Predicting future global distributions and biogeochemical impacts of the marine Cyanobacteria Prochlorococcus and Synechococcus

ADAM C MARTINY; FLOMBAUM, P; MICHAEL W. LOMAS

Granada

Congreso; 2015 Aquatic Sciences Meeting; 2015

ASLO

The Cyanobacteria Prochlorococcus and Synechococcus account for a substantial fraction of marine primary production. Here, we present quantitative niche models for these lineages that assess present and future global abundances and distributions. These niche models are the result of neural network, nonparametric, and parametric analyses, and they rely on observations from all major ocean regions. Using climate model projections of sea surface temperature as a result of increased concentrations of greenhouse gases at the end of the 21st century, our niche models projected increases in cell numbers of both Prochlorococcus and Synechococcus. The changes are geographically uneven but include a poleward expansion in area as well as increased abundances in regions where the lineages already are common. Thus, our global niche models suggest that oceanic microbial communities will experience complex changes as a result of projected future climate conditions. We furthermore analyze the impact of these changes on two key biogeochemical features ? NPP and the C:N:P ratios of surface particles. Our results suggest that future changes in marine Cyanobacteria may affect biogeochemistry in ways not currently captured by ocean models.