MESOPP partners use different tools to study micronekton : active acoustic observations and ecosystem models. This month, we focus on the model : SEAPODYM-MTL.

Developed by the Marine Ecosystem Team at CLS (Toulouse), SEAPODYM-MTL is a model predicting micronekton biomass over the global ocean. Whereas other models described taxa at a fine scale, in SEAPODYM-MTL, micronekton is considered as an ensemble of functional groups. These groups are only defined by their vertical behaviour. Indeed, micronekton may undergo diel vertical migration : inhabiting the surface at night and deeper layers during the day In SEAPODYM-MTL model six functional groups of micronekton, migrating and non-migrating, comprise numerous species sharing the same vertical behaviour. The model is based on a system of advection-diffusion-reaction equations solved on a regular grid over a three-layer ocean domain. Currently the global configuration model resolution is 1/4° x 1/4° weekly. The figure shows the daily surface micronekton biomass during the last week of August 2016, in grammes of wet weight per metre square and the animation

P. Lehodey et Al (2014) Optimization of a micronekton model with acoustic data. ICES Journal of Marine Science. 2014