Macro-zooplankton and PlankTOM10

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