U.S.-New Zealand Collaborative Research: The Biogeochemical Cycling of Iron in Waters of the Subantarctic Southern Ocean (FeCycle)

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0238615McKayA multidisciplinary and multinational research group working on board a New Zealand ship and led by Dr. Philip Boyd of University of Otago, New Zealand, will seek to gain a better understanding of the role of iron in the structure and function of the ecosystems of the Southern Ocean. This award supports Dr. Robert McKay of Bowling Green State University to participate in this field research as the lead Principal Investigator for a group of three U.S. scientists and a graduate student involved in the same research cruise and supported by separate grants. His U.S. co-Principal Investigators and their award numbers are Steven Wilhelm of the University of Tennessee at Knoxville (0240092) and David Hutchins of the University of Delaware (0236987). The specific research foci of the three U.S. scientists differ. Dr. McKay will measure diagnostic indicators of iron limitation such as the ratio of flavodoxin to ferrodoxin. Dr. Wilhelm and Dr. McKay will evaluate degrees of iron stress in the phytoplankton community using state-of-the-art prokaryotic bioreporter constructs. Dr. Hutchins will simulate changes in diapycnal iron inputs using a novel shipboard natural community chemostat system. He will also apply a newly developed trace metal clean surface wash method to measure scavenged and interior pools of particulate iron.The micronutrient iron limits phytoplankton growth and photosynthesis over most of the large Southern Ocean surrounding Antarctica. This in turn affects the global carbon cycle.Most studies of iron in the ocean have come from adding artificially high levels and monitoring the changes seen in the affected body of water. Very little is known about the major pools, fluxes and biogeochemical pathways of this limiting nutrient under unperturbed natural conditions. This research effort will employ several novel techniques to assess microbial impacts on and reactions to iron levels in a natural oceanic environment. This will be a significant contribution to the ability to model the natural marine iron cycle in an important region of the world's ocean. If successful, the innovative techniques employed will have wide value to other marine scientists. It will have educational impacts for the US graduate student who will participate and for students of the US investigators who will learn about the work.