The role of marine plankton in the global climate Bas Kooijman Dept Theoretical Biology Climate Center Vrije Universiteit Tuesday 15 Oct 2002

Biogeochemo- research by Theor Biol VUA Past projects: Global Emiliania Modelling Initiative (GEM) Peter Westbroek (RUL) & Jan van Hinte (VUA) Mast II: European program NOP II: VUA: modelling nutrient limited growth (Kooijman, Zonneveld) RUL: molecular aspects (Westbroek, Corstjens) NIOZ: growth experiments (Riegman) RUG: DMS (Gieskes, van Rijssel) Current projects: Stochiometric contraints in producer/consumer interactions Kuijper, Kooi, Kooijman, Andersen (Southampton) Time scale separation in producer/consumer interactions Kooi, Kooijman, Auger (Lyon), Poggiale (Marseille) Primary production in ocean circulation models Kooijman, Kooi, Dijkstra (IMAU) Self organisation of trophic structures in ecosystems Troost, Kooi, Kooijman, Metz (RUL), Loreau (Paris)

Dynamic Energy Budget theory for metabolic organisation of all life on earth first principles quantitative Biological equivalent of Theoretical Physics biogeochemical perspective Primary target: the individual with consequences for sub-organismal organization supra-organismal organization Relationships between levels of organisation Practical applications: direct links with empiry ecotoxicology biotechnology medicine/ health care DEB info at

Climate affects marine plankton temperature affects all physiological rates nutrient supply via erosion from terrestrial systems water cycle ocean circulation (wind forcing, plate tectonics) wind-induced primary production light availability (albedo) Climate change induces extinction and speciation in combination with biotic factors (competition)

Marine plankton affects climate organic carbon pump transport of atmospheric CO 2 to deep ocean (1000 year memory) linked to nutrient cycling, terrestrial ecosystems calcification (inorganic carbon pump) precipitation of CO 2 in CaCO 3 burial by plate tectonics albedo emission of DMS cloud formation, effects on radiation Half rules: Half of evaporation is from land (plants compensate land/sea difference) Half of present primary production is from marine plankton Half of carbonate precipitation is by reefs (corals), the rest by plankton (forams and coccolithophores)

Rates depend on temperature Arrhenius plot for the population growth rate of E. coli Data Heredeen et al 1979 low and high temperature inactive state of catalysator 10 3 /T, K -1 ln pop. growth rate, h -1 Arrhenius temperatures Lower K Midrange 4370 K Upper K Tolerance range 293 – 318 K

Rock cycle SiO 2 + CaCO 3 CO 2 + CaSiO 3 H 4 SiO HCO Ca ++ 2 CO H 2 O weathering burial sedimentation out gassing Photosynthesis: H 2 O + CO 2 + light  CH 2 O + O 2 Fossilisation: CH 2 O  C + H 2 O Burning: C + O 2  CO 2 Calcification: 2HCO Ca ++  CaCO 3 + CO 2 + H 2 O Silification: H 4 SiO 4  SiO 2 + 2H 2 O pH of seawater = % DIC = HCO 3 - not available to most org. evaporationraining After Peter Westbroek

Calcification Original hypothesis: E.huxleyi uses bicarbonate as supplementary DIC source; CO 2 might be growth limiting However: non-calcifying strains have similar max growth rate New hypothesis: carbonate is used for protection against grazing Emiliania huxleyi

Nutrients from rocks to plankton by plants + micro’s Plants started to explore the terrestrial environment in the Silurian closed vegetations during Devonian Filter-feeding reefs flourished during the Silurian and Devonian Hypotheses: reefs developed in presence of plankton nutrients released by plants from rocks entered oceans and stimulated plankton growth followed by a reduction due to the formation of Pangaea landscape lower Devonian reef upper Devonian

Growth on reserve Optical Density at 540 nm Conc. potassium, mM Potassium limited growth of E. coli at 30 C Data Mulder 1988; DEB predictions fitted OD increases by factor 4 during nutrient starvation internal reserve fuels 9 hours of growth time, h

Organic carbon pump Wind: weakmoderate strong light + CO 2 “warm” no nutrients cold nutrients no light readily degradable poorly degradable no growth growthpoor growth bloom producers bind CO 2 from atmosphere and transport organic carbon to deep ocean recovery of nutrients to photo-zone controls pump

Grazing accelerates export copepodstintinnids appendicularians Fecal pellets sink fast most nutrients remain in photo-zone Appendicularians produce marine snow (1 feeding house/ 2 hours) Dead bodies decompose fast

Synthesizing Unit dots: arrival and production events gray areas: periods blocked for binding Flux C: transformation: 1 A + 1 B 1 C

