Southern Ocean Ecosystems: Environmental Change and Conservation
To conduct the scientific research necessary for understanding the impact of global change on Southern Ocean ecosystems, the effective conservation of Antarctic and Southern Ocean wildlife and the sustainable, ecosystem-based management of Southern Ocean fisheries.
Marine ecosystem change
Australian Antarctic Division Program Leader Dr Andrew Constable:
Southern Oceans Ecosystems Change is about trying to understand what the historical changes in the Southern Oceans ecosystems have been, looking at the state of ecosystems as they are now and then trying to forecast what changes might occur in the future. One of the key problems for us is to understand what climate change impacts will have on southern ocean ecosystems and that has large ramifications for what Australia would like to achieve in the region.
Australia spends most of its research effort in the Indian sector of the southern ocean which is south of Australia but also to the west. We have a territory at Heard Island and McDonald Islands in the southern Indian Ocean and we also have the stations throughout the eastern Antarctica.
Southern ocean ecosystems are very important for some of the global systems: the productivity that occurs in the southern ocean, the plankton converting carbon into mass and the sinking of that mass into the deep ocean. There’s a key part of the carbon cycle. One of the big questions at present is what result there is of the take-up of carbon in the ocean which is giving rise to acidification. What’s that going to do to the ecosystem? We already know that there are some species at the low traffic levels, those phytoplankton but also some zooplankton, which are being impacted by changes in pH of the oceans.
Some laboratory experiments here at the Australian Antarctic Division that have been undertaken by our krill biology program is showing that krill larval development may be impacted by a change in pH and it’s forecast that krill populations could be impacted in the next fifty to a hundred years if this goes on. That will have serious ramifications for the southern ocean food webs but setting up large scale programs to measure change is a real challenge.
We’ve been doing that effectively at Bechervaise Island at our Mawson Station. We have had a program there monitoring the Adelie penguin colonies, measuring their diet and how that’s changing, measuring the impacts of sea ice on adelie penguins and so on. We’ve been doing that now for some thirty years.
One of the parts of our strategic plan is look at the conservation of wildlife generally and the main components of that stream of our work is to look at what’s going to happen to whales. Are they going to recover? That’s a big question and also what’s going to happen to penguins, seals, flying birds and so on. We need to know about the dynamics of those populations, how many are there, what are the key drivers of the populations and what will affect their change.
There are two main areas of interest for Australia in managing fisheries. There’s the fisheries for toothfish and ice fish at Heard Island and McDonald Islands in the Southern Indian Ocean and there’s also the potential for krill fishing in the higher latitudes around eastern Antarctica. Those two types of fisheries present various problems for the mission on the Conservation of Antarctic Marine Living Resources, CAMLR for short. CAMLR, it’s the only international convention designed to ensure conservation of marine living resources in a region and then having requirements for how fishing can be undertaken to be consistent with conservation. So for krill fisheries, the questions that many Australian scientists have been addressing is what could the impacts of a krill fishery have on predators of krill. What we need to know about is, what could the impacts of krill fishing have on the recovery of whales? So we need to know about, well how many whales are there? What do they need in relation to krill? And then, how can we be sure that they can retain that food supply with an escalation of the krill fishery?
The Australian fishing industry has been successful in getting marine stewardship council certification for both the the Patagonian tooth fish and the mackerel ice fish fisheries at Heard Island and that’s a substantial achievement. That’s a recognition that the management practices and the research in the region will deliver sustainable fisheries in the long-term.
There are a number of research programs that we need to continue in the region so with the fishing industry and the Australian Fisheries Management Authority, scientists here at the Australian Antarctic Division have been looking at what the effects of fishing might be on benthic habitats, both trawling and long lining and trying to develop a better understanding of how the fisheries can be managed in such a way that the conservation of benthic habitats will be achieved in the long-term.
There’s been an agenda to establish a representative system of marine protected areas globally. The deadline is 2012 to try and have substantial progress towards that and Australia sees that the establishment of marine protected areas in eastern Antarctica can not only help conserve marine biodiversity but also provide reference areas we need to understand the dynamics of these ecosystems.
So our teams have a number of different components. We have laboratory technicians, we have our researchers and we have our field staff. What happens with our field staff is that they’re specially trained people that can deploy our nets, can tag different kinds of animals, can basically live in the field for long periods and monitoring animals. Tracking where they go in the ocean, what food they’ve eaten, and basically have to live in Antarctica up to six months in some cases.
So our marine research is not just based at the stations but we also use the Australian resupply vessel, the Aurora Australis and we run marine science voyages, anything up to sixty, seventy days where we can try to look at measuring abundance of krill, looking at the abundance of fish, also trying to go to places where we know that the predators go and see what’s there as well. So we try to link our research across the whole ecosystem and get the best we can for the time that we have at sea and also on station.