Feedbacks Between Ocean Ecosystems, Ocean Biogeochemistry...

Val d'Aosta 2 June 08 1

Feedbacks Between Ocean Ecosystems, Feedbacks Between Ocean Ecosystems, Ocean Biogeochemistry and ClimateOcean Biogeochemistry and Climate

Ken DenmanKen DenmanCanadian Centre for Climate Modelling and Analysis

Environment Canada c/o University of Victoria, BC, Canada

&Institute of Ocean Sciences, Fisheries and Oceans Canada

Email: [email protected]

U. Victoria


Outline of TalkOutline of Talk

• Linkages, transports & transformations• Anthropogenic climate change: past and future• Global ocean biogeochemical patterns• North Pacific climate change• Observed changes in NP biogeochemical cycles• Changes in ocean acidity: global and in N. Pacific• Can we predict the response of organisms?


Ocean Ecosystems Ocean Ecosystems ClimateClimate

Direct links between ocean ecosystems and climate, e.g.Direct links between ocean ecosystems and climate, e.g.– thermal regulation of physiological rates– phytoplankton pigments regulate the vertical profile of

absorption of incoming solar radiation and hence upper ocean temperature profile

Indirect links via 'Biogeochemistry', e.g.Indirect links via 'Biogeochemistry', e.g.– ocean biota regulate sequestration of atmospheric CO2 by the

ocean by affecting surface pCO2, pH, export of C to ocean interior via 'biotic pumps'

– oceanic biota regulate dissolved O2 concentrations, and hence production of gases N2 and especially N2O

– temperature affects biological sources and sinks for O2

Physical transport, e.g.Physical transport, e.g.– advection, mixing, gravitational sinking (& buoyant rising)


Linked Ocean Cycles: Linked Ocean Cycles: Transports and TransformationsTransports and Transformations

• Cycles of C, N, O, P, Si, S, Fe, etc. are linked via the 'Redfield ratios' – more or less!more or less!

• Most, but not all, transformations of chemical form are mediatedby the marine ecosystem

• There are critical pointscritical points where the cycles depart from Redfield ratios during transformation,

• Many involve N, e.g nitrification, denitrification, uptake and release by organisms, bacterial remineralization releasing dissolved inorganic nutrients over different depth ranges

• What factors regulate these critical points and how will they change with a changing climate?


The World Has Warmed But Not EvenlyThe World Has Warmed But Not Evenly

Globally averaged, the planet is about 0.75Globally averaged, the planet is about 0.75°°C warmer than it was in C warmer than it was in 1860, based upon dozens of high1860, based upon dozens of high--quality long records using quality long records using thermometers worldwide, including land and ocean.thermometers worldwide, including land and ocean.

Eleven of the last 12 years are among 12 warmest since 1850 Eleven of the last 12 years are among 12 warmest since 1850 in the global average.in the global average.

AR4 WG1 Fig.3.9

( + significant at 5% level)+


Most of the Heat is Going into the OceansMost of the Heat is Going into the Oceans

And it has And it has penetratedpenetratedto at least to at least 3000 m3000 m

19611961--2003200319931993--20032003

from IPCC AR4 WG1 Fig. 5.4from IPCC AR4 WG1 Fig. 5.4


Largest warming is since 1975 & in N. HemisphereLargest warming is since 1975 & in N. Hemisphere

Land

Total

SST

Pacific Ocean

Indian Ocean

Atlantic Ocean

IPCC AR4 WG1, Fig. 3.5


Smoothed annual anomalies for precipitation (%) over land from 1Smoothed annual anomalies for precipitation (%) over land from 1900900to 2005; other regions are dominated by variability (from Fig. 3to 2005; other regions are dominated by variability (from Fig. 3.14).14)

Increases

Decreases

Land Precipitation Is Changing Significantly Over Broad AreasLand Precipitation Is Changing Significantly Over Broad Areas

CRUNODC


The Future: SRES ScenariosThe Future: SRES Scenarios

2000 2100Year

CO

2E

mis

sion

s (G

tC/ y

r)

