W63- Advanced Biogeochemistry, Marine Optics

W63

Advanced Marine Biogeochemistry, Marine Optics

ECTS

5

Specialities

HO

Keywords

Chemical composition of the ocean, ocean-atmosphere gas exchange, biogeochemistry in the ocean and climate, coupled physical/biogeochemical processes, mixed layer, mesoscale, coastal upwelling, data, modelling, optical properties of sea water; biogeochemical proxy, ocean color remote sensing.

Description

The aims of this teaching unit are to provide to the students knowledge on the biogeochemistry of the ocean on coupled physical/biogeochemical processes and its interactions with climate. General laws and associated equations will be presented as well as measurement techniques, modelling, data analysis with reading of scientific papers, practical work on computers and lab and exercises.

Coordinators

Prof Dr Isabelle DADOU, Univ. Paul-Sabatier, LEGOS, Isabelle.Dadou@legos.obs-mip.fr

Prof. Hubert LOISEL, Univ. Littoral Côte d’Opale UMR LOG, hubert.loisel@univ-littoral.fr

Lectures

Marine Biogeochemistry (7 hours: C and E), Lecturer: Isabelle Dadou (P. Van Beek)

 1) Introduction – bases: chemical composition of the ocean, vertical/horizontal distributions of chemical elements, and control by biology (primary production – remineralization), main horizontal and vertical mixing mechanisms, in situ measurement techniques (no-autonomous and autonomous sensors).

2) Ocean-atmosphere gas exchanges: Dalton’s law of partial pressures, gas solubility, exchange rate and fluxes between the atmosphere and the ocean.

3) Nitrogen cycle in the ocean: why studying this cycle? Main nitrogen compounds and transformations; spatial distribution; important physical and biological processes for this cycle in the ocean.

4) Carbon cycle in the ocean : why studying this cycle? The role of the ocean in this cycle, different chemical and biological species of the carbon cycle in the ocean; important processes (thermodynamics, chemistry and biology) for this cycle.

5) Biogeochemistry, climate and natural resources: important processes, the feedbacks, links with the halieutic resources, anthropogenic forcing (pollution, overexploitation…).

Physical-biogeochemical interactions in the ocean (X hours: C and E). Lecturer: Isabelle Dadou (Marine Herrmann)

1) Importance of coupling between the physics and biogeochemistry in the ocean: Main processes and associated equations, Box models and primitive equation models (advection-diffusion)

2) Source and sink terms in biogeochemistry, trophic web: Biodiversity (phytoplankton, zooplankton, bacteria), Scheme of a trophic web associated equations and parameterisation of processes.

3) Mixed layer in the ocean (vertical structure of the surface layer of the ocean): Equations of the mixed layer; atmospheric dynamical and heat forcing; Temperate waters: deepening/stratification of the mixed layer, mechanisms of the spring bloom; Tropical waters: vertical structures of the mixed layer and associated biogeochemical vertical distribution

4) Mesoscale processes in the ocean: Characterisation of the physical eddy environment (mesoscale), main processes (eddies, meanders, instability, waves,…) observations (in situ, satellite), modelling; Biogeochemical oceanic mesoscale variability, observations (in situ, satellites) modelling

5) Coastal area (continental shelf, slope and interaction with the open ocean): Importance for halieutic resources, region under high anthropogenic forcing, sources/sinks of greenhouse gases…; Eastern boundary upwelling and Coastal area under river discharge influence: observations, main processes, equations, modelling.

Coupled physical/biogeochemical modelling (x hours). Lecturer: Marine Herrmann, Isabelle Dadou and Minh Nguyen Nguyet

P1) Presentation and work (equation/numerical methods) on a simple biogeochemical model (NPZD) - P2) Presentation and work (equation/numerical methods) on a hydrodynamical model and numerical schemes (tracer advection) (the same ROMS as the one studied in the first year of the Master) - P3) Real case study: Gulf of Tonkin –study of coupled physical/biogeochemical processes of this upwelling (productivity, biomasses, ..)

Practical work in lab (4 hours: PW): Isabelle Dadou, Hubert Loisel, Trinh Bich Ngoc

Laboratory measurements on the properties (carbon, nitrogen) of organic matter and nutrients in the ocean.

Ocean color and applications: (20 h course + tutorial). Lecturer: Hubert Loisel)

1) Presentation of the inherent optical properties (IOPs) of sea waters

2) Relationships between IOPs and the biogeochemical parameters; how IOPs measured at different spatio-temporal scales can provide relevant information on biogeochemical and physical processes.

3) Introduction to satellite observation of ocean color: principles and applications

Instructors

Prof Dr Isabelle Dadou, Univ. Paul-Sabatier (Toulouse 3), LEGOS, France

Dr Marine Herrmann (CR IRD), Univ. Paul-Sabatier (Toulouse 3), LEGOS, France

Dr NGUYEN Nguyet Minh (MCF), USTH, Hanoi, Vietnam

Prof. Hubert LOISEL, Univ. Littoral Côte d’Opale UMR LOG

Trinh Bich Ngoc (Engineer - Technical assistant), USTH, Hanoi, Vietnam

Control

examination + practical + personal work