US GLOBEC Pan-Regional Synthesis WorkshopBoulder, Colorado

18-21 February 2008

End-to-end Energy Budgets in US GLOBEC Regions

University of Rhode Island Dian Gifford Jeremy Collie

Woods Hole Oceanographic Institution John Steele

University of Massachusetts, Dartmouth Jim Bisagni

Old Dominion University Eileen Hofmann Tosca Ballerini

British Antarctic Survey Eugene Murphy Nadine Johnston Martin Collins

University of South Florida Kendra Daly Marina Marrari

H.T. Harvey & Associates David Ainley

University of Maine Andy Thomas

University of Western Washington Suzanne Strom

University of Alaska, Fairbanks Ken Coyle

Oregon State UniversityJim Ruzicka

NMFS/AFSC Kerim Aydin Anne Hollowed Sarah Gaichas Bob Foy

NMFS/SWFSC Steven Bograd

NMFS/NWFSC Ric Brodeur

USGS, Madison Chris Ribic

Woods Hole Associated Scientists Cynthia Tynan

Virginia Institute of Marine Science Walker Smith

E2E - now a serious area of research with potential application to ecosystem management, including fisheries management

Meaning of E2E - not always clear

Science E2E: trophic web from bacteria to whales and humans

Management E2E: science at the bottom end & management at the top

What is End-to-End ??

Functional complexity

Tro

phic

level

Predators

Life History

Without Life History

Chemistry

Zooplankton-Fisheries focus

Phytoplankton-Nutrient focus

Physical Ocean

GLOBEC IS SPECIES-CENTRIC

GLOBEC

DeYoung et al. 2004

Species-centric v. Trophic centric

** The approaches are complementary** The approach used depends on the questions asked** No single model integrates across trophic levels & provides taxonomic resolution

WE USE GLOBEC SPECIES-CENTRIC DATA TO CONSTRUCT TROPHIC-CENTRIC FOOD WEBS

Q: Is biological production controlled by bottom-up (i.e., climate) or top-down (i.e., fishing) processes?

Q can be asked of any ecosystem, given sufficient data

The Big Question

Loss

Detritus Micro-zooplankton

Ammonia

Meso-zooplankton

-

Small phytoplankton

Large phytoplankton

Suspension feeders

Deposit feeders

Feces

Loss

Loss

Loss

Loss

Carnivorous benthos

Carnivorous plankton

Planktivorous fish

Benthivorousfish

Piscivorousfish

Juvenile fish

NO3

Upper web:

-juvenile fish

-3 fish feeding guilds

-carnivorous ZP

-carnivorous

benthos

Lower web:

-nutrients

-2 categories PP

-detritus, feces

-zp

-mesoZP

-DF+SF benthos

-N recycling

GENERAL APPROACH (GB)

Fig. 1. GLOBEC GB region.

Fig.2. NCC model domain Blue circles (spring), red circles (summer) GLOBEC & BPA pelagic trawl coverage, 2000.

Fig. 3. Management areas included in the ecosystem models for the Eastern Bering Sea (EBS), (GOA) and Aleutian Islands (AI).

Figure 4. SO study region. LTER is Palmer Long-term Ecological Research (LTER) site., AMLR is US Antarctic Marine Living Resources (AMLR) region. These regions provide a continuum of data sets along the western Antarctic Peninsula. Filled circles are locations of current meter moorings for US SO GLOBEC field studies. Star is the intermediate ice edge study region. and South Georgia (SG) provides the downstream study region. MB is Marguerite Bay, BS is Bransfield Strait, GS is Gerlache Strait, and SG is South Georgia in the Scotia Sea..

STUDY REGIONS

Regional Characteristics

Workplan-1

Task 1. Assemble/update E2E models for each region.

The regions differ in hydrography, trophic structure and physical forcing. Initial requirement is for transportable data sets and end-to-end models for each region. We draw upon the species-centric data and models for each region to develop trophic-centric models (e.g. Steele et al. 2007).

Task 2. Model Skill Assessment -provides guidance for model improvements -quantitative basis for cross-system comparisons

-comparison with in situ data using a suite of statistical approaches of

escalating rigor -evaluation of how well each model captures basic fluxes of e.g.,

primary production, secondary production and export production

WORKPLAN-II

Task 3. Determination of diagnostics

Model diagnostics are the primary end results of the entire project and permit cross-regional comparisons.

Diagnostics common to all 4 regions.Diagnostics will be extracted from the regional models to

evaluate effects of top-down (fishing pressure) and bottom-up (climate change) forcing across the 4 regions.

Diagnostics not known in advance, but comparisons based on concentration or biomass are unlikely to be useful. Obvious candidate diagnostics are material fluxes, which avoid issues of among-region species and biomass differences. Potential candidate fluxes: primary production, mesozooplankton production, benthos production, and nutrient fluxes.

Every diagnostic will not necessarily apply to all regions, e.g., macronutrient fluxes are less important for primary production in the SO than for GB.

Among-model comparisons of diagnostics.

WORKPLAN -III

WORKPLAN-IV

Task 4: Methods for among-model comparison of diagnostics.

Diagnostics for the models in the different regions will be compared using quantitative methods that will be developed as part of this project. 0-order diagnostics: Descriptive comparisons of trophic structure across the 4 regions are the 0-order activity for this task. This can include statistical methods of comparison and quantitative measures of trophic or size structure. 1st-order diagnostics: Linear mass-balance and inverse methods will be used as beginning 1st-order comparisons while we investigate the use of approaches such as parameter optimization via variation adjoint methods in the four regions (e.g., Friedrichs et al. 2007). Linear and mass balance analyses can be based on existing top-down (ECOPATH), bottom-up (Inverse) or combined (Steele et al. 2007) approaches.

2nd-order diagnostics. Potential 2nd order methods involve dynamic simulation either as direct representation of parts of the web or perturbation analyses of mass balance solutions.

The comparison approaches chosen rely upon estimation of similar processes in the 4 regions.

Potential new production (PNP) is an example of a process common to all regions. PNP = the difference between the rate of change of “nitrate storage”, vertically-integrated between the surface and the depth of the euphotic zone and “nitrate vertical flux” into the euphotic zone (Bisagni 2003; Steele et al. 2007).

We expect that this particular diagnostic will be more relevant for some regions (GB) than others (SO), but this type of calculation will allow us to quantify these differences. Data sets adequate for the calculation of PNP exist for each study region from historical data sources and GLOBEC program observations.

WORKPLAN- IV, continued

Responsibilities of scientific investigators

Q: What happens to cod (or any target species) if we alter the food web?Q: How do altered nutrient inputs impact the upper web?Q: What happens if carnivorous ZP (jellies) are eliminated? Or bloom?Q: What happens if microzooplankton are reduced or increased?Q: Does reducing the flux of PP to the benthos affect the upper web?

Etc………..

Once the E2E webs are constructed,We can ask other kinds of questions:

What does it take to construct end-to-end energy budgetsfor GLOBEC study regions?

**Interdisciplinary expertise

**Time series of biota, chemistry, physics, climate: the longer the better

**Standing stocks of all trophic levels, not just target species

**Rate measurements and transfer functions for all trophic levels, not just target species

**Knowledge of physics and fluxes

**$$$$$

Thank you

With apologies that I can’t be at the workshop --- Dian