Arctic acid test

Abstract

A team of researchers and explorers have set off to gather vital winter Arctic Ocean measurements. Nigel Williams reports. A team of researchers and explorers have set off to gather vital winter Arctic Ocean measurements. Nigel Williams reports. Scientists and explorers set out earlier this month on an Arctic expedition to examine the impact of an acidifying ocean on the region's animals and plants. The Catlin Arctic Survey will set up base in northern Canada for some of the scientists while a separate team will undertake a 500 km trek across sea ice off Greenland. Both will investigate the impact of ocean acidification on marine life, while the explorers will also measure variations in sea-ice thickness. Last year's Catlin Arctic survey showed the Arctic ice was thinner than expected. The expedition is also the first to take water samples from the sea ice in winter, as all previous Arctic measurements have been taken from ships in open water in summer. As well as taking water samples, the researchers will collect plankton, pteropods — a type of swimming sea snail — and other local marine life and examine their reaction to increasing levels of acidity and also test how much carbon dioxide passes through the sea ice from the air into the sea. Globally, oceans have seen a 30 per cent increase in acidity on pre-industrial levels that some scientists believe on current projections the pH of the oceans by 2050 could reach levels not seen for 20 million years. The Catlin scientists aim to establish the acidity of the Arctic Ocean, which appears to be acidifying faster than the rest of the world's oceans because cold water absorbs more carbon dioxide. Marine life that is dependent on calcification, such as corals, crustaceans and molluscs, is particularly sensitive to changes in acidity because the calcium carbonate that forms the shells or skeletons is vulnerable in more acidic water. Pteropods, which are an important part of the marine food chain, are among the organisms potentially at risk. “We understand from models projecting future ocean chemistry that the Arctic Ocean is particularly vulnerable to ocean acidification because cold water absorbs carbon dioxide more effectively than warm oceans, so much so that it may become corrosive to some shelled organisms within a few decades,” says Carol Turley of the Plymouth Marine Laboratory. Jean-Pierre Gattuso of CNRS-University Pierre and Marie Curie, who has researchers in the team said: “The oceans absorb about a quarter of human-made carbon dioxide. This has been limiting the amount of greenhouse gas in the atmosphere and mitigating climate change. However, the massive amounts absorbed — about 24 million tons every day — considerably upset the ocean chemistry by increasing the acidity of seawater.” Pen Hadow, the director of the survey, who also led last year's expedition, said the Arctic Ocean's vulnerability motivated the trip. “We know that disappearing ice cover and the potential impacts of acidity are parts of some big ocean changes. Since ocean acidification is widely viewed as a bellwether for wider global change, it is important we understand better what is happening.” The ice base on the western shore of Ellef Rignes Island in Canada will be home to a team of six scientists who will work on the ice, protected by two guides to ward off polar bears attracted by the human activity. The Catlin Group, international speciality insurers, sponsors the survey to allow scientists to obtain data that can be used to forecast the risk posed by the changing environment.“Since ocean acidification is widely viewed as a bellwether for wider global change, it is important we understand better what is happening.” “Since ocean acidification is widely viewed as a bellwether for wider global change, it is important we understand better what is happening.” Hadow says: “Our aim at the Catlin Arctic Survey is to make it possible for science work to be undertaken that would otherwise be exceptionally difficult to do. The scientists will be able to work safely thanks to the skills of our polar support team who will be guiding them out onto the floating sea ice. Our Ice Base will have all the facilities they need to conduct analyses and to survive in the extreme conditions of the Arctic winter and spring.”