Evidence for enhanced phosphorus regeneration from marine sediments overlain by oxygen depleted waters

Phosphorus regeneration and burial fluxes determined from in situ benthic flux chamber and solid phase measurements at sites on the Californian continental margin, Peruvian continental slope, North Carolina continental slope, and from the Santa Monica Basin, California are reported. Comparison of these sites indicates that O2-depleted bottomwaters enhance P regeneration from sediments, diminishing overall phosphorus burial efficiency. Based on these observations, a positive feedback linking ocean anoxia, enhanced benthic phosphorus regeneration, and marine productivity is proposed. On shorter timescales, these results also suggest that O2 depletion in coastal regions caused by eutrophication may enhance P regeneration from sediments, thereby providing additional P necessary for increased biological productivity.