Scraping the bottom
Iceberg scouring is a major factor affecting the diversity and abundance of marine benthic communities in Antarctica’s highly dynamic ecosystem. Reporting in the journal Marine Ecology Progress Series biologist Dr Dan Smale describes the link between the frequency of scouring events and the distribution of marine invertebrate animals in near-shore habitats. Until now little was known about the direct effects of this natural phenomenon on marine life.
During a two year study around 125 animals were sampled from the shallow water around British Antarctic Survey’s Rothera Research Station. Dr Smale conducted a series of dives to place concrete blocks topped with plasticine at a variety of depths. The blocks revealed the severity of impact from iceberg scraping, which was then linked to the structure of the marine animal assemblages.
The study showed, for the first time, that where there was increased ice scouring there were fewer species, fewer individuals and less of the seabed colonised than other ice-free areas. Dr Smale concludes that climate-related changes is affecting sea ice and glacier dynamics and consequently affecting the frequency of ice scouring in the region. Such changes in the intensity of ice scouring will have important implications for the unique assemblages of animals and plants that inhabit shallow water habitats around Antarctica.
The paper ‘Ice disturbance intensity structures benthic communities in nearshore Antarctic waters’ by Dan Smale was published in Marine Ecology Progress Series 349: 89-102 (Nov 2007)