Biochemical characteristics of surface sediments on the eastern Weddell Sea continental shelf, Antarctica: is there any evidence of seasonal patterns?

• Main Authors: Enrique Isla, Dieter Gerdes, Sergio Rossi, Ida Fiorillo, Elisabet Sañé, Josep-Maria Gili, Wolf E Arntz
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2011
• Subjects: Antarctic; The Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1048.6034; http://www.icm.csic.es/bio/papers/1739.pdf

Abstract Biochemical characteristics of seaXoor sediment oV Austasen in the southeastern Weddell Sea were assayed in samples recovered in the early autumn and late spring of 2000 and 2003, respectively. Sediment was separated in the grain-size fractions >200 m and <200 m to distinguish biochemical characteristics in the fraction available for benthic suspension feeders (<200 m). In the bulk sediment, the lipid (LPD) and carbohydrate (CHO) contents were signiWcantly diVerent between seasons with higher LPD content in the early autumn and higher CHO content in the late spring. In the grain-size fractions <200 m, the LPD and protein (PRT) contents were signiWcantly higher in the early autumn meaning that in this season the fraction available for benthic suspension feeders presented higher nutritive value. The relatively higher CHO concentrations observed in each fraction in the late spring were attributed to refractory matter, whereas the higher PRT and LPD concentrations found during the early autumn were associated with planktonic material settled after the summer phytoplankton bloom. Our results suggest that there is seasonal variation in the composition of organic matter in the sediment, with better nutritive quality in the early autumn, especially in the grain-size fraction available for benthic suspension feeders. These variations also suggest that the benthic community exploits the fresh organic matter accumulated after the summer throughout the Antarctic dark months leaving the sediment almost exhaust of LPD and with higher CHO contents, presumably of refractory nature, at the onset of the seasonal phytoplankton bloom of the following year.