Master WAPE Courses


BIOG - Biochemical cycles in the ocean

Physical-Biogeochemical Coupling and Carbon Cycle in the Ocean


Marina Lévy, Laurent Bopp & Xavier Capet
3 ECTS

This course has been specifically designed for WAPE

Course description

This course introduces the basic concepts of marine biogeochemistry, its link with oceanic circulation and physics, and how it is modelled and observed.
The students will be exposed to state-of-the-art ocean science through a regional approach: several physical and biogeochemical regimes that dominate in coherent parts of the global ocean (Peru-Chile upwelling, Indian ocean, North Atlantic) will be studied and contrasted with a particular emphasis on physical control and on turbulent processes at meso- and submeso-scale (1-100 km typical length scales).

The range of applications includes key environmental issues such as cycling of green house gases, regional/global climate change and its impact on marine foodwebs, design of marine protected areas, ocean acidification and marine pollution.

The course consists in 8 classes of 3h each and 2 modelling sessions of 3h
•    Class 1 (XC): Physical oceanography: basic concept and regional examples
o    The ocean: a rotating stratified fluid
o    The atmospheric drivers of oceanic circulation
o    The oceanic mixed layer: basics
o    Regional oceanography

•    Classes 2 and 3 (XC): Ocean turbulence and their advective/diffusive consequences
o    Spatial heterogeneity and time variability: why scales matter?
o    Mesoscale/submesoscale turbulence: definition and basic concepts
o    Baroclinic instability
o    Frontogenesis
o    Atmosphere/ocean interactions at mesoscale/synotic scale
o    Regional differences in turbulence regimes
o    The oceanic boundary layer in a turbulent ocean
o    Wind/wave/current interactions (Langmuir cells)

•    Class 4 (LB): Introduction to Marine Biogeochemistry
Marine phytoplankton populations - descriptive view
o    Photosynthesis
o    Global distribution of chlorophyll
o    Seasonal variations
o    Diversity of phytoplankton: traits (particularly cell size)
o    Who is living where and when
o    Nutrient and light acquisition
o    Growth rate, nutrient affinity cell size

•    Class 5 (ML): Phytoplankton in a fluid environment
o    Advection and diffusion
o    Ocean currents and turbulence
o    Spring blooms - sverdrups model
o    Biodiversity of phytoplankton - advection/mixing of "provinces"

•    Class 6 (LB): Marine biogeochemistry and climate
o    The oceanic carbon cycle
o    Ocean acidification
o    Air-sea gas exchange (CO2, DMS, O2)

•    Class 7 (ML): Physical-biogeochemical coupling at mesoscale and submesoscale
o    North Atlantic example
o    Model process studies
o    Satellite observations

•    Class 8 (ML): Regional examples
o    Eastern upwelling systems including Oxygen minimum zones
o    Arabian Sea

•    Modelling session 1(LB): simulations of a seasonal cycle in 1D with the biogeochemical model PISCES
•    Modelling session 2 (LB) : example of a 3D simulation

Marina Lévy (ML) is Directeur de Recherche at CNRS and head of the team PHYBIOCAR (Physics-Biogeochemistry-Carbon) of the Laboratoire d'Oceanographie et du Climat in Paris (LOCEAN, http://www.locean-ipsl.upmc.fr/~marina). Her research is focused on the influence of ocean dynamics on ocean biogeochemistry, at basin, regional, mesoscale and submesoscales.

Laurent Bopp (LB) is Chargé de Recherche at CNRS and head of the team BIOMAC (Marine Biogeochemistry and Climate) at Laboratoire des Sciences du Climat et de l'Environnement in Saclay (LSCE, http://www.lsce.ipsl.fr). His research is focused on the interactions between marine biogeochemistry and climate, on time scales ranging from the last million of years to anthropogenic global warming.

Xavier Capet (XC) is Chargé de Recherche at CNRS. He is part of the ocean turbulence team in Laboratoire de Physique des Océans in Brest (LPO, http://wwz.ifremer.fr/lpo). His main research interests are mesoscale/submesoscale turbulence and its effect on the functioning of the ocean, with upwelling systems and the Southern Ocean as favorite regional contexts.