slide1
Download
Skip this Video
Download Presentation
Marine biology and geochemistry in Earth System Models Andrew Watson School of Environmental Science University of East Anglia Norwich NR4 7TJ UK

Loading in 2 Seconds...

play fullscreen
1 / 35

Marine biology and geochemistry in Earth System Models Andrew Watson School of Environmental Science University of Eas - PowerPoint PPT Presentation


  • 214 Views
  • Uploaded on

Marine biology and geochemistry in Earth System Models Andrew Watson School of Environmental Science University of East Anglia Norwich NR4 7TJ UK. Major effects of marine biology on the Earth system. . “Biological pump” for atmospheric CO 2

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Marine biology and geochemistry in Earth System Models Andrew Watson School of Environmental Science University of Eas' - bernad


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Marine biology and geochemistry in Earth System Models

Andrew Watson

School of Environmental Science

University of East Anglia

Norwich NR4 7TJ

UK

major effects of marine biology on the earth system
Major effects of marine biology on the Earth system.
  • “Biological pump” for atmospheric CO2

- sets natural atmospheric CO2 on time scales 102 – 105 years.

  • Sulphur gas impact on cloud albedo via CCN production.
  • Production of sediments – carbonate sink and organic carbon sink.
    • Major influence on atmospheric CO2 and O2 over millions of years.
why do you need biology and geochemistry in earth system models
Why do you need biology and geochemistry in earth system models?
  • Studies of the long-term habitability of the earth:
    • Faint young sun
    • major glaciations
    • Sudden warmings
    • Response to major impact events
slide6

Weathering of rock:

CO2 + XSiO3= XCO3+SiO2

Weathering of organics:

CH2O+O2 = CO2 + H2O

Burial of organics:

CO2 + H2O = CH2O+O2

Ocean

Oceanic crust

Metamorphism of rock;

XCO3+SiO2=CO2 +XSiO3

Weathered sediment from continents

Long term (>105 year) concentrations of atmospheric CO2, O2, CH4 etc are set by biota-geochemical interactions.

major glaciations

Quaternary

Permo-Carboniferous

Ordovician

Neoproterozoic

Paleoproterozoic

Major glaciations
  • Some (or all?) may be related to changes in greenhouse gases, driven by biological change.
slide8

A Neoproterozoic

Snowball Earth?

why do you need marine biology and geochemistry in earth system models
Why do you need marine biology and geochemistry in earth system models?
  • Studies of the long-term habitability of the earth
  • The Quaternary climate: the classic Earth system problem.
    • CO2 changes are largely ocean-driven.
    • Cannot be correctly modelled without representation of
      • short-term processes (e.g. air-sea exchange
      • Long-term processes (sedimentary accumulation and dissolution).
vostok core proxies

CO2: controlled by

ocean chemistry,

biology,circulation?

Deuterium

in ice: proxy for

local temperature

Vostok core proxies

Methane:sourced

from wetlands?

Atmospheric dust:

signal “leads” other

indicators

Sea-salt sodium:

proxy for

wind strength?

Atmospheric d18O:

proxy for biosphere

productivity?

The driver?

Summertime

insolation,

N. hemisphere

Source: Petit, J.R. et al., 1999. Nature,399: 429-436.

why do you need marine biology and geochemistry in earth system models11
Why do you need marine biology and geochemistry in earth system models?
  • Studies of the long-term habitability of the earth
  • The Quaternary climate: the classic Earth system problem.
  • Short term (~100 year) feedbacks on global change…
possible marine biological effects on carbon uptake next 100 years
Possible Marine biological effects on carbon uptake, next 100 years.

Process Effect on CO2 uptake

  • Iron fertilisation or change in atmospheric iron supply.
  • NO3 fertilisation
  • pH change mediates against calcite-precipitating organisms
  • Reduction in overturning circulation interaction with nutrient utilisation
  • Other unforeseen ecosystem changes

?

modelling the marine ecosystem in esms
Modelling the marine ecosystem in ESMs
  • Complex ecosystem – too costly (and not enough knowledge) to model at species level.
  • Simple models, “NPZD” – single nutrient, primary producer, consumer.
  • More complex, “functional groups” of phytoplankton, size classes of zooplankton.
biogeochemical functional groups
Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups15

10m

Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need lower Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups16

10m

Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups17

10m

Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups18

10m

Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups19

10m

Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
biogeochemical functional groups20
Biogeochemical functional groups
  • Nutrients
    • NO3, PO4, Si, Fe
  • Phytoplankton Fix carbon
    • Diatoms “large”, need Fe, NO3, Si.
    • Non-Diatoms “small”, need Fe, NO3
      • Coccolithophores produce CaCO3
      • Phaeocystis produce DMS
      • Others
  • Zooplankton
    • Mesozooplankton Eat everything, produce large sinking flux
    • Microzooplankton Eat small phytoplankton, produce small sinking flux
  • Bacteria
  • Viruses
slide21

Nitrate concentrations in surface water – the “HNLC” regions

Annual mean surface nitrate, mol kg-1

slide23

In all the HNLC regions,

iron release experiments have now shown that diatom blooms are stimulated by addition of iron. These depress surface CO2 and nutrients.

Why? Large cells such as diatoms have small surface-to-volume ratio. Their growth is limited at low Fe concentrations by rate of diffusive transport of Fe into the cell.

slide24

Effect of iron on HNLC ecosystems

Large-cell system

small-cell system

-inefficient recycling

-efficient recycling

-substantial export

-little particle export

Strongly iron-limited

Weakly iron-limited

"large"

"small"

phyto-

phyto-

plankton

plankton

nut-

rients

meso-

micro-

zoo-

zoo-

plankton

plankton

slide25

gas

exchange

remineralization

Two-component plankton biogeochemistry – BIOGEM (Ridgwell)

aeolian

dust

deposition

e

temperature

+

insolation

dissolution

atmospher

un-off

non-diatom

diatom

r

productivity

productivity

ocean

surface

continental

scavenging

ior

inter

dissolution

ocean

sedimentation

sedimentary

diagenesis

sediments

burial

Fe

C

dust

KEY:

CaCO

PO

Si

3

4

f 1 temperature dust
f1 : temperature  dust

Data from the Vostok ice core.

f 2 dust atmospheric co 2
f2 : dust  atmospheric CO2
  • Marine biological effect: results of two different models and a hypothetical response

Bopp et al

Ridgwell

f 3 atmospheric co 2 temperature
f3 : atmospheric CO2 temperature.
  • Use climate sensitivities for glacial – interglacial cycle from models, 2ºC antarctic temperature change for 200-280 ppm CO2 change.
conclusions
Conclusions
  • Simple marine biology sub-models for earth system models now exist.
  • First order effects on climate dynamics over periods > 102 years.
  • Magnitude of effects uncertain.
  • To do list:
ad