Biological modulation of upper ocean physics: Simulating the biothermal feedback effect in Monterey Bay, California

Abstract

Marine phytoplankton and associated organic materials absorb a substantial quantity of solar shortwave energy penetrating the upper ocean. Most of this absorbed energy is lost as heat and thereby contributes to the warming of near-surface waters. Here we examine this biothermal feedback effect on upper ocean physics and air-sea energy exchange using a fully integrated ocean-atmosphere-biological modeling system. Our model simulations show that a local phytoplankton bloom may impact upper ocean physics in such a way as to promote the spatiotemporal persistence of the bloom itself within a semi-enclosed coastal embayment. This is accomplished primarily via enhanced thermal stratification that promotes vertical stability and more efficient utilization of macronutrients. Modulations of wind stress patterns due to perturbations in the local surface pressure gradients also arise as a result of the simulated biothermal warming of surface waters. The model evidence suggests that the observed persistence of phytoplankton blooms in the northern Monterey Bay, California, may be enhanced by similar synergistic interactions between ocean biology and physics. Key Points An integrated ocean-atmosphere-biology modeling system is developed Biothermal feedback to physics alters the ocean-atmosphere model results Biothermal feedback also enhances the simulated phytoplankton growth ©2014. American Geophysical Union. All Rights Reserved.