Mitchell, Brian (Greg): Scripps Institution of Oceanography (Project Lead)
Project Funding:
2014 - 2015
NRA: 2013 NASA: Ocean Biology and Biogeochemistry
Funded by NASA
Abstract:
Changes in the carbon cycle of the Southern Ocean during glacial / interglacial climate transitions have been directly linked to major changes in atmospheric CO2 and greenhouse gas climate forcing (Sarmiento and Toggweiler 1984). Martin et al. (1990) demonstrated that iron deficiency limits phytoplankton productivity in the Southern Ocean. The Southern Ocean plankton ecology system has the largest inventory of pre-formed nutrients in the global oceans and thus is considered to be a region with a large potential for climate feedback through changes in net community production (NCP) (Sigman et al. 2010; 2013). The rate of iron delivery to the photic zone combined with upper ocean stratification regulates primary production in the Southern Ocean. These discoveries motivated major multi-agency interdisciplinary projects in the region (JGOFS, SOFEX and GASEX) yet we still lack an ability to constrain NCP estimates better than a factor of 2x. Therefore it is essential to understand the integrated dynamics of ocean, ice and atmosphere interactions to quantify the magnitude and uncertainties of carbon fluxes, and to carry out climate prediction scenarios. Key questions that must be addressed include: 1) Will warming and acceleration of glacial melt increase surface buoyancy and stratification, thereby reducing iron input to the surface ocean? 2) Will glacial melt deliver more atmospheric iron stored for millennia in the ice, and fresh water buoyancy to the surface ocean, thus increasing productivity? 3) Will stronger winds and reduced sea ice lead to deeper mixing and coastal upwelling delivering more iron to the system? These system-level questions are directly relevant to the high-level goals defined by NASA's Carbon Cycle and Ecosystems Roadmap as focused by NASA's Ocean Biology and Biogeochemistry Program and motivate NASA's PACE advanced hyperspectral ocean color satellite mission.
More details may be found in the following project profile(s):
