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

Abstract

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.