The atmosphere’s composition determines the Earth‘s climate and habitability. This composition is, in turn, strongly determined by biological, physical and chemical processes occurring within the oceans. For example, gas exchange across the enormous surface area of the global ocean, together with ocean circulation and biology, plays a crucially important role in controlling the present-day level and growth rate of CO2 in the atmosphere.
The oceans are recognised as the source for a range of chemical species, including N2O, that play key roles in the atmosphere and in the Earth’s radiative budget. There are indeed numerous atmosphere-ocean interactions, involving both gases and particles, which are mediated by marine biogeochemical processes. Several such interactions are already recognised to be of major significance not only for climate, but may also be triggers for major changes in ecosystems, particularly in the context of global change. In particular, changes in the loading of atmospheric dust are now recognised to have strong effects on ocean productivity but may also have significant influences on ocean climate. Changes in emissions or uptake of trace gases (including but not limited to CO2) can strongly affect the chemistry of the troposphere and/or the chemistry and biology of the upper ocean.
Increasingly, mankind is altering the particulate and gaseous composition of the atmosphere on a global scale (Figure 1) and is therefore altering the interplay between the physical climate system and biogeochemistry. The human impact on atmosphere-ocean transfers can be mediated both by “direct” forcing (e.g. increased CO2, increased tropospheric ozone, increased dust erosion from soils followed by Aeolian transport to the open ocean) as well as via “indirect” forcing associated with altered radiative transfer or climate change and consequent effects on the uptake or emission of trace gases or particles. Such forcing changes impact, in turn, the atmospheric composition, ocean productivity and climate via feedback processes.
Over the past few decades, we have moved from a situation in which such global change impacts were considered to be interesting ‘geophysical experiments’ to the present situation where the effects of ‘Anthropocene’ forcing are becoming increasingly significant for the chemistry and biology of our planet and vice versa. The environmental problems facing human society over the next 100 years are, as a result, increasingly global and interdisciplinary in scope. The effects of such global-scale forcing will become increasingly noticeable for their regional and local impacts on human society over the coming decades.
Figure 1: Interdisciplinary Earth System Linkages within SOPRAN and international SOLAS (Surface Ocean - Lower Atmosphere Study).
It is impossible to address such issues with traditional single-discipline approaches to research and education. However in order to stimulate the new, interdisciplinary “Earth System thinking” that is necessary for tackling modern and future environmental problems, there is an need to support interdisciplinary global change research and encourage interdisciplinary education. This requires explicit consideration of the coupled nature of the Earth System within global change research projects.
With these needs in mind, our proposed SOPRAN project depends explicitly on integrating the contributions and expertise of scientists trained in physics, chemistry and biology. Specifically, atmospheric chemists and physicists, chemical, biological and physical oceanographers and marine ecologists will tackle problems of common interest and relevance to human society. Hence as well as being an important research program in its own right, the SOPRAN research themes provide a context within which diverse research communities, that are presently operating separately, can be joined in highly innovative research and within which the next generation of scientists can be trained.