Sources and distribution of biomarkers in surficial sediments from a polar marine ecosystem (Potter Cove, King George Island, Antarctica)

MACCORMACK, WALTER P.; MARTINS, CÉSAR C.; DAUNER, ANA LÚCIA L.; HERNÁNDEZ, EDGARDO A.

POLAR BIOLOGY

SPRINGER

Año: 2017 vol. 40 p. 2015 - 2025

0722-4060

Sedimentary organic matter (OM) represents the energy supply for the shelf benthos at the Antarctic Ocean, and has yet to be properly characterized in terms of sources and composition for the Potter Cove region, King George/25 de Mayo Island. This energy input occurs mainly during the brief summer and provides the majority of available energy for the year, in a region with high endemism and limited source variety of sedimentary OM. Thus, the aim of this study is to identify the OM origin and degradation degree based on the spatial distribution and type of organic biomarkers. Twelve surficial sediment samples were collected and analyzed for the presence of n-alkanols and sterols. The different spatial patterns between the analyzed compounds indicated distinct OM sources and degradation degrees. First, relatively fresh phytoplankton organic matter and an enhanced bacterial activity were associated with the occurrence of seaweeds detritus and represent the source of n-alkanols. Second, relatively fresh material mainly associated with seaweeds debris were identified as the source of macroalgae sterols. Our results shed some light into the base of the Potter Cove trophic benthic chain and increase our understanding on the region?s biogeochemical processes relating to OM recycling. It also provides a baseline for assessing future changes in the structure of the benthic food web in this environment, which is subject to noticeable glaciers retreat.