Low and mid-trophic levels hindcasts of the Copernicus Marine Service catalogue: new release and contribution to the Ocean State Report.

Since mid-2019, meso-zooplankton and micronekton density hindcast (large past time series that are processed with time-consistent forcings) are available and regularly extended for the Copernicus Marine Service catalogue. The product (also known as MICRORYS) is computed using SEAPODYM-LMTL, the Lower and Mid Trophic levels model of the Spatial Ecosystem And POpulation DYnamic Modeling framework. Meso-zooplankton organisms (200µm-2mm) constitute the low-trophic level. These organisms are transported along with the water masses. Micronekton organisms, constituting the mid-trophic level, are bigger organisms (2-20cm) able to swim over short distances. SEAPODYM models the spatial and population dynamics of the LMTL population with a system of advection-diffusion-reaction equations. The vertical dimension is simplified into three layers (namely epipelagic, upper, and lower mesopelagic). Layers matches the vertical distribution of organisms that is observed. The six micronekton groups are defined according to their diel vertical migration from the surface at night to the deep ocean during the day. MICRORYS product uses a global configuration of SEAPODYM at 1/12° daily resolution. We will present the latest release (dec. 2024) computed with a new computational grid with better geometrical properties. We will also visit new applications of micronekton  biomass densities as prey fields for marine predators to better understand their behaviour. We will end with new contribution related to mid trophic levels to the Ocean State Report and the description of potential Ocean Monitoring Indicators.