Billett DSM

Clarke A

Jumars PA

Karl DM

Smith CR

Swadling KM

Taghon GL


            The deep West Antarctic Peninsula (WAP) shelf is characterized by intense deposition of phytodetritus during spring/summer months, while very little food material reaches the seafloor during winter. The response of the shelf benthic megafauna to this highly variable food supply is still poorly understood. In order to characterize the deposition of phytodetritus and the megabenthic community response, we deployed a seafloor time-lapse camera at approximately 590 m depth on the mid WAP shelf west of Anvers Island for 15 months. Seafloor photographs were taken at intervals of 12 or 24 h nearly continuously from 9 December 1999 (austral winter) to 20 March 2001 (summer) and analysed for phytodetritus deposition and megafaunal dynamics. Seafloor images indicated a marked seasonal arrival of greenish phytodetritus, with large interannual and seasonal variability in the coverage of depositing phytodetrital particles. The surface-deposit-feeding elasipod holothurians
            Protelpidia murrayi
            and
            Peniagone vignoni
            dominated the epibenthic megafauna throughout the year, frequently constituting more than 80% of the megafaunal abundance, attaining total densities of up to 2.4 individuals m
            −2
            . Elasipod abundances were significantly higher in summer than winter. During summer periods of high phytodetrital flux,
            Pr. murrayi
            produced faecal casts at higher rates, indicating intensified population-level feeding activity. In March–June 2000, faecal casts lasted longest, suggesting lower horizontal bioturbation activity during autumn–winter. Our data indicate that the
            Pr. murrayi
            population increases its feeding rates in response to increasing amounts and/or lability of organic matter on the sediment surface. Assuming that this species feeds on the top millimetre of the sediment, we estimate that, during periods of high phytodetrital flux, the
            Pr. murrayi
            population reworks one square metre of sediment surface in approximately 287 days. We suggest that
            Pr. murrayi
            is an important species for organic-carbon recycling on the deep WAP shelf, controlling the availability of deposited labile phytodetritus to the broader shelf benthic community.
          </jats:p

P. Y. G. Sumida

C. R. Smith

A. F. Bernardino

P. S. Polito

D. R. Vieira

Crossref

Royal Society Open Science

Seasonal dynamics of megafauna on the deep West Antarctic Peninsula shelf in response to variable phytodetrital influx

Seasonal dynamics of megafauna on the deep West Antarctic Peninsula shelf in response to variable phytodetrital influx

Abstract

Similar works

Full text

Available Versions

Crossref