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Studying the oceans to predict climate change

A major factor influencing climate change is the accumulation of carbon dioxide in the Earth’s atmosphere. The role of the oceans in the CO2 carbon cycle is important. They soak up a third to a half of all the extra CO2 generated. But to predict the course of future changes we need an accurate knowledge of the processes occurring now. To help meet this challenge an innovative partnership has been established between one of the world’ major industrial groups, the Swire Group and the UK’s National Oceanography Centre, Southampton to launch the SNOMS (Swire NOCS Ocean Monitoring System) Project. The Swire Group Charitable Trust has funded the design and assembly by NOCS of a system to measure the partial pressure of CO2 in the surface waters of the world’s oceans. In June 2007 the equipment was installed on the Swire Shipping’s vessel Pacific Celebes, which trades out of Singapore on a five-month round-the-world service.

Using large commercial vessels like Pacific Celebes to collect scientific data enables samples to be taken over sustained time periods and long distances, at little or no cost to the scientific community, and modern communications systems enable information to be transmitted to shore for analysis in real time.

Long-term monitoring is essential to distinguish progressive climate change from natural oscillations, which tend to have time scales in the five and ten year range. This is where liners like Pacific Celebes, which stick to well-defined routes, come in. They have huge potential to allow repeated observations over many years. SNOMS is a part of the wider International Ocean Carbon Coordination Project (IOCCP http://ioc.unesco.org/IOCCP), which has promoted the use so-called “ships of opportunity” to assist with data collection. Information from the SNOMS project is made available to a network of scientific organisations linked to the United Nations via UNESCO and the World Meteorological Organisation, and to the wider public via the project’s website: www.noc.soton.ac.uk/snoms. (The current position of the Pacific Celebes can be found on the website.)

The system was designed to be serviceable by the ship's crew, who are now key members of the science team. It centers around an enclosed stainless steel tank located at the bottom of the engine room. The tank is connected to the ship’s seawater supply and contains devices for measuring dissolved carbon dioxide and oxygen, total dissolved gas pressure (for estimating dissolved nitrogen), temperature and conductivity. The information is collected by a data-logging control computer, which also receives input from a temperature sensor mounted on the ship’s hull and from measuring equipment on the highest deck on the ship. There sensors measure humidity, air temperature and atmospheric CO2 content, and ship’s position. An Iridium satellite communications modem transmits the information to NOCS.

David Hydes comments: “More data will continue to be needed for some time yet to help us determine regional differences, and understand the interaction of biogeochemical and physical processes through time. Extending the marine CO2 system database is crucial to aid improved accounting of the Earth’s carbon budget and ultimately to guiding amelioration strategies. Even at this early stage the SNOMS project has been very impressive in showing how well commercial and research organisations can work together to reduce the serious short fall in human knowledge about our small green planet. SNOMS provides a perfect example of how the aims of the IOCCP Ship of Opportunity project can be met very effectively when cross sector partnerships such as SNOMS evolve.”

 

David Hydes
National Oceanography Centre, Southampton (NOCS)