1. ARCTIC SYNTHESIS Ecosystem Modeling Status Yvette H
ARCTIC SYNTHESIS Ecosystem Modeling Status Yvette H. Spitz and Léo Berline OSU-COAS

2. Chlorophyll a
SeaWifs climatology
Model 1986
White line : ice edge

3. 11-component model
Observations

4. Coded new ecosystem model
2 phytoplankton (pico and diatom) and 2 zooplankton
Full microbial loop
Nitrate, Ammonium and Silicate
Diagnostic preliminary runs 3D

5. Nitrate concentration after one year of run

6. Problem vertical diffusion
High surface nitrate concentration in the north Chukchi Sea
Depth (m)
Time (month)

7. Deep mixing that leads to high nutrient in the surface and therefore artificially high bloom. Changed Eq of state in POP (Jacket and McDougall, 1995, instead of the traditional polynomial fit to the UNESCO eqn of state), which improved slightly the density field
Light penetration and mixing seems to pose problems for us - Ice model might need tuning
Open Boundary conditions at the Strait might help to retain some nutrient on the shelf

8. Salinity
UNESCO Eq of State
New Eq of State

9. Temperature
New Eq of State
UNESCO Eq of State

10. Nitrate initial condition for winter
Levitus in GIN
Colony in Can Basin
Value from literature on shelves

11. Location 1D model Tests
3 different ice cover
Greenland
SHEBA
Chukchi

12. Greenland 1D outputs
Blue : model, Red: obs (Cota)
NO3
Chl

13. Greenland 1D outputs T-Dependence of growth
Blue : model, Red: obs (Cota)
T-Dependence of growth
NO3
Chl

14. Chukchi 1D outputs Blue : model, Red: obs (SBI)
July, end of simulation

15. Questions Greenland Chukchi Modeled phytoplankton
Is nitrate not depleted in summer?
Is it general for GIN?
Chukchi
Is benthic remineralization important?
Need to go further north to avoid contamination by Bering Strait
Modeled phytoplankton
Main taxa: Diatom, auto. Dinoflagellates ok?
Importance phaeocystis?
Chl/C Value valid arctic-wide?