A2

A1B

B1TAR Fig. 3.12a

Economists and social scientists must forecast Economists and social scientists must forecast humanhuman behaviourbehaviour and response to changeand response to change


Projected Surface Warming to 2100Projected Surface Warming to 2100(relative to 1980(relative to 1980--1999 mean)1999 mean)

AOGCMs

Hierarchy of independentmodels and observationalconstraints


Positive Feedback between the Carbon Positive Feedback between the Carbon Cycle (Land + Ocean) and Climate ChangeCycle (Land + Ocean) and Climate Change

from IPCC AR4 WG1 Fig. 10.20from IPCC AR4 WG1 Fig. 10.20

CC44MIP models forced by MIP models forced by 'A2' CO'A2' CO22 emissionsemissions

IPCC AR4 models forced by CO2 concentrations

Greater reductions in Greater reductions in COCO22 emissions would emissions would be needed to achieve be needed to achieve the same COthe same CO22 conc.conc.stabilization levelstabilization level

C4MIP models project an additional ~1oC

warming added to the 'official' IPCC AR4 projections for 2100


Change in SurfaceChange in SurfaceAir TemperatureAir Temperature

(°C, relative to 1980(°C, relative to 1980--1990 period)1990 period)

Stippled areas: multi-model mean exceeds inter-model std dev.

TT highest in northern Polar highest in northern Polar regions during northern winterregions during northern winter

Elsewhere,Elsewhere, TT higher over landhigher over land

AR4 WG1 Fig. 10.9

( T, annual)

Fig. 11.21

Val d'Aosta 2 June 08 13BottomBottom –– Number of models out of 21 that project precipitation to increaNumber of models out of 21 that project precipitation to increasese

10°C

-1°C

50%

-50%

21

0

A1BA1B


Projections of Future Changes in PrecipitationProjections of Future Changes in Precipitation

New in AR4:New in AR4: Drying in much of the subtropics, more rain Drying in much of the subtropics, more rain in higher latitudes, in higher latitudes, continuing the broad pattern of rainfall continuing the broad pattern of rainfall changes already observedchanges already observed..


Future COFuture CO22 EmissionsEmissionsScenariosScenarios

[from[from RaupachRaupach et al., et al., US. Proc. US. Proc. NatlNatl AcadAcad SciSciVol. 104, 12 June 2007]Vol. 104, 12 June 2007]

20062005

20062005

Observed rate of increase Observed rate of increase (3.3 % /year) for 2000(3.3 % /year) for 2000--2006 exceeds all scenarios 2006 exceeds all scenarios 2004 Carbon emissions per 2004 Carbon emissions per person:person:

Globe (Canada) Globe (Canada) ~1.2~1.2 tonnestonnes/year ( ~5.5)/year ( ~5.5)= 4 = 4 tonnestonnes COCO22 /year ( ~20)/year ( ~20)


Annual Average Surface Nitrate ConcentrationsAnnual Average Surface Nitrate ConcentrationsWorld Ocean Atlas 1994World Ocean Atlas 1994

From:From: Denman and Peña, 2000. In: The Denman and Peña, 2000. In: The Changing Ocean Carbon Cycle, CUP.Changing Ocean Carbon Cycle, CUP.


'1995' Annual CO'1995' Annual CO22 Flux Ocean to Air Flux Ocean to Air Takahashi et al. 2002 (corrected to 10 m winds)Takahashi et al. 2002 (corrected to 10 m winds)

mol-C m-2 yr-1


'Anthropogenic' CO'Anthropogenic' CO22 in the Ocean in 1995in the Ocean in 1995

48% of fossil fuel emissions: Most in N. Atlantic and northern edge of Antarctic Circumpolar Current

• Some in N. Pacific, probably associated with subduction and deeper winter mixing in western basin IPCC AR4 WG1, Fig. 5.10IPCC AR4 WG1, Fig. 5.10

[after Sabine et al. 2004, Science 305; Key et al., 2004, GBC, 1[after Sabine et al. 2004, Science 305; Key et al., 2004, GBC, 18, GB4031]8, GB4031]


CaCOCaCO33 Saturation Layer in N. Pacific is ShrinkingSaturation Layer in N. Pacific is Shrinking

Feely et al. 2004. Science, 305: 362-366.

