TWP2: Modeling of the impact of continental nutrient inputs on the dynamics of

planktonic diversity

Alekseenko Elena, PhD Scientific adviser: Melika Baklouti

Other collaborators: François Carlotti , Pierre Garreau, Arnaud Guyennon

Mediterranean Institute of Oceanography

Scientific objective Impact of the high continental

NO3:PO4 ratio on the structure of the food web?

3D modeling of NW Med Sea. Coupled model MARS3D/ECO3M-

MED .

Scientific strategy:

Why to choose Mnemiopsis leidyi?

Reports of M. leidyi blooms in Mediterranean Sea (Fuentes, 2009, Boero, 2009, Kilie&Lucas, 2013)

•  Chosen species – comb-jelly Mnemiopsis leidyi :

•  An alien species which successfully colonizes Mediterranean coasts in the last decades

•  Implementation of jellyfish

into Eco3M model (Alekseenko et al, in prep.)

Eco3M-Med biogeochemical model

0D scenarios on the Mnemiopsis leidyi behaviour

Feeding by constant food concentration of 10 ind/l after 5, 30, 40, 60, 80 days of starvation

For the appropriate Mnemiopsis leidyi implementation into the Eco3M-MED model numerous 0D tests were made on its physiology: •  Growth rate and reproduction •  Grazing •  Mortality •  Metabolic requirements •  Temperature impact •  Feeding after starvation depending on the food quality and quantity

Mn

emio

psi

s le

idy

i a

bu

nd

an

ce (

ind

/l)

M.L has strong survival ability at high food concentration

A case study on the NW Mediterranean Sea

under the influence of the Rhone River Model bathymetry

Modeled scenarios •  high/low NO3:PO4 ratio of the Rhone River ; •  with/without jellyfish

Modeled region – Gulf of Lions under impact of the Rhone River

Total  Carbon:  0.0040  mol/l  

Carbon repartition

Total  Carbon:  0.0063  mol/l  

 in  %  from  Total  Carbon,    in  the  zone  III  at  two  contrasting  situations  

Scenario:  no  Jellyfish,  Rhone  NO3:PO4  of  2010  

10th  April  2010 10th  September  2010

BAC µZoo                    nZoo phytoplankton Copepod Nonliving:  POC,DOC

Bloom  period  •  more  diatoms  

•  more  Carbon  biomass

Stratified  period  •  intense  microbial  loop  

•  DOC  accumulation

BAC +10.4%

PHY -2.5%

SZOO +7%

COP -9.67%

JEL -2.9%

9.719

0.078

0.116

2.954

5.801

5.491

BAC +9.6%

PHY -10.7%

SZOO +0.5%

COP -9.70%

JEL ref

9.738

0.079

0.111

2.616 5.566

5.488

BAC ref

PHY ref

SZOO

ref

COP ref

10.942

0.106

2.781 6.757

Units: fluxes over summer period in mmolC/m3

BAC +5.3%

PHY -9.9%

SZOO +16%

COP -6.6%

11.385

0.108

2.877 6.871

Community shifts N

O3:

PO

4 2*

NO

3:P

O4

NO JELLYFISH WITH JELLYFISH

Conclusions

 •  The  presence  of  jellyfish  in  the  system  activates  the  microbial  loop  during  the  

summer  period,  which  is  more  reinforced  with  the  NO3:PO4  increase  

•  The   impact   of   the   NO3:PO4   increase   on   copepods   and   jellyfish   is   weaker  due  to  their  lower  growth  rates.  Therefore,  for  studying  such  impacts  on  these  organisms,  longer  simulations  are  needed  

These  preleminary  results  show  the  complex  plankton  dynamics  induced  by  nutrient  changes  and  how  it  could  impact  the  higher  

trophic  levels.  

•  Mnemiopsis  leidyi  species  was  implemented  into  te  Eco3M-­‐MED  model  

•  Variety  of  0D  scenarios  on  the  physiological  processes  was  made    

•  3D  modelling  with  different  NO3:PO4  ratios  in  the  Rhone  River  showed:    

Thank you for your attention! ●  Accepted publication:

●  Alekseenko E., Raybaud V., Espinasse B., Carlotti F., Queguiner B., Thouvenin B., Garreau P., Baklouti M. (2014) ”Seasonal dynamics and stoichiometry of the planktonic community in the NW Mediterranean Sea: a 3D modeling approach”. Ocean Dynamics.

●  Newsletter article ●  V. Garnier, I.L. Pairaud, A. Nicolle, E. Alekseenko, M. Baklouti, B. Thouvenin, F. Lecornu, P. Garreau.”MENOR: a high

resolution (1.2 km) modelling of the North-Western Mediterranean Sea; Routinely run by the PREVIMER; Operational Forecast System”, Newsletter Mercator N49

●  Participation in conferences ●  CIESM, November 2013, Marseille, France: E.Alekseenko, Thouvenin B., Tixier C., Tronczynski J., Baklouti M.,

Garreau P., Verney R., Carlotti F., Espinasse B., Queguiner B., Loizeau V. “Modeling of the PCB transfer into the trophic chain of the Gulf of Lions; 3D coupled model application.”. Poster and oral presentation

●  EGU 2014, May 2014, Vienna, Austria: Alekseenko E., Baklouti M., Carlotti F., Guyennon A., Garreau P. “Modeling of the impact of Rhone River nutrient inputs on the dynamics of planktonic diversity. Oral presentation

●  DIOXIN, September 2014, Barselona, Spain: E.Alekseenko, Thouvenin B., Tixier C., Tronczynski J., Baklouti M., Garreau P., Verney R., Carlotti F., Espinasse B., Queguiner B., Loizeau V. “Modeling of the PCB transfer into the trophic chain of the Gulf of Lions; 3D coupled model application.”. Poster

●  Publication in preparation ●  Alekseenko E., Baklouti M., Carlotti F. “Mnemiopsis Leidyi modelling; Eco3M-Med approach”

Scientific production

What evolution in the future ( c h a n g e s i n a g r i c u l t u r a l practices and other anthropic pressures from the continental domain)? Other models from the LABEX

(hydrological, socio-economical,...)

Evolution of nutrient inputs (continental)

Agriculture

Urbain Zone

Industry

Perspectives Application of the

model MARS3D/ECO3M of NW Med Sea