Physical-biological interactions: regional to basin scales I. Pseudocalanus spp.: MARMAP data II. P. moultoni and P. newmani: U.S. Globec Georges Bank broadscale surveys in 1997 III. Calanus finmarchicus: U.S. Globec Georges Bank broadscale surveys IV. Toward a basin scale approach: lessons from the JGOFS program on physical-biogeochemical interactions at large scales

General circulation during the stratified season Beardsley et al. (1997)

A finite-element model of the Gulf of Maine / Georges Bank region (Lynch et al., 1996)

Pseudocalanus spp. MARMAP Concentration (# m -3 ) Two population centers: Western Gulf of Maine Georges Bank Davis (1984) hypothesis: Western Gulf of Maine is a source region for the Georges Bank population

A first attempt to simulate the observed Pseudocalanus spp. distributions…

P. moultoni P. newmani 1997 Broadscale Survey Data Species-specific PCR (Bucklin et al., 2001)

Observations: P. Moultoni Models Observations: P. newmani

Are the inverse solutions ecologically realistic? R(x,y,t) bounded by –100 to +100 individuals m -3 day -1 [most fall between -10 to +10] C 5 moulting potential: Mean C 5 abundance 2500 individuals m -3 (Incze pump samples: April 1997, May 1997, June 1995) Stage duration in GB conditions: 5 days (McLaren et al., 1989) Implied moulting flux of 500 individuals m -3 day -1

Are the inverse solutions ecologically realistic? Predation potential: Model predicted rates of 3-10% day -1 Bollens et al. specific rates of predation on C. finmarchicus and Pseudocalanus spp. copepodites based on observed predator abundance and feeding rates

Physics -- assumes perfect knowledge of the circulation -- 2-D transport (no vertical shear) Biology -- density dependence vs. “geographic” formulation -- multistage models, behavior, etc. Observational limitations -- only adults sampled -- upper 40m Caveats to interpretation of these solutions

C. finmarchicus climatology: Globec Broadscale surveys N3N3 N4N4 N5N5 N6N6 C6C6 C5C5 C4C4 C3C3 C2C2 C1C1 Jan Feb Mar Apr May Jun Time Log(abundance) Durbin et al.

F i : molting flux F i (T,Chl) computed (Campbell et al. 2001) R: sources of N 3 Inferred (monthly) μ i : mortality Inferred (monthly) C i off-bank Inferred (initial conditions) N 3 N 4 N 5 N 6 C 1 C 2 C 3 C 4 C 5 C 6 R μ N4 μ N5 μ N6 μ C1 μ C2 μ C3 μ C4 μ C5 μ C6 C. finmarchicus model X. Li et al.

Inferred off-bank initial conditions N 3 N 4 N 5 N 6 C 1 C 2 C 3 C 4 C 5 C 6

C. finmarchicus solution: January- June

Inferred Mortality N3N3 N4N4 N5N5 N6N6 C6C6 C5C5 C4C4 C3C3 C2C2 C1C1 Jan-Feb Feb-Mar Mar-Apr Apr-May May-Jun

Spatially averaged mortality rate: seasonal variation

Spatially averaged mortality rate: January-June average

Term-by-term analysis Transport terms: large magnitude, but net effect is small Primary balance: tendency/molting/mortality

Spatially averaged mortality rate Black: central case Gray: off-bank sources=0 (including ICs) Mortality (d -1 ) Stage

Biological control of the vernal population increase of C. finmarchicus on Georges Bank only slightly smaller than Advective delivery Advective loss Georges Bank Advective delivery Advective loss Georges Bank ×

National Science Foundation NCAR: Scientific Computing Division Eddy-driven sources and sinks of nutrients in the upper ocean: results of a 0.1° resolution model of the North Atlantic McGillicuddy, D.J., Anderson, L.A., Doney, S.C. and M.E. Maltrud

New Production in the Open Ocean

An eddy-resolving nutrient transport model Euphotic Zone: NP=NP(I,NO 3,T) Aphotic Zone: Relaxation to clim. NO 3 (σ T )

Simulated Annual New Production BATSEUMELI NABE OWSI

Vertical advection Horizontal advection New Prod Conv + Diff Total Mean Eddy Annual New Production Term Balances

Observed Annual New Production = 0.5 mol N m -2 yr -1 New Production at BATS: New Production at BATS: Three Models, Three Different Nutrient Transport Pathways

Coarse (1.6º) Eddy-resolving (0.1º) Sea Surface Temperature log (New Production)

Toward a basin-scale model of C. finmarchicus Planque et al. (1997)

END

References McGillicuddy, D.J., Lynch, D.R., Moore, A.M., Gentleman, W.C., Davis, C.S., and C.J. Meise, 1998b. An adjoint data assimilation approach to diagnosis of physical and biological controls on Pseudocalanus spp. in the Gulf of Maine - Georges Bank region. Fisheries Oceanography, 7(3/4), McGillicuddy, D.J. and A. Bucklin, Intermingling of two Pseudocalanus species on Georges Bank. Journal of Marine Research, 60, McGillicuddy, D.J., Anderson, L.A., Doney, S.C., and M.E. Maltrud, Eddy- driven sources and sinks of nutrients in the upper ocean: results from a 0.1 degree resolution model of the North Atlantic. Global Biogeochemical Cycles, 17(2), 1035, doi: /2002GB See “publications” link for more informationhttp://