Ecoregions in the Mediterranean Sea Through the Reanalysis of Phytoplankton Functional Types and Carbon Fluxes

Ciavatta, S; Kay, S; Brewin, RJW; Cox, R.; Di Cicco, A; Nencioli, F; Polimene, L; Sammartino, M; Santoleri, R; Skakala, J; Tsapakis, M.. 2019 Ecoregions in the Mediterranean Sea Through the Reanalysis of Phytoplankton Functional Types and Carbon Fluxes. Journal of Geophysical Research: Oceans, 124 (10). 6737-6759. https://doi.org/10.1029/2019JC015128

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Official URL: http://dx.doi.org/10.1029/2019JC015128

Abstract/Summary

In this work we produced a long‐term reanalysis of the phytoplankton community structure in the Mediterranean Sea and used it to define ecoregions. These were based on the spatial variability of the phytoplankton type fractions and their influence on selected carbon fluxes. A regional ocean color product of four phytoplankton functional types (PFTs; diatoms, dinoflagellates, nanophytoplankton, and picophytoplankton) was assimilated into a coupled physical‐biogeochemical model of the Mediterranean Sea (Proudman Oceanographic Laboratory Coastal Ocean Modelling System‐European Regional Seas Ecosystem Model, POLCOMS–ERSEM) by using a 100‐member ensemble Kalman filter, in a reanalysis simulation for years 1998–2014. The reanalysis outperformed the reference simulation in representing the assimilated ocean color PFT fractions to total chlorophyll, although the skill for the ocean color PFT concentrations was not improved significantly. The reanalysis did not impact noticeably the reference simulation of not assimilated in situ observations, with the exception of a slight bias reduction for the situ PFT concentrations, and a deterioration of the phosphate simulation. We found that the Mediterranean Sea can be subdivided in three PFT‐based ecoregions, derived from the spatial variability of the PFT fraction dominance or relevance. Picophytoplankton dominates the largest part of open ocean waters; microphytoplankton dominates in a few, highly productive coastal spots near large‐river mouths; nanophytoplankton is relevant in intermediate‐productive coastal and Atlantic‐influenced waters. The trophic and carbon sedimentation efficiencies are highest in the microphytoplankton ecoregion and lowest in the picophytoplankton and nanophytoplankton ecoregions. The reanalysis and regionalization offer new perspectives on the variability of the structure and functioning of the phytoplankton community and related biogeochemical fluxes, with foreseeable applications in Blue Growth of the Mediterranean Sea.

Item Type: Publication - Article
Subjects: Earth Observation - Remote Sensing
Ecology and Environment
Marine Sciences
Oceanography
Divisions: Plymouth Marine Laboratory > National Capability categories > Modelling
Plymouth Marine Laboratory > National Capability categories > National Centre for Earth Observation
Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Plymouth Marine Laboratory > Science Areas > Marine Ecosystem Models and Predictions
Depositing User: Francesco Nencioli
Date made live: 28 Sep 2020 12:48
Last Modified: 28 Sep 2020 12:58
URI: http://plymsea.ac.uk/id/eprint/8876

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