A shift in the biogenic silica of sediment in the Larsen B continental shelf, off the Eastern Antarctic Peninsula, resulting from climate change

PLoS One. 2013;8(1):e52632. doi: 10.1371/journal.pone.0052632. Epub 2013 Jan 2.

Abstract

In 2002, section B of the Larsen ice shelf, off of the Eastern Antarctic Peninsula, collapsed and created the opportunity to study whether the changes at the sea surface left evidence in the sedimentary record. Biogenic silica is major constituent of Antarctic marine sediment, and its presence in the sediment column is associated with diatom production in the euphotic zone. The abundance of diatom valves and the number of sponge spicules in the biogenic silica was analyzed to determine how the origin of the biogenic silica in the upper layers of the sediment column responded to recent environmental changes. Diatom valves were present only in the upper 2 cm of sediment, which roughly corresponds to the period after the collapse of the ice shelf. In contrast, sponge spicules, a more robust form of biogenic silica, were also found below the upper 2 cm layer of the sediment column. Our results indicate that in this region most of the biogenic silica in the sedimentary record originated from sponge spicules rather than diatoms during the time when the sea surface was covered by the Larsen ice shelf. Since the collapse of the ice shelf, the development of phytoplankton blooms and the consequent influx of diatom debris to the seabed have shifted the biogenic silica record to one dominated by diatom debris, as occurs in most of the Antarctic marine sediment. This shift provides further evidence of the anthropogenic changes to the benthic habitats of the Antarctic and will improve the interpretation of the sedimentary record in Polar Regions where these events occur.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antarctic Regions
  • Climate Change*
  • Diatoms
  • Geologic Sediments*
  • Greenhouse Effect
  • Ice Cover*
  • Lead
  • Oceans and Seas
  • Silicon Dioxide / chemistry*
  • Temperature

Substances

  • Lead
  • Silicon Dioxide

Grants and funding

This study was supported by the Spanish Ministry of Science and Innovation, through the project CLIMANT (POL2006-06399) and the graduate program fellowship FPU AP 2005-5060. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.