US GLOBEC Before and After

Eileen Hofmann

Old Dominion University

Outline of Presentation

• Understanding prior to GLOBEC

• Advances in understanding physical-biological interactions resulting from GLOBEC science

• Moving forward from what has been learned from GLOBEC

Pre-GLOBEC

• Recruitment to marine fish populations depended on

• Critical period - variations in larval feeding and nutrition

> larval feeding was viewed in terms of a direct link from zooplankton to the consumer

• Aberrant drift - advection into favorable or unfavorable environmental conditions

> the scales of the physical environment were known but the details of the scales that were relevant to the planktonic organism were essentially unexplored

Pre-GLOBEC

• Physical oceanography and biological studies were essentially separate disciplines

> difficulties in attributing causes, effects and mechanism

• Studies restricted to a limited locations and short times

> decadal and longer time variability not recognized as

driving forces • Lack of linkage and cohesion between the

observational and modeling communities

Science Challenge

• To understand the dependence of marine population dynamics on the physical structure of the ocean and to link this to ecosystem dynamics (NAS, Steele et al., 1987)

• GLOBEC Goal “…. understand how climate change and

variability will translate into changes in the structure and dynamics of marine ecosystems and in fishery production”

Scales of Processes

• View that marine ecosystems operate along a continuum defined by space and time underpinned much of the research that was undertaken during GLOBEC

• GLOBEC --> View has evolved to one in which marine ecosystem variability and population recruitment result from the integration of processes across all scales and includes direct as well as indirect interactions

Processes at all scalesinfluence variability of marine organisms and

populations

Studies of marineecosystems require

integration of theenvironmental drivers

and biological responses

Scales of Processes

• Pick out key scales and follow these through system

• Multiple optima in ecosystems and have begun to understand interactions that produce these

Scale of aggregation dependson view of system

Scales of spatial variation

Scale of aggregations - exploited by different predators

Krill are important to different parts of the food web because of a spatial structure that covers many scales

Longevity and overwinter survival allows spatial and temporal transfer Makes energy available to predators

Structure modifies the operation of the ecosystem

GLOBEC - Recruitment patterns

Why patterns occur and what are key processes?

Knowledge of scale interactions have resulted in additional hypotheses about physical-biological

controls on recruitment

Alternative food web structures

Implications for production and maintenance of

predators

Understand the causes for changeand key processes

Development of conceptual frameworks forrecruitment that encompass multiple scales

OCEAN CLIMATE PARAMETERS

TransportTemperature

Light conditionsTurbulence

Predators

Phytoplankton

Copepods

Cod larvae and early juveniles

Development of field and modeling programs to testconceptual models of ecosystem structure and function

Modeling Physical-Biological Interactions

• Modeling is central to GLOBEC science• Built on scientific and technological advances,

such as realistic circulation models• Integration of IBMs with circulation models

resulted in ability to determine transport pathways, residence times, controls on growth

• Allowed identification of spawning areas, recruitment regions, connectivity of populations at a range of scales

Realistic RegionalCirculation Models

Coastal Gulfof Alaska

West Antarctic Peninsula

Include sea ice, couplingto atmospheric models

and larger scale models

Georges Bank

AdvectionAutochtonous – Allocthonous production

Displaces production

Disconnects Production - Mortality

Production - Export

Connection between spawning and

recruitment regions

Inclusion of detailed biology provides process understanding

Importance of comparative studies

Population connectivity at regional to circumpolar scales

Thorpe et al. (2007)

Spiers et al. Tian et al. (2009)

Speirs et al.(2006)

Physical-biological modelsevolved to systems of

interconnected modules

Developed around data setsfrom GLOBEC programs

NEMURO - minimum trophic structure and biological

relationships … thought to be essential in describing

ecosystem dynamics in the North Pacific

Top down and bottom up controls operate simultaneously but

relative effect of each is variable

GLOBECTarget species

Approach

deYoung et al. (2004)

GLOBEC science evolvedto include humans

as part of themarine food web

Importance of top predators

including humans

Perry et al. (2010)

Barange et al. (2010)

Physical-biological Interactions GLOBEC Science

• Ecosystems result from interactions across multiple scales

• Comparative studies provide insights beyond those from single program

• Target species approach allowed picking out key processes - compare with other systems

• Top predators, including humans, are integral parts of food web

• Physical, biological, observational, and observational communities focused on integrated research programs

Climate/

JGOFS

Heat Distribution/

Biogeochemistry

Budgets/

Elemental cycles

Weather/ GLOBEC

Synoptic patterns/

Population dynamics

Events/

Species

Future Directions

Next challenge

Provide meaningful forecasts and projections

of marine population variability and response to

climate change and human impacts

Link regional andbasin-scale models

Expand beyond regional focus

Methods forDown/Up

Scaling of Physical-biological

Models

Temperature warming and cod recruitment

Fogarty et al. (2008)

Climate Projections Ecosystem Responses

Relevance to Global Ecosystems

Global carbon budget models lack biological detail

Current models do not capture what is known aboutecosystems and harvesting/human impacts

What Needed?

• Sustained observations that support predictions and forecasts

• Continued integration of observations and models from outset of programs

• Explicit inclusion of human dimension • Estimates of uncertainty and communication

of this to policy makers• Educational outreach to public sector

Concluding Remarks

• GLOBEC science advanced state of models, data sets, and conceptual understanding of physical-biological interactions that underlie marine population variability

• Provides basis to develop the integrative research programs between the natural, social, and economic sciences that are needed to understand and sustain the world’s ocean in an era of increasing change and uncertainty