Collaborative East Antarctic Marine Census

A tri-nation survey of the plankton, fish, benthos (sea-floor life) and oceanography is underway in the waters off the East Antarctic coastline.

The Collaborative East Antarctic Marine Census, or CEAMARC, involves scientists from Australia, Japan and France, and forms part of a major Australian Antarctic Division-led project for the International Polar Year — the Census of Antarctic Marine Life (Australian Antarctic Magazine 12: 6–7).

The collaborative census aims to understand the processes that have lead to the evolution and survival of marine life existing in the region today, so that scientists can predict how these organisms may respond to future climate-related changes in their environment.

CEAMARC leader, Dr Graham Hosie, of the Australian Antarctic Division, says the census region, adjacent to Terre Adélie and George V Land in Antarctica (see map), offers some of the best conditions to study the effects of sea ice dynamics on the resident marine life, especially the krill-salp-plankton interaction and its flow-on effects to fish, penguins, seals and benthic organisms.

Of particular interest to the scientists is the diversity of fish, cephalopods (such as squid and octopus), plankton and benthic organisms below 200m depth, and the environmental conditions in which they live.

‘Some important differences in the biology and genetics of fish caught between the surface and 200m depth were observed during previous studies in the region, suggesting divergences between populations,’ Dr Hosie says.

‘So we are investigating the diversity of the pelagic (open ocean) and benthic fauna, from gene to habitat level, and comparing these with similar studies in other sectors of the Southern Ocean.’

Understanding the fish community composition and structure is particularly important to explain the distribution of bottom- and near-bottom-dwelling fish, and the impacts of commercial trawling. The research will also help scientists understand how communities have adapted to the unique Antarctic environment.

The census will also target different zooplankton (free drifting marine animals) ranging from gelatinous zooplankton, such as jelly fish, to mesozooplankton (0.2–20mm in size) and deep water zooplankton. Many of these organisms have been poorly studied and some are difficult to sample and preserve because of their fragility.

To overcome this problem, the census is using video imaging to observe gelatinous zooplankton and cephalopods. More traditional sampling equipment, such as plankton nets, beam trawls, benthic sleds and sediment grabs will be used to sample more robust organisms.

The census will be conducted from three ships: Australia’s Aurora Australis, Japan’s Umitaka Maru and France’s l’Astrolabe. The ships will also be used to collect oceanographic data for another International Polar Year project and to sample plankton on route for the Southern Ocean Continuous Plankton Recorder Survey.

All data collected will be transmitted to the Scientific Committee on Antarctic Research Marine Biodiversity Information Network — the central repository for the Census of Antarctic Marine Life.

WENDY PYPER, Information Services, AAD