S N

Present

Pre-industrial


InIn UndersaturatedUndersaturated Regions, CaCORegions, CaCO33 Shells Dissolve Shells Dissolve and 'Neutralize' Anthropogenic' COand 'Neutralize' Anthropogenic' CO22

23232 Ca2HCOOHCaCOCO

From: Archer, D.E., 1996. Global Biogeochemical Cycles, 10(1), 159-174.


Apparent Oxygen Utilization (AOU) Regions Apparent Oxygen Utilization (AOU) Regions Present day AOU (mol m-3) at300m (World Ocean Atlas 2002)

Decreasing ODecreasing O22 in low Oin low O22 regions may lead to:regions may lead to:• Hypoxia in adjacent upwelling regions, affecting organisms &increasing sediment denitrification

• Increasing water column denitrification in low O2 layers• Denitrification results in N2 and N2O production

[from[from MeissnerMeissner, Galbraith & , Galbraith & VölkerVölker, 2005, Paleoceanography,20 , 2005, Paleoceanography,20 ]]

PaleoPaleo 1515N indicates N indicates more denitrification & production of Nmore denitrification & production of N22 0 in warm 0 in warm periods relative to LGMperiods relative to LGM [Galbraith et al., 2004,[Galbraith et al., 2004, PaleoceanographyPaleoceanography, 19], 19]


Spatial pattern of projected warmingsimilar to that of the PDO first EOF:

A. SST anomaly (November SST anomaly (November –– March),March),first EOF (i.e. PDO), for 1901first EOF (i.e. PDO), for 1901--19991999(from Hadley Centre SST analysis)(from Hadley Centre SST analysis)

&Ensemble mean of SST first EOF, Ensemble mean of SST first EOF, for A1B SRES scenario, 2002for A1B SRES scenario, 2002--20992099(10 IPCC(10 IPCC--AR4 models from PCMDI site)AR4 models from PCMDI site)

B. Projected model average decadal winter mean SST (2040-2049),relative to 1980-1999 patternfrom the Hadley Centre data

Expected Warming Expected Warming vsvs Pacific Decadal OscillationPacific Decadal Oscillation

B

Jim Overland and Jim Overland and MuyinMuyin WangWang2007, EOS/AGU 88(16)2007, EOS/AGU 88(16)

A

SST

(oC

)


NE Pacific Ocean: The Future? NE Pacific Ocean: The Future? from DFO Ocean Status Reports (Chair: W. Crawford, IOS)from DFO Ocean Status Reports (Chair: W. Crawford, IOS)

http://www.pac.dfo-mpo.gc.ca/sci/psarc/OSRs/Ocean_SSR_e.htm

Sept. 97 – July 98: Chlorophyll from SeaWiFS Ocean Colour SensorCourtesy NASACourtesy NASA

OSPMaximum winter mixed layer Maximum winter mixed layer depth is DECREASINGdepth is DECREASING

Year

Dep

th (m

)

courtesy Howard Freeland, IOScourtesy Howard Freeland, IOS


Subsurface Oxygen Decrease is WidespreadSubsurface Oxygen Decrease is Widespread

After Deutsch et al. (2005)After Deutsch et al. (2005)

IPCC AR4 WG1Fig. 5.12

O2 (μmol kg-1)


Apparent Oxygen Utilization DecreasingApparent Oxygen Utilization Decreasinginin OyashioOyashio RegionRegion

AOUAOUOO22(surface outcrop) (surface outcrop)

–– OO22(( const)const)

i.e. increasing AOU i.e. increasing AOU decreasing Odecreasing O22

= 27.2 (~630m)

= 26.7 (~190m)

[from Ono et al. 2001, Geophys Res Lett 28]


Crawford et al. 2007 Crawford et al. 2007 ProgProg.. OceanogrOceanogr. 75(2). 75(2)