Simultaneous nutrient limitation Specific growth rate of Pavlova lutheri as function of intracellular phosphorus and vitamin B 12 at 20 ºC Data from Droop 1974; SU-based DEB model fitted P content, fmol/cell B 12 content, mol/cell Conclusions: SU-based model fits well biomass composition varies considerably no high P-high B 12 due to damming up uptake of abundant nutrient is not reduced by rare one composition control by excretion growth limiting reserve increases with growth rate, other reserves can decrease

C,N,P-limitation Nannochloropsis gaditana (Eugstimatophyta) in sea water Data from Carmen Garrido Perez Reductions by factor 1/3 starting from 24.7 mM NO 3, 1.99 mM PO 4 CO 2 HCO 3 - CO 2 ingestion only No maintenance, full excretion N,P reductionsN reductions P reductions 79.5 h h -1

C,N,P-limitation half-saturation parameters K C = mM for uptake of CO 2 K N = mM for uptake of NO 3 K P = mM for uptake of PO 4 max. specific uptake rate parameters j Cm = mM/OD.h, spec uptake of CO 2 j Nm = mM/OD.h, spec uptake of NO 3 j Pm = mM/OD.h, spec uptake of PO 4 reserve turnover rate k E = h -1 yield coefficients y CV = mM/OD, from C-res. to structure y NV = mM/OD, from N-res. to structure y PV = mM/OD, from P-res. to structure carbon species exchange rate (fixed) k BC = h -1 from HCO 3 - to CO 2 k CB = 79.5 h -1 from CO 2 to HCO 3 - initial conditions (fixed) HCO 3 - (0) = mM, initial HCO 3 - concentration CO 2 (0) = mM, initial CO 2 concentration m C (0) = j Cm / k E mM/OD, initial C-reserve density m N (0) = j Nm / k E mM/OD, initial N-reserve density m P (0) = j Pm / k E mM/OD, initial P-reserve density OD(0) = initial biomass (free) Nannochloropsis gaditana in sea water

Producer/consumer stoichiometry consumer producer reserve density of producer total nutrient (constant) no free nutrient no -maintenance no -reserve no need for reserveneed for reserve Bifurcation diagrams by Bob Kooi

Diauxic growth time, h biomass conc., OD 433 acetate oxalate Substrate conc., mM Growth of acetate-adapted Pseudomonas oxalaticus OX1 data from Dijkhuizen et al 1980 SU-based DEB curves fitted by Bernd Brandt Adaptation to different substrates is controlled by: enzyme turnover 0.15 h -1 preference ratio 0.5 cells

Diauxic growth biomass conc., OD 590 Growth of succinate-adapted Azospirillum brasilense intracellular amounts followed with radio labels data from Mukherjee & Ghosh 1987 SU-based DEB curves fitted by Bernd Brandt Adaptation to different substrates is controlled by: enzyme turnover 0.7 h -1 preference ratio 0.8 time, h fructose conc, mM succinate conc, mM succinate fructose cells suc in cells fruc in cells

1-species mixotroph community Mixotrophs are producers, which live off light and nutrients as well as decomposers, which live off organic compounds which they produce by aging Simplest community with full material cycling

1-species mixotroph community Cumulative amounts in a closed community as function of total C, N, light E: reserve V: structure D E : reserve-detritus D V : structure-detritus rest: DIC or DIN Note: absolute amount of detritus is constant

Canonical community Short time scale: Mass recycling in a community closed for mass open for energy Long time scale: Nutrients leaks and influxes Memory is controlled by life span (links to body size) Spatial coherence is controlled by transport (links to body size)

Self organisation of ecosystems’ trophic structure Aim: understand ecosystem dynamics future application in planetary modelling of life’s actions characterize functional aspects, and link to structure effects of total nutrient amounts and light Method: all organisms in closed ecosystem follow DEB rules constant parameters for each individual during life span food preference parameters values diffuse across generations extensive parameters co-diffuse across generations body size scaling relationships for life histories start with one single mixotroph in well-mixed closed system use theory for adaptive dynamics to understand speciation

Some conclusions simultaneous nutrient limitations on producers’ growth is well captured by DEB theory based on SU’s surface area/volume interactions dominate (transport) kinetics on all space/time scales and are basic to DEB theory wind is in proximate control of primary production in oceans rate of organic carbon pump is controlled by nutrient recycling factors: sinking, decomposition, grazing need for clear time scale separation organic carbon pump is only of interest on time scale of ocean turnover calcification is important at longer time scales plants reduce erosion on short time scale, increase it on long time scale long term behaviour of ecosystems is controlled by leaks and inputs of nutrients, with important roles for continental drift and vulcanism climate-life interactions can only be understood in a holistic perspective coupling of biogeochemical cycles with climate (water, heat)

Further reading S. A. L. M. Kooijman 2002 Global aspects of metabolism; on the coevolution of life and its environment. In: J. Miller, P. J. Boston, S. H. Schneider and E. Crist, eds., Scientists on Gaia. MIT Press,, Cambridge, Mass., to appear. Downloadable from: From which you can also download this slide collection Thank you for your attention