Understanding the roles of multiple climate change drivers in altering phytoplankton habitats

Stephanie Dutkiewicz, Massachusetts Institute of Technology, stephd@mit.edu (Presenter)
Jeff Morris, University of Alabama at Birmingham, evolve@uab.mit.edu
Michael Follows, MIT, mick@mit.edu
Jeff Scott, MIT, jscott@mit.edu
Oliver Jahn, MIT, jahn@mit.edu
Sonya Dyhrman, Lamont, Columbia University, sdyhrman@ldeo.columbia.edu
Ilana Berman-Frank, Bar-Ilan University, ibermanfrank@gmail.com

Phytoplankton form the base of the marine foodweb and contribute significantly to the export and storage of carbon in the deep ocean. Combinations of traits, such as cell size and nutrient requirements, mediate the relative fitness of diverse phytoplankton populations in different environments shaping their observed biogeography. These organisms face multiple environmental changes ('drivers'), including warming waters, alterations to light environment, changes to the supply of crucial nutrients, and the drop in ocean pH ('ocean acidification') caused by rising atmospheric pCO2. We employ a marine ecosystem model, with diverse and flexible phytoplankton communities, coupled to an Earth system model of intermediate complexity to explore a subset of these drivers and interactions that may alter the biogeography of phytoplankton populations in a future world. In the model, warming drives a reorganization of biogeography, mediated by physical dispersal of phytoplankton to accommodate shifting habitats. Stratification and declining supply of nutrients has less impact on large-scale habitats but shifts the functional composition of communities to favor smaller phytoplankton better adapted to oligotrophic conditions. In the simulations, relative changes in fitness due to the differential response of maximum growth rate to expected elevations of pCO2, suggested by a meta-analysis of acidification experiments, significantly altered community structure and biogeography. We find that ranges of some phytoplankton types are reduced, while those of others (potentially minor players in the present ocean) expand. Combined change in areal extent of range and in regionally available nutrients, as well as shifts in relative fitness leads to global “winners and losers.”

Presentation Type:  Poster

Session:  Theme 1: Tracking habitat change through new integrative approaches and products   (Mon 1:30 PM)

Associated Project(s): 

• Follows, Mick: Interpreting ecological variability using remotely observed optical properties and ocean models. ...details

Poster Location ID: 15