French versionAlgorithms development for a marine environment simulator driven by computers
Supported by the French Bioinformatics program
Project leader:
O.Bernard
(INRIA Sophia-Antipolis)
Involved research teams :
(Modelling and control of renewable resources) .
|
O.Bernard, J.-L.Gouzé, C.Prévost
|
(Laboratory of Oceanography and Biogeochemistry, Marseille) |
Y.Leredde, J.-C.Poggiale, D.Nérini, C.Manté,
|
|
(Laboratory of Oceanography, Villefranche) |
L.Pawlowski et
A .Sciandra |
The aim of the project is to experimentally reproduce the environment of phytoplanctonic cells as it could be meet in the marine environment. The experiments carried out with this simulator of marine environment will provide data to better understand and study the mechanism of carbon incorporation by the phytoplankton during photosynthesis. The obtained models should therefore contribute to improve the forecasting of the amount of carbon dioxide fixed during primary production. They should therefore led to better describe the carbon fluxes between the oceans and the atmosphere.
Summary of the accomplished work :
A new model describing phytoplankton growth limited by nitrogen, light
intensity and temperature was developed and validated. This model was coupled
to a costal hydrodynamic simulation software (SIMPHONIE) in order to simulate
the evolution of the 3-D spatial distributions of the physical, chemical
and biological variables in the water column. The obtained fields were
then used to estimate the Lagrangian trajectories of the particles. Finally,
the simulation code allowed to compute the physico-chemical environment
of phytoplanktonic cells, with respect to their initial position. The obtained
trajectories where then sorted using statistical procedures. It generated
set of environment classes which are differently perceived by the algae.
In parallel, the software driving the bioreactors in which the marine conditions
will be simulated has been under development. An UML approach has generated
a model of the information fluxes. A database under MySQL has been implemented
and the software is currently developed using JAVA.
Summary of the main points
of the project:
Development
of the software driving the bioreactors
Summary
of the work carried out: the goal was to centralize the information
from the various automaton performing the measurements and to store this
information in a data base. Finally, this software will serve as a platform
to implement the control algorithms that must be used to achieve the desired
evolution of the physico-chemical concentrations within the chemostat.
A prototype of the software was developed using TCL/Tk. The information
fluxes and the interactions between the software modules were analyzed.
They were then modeled using an UML approach. The software is centered
around a MySQL data base containing the parameters of the automaton, and
the data issued from the automaton. The final version in JAVA is currently
under development.
Available
report (in French):
Development
of a phytoplanktonic growth model.
Summary
of the work carried out: a first model, named BioLov1, was developed.
It represents growth and photosynthesis of a cell population simultaneously
limited by light and nitrogen. The mathematical study of its qualitative
behavior demonstrates that it correctly describes the steady input-output
behavior which has been experimentally observed. In other words it means
that the trends of the variables after an increase of the inputs are respected.
Methods to determine the parameter values has been proposed and the dynamical
behavior has been analyzed. Once its parameter values have been identified,
the model fits correctly the experimental data. The model was then modified
to take into account the temperature effect. The experimental qualitative
response to a temperature increase were then used to validate the qualitative
model behavior. Model BioLov2 represents thus the simultaneous effect of
light, nitrogen and temperature.
Available
reports (in French):
Summary
of the work carried out: these work relies on the 3-D costal hydrodynamic
simulation software (SIMPHONIE). A lagrangian tracking of the particles
has been developed in the existing code. The velocity field computed from
the model is used to estimate the lagrangian trajectories of the phytoplanctonic
cells. The physico-chemical environment of the particle can then be derived.
We considered a schematic oceanic situation: a costal upwelling generated
by a constant wind (5 m.s-1). This model was then coupled to
the biological model BioLov2 describing phytoplanctonic growth when nitrogen,
light and temperature are limiting. The obtained simulations were then
used to compute the environment of the cells starting from various initial
positions. This study generated then a large number of trajectories characterized
by very different physico-chemical stories. The obtained trajectories where
then sorted using statistical procedures. It generated a set of environments
classes which are differently perceived by the algae. Each class corresponds
to a type of evolution of the cell environment and will be reproduced within
the SEMPO system in the next steps.
Available
reports (in French):
P.Cinque et Y.Leredde
G.Mauguin, Y.Leredde, D.Nérini, C.Manté,O.Bernard, L.Pawlowski et A .Sciandra