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GLOBEC GB-4B PI Meeting (6/23/2008)

GLOBEC GB-4B PI Meeting (6/23/2008).

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GLOBEC GB-4B PI Meeting (6/23/2008)

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  1. GLOBEC GB-4B PI Meeting (6/23/2008) Processes controlling copepod distribution in the Gulf of Maine - Georges Bank regionR. Ji & C. DavisDepartment of BiologyWoods Hole Oceanographic InstitutionWorking with:PI team:Chen, Beardsley, Townsend, Runge, Durbin, FlaggUMASS-D modeling group:Q. Xu, G. Cowles, R. Tian, S. Hu, D. StuebeDavis Lab:Q. Hu, C. PetrikNMFS:D. Mountain, J. Hare, M. Taylor

  2. Dominant copepods Cf, Pn Cf, Pn Ctyp Pm, Os • (Based on Davis 1984, 1987; Durbin&Casas, 2006) • Peak in different season • Different external sources • Difference in life history traits Cham, Ctyp, Tl Ctyp Cfin: Calanus finmarchicus Pcal: Pseudocalansu spp. Pm: Pseudocalanus moultoni Pn: Pseudocalanus newmani Os: Oithona spp. Cham: Centropages hamatus Ctyp: Centropages typicus Tl: Temora longicornis Food-limit Resting egg Egg carrier Cfin x Pcal x x Os x x Cham Ctyp x Yellow: abundant in summer/fall White: abundant in winter/spring Tl x x

  3. Pcal Mar-Apr Jan-Feb May-Jun Jul-Aug Sep-Oct Nov-Dec

  4. Pcal • “Cold-water” species, peak in spring and early summer • Higher development rate in lower temperature • Lower EPR compare to Ctyp, Cfin, similar to Cham • Lower egg mortality (egg carrier) • High concentration in shallow area (food limitation?) • Maintain population size on the Bank, supply from upstream (match Davis 1984) • Decrease of abundance after summer: • high mortality rate in the model (T-dependent, increase of predator in summer, Q10, visual predator) • other possible reason: less food (tested, false), less EPR in warmer water (no exp support)

  5. Ctyp Mar-Apr Jan-Feb May-Jun Jul-Aug Sep-Oct Nov-Dec

  6. Ctyp • “Warm-water” species, peak in later summer and fall • Lower development rate in cold temperature • higher EPR compare to Pcal and Cham • Higher egg mortality (“broadcaster”) • Higher concentration in shallow area, but not confined in shallow area (food limitation less obvious, dispersive?) • Increase of abundance after summer (EPR increase)

  7. Cham Mar-Apr Jan-Feb May-Jun Jul-Aug Sep-Oct Nov-Dec

  8. Cham • “Warm-water?” species, peak in mid-summer, relatively high population in fall than winter/spring • Lower development rate in cold temperature • Lower EPR compare to Cfin and Ctype, similar to Pcal • High egg mortality (“broadcaster”) • High concentration in shallow area only (especially GB): Resting egg strategy + food limitation

  9. Working hypothesis(from proposal) “… The same model structure will be used for all species, changing only the parameter values (temperature/food/life-stage dependent egg production rate, development rate, growth rate, and normalized stage-dependent mortality) and behaviors, and thus expediting the model runs. The inputs of characteristic life history traits of each species together with its initial abundance patterns should generate its observed characteristic seasonal/spatial patterns…”

  10. Model Framework Physical models Major features Atmospheric Model MM5/WRF • Fully 3-D coupling • FVCOM-based (fvcom.smast.umassd.edu) • Food web model - NPZD (Ji et al., in press) • Mean-age zoop model (Hu et al., 2007) Ocean GCM Satellite SST, U,V Buoys T,S,U,V Altimeter Global Tidal Model Ocean Model (FVCOM) Freshwater Input Food web model Zooplankton model Nitrogen Phytoplankton Egg Nauplii Copepodite Adult Detritus Zooplankton

  11. A Generic Copepod Model *Dimensionless, change parameters only

  12. Belehradek function (egg)

  13. Belehradek function (Nauplii)

  14. Belehradek function (Copepodite)

  15. EPR (T dependent) cfin

  16. EPR (Food dependent)

  17. Pcal (vavg) Jordan Basin GB Crest

  18. Exp. 1 • Change D=f(T) to Cham/Ctyp • Population can’t be maintained • To maintain population: • 1. increase EPR (Ctyp) • 2. Resting egg (Cham) Jordan Basin GB Crest

  19. Exp. 2 Jordan Basin • Follow Exp. 1, but increase EPR • Population peak in summer/fall • Population size exploded possible reason: egg mortality “broadcaster” vs “carrier” GB Crest

  20. Exp. 3 Jordan Basin • Follow Exp. 2, but increase egg mortality (from 3% to 15%) • Population peak in summer, not in fall, similar to Pcal in Exp. 1 (mortality issue?, see Exp. 4) GB Crest

  21. Exp. 4 Jordan Basin • Follow Exp. 3, decrease Q10m • Population peak in summer/fall GB Crest Mortality T-dependent might be different between Ctyp and Pcal. Any biological reason?

  22. Exp. 5: Pcal GoM contribution • Increase initial concentration of Pcal in GoM by 10x • Examine the contribution of GoM population from last year

  23. Ex. 6: Self-sustainability on GB No GB initial population Initialize GB only

  24. Ex. 7: Effect of upstream input A: Baseline run B: No upstream input from Nova Scotia Yr 3 Yr 2 Yr 1

  25. Resting egg strategy (no mortality)

  26. Resting egg strategy (with mortality)

  27. Summary • Different life history traits + environmental condition determine the spatiotemporal distributional patterns of dominant copepod species • Different reproduction strategies are used to maintain population in GoM or on GB, including r-strategy (e.g. “broadcaster” for Ctyp) and prolonged life history (e.g. resting egg for Cham). • Pcal population is difficult to maintain in GoM/GB without upstream input, posibily due to k-strategy (“egg carrier”, less dispersive) • Mortality control the population size, a sensitive parameter but difficult to estimate

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