Benthic communities of Potter Cove: Observed patterns and explanatory models.

FERNANDO MOMO; RICARDO SAHADE; MARCOS TATIÁN

POLARFORSCHUNG

Año: 2008 vol. 571 p. 162 - 167

0032-2490

A variety of factors have been proposed to determinate the community structure of Antarctic benthos. For instance, physical disturbance caused by ice action (Sahade et al. 1998a) and biological interactions (Iken et al. 1998). It is know that the shallow sublittoral zone of Antarctica is unfavourable to the establishment of sessile animals owing to ice impact, icebergs and anchor-ice (Dayton et al. 1970, Gili et al. 2006). Recently, more attention has been focused in the possible effects of ice melting, especially for the increase of inorganic matter concentration at the water column (Tatián et al, this volume). A complex spatial structure have been described for the benthic communities at Potter Cove (Sahade et al. 1998b) determining different responses to detritus and ice perturbation. Depending on the type of substratum, the hydrological characteristics and the perturbation regime, the dominant species are different at different zones of the cove. The inner Cove is the less stressed zone, with less ice disturbance and more available food amounts (Sahade et al. 1998). However, this zone can be the most affected by an increment in ice melting with the correlative enhancement of inorganic particles in the water column. The relatively high density of the bivalve Laternula elliptica at 15 m may be explained by their capacity to bury themselves, enabling them to avoid the ice impact. The pennatulids are also very abundant in these areas due to their high growth rates with a nearly complete generation cycle in one year, thus acting as opportunistic species with a r-strategy (Sahade et al. 1998b). In order to explain the observed patterns, it is important to develop dynamic models that capture the main biological and ecological relationships and be capable to predict future changes in the community structure. The objective of this work is to present a mathematical model that includes biological interactions and physical perturbations in an explanatory framework of the benthic community structure at Potter Cove.