K. Tsiaras, G.. Petihakis, G.. Triantafyllou, Hellenic Centre for Marine Research (HCMR), Greece
Within Operational Ecology (OPEC) project, coupled modeling systems were implemented in four European regional seas (North-East Atlantic, Baltic, Mediterranean and Black Seas) reconstructing the recent past and exploring the skill for future predictions, in support of an ecosystem-based management through MSFD descriptors. OPEC provided direct access to key environmental indicators, including those related to eutrophication, such as chlorophyll, nutrients and oxygen. Within OPEC, the Mediterranean coupled hydrodynamic/biogeochemical model (POM-ERSEM), currently operational within the POSEIDON forecast system (<a href=" www.poseidon.hcmr.gr' target="_blank"> www.poseidon.hcmr.gr </a>) was upgraded to assimilate satellite Chl-a. A new data assimilation algorithm was developed based on a Hybrid (Ensemble Kalman filter/ Optimal Interpolation) scheme that combines a flow-dependent ensemble error covariance with a static background covariance built from a set of empirical orthogonal functions (EOFs). The same coupled model has also been implemented on a regional scale (N. Aegean) within SESAME and MEECE EU-projects projects, to examine the impact of river nutrient load variability on the ecosystem functioning over the last decades. The increased phosphate river loads in the early 80's resulted in nitrogen and silicate deficiency in N. Aegean coastal, river-influenced regions, causing a relative decrease of diatoms and an increase of dinoflagellates. Such an increase was simulated in the late 90s in the Thermaikos Gulf, in agreement with the observed increased occurrence of Harmful Algal Blooms. Recently, within project SEAMAN, gelatinous ctenophore Mnemiopsis Leidyi that is also closely related to eutrophication was added in ERSEM functional groups in a simplified approach to study its effect on small pelagic fish.
Operational Ecology, D5, Descriptor 5, modelling, ecosystem based management, OPEC, biogeochemical, hydrodynamic, SESAME, MEECE, river nutrient load, phosphate
Workshop of the Network of Experts for ReDeveloping Models of the European Marine Environment
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