In the second presentation, Professor Tim Jickells (School of Environmental Sciences, UEA) spoke on Atmospheric Nitrogen Inputs to the Marine Environment. As visualised from orbiting satellites, the colour of the earth’s oceans reveals chlorophyll distribution and is hence a map of phytoplankton distribution. All productivity in oceans is driven by marine phytoplankton, which needs N, P, Si, Fe and light to survive and multiply. Sources of oceanic nitrogen inputs are summarised to the right.
Surveys of the oceans reveal the extent and complexity of nitrogen speciation in the marine environment. Sampling is carried out from the RRS James Cook (pictured left) in the Atlantic and on island sites (e.g. at the Cape Verde Atmospheric Observatory). Current work carried out primarily through the ‘Atlantic Meridional Transect’ cruise series (AMT; http://www.amt-uk.org/) shows high phytoplankton productivity in northern waters (due to deposition of European/US N-rich emissions), but low productivity near the equator (influenced by African emissions) and low productivity in Southern Oceans.