Intertidal macrozoobenthos in sandy beaches of Bahía Nueva (Patagonia, Argentina) and their use as bioindicators of environmental impact

Abstract

Se recolectaron muestras de macrozoobentos en playas arenosas de la ciudad de Puerto Madryn y áreas adyacentes, en noviembre de 2005. Los análisis multivariantes (ANOVA, nMDS, ANOSIM, SIMPER y RDA) permitieron caracterizar el área en base a la relación entre las variables biológicas y ambientales. Las áreas afectadas por los desagües procedentes de las fábricas de pescado y los pluviales, fueron definidas como “zonas pertur- badas”, debido a la dominancia de los poliquetos indicadores de contaminación Boccardia polybranchia y Capitella “capitata” sp., asociados a altos valores de amonio, fosfatos y materia orgánica. Por el contrario, las playas arenosas localizadas a 15 km de la ciudad fueron consideradas como “zonas no perturbadas” debido a que dominaron Psammodrilidae y Puelche orensanzi, con altos valores de nitratos y oxígeno disuelto. Estos taxa podrían ser buenos candidatos como indicadores de zonas limpias para futuros estudios. Se registra por primera vez la familia Psammodrilidae en el Atlántico Sur.

Macrozoobenthos were collected from urban sandy beaches of Puerto Madryn and adjacent areas in November 2005. Multivariate analysis techniques (ANOVA, nMDS, ANOSIM, SIMPER and RDA) were used to characterize the area based on the relationships among biological and environmental variables. The areas affected by outfall of fishery factories and pluvial effluent were defined as "perturbed zones" due to the dominance of the pollution indicator polychaetes Boccardia polybranchia and Capitella "capitata" sp., which are associated with high values of ammonium, phosphates and organic matter. However, sandy beaches located 15 km from the city were considered as "unperturbed zones" because Psammodrilidae and Puelche orensanzi dominated, and they had high values of nitrates and dissolved oxygen. These taxa seem to be good candidates as indicators of clean zones for further studies. This is the first record of the family Psammodrilidae in the South Atlantic.