Project: Tracking the temporal and spatial variability of dissolved organic matter, its diagenetic state and bioavailability during various bloom states in the North Atlantic

Tracking the temporal and spatial variability of dissolved organic matter, its diagenetic state and bioavailability during various bloom states in the North Atlantic
Craig Carlson
ID: 1537943

The North Atlantic phytoplankton bloom is among the most conspicuous biological events annually recorded. This bloom represents a hot spot of biological activity during which a significant amount of dissolved organic matter is produced through bloom-associated food web processes. While recent work has shed some light on the spatial distribution of dissolved organic matter during the North Atlantic bloom, temporal resolution of dissolved organic matter variability in the context of the North Atlantic bloom is lacking. This project aims to understand the temporal and spatial dynamics of dissolved organic matter, its compositional variability, as well as the mechanisms that control its accumulation, persistence and export in the North Atlantic. This project will leverage a large, recently funded, NASA field-program called the North Atlantic Aerosols and Marine Ecosystem Study (NAAMES) designed to evaluate the fundamental controls of the north Atlantic phytoplankton bloom initiation, its magnitude and interannual variability. Results from this research will provide a mechanistic understanding of carbon cycling in the context of the North Atlantic phytoplankton bloom. The research will be carried out at the University of California ? Santa Barbara, a Hispanic-serving institution, and will involve educational opportunities for students from elementary through graduate school.

Recent work examining the spatial distribution of dissolved organic matter in the North Atlantic coupled to measurements of water mass ventilation rates has estimated that a significant amount of carbon is vertically exported out of the surface ocean to deep waters as dissolved organic matter. However, an overarching gap in dissolved organic matter knowledge is the lack of valuable temporal resolution necessary to investigate the mechanisms that control dissolved organic matter production, accumulation, or its change in quality and bioavailability as a result of changing bloom phases and phytoplankton cycles. This research will examine the temporal and spatial variability of dissolved organic matter dynamics along a repeated meridional transect during four distinct phases associated with the North Atlantic spring phytoplankton bloom including 1) pre-bloom, mixing phase, 2) nutrient-replete, increasing biomass phase, 3) nutrient-stressed decreasing biomass phase, and 4) post bloom stratified phase. This will be accomplished by coupling continuous water column and surface layer ecosystem properties from autonomous in situ sensors, and satellite observations with four 26-day coordinated ship and airborne field campaigns.