Title: Distributions of phytoplankton biomass in the ocean: connections to growth and implications for marine biogeochemical cycles
Abstract: Phytoplankton biomass is a fundamental measure of life and carbon flux in the oceans. In particular, the rate of primary production is the product of phytoplankton biomass and its growth rate. While remote sensing products have come a long way toward measuring phytoplankton biomass, they still generally rely on conversion factors and basic assumptions of carbon to chlorophyll ratios, both of which can vary widely. Recent work has also begun to describe phytoplankton community composition, which is a critical factor in understanding export out of the euphotic zone. Satellite data-based phytoplankton functional type (PFT) algorithms are either based on size class or phytoplankton pigments, neither of which have a direct and well constrained relationship with growth rate. Published satellite biomass estimates also lack insight into mechanistic controls and therefore have potentially limited utility in describing ecological processes and forecasting how they may change in the future. Improved estimation of phytoplankton biomass, its relation to environmental variables and impacts on ocean biogeochemistry is a critical step in advancing our understanding of change in the ocean, and validating predictive remote sensing algorithms. In this talk I’ll present taxon-specific carbon content data from cruises that span a range of primary productivity, and begin to link these to biogeochemical patterns in the ocean.