Macro-zooplankton and PlankTOM10
Róisín Moriarty
Macro-zooplankton
Amphipod
Physalia physalis Ctenophores
Decapod nauplii
Fish larvae
Salp blastozooid
ChaetognathLarvacean
Pelagic polychaete
Pteropod Krill/Euphausid
What are macro-zooplankton?
• plankton– drifting organisms– horizontal position defined by the currents
within the body of water the inhabit• zoo
– animal• macro
– >2000μm
The global carbon cycle
• What factors control transport of carbon (CO2) from the surface to the deep ocean?
The global carbon cycle
Oceanic sink for CO2
• solubility pump– dissolution in cold
waters of high latitudes
– transfer via ocean circulation
– release in warm or upwelling regions
The global carbon cycle
Natural carbon cycle• biological pump
– C-fixation in the euphotic layer (primary production)
– most is recycled– some is exported
beneath (export production)
Macro-zooplankton in the global carbon cycle
• Why am I interested in the role macro-zooplankton play in the carbon cycle?
Dynamic Green Ocean Models (DGOMs)
• feedbacks between marine ecosystems and climate– understand– quantify
• global biogeochemical model– PlankTOM10
• terrestrial equivalents – Dynamic Global Vegetation Models (DGVMs)
PlankTOM10 a dynamic green ocean model
• explicit representations of ecosystem processes– account for changes caused by ecosystems
• key questions– causes of glacial-interglacial changes in
atmospheric trace gases and aerosols
– change in oceanic uptake of CO2
Example of a feedback between climate and ecosystem
Types of models - simple (NPZD) to complex (ecosystem)
NPZD and ecosystem models
• NPZD – e.g., carbon export– simple box for phyto- and zoo-plankton
• ecosystem – e.g., carbon to higher trophic levels– species specific
• local or regional
Problems with NPZD and ecosystem models
• detail– NPZD - not enough; ecosystem - too much
• information– time and resources
• different questions– change in nutrient supply– fisheries and higher predators
PlankTOM10 - A biogeochemical model
Marine
Ecosystem
NEMO 2.3
PlankTOM10• biology as Plankton
Functional Types (PFTs)
• physical processes
PlankTOM10 - PFTs
• Plankton Functional types (PFTs) represent biology
• Biogeochemical processes are closely linked to PFT assemblages (Falkowski et al., 2003)
PFTs
• Explicit biogeochemical role• Distinct set of physiological process rates or
environmental conditions• Behaviour of one impacts on another • Quantitative importance in one or more areas
of the world ocean
Macro-zooplankton and the global carbon cycle
• How do macro-zooplankton function in the export of carbon from the surface layers of the ocean to the deep sea?
Macro-zooplankton and carbon export
• fecal pellets– sink ~100s-1000s
metres per day– escape recycling
• discarded feeding apparatus
• discarded body parts
Modelling macro-zooplankton and carbon export
• characterise– physiological processes– trophic interactions
• from– published results– >> round-up all available data
Modelling macro-zooplankton and carbon export
• physiological processes– growth – respiration– excretion – egestion (fecal
pellets)– mortality
• trophic interaction– feeding
preferences
MAC
POCl
MES
PRO
FIX PHA
DOC
DIC
POCs
COC
BAC
DIA MIXPIC
grazingexcretion,
exudation & sloppy feeding
MGE
ξ
1 - σ
1 - ξ - MGE
σ
g0°C , K1/2, H, pF , aT
k
k
kkk
k
kk kk
k
mortality starvation
m0°C , bT
feeding respiration
Macro-zooplankton growth and respiration data
Validation of PlankTOM10
• reproduce mean state and variability
– CO2, O2, N2O and DMS fluxes
• reproduction of the seasonal cycle – chla in today’s oceans
• macro-zooplankton validation– independent data set
Creating a macro-zooplankton validation data set
• data search– COPEPOD NOAA (O'Brien 2005)– raw KRILLBASE (Atkinson et al. 2004)
• abundance data• conversion from abundance to carbon
– species specific conversions• abundance converted to carbon
– all KRILLBASE data (SO)– ~5% COPEPOD data
Macro-zooplankton validation data set
Macro-zooplankton biomass μMC
Macro-zooplankton abundance #/L
Macro-zooplankton in PlankTOM10
Model macro-zooplankton biomass (μMC)
Macro-zooplankton observation vs. model
Modelmacro-zooplankton
biomass μMC
Observationmacro-zooplankton
biomass μMC
Thank you!
Bill Sturges, Tim Jickelles and Alistair Crame
Corinne Le Quéré, Erik Buitenhuis, Andrew Hirst and Eugene Murphy
FAASIS students
Questions?
Final remarks
• Further sensitivity analysis• Submit Thesis in May/June• Outputs
– 1 data set submission – 3 papers from thesis chapters– contribution to synthesis paper on metabolic
rates
Quick introduction
• The Role of Macro-zooplankton in the Global Carbon Cycle
• ~3 years– British Antarctic Survey, Cambridge
Physical processes
• GCM - NEMO 2.3 (Madec 2008) – horizontal resolution
• 2° longitude, 1.1° latitude • LIM - thermodynamic sea-ice model (Timmermann et
al. 2005)• Mixing
– turbulent kinetic energy model (Gaspar et al. 1990)– sub-grid eddy induced (Gent & McWilliams 1990)
PlankTOM10
• 39 biogeochemical tracers• full phosphate, silicate, carbon, oxygen & simplified iron
cycles• phosphate, nitrate & ammonia fixed to Redfield ratio• nitrification & de-nitrification implicit in phosphate/ nitrate
pool• dissolved compartments; inorganic nutrients, oxygen &
alkalinity
• detrital compartments; DOC, POCl, POCs,CaCO3, SiO2, Fe content of POCl