A UCC expedition leaves Galway today to retrieve deep water coral samples that could reveal past climatic conditions, writes Lorna SigginsMarine Correspondent
IRISH SCIENTISTS are leading an ambitious new expedition to collect samples of cold-water coral which may provide a "missing link" in international climate change research.
The multinational expedition, which leaves Galway today, will spend almost a month at sea, collecting 70-metre-long cores or "environmental time capsules" from deepwater reefs as far west as 660km from the Connemara coast.
Living reefs won't be targeted, and the samples will be collected outside Ireland's four marine Special Areas of Conservation (SAC), according to Dr Andy Wheeler of University College, Cork (UCC). Dr Wheeler is co-ordinator of the European Science Foundation (ESF) carbonate programme, and is chief scientist on board.
The Marine Institute is giving ship-time on the Celtic Explorer, and Germany's University of Bremen has developed the drilling rig which will be used for the work. Scientists from Belgium and the Netherlands will also participate. The newly designed German rig, called MeBo, can be deployed off the vessel to be lowered onto the seabed, where it can penetrate solid rock.
The MeBo rig is a more sophisticated and cost-efficient piece of technology than that used on a previous voyage of this type in these waters, Dr Wheeler says. That previous initiative was undertaken by the 143-metre Joides Resolution for the International Ocean Drilling Programme (IODP) in April, 2005.
Two Irish scientists joined that expedition on the converted oil-drilling ship equipped with 12 different scientific laboratories, named after Captain Cook's HMS Resolution and sponsored by the Joint Oceanographic Institutions for Deep Earth Sampling.
"That expedition drilled one reef - the Challenger mound in the Belgica province on the edge of the Porcupine Seabight, off the south-west coast of Ireland," Dr Wheeler recalls. "It also established that these reefs were true structures, built over two-and-half million years.
"We are hoping to drill through five different mounds in five different settings on the Porcupine Bank, northern Porcupine Seabight and on the Rockall Bank, with the deepest site being 1,000 metres," he says.
Live reefs have a thick cover of live coral, and are easily distinguishable from dead reefs, he emphasises. "In a sense, we will be drilling back through time."
The aim of the project is to provide a "missing link" in climate change research and inform climate modelling, Dr Wheeler points out. "We know that there is too much carbon in the atmosphere, and that one third is absorbed by the ocean, but we don't know how much of it is locked away in these reefs.
"We need to learn how these reefs respond when the oceans warm, how they record climate change, and how much carbonate is being stored. The cores we collect should give us a record of growth over several million years, helping us to resolve these issues."
Deepwater corals and carbonate mounds formed over thousands of years off the Irish west coast have been mapped by the State's national seabed survey, while the environmental protection of same has been the subject of work by Dr Anthony Grehan and colleagues at NUI, Galway's department of Earth and ocean sciences.
A French-Irish expedition using the French research ship, L'Atalante, yielded some of the first graphic images in 2001, and a further international expedition in 2003 confirmed that 60 per cent of European deepwater corals lay off this coastline. Dr Boris Dorschel, a UCC colleague, also travelling on the expedition, says more than 1,000 reefs have been counted in these waters, many of which are several hundred metres tall and "kilometres across".
"That's a lot of carbonate locked up in these reefs, linked to dissolved CO2 in the oceans and the greenhouse gas in the atmosphere," he says. "Understanding this link between CO2 in the atmosphere and how it gets locked up in sediments is crucial for climate modelling. We need to drill so we can work out how quickly these vast reserves have accumulated."
The cores will be kept at a constant temperature of four degrees on board the ship during the voyage, and will be stored in the University of Bremen. Some of the samples may also be stored in nitrogen, to allow for study of deep biosphere bacteria, Dr Wheeler says.