAMINSKY, JULIETA; VARISCO, MARTÍN; SAHADE, RICARDO; ARCHAMBAULT, PHILIPPE

Rimouski

Workshop; Workshop on the PROMESSe project: results and opportunities; 2017

Programa PROMESse

Benthic biodiversity distribution is closely related to habitat complexity. In the context of increasing anthropogenic pressures, it is necessary to develop biodiversity models considering habitat distribution to improve management and conservation of marine and coastal ecosystems. San Jorge Gulf (45° - 47° S, Argentina) is part of the Patagonian Shelf Large Marine Ecosystem, one of the most productive ecosystems of the Southern Hemisphere. The general objective of this study was to characterize the spatial distribution of benthic biodiversity of the San Jorge Gulf (SJG). First, we described the physic-chemical characteristics of the benthic environment. Then, we identified taxonomic and functional assemblages for epifauna and infauna organisms. Afterwards, we evaluated the relationship between benthic environment and assemblages? distribution. We hypothesized that the distribution of benthic assemblages is associated with depth, sediment size and concentration of sediment organic matter as environmental factors, and that the most diverse assemblages are present in areas with higher concentrations of organic matter. Data from R/V Oca Balda (2000) and R/V Coriolis (2014) oceanographic missions in SJG were used. Our results show that areas near headlands present coarse sediments, higher temperatures and chlorophyll a in the bottom water. In contrast, central deep area is characterized by fine sediments, higher content of organic matter, and bottom water with lower temperatures, oxygen availability and chlorophyll a concentrations. Epifauna showed a rather spatial pattern characterised by the occurrence of opportunist crawlers and deposit subsurface burrowers associated to deep area conditions. On the contrary, epifauna is characterised by a high diversity of life strategies towards Cape Tres Puntas, including predator swimmers or crawlers, filter sessile or burrowers and deposit subsurface burrowers. In the case of infauna, no spatial patterns were identified, probably related with sampling effort. However, it is possible to mention that deposit subsurface or filter burrowers, deposit subsurface burrowers, deposit surface burrowers, filter sessile and predator burrowers were among the most abundant functional groups for infauna. The presence of spatial patterns might enable to predict benthic biodiversity distribution in the SJG, particularly considering grain size and organic matter variables.