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EPOCA Kick-off Meeting June 2008: Nice

Theme 1 Ocean chemistry and biogeography

What is the past and recent variability of ocean carbonate chemistry (including nutrients and trace metals) and geographical distribution of marine organisms?

Among other methods, paleo-reconstructions will be used to investigate the response of (mainly) calcifying organisms to past changes in ocean acidification.

Objectives

1. Determine oceanic carbonate chemistry evolution over a range of time scales in systems of natural variability (Glacial to Interglacial, Holocene) and in human perturbed systems (industrial era)

2. Integrate proxy records with present day observations (link to WP3)

3. Improve understanding of proxy incorporation during calcification (link to WP4)

WP2 Past variability of ocean chemistry (paleo-reconstruction)

Objectives

4. Evaluate the response of calcifying organisms to past changes in ocean acidification

5. Assess the role of carbonate dissolution in the natural carbonate chemistry of the ocean

6. Advance the parameterization of climate and biogeochemical processes affected by ocean acidification in model predictions (link to WP10, WP12)

Determination of the evolution of oceanic carbonate chemistry

over a range of time scales in systems of natural variability and in human perturbed systems

Determination of the evolution of oceanic carbonate chemistry

over a range of time scales in systems of natural variability and in human perturbed systems

Rapid Events

Glacial-interglacial changes in ocean carbonate system

Records of the industrial age

Work and participants

1. Analyses of foraminifera and coccoliths (geochemistry, isotopes, morphometry) from marine sediment cores for paleo reconstruction Cambridge, Bergen, Amsterdam, CEREGE, AWI, Bern

2. Analyses of foraminifera and coccoliths from core-tops, sediment traps and water column samples for integration of proxy and present day records Cambridge, Bergen, Amsterdam, CEREGE, AWI, Bern

1. Analyses of cold water corals: field calibration and geochemistry LSCE

Work and participants

4. Determination of the dissolution kinetics of biogenic carbonates Brussels

5. Model simulation (including a sediment module) of Glacial to Interglacial rain ratio and carbonate compensation response Bergen, Bern,Bristol

6. Model simulation of Cretaceous/Paleogene acidification event LSCE,Southampton,Bristol

System where atmospheric CO2 defined by ocean-atmosphere interactions with internal and external carbon reservoirs

System where atmospheric CO2 change shows response in oceans

“Paleo-analogs”

There are no good analogs for the perturbations we are making. The world has never before seen such a rapid rise in greenhouse gases with the present-day configuration of the continents and with large amounts of polar ice.

The simplest use of the paleo record - just going back to a point that had similar conditions to what we expect for the future - doesn't work very well because because there are no good analogs for the perturbations we are making. So more sophisticated approaches must be developed.

Exception is Records of the Industrial Age

Records of the industrial age

Challenge:

Obtain marine records that define seawater carbonate chemistry

Investigate whether/to what extent records modified by increase in anthropogenic CO2

Archives

Corals

Rapidly-accumulating sediment cores

Core tops

Water column samples (trap, tow)

Experimental systems (lab and field)

Tools

Foraminifer shell weightCoccolith massShell chemistry (13C, 11B, Sr/Ca, B/Ca….)

Calibrate/improve with links to other WPs

Examples from EPOCA proposal…..

Planktonic foraminifer G. Bulloides normalised shell mass and glacial-interglacial [CO3

2-]

Barker & Elderfield (2002)

B/Ca- [CO32-] in benthic foraminifera and [CO3

2-] reconstruction of N. Atlantic glacial water column

Yu and Elderfield (2007)

Records of the industrial age from North Atlantic

Records of the industrial age from North Atlantic

RAPID core-21-12B southern Gardar Drift

57o 27.09’N 27o 54.53’W 2630m water depthBoessenkool et al (2006)Iglesias Rodriguez et al (2008)Elderfield et al unpublished data

Records of the industrial age from North Atlantic

Core HM01-128-04 Ormen Lange63o 45.8’N 05o 15.3’E 845.4m water depth

Carin Andersson Dahl (Berknes Centre, Bergen) unpublished data

Records of the industrial age from North Atlantic

Core HM01-128-04 Ormen Lange63o 45.8’N 05o 15.3’E 845.4m water depth

Carin Andersson Dahl (Berknes Centre, Bergen) unpublished data

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B

JJJJJJJJJJJ

JJ

J

J

J

25

20

15

10

5

0

1850 1900 1950 2000

B HM01-128-04MCBJ P1-003MC

Age AD

Ormen Lange cores HM01-128-04 and P1-003MC210Pb dating methodSedimentation rate = 1.3 to 2.2 mm a-1

0.5 cm intervals ≈ 2.3 to 3.8 years 1865-2000 ADAndersson Dahl

Gardar Drift core RAPID-21-12B

210Pb dating methodLinear sedimentation rate = 2.3 ± 0.2 mm a-1

Sampled at 0.5 cm intervals ≈ 2.2 ± 0.2 years 1770-2004 AD

Boessenkool et al (2006)

No long term trend in coccolithophore species composition

Iglesias Rodriguez et al (2008)

40 % increase in average coccolith mass since ca 1950

Iglesias Rodriguez et al (2008)

Shell weight of G.bulloides in 250-350µm

12 % decrease in planktonic foraminifera mass since ca 1900

increase in average coccolith mass

decrease in planktonic

foraminifera mass

decrease in G bulloides Sr/Ca

related to calcification rate - [CO32-] - inorganic calcite

Lessons from the past

Shell weight and Sr/Ca can vary for other reasons

G. Bulloides shell weight and 18O in Southern Ocean

Low shell weight at interglacial (high CO2) times

Greaves et al (2008)

2.5

3.0

3.5

4.0

4.5

5.0

5.5 0.80

0.84

0.88

0.92

0.96

1.00

1.04

1.08

0 200 400 600 800 1000

d18OSr/Ca

Age

5 7 9

11 13 15 17 19

18

16

14

12

108

6

Benthic foraminiferal Sr/Ca and 18O in Southern Ocean

An idea for paleo rain ratio

Late Glacial Maximum carbonate saturation in the North Atlantic Ocean and rain ratio

Conclusions

1. Industrial age records a challenge but very important

2. EPOCA must enable integration of modern observational studies with paleo records

Combination of 1 and 2 potential to make a very significant contribution to understanding of effects of ocean acidification

3. Records of Glacial-Interglacial periods and rapid events also relevant