The Plymouth Marine Science and Education Foundation (PlyMSEF) is delighted to announce that this year's Plymouth Marine Science Medal Lecture, hosted by the Marine Institute, will be given by invited guest speaker Professor Doug Wallace from Dalhousie University, Halifax, Nova Scotia, Canada.
The ocean breathes. In a manner analogous with our lungs and blood stream, it exchanges both oxygen and CO2 across the ocean surface, and the ocean’s circulation transports the gases towards and away from regions of the ocean interior where they are metabolised.
The Labrador Sea, between Labrador and Greenland, plays a particularly important role for ‘breathing in’ oxygen from the atmosphere. The oxygen uptake in that region contributes vital life-support to fish and microbes in the deeper parts of the Atlantic, Pacific and Indian Oceans. The “breathing in” takes place during wintertime, when surface waters become cold and dense enough to sink to depths of 1-2 kilometres. The breathing continues all winter long, due to progressive exposure of deeper water with low oxygen content to the atmosphere. The ocean gulps up enormous quantities of oxygen from the atmosphere, especially as a result of massive injection of air bubbles produced during storms. During summer, on the other hand, photosynthesis by phytoplankton produces oxygen, some of which is released back to the atmosphere.
The story for CO2 is quite different: the region is a net sink for CO2 over the annual cycle, due mainly to biological uptake in summer. During winter, only a small amount of respired CO2 is released back to the atmosphere: in part because increasing atmospheric CO2 has diminished the natural process of CO2 outgassing, causing more CO2 to be stored in the ocean.
The lecture will present results collected over the past year with a unique, Canadian-designed underwater winch, the SeaCycler, which allows for year-round profiling of oxygen, carbon dioxide and many other related, biological and physical parameters.
The resulting data reveal, in unprecedented detail, how the breathing of the Labrador Sea operates, and starts to show how the depth of breathing, and hence the amount of oxygen and carbon dioxide exchanged with the atmosphere, may vary under changing climate conditions. For example, the close proximity of the Labrador Sea to melting sea- and glacial-ice of the Arctic and Greenland, raises the question whether increased buoyancy due to increased freshwater input, might cause the Labrador Sea’s breathing to become shallower in coming decades, potentially reducing the oxygen supply to the ocean interior.
This free lecture is open to all and doors will open from 17:30 for 18:00 start. The lecture will finish around 19:30 and will be followed by a drinks reception.
Registration is essential - please register your place via the above link.