Effects of Climate Change on the Biophysics of the Ocean

Climate model predictions of the next century generally portend increased ocean temperatures, increased vertical stratification, and a poleward shift of the physical regimes that are associated with different ocean biomes, including a shrinking of seasonally ice covered regions. The general direction of the predicted physical changes is consistent between models, but direct prediction of the impact of the physical changes on the unicellular plants and animals that make up the base of the food chain in the ocean is a major challenge that we have attempted to address using both empirical and theoretical models. The empirical model predictions are highly sensitive to how the data used to set the model up are parameterized, but theoretical models tend to give reasonably consistent results suggesting that the subtropics will become less productive due to reduced upward nutrient supply, while the subpolar and polar regions will tend to become more productive due to an extension of the growing season as deep wintertime mixing events terminate earlier in the year.