Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 1/18 Ocean Biogeochemistry Nicholas Stephens Max-Planck-Institut für Biogeochemie, Jena

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 2/18 Aims of present studies Synthesise current understanding/ experimental findings –N 2 and N cycle –Associated biology –Ocean processes Decoupling of N:P

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 3/18 Aims of present studies DGOP goal is to build global biogeochemistry models based on PFT’s Understand and quantify the feedbacks between marine ecosystems and climate

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 5/18 The role of biology Resulting C fluxes and DIC concentrations are affected by photoautotrophic C fixation C fixation and the contribution to export is a function of community structure and physiology Growth is regulated by availability of other nutrients (DIN, PO4, Fe), and physical variables such as temp

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 4/18 Ocean-atmosphere carbon fluxes IPCC, third assessment Nitrogen fixation

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 6/18 Effects on biogeochemical cycles

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 7/18 Present model: PlankTOM6.0 DIN SiFePO4 Diatoms N 2 fixers Calcifiers Nanophyto plankton Mesozoo- plankton Microzoo- plankton Bacterial remineralisation Light

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 8/18 Limitation of growth due to NO 3

Nick Stephens Greencycles Mid-Term Review meeting 21/02/2007 9/18 Limitation of growth due to PO 4

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Carpenter et al La Roche and Breitbarth, 2005 Staal et al Temperature relationship of N 2 -fixing PFT

strategy for forced atmospheric conditions Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18

µmolC L -1 CalcifiersN 2 fixers Mixed PhytoplanktonSilicifiers Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Results for a PlankTOM October simulation N 2 fixed = PgN yr -1, Primary Productivity = PgC yr -1, Export to 100m = PgC yr -1

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 µmolC L -1 Simulated monthly mean N 2 fixer concentration, April 2005

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Comparison to remote sensing information Westberry et al. 2006

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ a/18 The Working Group on Coupled Modelling (CLIVAR/WCRP) took place in September This working group guides the development of the Coupled Models which are used by hundreds of scientists to project the future state of climate, and evaluate those projections (e.g. the IPCC model archive). Here is a brief report of the state of the carbon cycle presented by Corinne Le Quéré during the September meeting. Full version available at

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ b/18 Ongoing model developments On land: fires land use CH 4 cycle N cycle more advance ecosystem dynamics (including competition and succession) Unresolved issues: importance of CO 2 fertilisation importance of forest regrowth temperature dependence of soil respiration CH 4 budget In the oceans: more advanced ecosystem dynamics (incl. grazers and incl. major efforts on biological data synthesis) relaxation of N/P ratio and quota models coastal ocean dynamics (over years) links with higher trophic levels Unresolved issues: importance of ecosystem dynamics impact of ocean acidification on ecosystems impact of recent changes in ocean physics and temperature (including on respiration)

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ c/18 Issues for model inter-comparison (C4MIP): fragmented understanding of the processes limited observations for validation incomplete models, thus they should not be expected to reproduce observation (e.g. no fires, no land use) no financial support for C4MIP activities no standards no shared 3D fields no archiving strategy Issues on the C-Cycle C-cycle - climate feedbacks will increase before they are constrained C-cycle – CO 2 feedbacks will increase before they are constrained C-cycle - climate feedbacks are highly dependent on the water cycle standards and archiving of C-cycle variables not organized

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Present activities Stephens N. and Flynn KJ. in prep. “Nitrogen-status of Gloeothece sp. cells reflects growth supported by different inorganic nitrogen sources” Stephens N. et al. in prep “Including N 2 fixation as a Plankton Functional Type in a Dynamic Green Ocean Model” Stephens N. in prep. “Nitrogen fixation and inorganic nitrogen assimilation in the cyanobacterium Trichodesmium spp. can be described using a mathematical model. Allen et al. in prep. “Evaluating and validating Plankton Functional Type models” as part of a recent AMEMR workshop

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Future plans Preparation of the PlankTOM10.0 model for coupling to the QUEST coupled model Preparation of the PlankTOM10.0 model for publication Investigating the response of the nitrogen cycle and implications for climate due to changing physical conditions

Nick Stephens Greencycles Mid-Term Review meeting 21/02/ /18 Acknowledgements Corinne Le Quéré, Erik Buitenhuis and members of the Green Ocean Project Greencycles Project Marie Curie Actions MPI-BGC, Jena UEA

Dust deposition (μmol N kg -1 month -1) World Ocean Atlas 2001

Bergman, botan website Trichodesmium erythraeum

Mean N:P (μmol N kg -1 /μmol P kg -1 ) World Ocean Atlas

DIN Phyto-uptake Leakage/lysis Remineralisation Diatom-uptake Regulation of N 2 fixation Cocco-uptake Physical processes N 2 fix/uptake

