Seasonal composition and activity of the intertidal macrobenthic community of Caleta Valdés (Patagonia, Argentina) applying in situ and ex situ experimental protocols

Abstract

Caleta Valdés (CV) is a coastal lagoon of the Patagonian Atlantic coast located in the Península de Valdés declared as Humanity Mundial Patrimony due to its remarkable biodiversity, ecosystemic richness, and pristine state. Marine mammal populations are well documented in this area but few studies have been carried out on the local macrobenthic communities. The goals of this study were (a) to evaluate for the first time the seasonal variation of the structure and activity (i.e., sediment reworking) of the intertidal macrobenthic communities of CV, and (b) to validate an ex situ experimental protocol for future ecotoxicological studies. To do so, sedimentary (granulometry, water content, and organic matter) and biological (macrobenthic assemblages, biodiffusive-like and advective sediment reworking components) parameters were analyzed using a combination of in situ and ex situ measurements. Overall, polychaete and crustacean dominated the macrobenthic community. The highest abundances were found in Spring-Summer along with a predominance of biodiffusors versus conveyors. Ex situ and in situ measurements demonstrated similar results, thus allowing validation of an ex situ experimental procedure for macrobenthic community and functioning studies. In addition, these results provide a first baseline of benthic information on CV that will be helpful to monitor the effects of potential pollution in Patagonian coastal systems.