The impacts of climate change variability on primary productivity and carbon distributions in the mid Atlantic bight and gulf of Maine
Source of Support: NASA Grant # NNX10AF01G
Award Amount: $59,526
Period Covered: 01/21/2010to 01/20/2013
Observations from the MODIS and SeaWiFS time series (1997-2012) and measurements from the extensive field campaign proposed here will be used to examine how inter-annual and decadal-scale climate variability affects primary productivity and organic carbon distributions along the continental margin of the U.S. East Coast. Estimates of daily primary productivity (PP) will be computed using the Ocean Productivity from Absorption of Light (OPAL) model (Marra et al. 2007). OPAL vertically resolves phytoplankton absorption of photosynthetically active radiation (PAR) and relates the chlorophyll-specific absorption coefficient to sea-surface temperature (SST), where SST is a proxy for seasonal changes in the phytoplankton community. OPAL will be validated with new field measurements of PP including dissolved organic carbon production. Field measurements of particulate (POC) and dissolved organic carbon (DOC) and the absorption coefficients of phytoplankton (aph) and colored dissolved organic matter (aCDOM) will allow us to extend the validation range (temporally and spatially) for our coastal algorithms (Mannino et al. 2008; Pan et al. in review) and reduce the uncertainties in satellite-derived estimates of OPAL PP, POC, DOC, aph and aCDOM. Furthermore, we will apply our extensive field data to derive region-independent ocean color algorithms for PP, POC, DOC aCDOM and aph using a neural network approach. We will rigorously validate and compare band-ratio and multivariate neural network algorithms. The U.S. Middle Atlantic Bight (MAB), George’s Bank (GB) and Gulf of Maine (GoM) stand at the crossroads between major ocean circulation features the Gulf Stream and Labrador slope-sea and shelf currents and are influenced by highly variable river discharge, summer upwelling, warm core rings, and intense seasonal stratification. Our work will focus on the impacts of variable river discharge, SST, wind stress and large-scale climate indices on primary production, and POC and DOC distributions. These processes are not unique to the MAB and GoM. Consequently, the results from the proposed activity can be applied to understanding how inter-annual and long-term variability in climate patterns can impact the carbon cycle of continental margins throughout the globe.