Dissolved ODissolved O22 Is Lower Closer to LandIs Lower Closer to Land% Oxygen Saturation% Oxygen Saturationon 26.5 on 26.5 -- surfacesurface

0 to 4646 to 6262 to 120

1956

1960

1964

1968

1972

1976

1980

1984

1988

1992

1996

2000

2004

P26 26.7 = -0.67 uM y-1

P4 26.7 = -1.2 uM y-1

0

50

100

150

200

250

1956

1960

1964

1968

1972

1976

1980

1984

1988

1992

1996

2000

2004

Oxy

gen

(µm

ol k

g-1)

F. Whitney, in: DFO Ocean Status Report F. Whitney, in: DFO Ocean Status Report 2006, W. Crawford (ed.)2006, W. Crawford (ed.)

(~170 m)

(~280 m)P426.7

OSP26.7


NutriclineNutricline:: NONO33¯̄ (( TT = 26.0) = 26.0) 2525 mmolmmol mm--33

Hales et al. 2005, J. Hales et al. 2005, J. GeophysGeophys. Res., 110, C10S119. Res., 110, C10S119

2626--27 May 200127 May 2001

45° 00' N45° 00' N


MayMay

AugustAugust

OO22

OO22

POCPOC

POCPOC

Coastal Upwelling Coastal Upwelling & Local & Local

Enhancement of Enhancement of Low OLow O22 WatersWaters

Hales et al., 2006, Global Hales et al., 2006, Global BiogeochemBiogeochem. Cycles, 20, GB3001. Cycles, 20, GB3001(50 μmol kg(50 μmol kg--11 1.151.15 mLmL/L)/L)

MayMay• small area of low O2 nearbottom, below

• high surface POC (mostly live phytoplankton)

• sinking POC creates biological O2 demand near bottom

AugustAugust•75m thick layer of low O2

•thin surface layer of POC


Dissolved oxygen profiles during the upwelling season, mid-April to mid-October

(42N to 46N)F. Chan et al., Science 319, 920 (2008)F. Chan et al., Science 319, 920 (2008)

Recent Changes off OregonRecent Changes off Oregon

19501950--9999n = 3101 castsn = 3101 casts

19501950--20052005+ 834 casts+ 834 casts

+2006+ 220 casts

(50(50 mmolmmol mm--33 1.121.12 mLmL/L)/L)


The Coastal Ocean: More Hypoxia Events?The Coastal Ocean: More Hypoxia Events?Dead zone off Newport, Oregon 2002,04,06

[[www.piscoweb.orgwww.piscoweb.org PISCO at OSU]PISCO at OSU]

(50(50 mmolmmol mm--33

1.121.12 mLmL/L)/L)

See also:See also:Grantham et al. 2004Grantham et al. 2004Nature, 229, 749Nature, 229, 749--753753


a)Very high > 600 ppm surface XCO2 near coast during upwelling events

b)Same section off Oregon as low O2

c)c) Very low pH watersVery low pH waters

High COHigh CO22High AcidityHigh AcidityUpwelling + Upwelling +

LocalLocalRespirationRespiration

a)

b)

Hales et al. 2005, Global Hales et al. 2005, Global BiogeochemBiogeochem. Cycles, 19, GB1009. Cycles, 19, GB1009

XCO2 = 372 ppm

XCO2 – mixing ratio of CO2 in dry air


Higher COHigher CO22 and Lower and Lower ppH Will Also Affect H Will Also Affect Continental Shelf EcosystemsContinental Shelf Ecosystems

Subsurface areas of low O2 may also be areas of high CO2 / low pH due to cumulative effect of respiration / remineralizationrespiration / remineralization of organic particulates by bacteria

In aerobicaerobic conditions:Organic Matter 'OM'Organic Matter 'OM' LossLossC106H175O42N16P + 150150 OO22

106106 COCO22 + 16 HNO3 + H3PO4 + 78 H2OSourceSource Dissolved nutrientsDissolved nutrients

Equations from Equations from SarmientoSarmiento and Gruber, 2007and Gruber, 2007


InIn AnerobicAnerobic ConditionsConditionsRespiration / remineralizationRespiration / remineralization of organic particulates by

bacteria use first NONO33¯̄, releasing NN22 (and NN22OO),

then use Mn and then use 236236FeFe22O3, then S, and then forming CH4

.