N 2 fixer Sedimentation DIN PO 4 Decay Fe N2N2 Heterotrophy O2O2

Summary Significance of biogeochemical processes and feedbacks N cycle leads to better representation of fluxes of C N 2 fixation needs a relationship to N Denitrification requires more substantial relationship to P

latest developments are done with NEMO, running on a linux cluster at the Univ. of East Anglia some developments done with OPA8.1, running on the German DKRZ super-computer we do mostly interannual simulations with NCEP forcing we focus on CO 2, O 2, and marine ecosystems large parallel data synthesis

phyto- plankton mixed silicifiers zoo- plankton proto meso PlSCES-T limitation by Fe, P, and Si Meso-zooplankton parameterisation based on global data compilation (difference to Olivier Aumont's PISCES model)

phyto- plankton calcifiers mixed silicifiers zoo- plankton proto meso PlankTOM 5 limitation by Fe, P, and Si Meso-zooplankton parameterisation based on global data compilation Micro-zooplankton parameterisation based on global data compilation (work with Richard Rivkin) Ballast effect based on Stokes law adjusted grazing preferences

pico-heterotrophs bacteria phyto- plankton pico-autotrophs N 2 -fixers calcifiers DMS-producers mixed silicifiers zoo- plankton proto meso PlankTOM 9 (under development)

pico-heterotrophs bacteria phyto- plankton pico-autotrophs N 2 -fixers calcifiers DMS-producers mixed silicifiers zoo- plankton proto meso macro PlankTOM 10 (planned for 2007)

N 2 fixed = PgN yr -1, Primary Productivity = PgC yr -1, Export to 100m depth = PgC yr -1 PlankTOM 6.0 simulation for 1 st October 2005 N 2 fixers Mixed phytoplanktonDiatoms Coccolithophores

Projection of atmospheric CO 2 up to 2060

anomalies in atmospheric forcing north equator south Temperature ( o C) Precipitations (m yr -1 )zonal wind stress (N m -2 )

model projection of climate change in 2060 temperature ice cover mixed layer depth

change in the CO 2 sink in 2060 (mol/m 2 /y) Calci fiers PO4PO4 FeFe PlankTOM PISCES-T

Laurent’s thesis -30 %+30 % Comparison to results from the thesis of Laurent Bopp export production at 100 m for 2xCO 2 PISCES-T PlankTOM-5

Prototype of the PlankTOM 10 Dynamic Green Ocean Model pico-heterotrophs Heterotrophic bacteria and Archaea phyto- plankton pico-autotrophs N 2 -fixers calcifiers DMSp-producers mixed silicifiers zoo- plankton proto meso macro 10 Plankton Functional Types (PFTs) selected for (a) their explicit biogeochemical role, (b) quantitative importance in at least one region of the ocean, (c) a distinct set of environmental and nutrient requirements for productivity, (d) a distinct impact on the rest of the community (e.g. composition).

Other DGOMs under construction with similar (but not identical) choices of PFTs: 1. ERSEM global (M. Vichi, I. Allen) 2. PISCES + (O. Aumont) 3. NEMURO (Y. Yamanaka) 4. BEC (K. Moore + S. Doney) 5. Hamocc5 (E. Maier-Reimer) 6. Gregg (W. Gregg et al.)

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x data available for parameterisation phytoplankton growth Based on IRONAGES results (C. Lancelot et al.) meso-zooplankton growth Buitenhuis et al., 2006

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x data available for parameterisation Even where an abundance of data exists does not necessarily imply well constrained parameters

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass satellite geochem. data available for parameterisation and evaluation

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass x#x#x##xx satellite geochem. data available for parameterisation and evaluation The only exhaustive (>5000 points) insitu database of biomass concentration exists for meso-zooplankton. Efforts are underway for a similar database on proto-zooplankton Gregg et al. have a database on percent distribution of ~500 data points The EU euroceans project has some funding for building a data base of PFT concentration before 2009, but it is not clear how much effort is needed.

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass x#x#x##xx satellite geochem. data available for parameterisation and evaluation Mesozooplankton biomass (µmol C L -1 )

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass x#x#x##xx satellite geochem. data available for parameterisation and evaluation A few algorithms can detect phyto-PFT from space (but they also need evaluation) PHYSAT PFTs (January synthesis map) Alvain et al., 2005

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass x#x#x##xx satellite geochem. xxxx data available for parameterisation and evaluation geochemical data can be used to assess that the sum of the processes is correct (e.g. biological, chemical, and physical). The data include concentrations of DIC, TALK, Si, PO4, NO3 and O2.

bacteria phytoplanktonzooplankton pico- hetero. pico- autotr. N 2 -fix.calcifiersDMS- prod. mixed- phyto silicifiersprotomesomacro rates x biomass x#x#x##xx satellite geochem. xxxx data available for parameterisation and evaluation the absolute top priority to evaluate DGOMs is to fill this table Especially biomass

Stephens, unpublished N:C calculations for batch cultures of Gloeothece

Estimates for pelagic N 2 fixation N 2 fixation ~ Tg N yr -1 (Sarmiento and Gruber, 1997) Denitrification estimated ~450 Tg N yr -1 Capone et al estimates for N 2 fixation in the N Atlantic are 3-4 times Sarmiento and Gruber (1997) estimates for same region Short residence times of N (<3000 yr) have potential for substantial change in N inventory N 2 fixation is part of a very dynamic ocean N cycle

5.5 – 8.7 T mol N yr -1 = 77 – T gN yr -1 C:N = 4.7 – 7.3 for Trichodesmium T gC yr -1 just for a 28 M km 2 area of the N Atlantic! Considering only Trichodesmium Estimates for new N considered conservative Estimates for pelagic N 2 fixation based fluxes per area in the Atlantic Ocean Capone, 2005; Sarmiento and Gruber, 1997; La Roche and Breitbarth, 2005

Mean N:P (μmol N kg -1 /μmol P kg -1 ) World Ocean Atlas 2001 Moutin et al Letelier and Karl, 2005 Capone et al Fu et al AMT

Richelia intracellularis Gomez et al. 2005

Rhizosolenia clevei Gomez et al. 2005

Chaetoceros compressus Gomez et al. 2005