The RRS Discovery left Liverpool yesterday with 24 scientists from eight UK institutions, led by the National Oceanography Centre, Southampton.

For the next month, the cruise will range across northwest European seas, circumnavigate the British Isles, and visit the territorial waters of seven different nations.

Through land use changes and the burning of fossil fuels (oil, gas and coal) for energy, humans are releasing vast amounts of carbon dioxide (CO2) into the atmosphere. This anthropogenic CO2 release is notorious as the likely cause of global warming. However, it is also responsible for another potentially major environmental problem – ocean acidification.

“The seawater around Britain now has a lower pH - a measure of acidity - than it did 20 years ago. This chemical change might not yet have any biological effects, but we just don't know what the impacts will be in a further 20, 50 or 100 years. This research cruise will help us to understand what the future may hold,” said Dr Phil Williamson, UEA coordinator for the UK Ocean Acidification research programme.

On the cruise, the researchers will study the impact of the changing chemistry on marine organisms and ecosystems, on the cycling of carbon and nutrients in the sea, and on how the sea interacts with the atmosphere to influence climate.

They will do this in three main ways. Their first approach will be to look at how the microscopic organisms living in surface waters vary between places where the chemistry of seawater is naturally more acidic or alkaline. By contrasting the observations over a range of different conditions, they hope to improve understanding of how acidification affects organisms living in their natural environment, where natural selection and adaptation have had time to play out.

Their second approach will be to conduct experiments using tanks of natural seawater collected from the surface of the sea and brought into a controlled laboratory on deck. The natural seawater (and the microbes it contains) will then be subjected to various levels of carbon dioxide that may occur in the future. This cruise will conduct the largest ever experiment to examine the effects of changing CO2 levels on real world samples out at sea as opposed to in the laboratory.

In a third approach, researchers from Heriot-Watt University will be studying how ocean acidification may affect deep-sea corals.

The research is part of the UK Ocean Acidification research programme (UKOA), funded by the Natural Environment Research Council (NERC) and two government departments, the Department of Environment, Food and Rural Affairs (Defra) and the Department of Energy and Climate Change (DECC).

The participating institutes are as follows: University of Southampton; National Oceanography Centre, Southampton and Liverpool; Plymouth Marine Laboratory; Heriot-Watt University; University of East Anglia; University of Essex; Marine Biological Association; and the University of Oxford.

You can follow the cruise at http://noc.ac.uk/news/rrs-discovery-cruise-366-6-june-2011

More information on the UK Ocean Acidification programme: http://www.oceanacidification.org.uk/