Ship departs to study Southern Ocean coral

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From ABC Radio Australia

Australia's national research vessel, the Southern Surveyor, is on its way for the Southern Ocean after leaving the Tasmanian capital Hobart, on a mission to study coral off the coast of Australia's island state. The ship will send an unmanned submersible up to two-and-a-half kilometres below the surface, to film live and fossilised coral. The mission hopes to gather much-needed information about changes in ocean temperatures over decades and even centuries.

Presenter - Corinne Podger
Speaker - Captain Fred Stein, head of the government research agency CSIRO's Marine and Atmospheric Research department, which is overseeing the Southern Surveyor project

STEIN: One of the things that's special about the coral in the Southern Ocean is that it's very slow growing. So because it's in colder deeper waters, it's slow growing and it captures a long record of the environment around it. And it has growth rings rather like trees.

PODGER: Yes, it rings similar to those in trees. What can studying them tell us about ocean chemistry and temperature over a long period of time?

STEIN: It can tell us what the ocean chemistry surrounding them has been, because the coral captures a record of that. I captures a record of the carbon in the surrounding water, being mainly made up of calcium carbonate. It also tells us about acidity, the water temperature at the time, the oxygenation, so how much oxygen is in it and one of the other particular features of it is of course the Southern Ocean covers a very large portion of the world's surface and the corals down there are almost the only way that we have of capturing some sort of climate record over almost geological time. So multi-millennial, hundreds-of-thousands of years. I think that's one of the issues that they hope to determine on this first exploratory voyage. Because we have so few samples of these sorts of corals which have been gathered scientifically, it's been very difficult for them to work out what kind of a record the corals might capture and that is one of the purposes of this particular voyage, is if you like, as a litmus test of the information that they can extract from it.

PODGER: What parts of the ocean temperature and climate change puzzle might this mission help to fill in?

STEIN: It'll certainly fill in the part of the puzzle that relates to widespread, long term changes in deep ocean water masses in the Tasman Sea and the Southern Ocean. Again as you may know, the water masses which come from Antarctica, that colder water which travels north along the bottom of the Pacific Ocean and then sort of wells up to bring nutrients to the Western half of the Americas, to the Northern Pacific. The nature and the temperature of that is a fundamental influence on so much of the world's weather, it's been hypothesised that it's a part of the major influence on the sort of long term glaciation and climate change. So this is really an integral piece in the puzzle, not just of the changes in our region, but also the changes to weather globally.

PODGER: Obviously, these are important issues for scientists. Are they important to the rest of us?

STEIN: Absolutely. One of the issues that this research will inform is what has been the long term change in the surrounding water masses in the Australian region. So, for instance, have we seen a long term drying of the continent or is that a reasonably recent phenomena. So again separating out those long term natural global climate change from the more recent anthropogenic climate changes.

There's also a concern that the changes that we're seeing in climate now, the warmer water moving south from their continent may be changing the ecology in and around Tasmania and in the Tasman Sea, which are important fishery resources for Australia. Is that recent or is that something which is more long term? We don't know the answers to that. If we find that man-made climate change is having a significant detrimental impact on our fisheries, that's something we must be aware of.

PODGER: The submersible will also be studying deep ocean bio-diversity in an area, the vast southeast marine reserve and I understand we know very little about that at the moment?

STEIN: That's correct. Indeed we know very little about our I guess ocean estate below about 2,000 metres and the southeast marine protected area has recently been declared, much of it is unexplored, has not been mapped in any detail.

PODGER: It must be a very exciting mission for the scientists involved?

STEIN: It is. We've been mobilising the ship ready for the voyage in the last couple of days and their excitement and enthusiasm for the work is really quite contagious. They are quite sure and again the scientific panel of international experts, which reviewed their work was quite sure that they would be finding some very interesting results.