The co-evolution of oceanic ecosystems and physical circulation Paul G. Falkowski Environmental Biophysics and Molecular Ecology Program Institute of Marine and Coastal Sciences And Department of Geology Rutgers University New Brunswick, New Jersey Email: [email_address] WOCE San Antonio November 20, 2002
THE GLOBAL SCALE OCEAN CIRCULATION INFLUENCE ON Photosynthetic Biomass, Primary and Export Production
FROM A POOL TO A FLUX MODELS OF NET PRIMARY PRODUCTION
“ Figure 9.10 A plot showing the correlation between external nutrient concentration (represented, in this case, by NO 3 ) and the maximum quantum yield for photosynthetic carbon fixation. The data were obtained from three regions in the North Atlantic: circles are from an upwelling region off norhwest Africa, squares are from a transition region, and triangles are from an oligotrophic region. (Data courtesy of Marcel Babin and Andre Morel)
Figure 1 A schematic representation of the eddy upwelling mechanism. The solid line depicts the vertical deflection of an individual isopycnal caused by the presence of two adjacent eddies of opposite sign. The dashed line indicates how the isopycnal might be subsequently perturbed by interaction of the two eddies. I 0 represents incident solar radiation, and 1% I 0 the base of the euphotic zone.
PHYSICAL SELCTION OF PHYTOPLANTKON TAXA NOT ALL CHLOROPHYLL IS THE SAME: THE ‘FUNCTIONAL GROUP’ ARGUMENT AND MARGALEF’S MANDALA
Cell N quota Growth rate, d -1 Diatom Cocco Droop model
Symbol Units Meaning State variables N cell L -1 Population density R µmol L -1 Resource availability Q µmol cell -1 Cell quota Physiological function µmol cell -1 h -1 Uptake rate Parameters D h -1 Dilution rate R 0 µmol L -1 Constant nutrient inflowing rate µ max h -1 Maximal growth rate K µmol cell -1 Growth rate half saturation const Q 0 µmol cell -1 Minimal cell quota Notational conventions i Subscript to distinguish terms pertaining to a given species t h Time Droop Model When equilibrium is reached between loss and growth rates, there will be a superior competitor, which has the smaller resource requirement (R i * ) (Tilman 1977).
THE OCEANIC FAX MACHINE TURBULENCE ON GEOLOGICAL TIME SCALES
CIRCULATION AS A GENETIC ISOLATING PROCESS SPECIATION AND SELECTION IN THE MODERN OCEAN
CONCLUSIONS <ul><li>THE OCEAN IS FUNDAMENTALLY A “BOTTOM UP” SYSTEM, HENCE, </li></ul><ul><li>TO THE EXTENT THAT THERMOHALINE CIRCULATION BRINGS NUTRIENTS INTO THE UPPER OCEAN, TO FIRST ORDER IT DCONTROLS THE DISTRIBUTION AND MAGNITUDE OF PHYTOPLANKTON BIOMASS, AS WELL AS NET AND EXPORT PRODUCTION </li></ul>
<ul><li>ON LONGER TIME SCALES, GLOBAL OCEAN CIRCULATION DISTRIBUTES AND GENETICALLY ISOLATES PHYTOPLANKTON – IT IS AN EVOLUTIONARY SELECTION MECHANISM ON TIME SCALES OF CENTURIES TO MILLIONS OF YEARS </li></ul><ul><li>POPULATIONS OF PHYTOPLANKTON NEVER SEE OCEAN CIRCULATION; THEY EXPERIENCE MESOSCALE MIXING PROCESSES, INCLUDING EDDIES, FRONTS, AND COASTAL UPWELLING. </li></ul><ul><li>MESOSCALE PROCESSES EXERT STRONG CONTROLS ON LOCAL SELECTION INDIVIDUAL TAXA – WE ARE STILL LEARNING HOW THESE CONTROLS WORK. </li></ul>
CHALLENGES FOR THE FUTURE <ul><li>THE MESOSCALE </li></ul><ul><li>PALEOPHYSICAL OCEANOGRAPHY </li></ul><ul><li>INTEGRATING OCEAN CIRCULATION WITH EARTH SYSTEMS PROCESSES </li></ul>
OUR FUTURE HUMANS HAVE ESCAPED THE RED QUEEN CONTROL– BUT ARE WE IN CONTROL OF OUR DESTINY?
THANKS TO DENNIS MCGUILLICUDDY SCOTT DONEY SASHA TOZZI ELENA LITCHMAN MICHAEL BEHRENFELD ZBIGNIEW KOLBER EDWARD LAWS NASA, NSF, ONR AND DOE