Journey to the Antarctic Ocean
Up to one million new species of microscopic sea life have been observed for the first time, promising new revelations about the marine ecosystem that could revolutionise our understanding of climate change's impact on the world's oceans. Each new life form was discovered by the crew of just one small research vessel, the Tara, which has recently completed a two-and-a-half year, 70,000 mile expedition.
The scientific journey, which is unprecedented in its scale, provides a snapshot of life at the bottom of the oceanic food chain. More than 30,000 samples of sea water were taken from locations across the globe, from the North Atlantic and Pacific Oceans, south to the remote Antarctic seas. The expedition's findings reveal the diversity and complexity of the tiny plankton that are a vital food source for fish and whales. In total, 1.5 million species of marine micro-organisms were recorded – significantly more than were previously believed to exist. They range from creatures that are one centimetre in length, to tiny life-forms that are measured in billionths of a metre. Studying their distribution and life cycle could provide important insights into the impact of climate change on the oceans.
The migration or extinction of microscopic species sensitive to sea temperature changes or acidification could cause the collapse of marine food chains, as well as the international fisheries that depend on them, scientists have warned. In a worrying indication of the reach of mankind's impact on the oceans, the Tara also encountered high levels of plastic pollution in the Antarctic. In the first research to quantify the scale of the problem in the remote Antarctic Ocean, scientists discovered that in a square kilometre of Antarctic sea, there could be as many as 50,000 plastic fragments.
Plastics that will remain in the sea for hundreds of thousands of years can get into the food chain, accumulating in the stomachs of fish, marine mammals and seabirds. They produce toxins – organic molecules such as phenols and phthalates – which can poison marine life and could, via fisheries, find their way into our food. The Antarctic Ocean phytoplankton (plankton species which survive by photosynthesis, like plants) are vital for the regulation of CO2 in the atmosphere – as are all of the thousands of similar species recorded by the crew.
Dr Chris Bowler, scientific co-ordinator of the expedition, said the study provided a "snapshot and health check" of the world's oceans. "Nobody has ever done this on the scale that we have before," he said. "We will be analysing results in the lab for a number of years. The task now is to understand the physical and climactic constraints that have created these ecosystems. "How much is pollution affecting them, how much is temperature change affecting them? If a species of plankton sensitive to temperature migrates, it could devastate that food chain and therefore local fisheries. We want to find out the role of each species within an ecosystem so that we can better predict what the oceans could be like in 50 or 100 years' time if we continue to change them." The Tara, a 36-metre long schooner, is a comparatively small ship to have undertaken a scientific mission on this scale. It is owned by the French fashion designer and environmental campaigner Agnès Troublé, who also provided half the funding for the €10m (£7.9m) expedition.
