Sewage impact on the composition and distribution of Polychaeta associated to intertidal mussel beds of the Mar del Plata rocky shore, Argentina

Abstract

The polychaete composition and distribution within mussel beds were studied in order to assess organic pollution due to domestic sewage in a rocky shore of Mar del Plata (Argentina) during 1997. Four stations and a control site were randomly sampled around the local effluent. Quantitative data on polychaetes, as well as sediment accumulated among mussels and its organic carbon content were measured. Polychaete distribution patterns are related to the organic matter gradient, being Capitella cf. capitata, Neanthes succinea (Frey & Leuckart, 1847) and Boccardia polybranchia (Haswell, 1885) the dominant indicator species close to the effluent. At medial distances, the cirratulids Caulleriella alata (Southern, 1914) and Cirratulus cirratus (Müller, 1776) are very important in abundance. The syllids Syllis prolixa Ehlers, 1901 and S. gracilis Grube, 1840 are distributed along the study area, but dominate at the medial stations and at the control site. The orbiniid Protoariciella uncinata Hartmann-Schröder, 1962 is subdominant at the control station.

Sewage-induced disturbance on polychaetes inhabiting intertidal mussel beds of <i>Brachidontes rodriguezii</i> off Mar del Plata (SW Atlantic, Argentina).

“…have been found in or around organically polluted zones (Pearson and Rosenberg, 1978). A previous study (Elías et al, 2003) recorded A. succinea for the first time in impacted areas of the southwestern Atlantic. Its response to short-term sewage impact is not evident in the March plots, because its density was lower than in November, but it shows a relationship with organic matter in the RDA.…”

“…However, densities in March were lower than in November (except at the control station), suggesting a negative effect of high organic matter loading. In a spatial scale study (Elías et al, 2003) this species has been suggested as an indicator of organically enriched sediments. Boccardia spp.…”

Two new species of Caulleriella (Polychaeta, Cirratulidae) from Argentina

“…Several stations were sampled since 1997 by means of replicate 78cm 2 corers; materials were sieved through 1mm mesh (VALLARINO et al, 2002;ELÍAS et al, 2003aELÍAS et al, , 2006.…”

“…nov. Caulleriella alata: ELÍAS, 2002;ELÍAS et al, 2003a: Etymology. The species is dedicated to Dr. Claudia S. Bremec, polychaetologist who shares our passion for the study of worms from the Argentine sea.…”

“…These studies were performed in order to obtain baseline information before the construction of a new sewer that will discharge wastes up to 3km offshore (11m depth), replacing the current one that discharges in the intertidal zone. These ecological studies have improved the knowledge of the regional polychaete fauna (e. g., ELÍAS & BREMEC, 1997, 2003ELÍAS et al, 2001ELÍAS et al, , 2003aELIAS, 2002;VALLARINO et al, 2002;RIVERO et al, 2005).…”