1. Example #2: Northwest Pacific Zooplankton
San
WS on Forecasting Ecosystem Indicators with Process-based Models
September 7-10, 2012, Friday Harbor, WA
Section 1: Examples of simple diagnostic models of ecosystem response to climate forcing
Example #2: Northwest Pacific Zooplankton
And next,
I will show the biogeographical change in copepods community.
It was reported that intensification of the AL also affected dynamics of Oyashio and Kuroshio.
Oyashio southern limit shifted southward, while Kuroshio flow increased after the 1980s.
Sanae Chiba, RIGC, JAMSTEC
Andrew Davis, Georgia Tech

2. Process 1 Process 2 Aleutian Low dynamics Winter Wind Stress
Wind-driven, Mixed Layer bottom-up process
Process 2
Advective transport by oceanic currents
Aleutian Low dynamics
Winter Wind Stress
Winter Vertical Mixing
Light & Nutrients availability
Subarctic circulation
Oceanic Currents Dynamics
*Lagged response in some cases
Advection
Advection
Climatic forcing
phytoplankton
Physical environment
Production
Phenology
Community structure
Chemical environment
Untill now, I have shown the scenario related to wintertime wind stress.
Zooplankton
Biological process
Production
Phenology
Community structure
Distribution shift
Conceptual Model for Climate – Ecosystem link in the subarctic NP

3. Low Frequency Variation in Zooplankton Biogeography
(May-Sept, Area mean)
(Yatsu et al. 2012, Yeosu Symposium)
< 5°C at 100 m: Oyashio
> 5°C at 100 m: Transition
bottom depth > 500 m
Data: Odate Collection
37 Species
Number of samples analyzed
Oyashio: 961
Transition zone: 969

4. Distribution of Cold Water Copepod Community
before & after RS in North & South Domains
(20.8%)
shift (Rodionov 2006)
(Chiba et al 2009, GCB)

5. Distribution of Warm Water Copepod Community
before & after RS in North & South Domains
(15.5%)
shift (Rodionov 2006)
(Chiba et al 2009, GCB)

6. Change in Copepod Community before & after RS in North & South Domains
Abundance
Diversity
Biogeographical distribution of the copepods community in the Oyashio and the Transition zone before 1976 and after 1981: total abundance (Log ind m-3) a), species diversity (H’) b) and the average community size (mm) c). (Chiba et al 2009, GCB)

7. Change in Oyashio & Kuroshio after RS for 1976 ~ 1981
March-May avg.
Oyashio shifted to South
Year avg.
Kuroshio Transport increased
(137°E)
Japan Meteorological Agency
The timing of shift detected by method by Rodionov (2006)

8. Change in Copepod Community before & after RS in North & South Domains
Background
Change in Copepod Community
before & after RS in North & South Domains
Both Northern and Southern Copepods concentrated in the narrow area in the Transition Region
This region is nursery ground of many commercially important fish species.
So results our study implies zooplankton community shift might caused not only
The temporal but also spatial match-mismatch with the higher trophic levels.
H1: In PDO positive (KO strong) yrs, more Northern (Southern) zooplankton area transported to South (North)

9. Passive Tracer Experiment by OFES global ocean model
to assess the effect of low-frequency transport on variations in zooplankton community in the KOE
OFES 3 days Output (1/10)° for
Climatology forcing: NCEP/NCAR reanalysis data
Release: March, Count: September
We used this model-derived current data to drive a Lagrangian transport algorithm we developed similar to one proposed by Binning and Celia (2002). This algorithm simulates both the advection and diffusion of passive tracers- particles with negligible mass and neutral buoyancy. In this case, these particles represented the zooplankton measured in the Odate collection. We released particles from both areas in March, coinciding with zooplankton spawning, then counted the number of particles from both regions ending up in the sampling area in September

11. Distribution of Cold Water Copepod Community
before & after RS in North & South Domains x RS x

12. Distribution of Warm Water Copepod Community
before & after RS in North & South Domains x RS x

13. Model vs. Observation: Cold Water Copepods Transport to South:
Zoo-N2NB
N.S.
Zoo-N2NB
N.S.
(May-September)

14. Model vs. Observation: Warm Water Copepods Transport to North:
Zoo-S2SB
R = 0.580
Zoo-S2SB
R =0.443
May-September

15. Change in Copepod Community before & after RS in North & South Domains
Background
Change in Copepod Community
before & after RS in North & South Domains
Or.. model setting should be revised…
This region is nursery ground of many commercially important fish species.
So results our study implies zooplankton community shift might caused not only
The temporal but also spatial match-mismatch with the higher trophic levels.

16. (Yatsu et al. 2012, Yeosu Symposium)
Time series of biomass and catch of commercially important fish species in KOE
LTL-HTL Link
QUESTION:
Did biogeographical shift of copepods cause Spatial Match-Mismatch with HTL?
Need to consider “Seasonality” in copepods transport and lifecycle for migrating fish.
(Yatsu et al. 2012, Yeosu Symposium) 16

17. Seasonality in Zooplankton Transport
August – September condition is most important for northward transport R

18. Available Zooplankton Dataset / LTL indices
in subarctic western NP
Odate Collection
1960s -1999, monthly-area mean (large missing data)
Warm-Cold species ratio (based on references)
Size index (larger or smaller than 2mm,Community mean size)
Developmental Stage of Major spp (e.g. Neocalanus spp.)
N & C SI of Major spp (e.g. Neocalanus spp.)
Species diversity (SID, ‘H)
PC Score
North Pacific CPR
, 3 transects/yr
Warm-Cold species ratio (based on references)
Size index (larger or smaller than 2mm,Community mean size)
Developmental Stage of Major spp (e.g. Neocalanus spp.)
N & C SI of Major spp (e.g. Neocalanus spp.)
Species diversity (SID, ‘H) (to be ready)
PC Score (to be ready)
Plus phytoplankton index: diatom-dinoflagellate rasio, etc.)

19. CPR Observation Data
Cool-warm spp distribution and variation of subarctic boundary
Batten, S.D. and Freeland, H.J. (2007). Fisheries Oceanography, 16,
PDO & Latitudinal Shift of Neocalanus spp.
North
Warm
CPR is C…..
NP CPR survey has been conducting…

20. Thank you 