us globec before and after eileen hofmann old dominion university
TRANSCRIPT
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