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Exploring cold water corals


Exploring cold water corals

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Deep underwater lie mysterious worlds that scientists are only now beginning to explore.

Steve W Ross is US coordinator, for the Traces project at the University of North Carolina Wilmington: “The deep sea is completely unknown, frontier territory. Everything you touch is potentially new, everything you see is something that somebody may have not seen before.” Furu Mienis is a Marine Geologist from the Royal Netherlands Institute for Sea Research: “I went down with the submersible to go and see them and it’s really dark down there, if you don’t have the lights of the submersible then you really can’t see anything.” In the darkness lie hidden reefs of what are known as cold water corals. Sandra Brooke is the Coral Conservation Director from the Marine Conservation Biology Institute: “We’ve got crustaceans and molluscs and all these invertebrates, and the fish come to feed on them and then the bigger fish come to feed on them.” It is late at night as research ship the Seward Johnson draws into harbour at Gulfport, Mississippi. There are many coral specialists on board – including Europeans collaborating with colleagues from the US. The scientists are tired but happy. Steve W Ross: “We’ve just come in from a 12 day cruise, we’ve covered something like two or three thousand miles of ocean, and sampled coral reefs all the way from the southern Gulf of Mexico into the central Gulf using a submersible and all kinds of other gear.” At dawn work begins to unload the carefully packed scientific samples. Scientists from the Netherlands and Britain are working with colleagues from the US under a European-funded research programme to better understand deep water corals throughout the Atlantic. Furu Mienis: “To work with the Americans it’s the opportunity to be able to do research on this side of the Atlantic, and to actually start comparing these systems, because we think somehow all these cold water coral reefs are connected, but we don’t know how yet.” Steve W Ross: “The Gulf stream is like a river. It starts in the Gulf of Mexico, flows around Florida, comes up off the coast of the Carolinas, shoots straight across to Europe and modifies European climate. As it does so it’s also transporting larvae of a variety of animals. The same coral reefs that are very important off Norway and off Scotland and off Ireland are the same corals that are important here on this side.” Without the submersible the team would be unable to get up close to the corals. And while most are the same species – called lophelia – they certainly are not identical. Furu Mienis: “The corals look for instance very different from the corals we have on the European side. The corals here are quite thick, they make really thick skeletons, while on the European side we have mainly really thin skeletons, so there are loads of differences and because of this new data we try to figure out where the changes come from.” Getting up close to the animals is a valuable and enlightening way to see how they behave in their natural habitat. Steve W Ross: “The crabs are quite interesting, they’re some of the more voracious critters on the reef, they roam around eating anything they can find. There’s one species of crab-like critter called a squat lobster. They sit up in the top of the coral with their arms outraised and they grab things as they swim by, we’ve seen them grab midwater fish like hatchet fish, they grab squid, they eat tunicates out of the water column.” Back on the dockside the Dutch team are loading up their deep-water probe, known as a lander. It has been sitting on the sea-floor for the past year recording water temperature, salinity and current speed right next to the corals. Identical devices are used in European waters, meaning data can be compared like for like. Furu Mienis: “What we’re trying to do look is also if we see daily variability near the sea floor, but also for instance seasonal changes, or annual changes even. We are close to New Orleans and we all know about the hurricanes that are passing by here, and maybe these hurricanes we could also see in these records here.” Gulfport was hit hard by Hurricane Katrina, and still bears the scars. The corals may carry a record of that storm, but also many other climatic events, as their colonies are built up over thousands of years. Steve W Ross: “So this is a black coral that we collected off in the Gulf of Mexico probably at about 500 metres depth. The value to us is that these are a chemical archive. The rings are like tree rings, they put down a ring every year and you can analyse the chemicals in the ring and find out all kinds of things about ocean ecology, ocean history, ocean climate, going back several thousand years. This doesn’t give a real good impression of what it looks like alive. A lot of these fine branches break off. This thing is big and the branches are quite flexible when it’s alive, so they face into the current and the little coral animals come out and feed on the plankton.” Despite being hidden deep underwater these intricate ecosystems are still affected by man. They can be damaged by deep sea trawling, and suffer from pollution. Sandra Brooke: “The ocean absorbs a vast amount of the carbon dioxide that we are releasing, it just sucks it up. And it doesn’t just stay in the surface layers – because the ocean is moving it gets pulled down to the depths. The problem with that is that when you dissolve carbon dioxide in water it turns it acidic. And the skeletons of the animals that form these reefs – the corals – they dissolve in acid.” The scientists here are concerned that deep water corals should be not only be studied, but also preserved. Sandra Brook: “We have an oasis in the deep sea desert and it needs to stay that way, and we just don’t know how valuable it is so we should protect it.” It is believed there are hundreds more deep water coral colonies yet to be discovered throughout the Atlantic.

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