'OM' + 104104 HNOHNO33

106106 COCO22 + 6060 NN22 + H3PO4 + 138 H2O


Adding COAdding CO22 Increases AcidityIncreases AcidityK1 K2

CO2 + H2O HCO3- + H+ CO3

2- + 2H+

29N, 15W

23N, 158W

32N, 64W

1985 2005

Left•• Surface pCOSurface pCO22increases with timeincreases with time

Right•• Surface pH Surface pH decreasesdecreases

pH = -log [H+]

IPCC AR4 WG1 Fig. 5.9IPCC AR4 WG1 Fig. 5.9


CCCmaCCCma Ocean Model Surface pH DecreaseOcean Model Surface pH Decrease

No EmissionsNo Emissions

Observed + A2 EmissionsObserved + A2 Emissions

0.10.1

0.140.14 –– 0.350.35

IPCCIPCCAR4AR4

Due primarily to adding CODue primarily to adding CO22 ,,not to the changing climatenot to the changing climate


''UndersaturationUndersaturation''of surface oceanof surface ocean

in N. Pacific & in N. Pacific & Southern Ocean Southern Ocean with respect to with respect to

aragonite (CaCOaragonite (CaCO33))in 2099in 2099

Organisms with Organisms with CaCOCaCO33 skeletalskeletalstructures will structures will tend to dissolvetend to dissolve

[from Orr et al., 2006Nature,437, 681]


Carbonate (CaCOCarbonate (CaCO33) Pump ) Pump --CoccolithophoridCoccolithophorid Emiliania huxleyiEmiliania huxleyi

Image courtesy of Southampton Image courtesy of Southampton Oceanography Centre, UKOceanography Centre, UK

SEM imageSEM image

SeaWiFS image SeaWiFS image 25 April 199825 April 1998

SeaWiFS image SeaWiFS image 16 July 200016 July 2000

MODIS 'true colour' image25 June 2006 (courtesy NASA)


PteropodsPteropods arearemade up of made up of

aragonite CaCOaragonite CaCO33

Limacina helicina [credits -NOAA]

LimacinaLimacina helicinahelicinaare an important food source for juvenile North Pacific salmon and also eaten by mackerel, herring and cod.

So What !So What !


High COHigh CO22Low pHLow pH

Feely et al., 2008,Feely et al., 2008,ScienceScience

pCOpCO22

DICDIC

pHpH

AragoniteAragoniteSaturationSaturation

T(T(ooCC))

Line 5Line 5 off Northern California, Cruise in May – June 2007

pH of ~7.75 is pH of ~7.75 is considered to considered to be "corrosive" be "corrosive"

to animalsto animals


Depth of Depth of 'Corrosive''Corrosive'pH < 7.75 pH < 7.75 Waters on Waters on ContinentalContinental

ShelfShelf

Feely et al., 2008 Feely et al., 2008 ScienceScience


LowerLower ppH Threatens Corals,H Threatens Corals,PteropodsPteropods && CoccolithophoridsCoccolithophorids

Cold water corals on sill (at ~60m depth) in Knight Inlet BC(courtesy Verena Tunnicliffe, U. Victoria)


How Fast Can Organisms Adapt & Evolve?How Fast Can Organisms Adapt & Evolve?

Our foodweb models need parameters that Our foodweb models need parameters that 'adapt/change' in response to changing ocean 'adapt/change' in response to changing ocean conditions:conditions:

• What is the species diversity within a functional group?

• What is the genetic diversity (plasticity) within a species?

• Is a century a long enough time for evolution via genetic mutations?

– Requires a minimum of ~25 generations??

Which species will be threatened with extinction?Which species will be threatened with extinction?

Thank-you

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