Macro-zooplankton and PlankTOM10 Róisín Moriarty

Macro- zooplankton Amphipod Physalia physalis Ctenophores Decapod nauplii Fish larvae Salp blastozooid Chaetognath Larvacean 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 (CO 2 ) from the surface to the deep ocean?

The global carbon cycle Oceanic sink for CO 2 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 CO 2

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 POC l MES PRO FIXPHA DOC DIC POC s COC BAC DIAMIXPIC grazing excretion, exudation & sloppy feeding MGE ξ 1 - σ 1 - ξ - MGE σ g 0°C, K 1/2, H, p F, a T k k k k k k k k k k k mortalitystarvation m 0°C, b T feeding respiration

Macro-zooplankton growth and respiration data

Validation of PlankTOM10 reproduce mean state and variability –CO 2, O 2, N 2 O 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 Model macro-zooplankton biomass μMC Observation macro-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, POC l, POC s,CaCO 3, SiO 2, Fe content of POC l