Taking stock – the Census of Antarctic Marine Life

The Arctic and Antarctic polar regions are vulnerable under current climate change predictions.

Warming is widespread in the Arctic, on sea and land. Changes are less clear cut in the Antarctic, except for the Antarctic Peninsula which has experienced rapid warming in recent years with significant ice-shelf break-up.

The International Polar Year (IPY), which began in March 2007 and runs to March 2009, will see a significant number of scientific research projects in both polar regions over two summer and winter seasons. Scientists from over 200 nations are investigating many facets of the polar environment in the context of climate change.

The Census of Antarctic Marine Life (CAML) is an internationally coordinated research programme that is running during IPY.

The aim is to build a snapshot of marine organisms in the Southern Ocean around Antarctica. New Zealand, led by the Ministry of Fisheries, is conducting a major survey in the Ross Sea region as part of our IPY activities.

A 50 day voyage in early 2008 saw a team of scientists on board RV Tangaroa collecting samples of living material throughout the water column – from the sea’s surface down to the seafloor in three distinctive areas of the Ross Sea region.

A northern area is characterised by deep sea abyssal plains at depths of 2,000- 4,000 metres with seamounts (undersea volcanoes) rising far above the plains towards the surface. A central area across the continental slope has a rugged undersea terrain that drops steeply from the shelf at 500 metres down to the abyss.

A southern area across the Ross Ice Shelf is relatively flat and deeply scoured by iceberg tracks.

The voyage took place in February and March at the time when the seasonal sea ice is least extensive, allowing the greatest possible access to the Ross Sea. In the summer of 2008, however, much more ice than usual remained in the Ross Sea region and scientists were forced to redesign their sampling plans to match the conditions encountered.

Over 30,000 biological samples from a wide range of organisms were collected, including viruses, bacteria, plankton, benthos (animals from the seabed), cephalopods (squid or octopus), and fish. Scientists also used high resolution cameras at all depths to obtain information on the way the animal communities are structured. Water chemistry and hydrological surveys were also completed, with samples of water from different depths taken to examine their microbial content and assess their role in the biological engine of energy transfer through the food-web in this ecosystem.

Experiments were carried out during the survey to assess the effects of ocean acidification on microplankton under laboratory conditions. Tissue samples from some of the animals will be used for genetic barcoding (a form of species identification), and others will be analysed to determine feeding relationships at different trophic levels in the food-web.

The 30,000 specimens will be analysed over the next three years. Species new to science – eight so far – will be confirmed and the biodiversity patterns in relation to the environment will be explored. This will increase our understanding of baseline information of the Ross Sea ecosystem and will be used to monitor changes over time. The results will also contribute to improved understanding of toothfish fishing and the impact it has on the ecosystems in Antarctic waters.

While the Ministry of Fisheries led this project, it has been a collaborative programme involving Land Information New Zealand, the Ministry of Foreign Affairs and Trade, Antarctica  New Zealand, Te Papa Tongarewa, the National Institute of Water and Atmospheric Research (NIWA), New Zealand universities, the United States and Italy. The voyage is part of the whole-of-government Ocean Survey 20/20 programme.