Quantifying the impact of submesoscale processes on the spring phytoplankton bloom in a turbulent upper ocean using a Lagrangian approach

• Published in: Geophysical research letters Vol. 43; no. 10; pp. 5160 - 5169
• Main Authors: Brody, Sarah R., Lozier, M. Susan, Mahadevan, Amala
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.05.2016; Wiley
• Subjects: Blooms; Carbon cycle; Computational fluid dynamics; Computer simulation; Density stratification; Displacement; Ecosystems; Eddies; Evolution; Fluxes; Heat; Heat flux; heat fluxes; Lagrangian modeling; Loads (forces); localized stratification; Marine; Marine ecosystems; Mixed layer; mixed layer eddies; Ocean currents; Phytoplankton; Phytoplankton bloom; phytoplankton blooms; Plankton; Spring; Stratification; Surface mixed layer; Time measurement; Time measurements; Tracking; Trajectories; Turbulence; Upper ocean; Vortices; AN, North Atlantic
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL068051

The spring phytoplankton bloom in the subpolar North Atlantic and the mechanisms controlling its evolution and onset have important consequences for marine ecosystems and carbon cycling. Submesoscale mixed layer eddies (MLEs) play a role in the onset of the bloom by creating localized stratification and alleviating phytoplankton light limitation; however, the importance of MLEs for phytoplankton in a turbulent surface mixed layer has not yet been examined. We explore the effect of MLEs on phytoplankton by simulating their trajectories with Lagrangian particles subject to turbulent vertical displacements in an MLE‐resolving model. By tracking the light exposure of the simulated phytoplankton, we find that MLEs can advance the timing of the spring bloom by 1 to 2 weeks, depending on surface forcing conditions. The onset of the bloom is linked with the onset of positive heat fluxes, whether or not MLEs are present. Key Points We test the importance of mixed layer eddies to phytoplankton blooms using a Lagrangian approach Mixed layer eddies can advance the timing of the bloom by 1 to 2 weeks Blooms are tightly linked to heat fluxes, whether or not mixed layer eddies are present