Val d'Aosta 2 June 08 1 Feedbacks Between Ocean Ecosystems, Feedbacks Between Ocean Ecosystems, Ocean Biogeochemistry and Climate Ocean Biogeochemistry and Climate Ken Denman Ken Denman Canadian 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
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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
• 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?
Val d'Aosta 2 June 08 3
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
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?
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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)+
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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
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
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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
Val d'Aosta 2 June 08 9
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
Val d'Aosta 2 June 08 10
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
Val d'Aosta 2 June 08 11
Positive Feedback between the Carbon Positive Feedback between the Carbon Cycle (Land + Ocean) and Climate ChangeCycle (Land + Ocean) and Climate Change
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
Val d'Aosta 2 June 08 12
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
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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..
[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:
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.
Val d'Aosta 2 June 08 17
'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
Val d'Aosta 2 June 08 18
'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]
Val d'Aosta 2 June 08 19
CaCOCaCO33 Saturation Layer in N. Pacific is ShrinkingSaturation Layer in N. Pacific is Shrinking
From: Archer, D.E., 1996. Global Biogeochemical Cycles, 10(1), 159-174.
Val d'Aosta 2 June 08 21
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
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]
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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
Jim Overland and Jim Overland and MuyinMuyin WangWang2007, EOS/AGU 88(16)2007, EOS/AGU 88(16)
A
SST
(oC
)
Val d'Aosta 2 June 08 23
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)
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
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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
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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)
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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
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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
Val d'Aosta 2 June 08 32
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
Cold water corals on sill (at ~60m depth) in Knight Inlet BC(courtesy Verena Tunnicliffe, U. Victoria)
Val d'Aosta 2 June 08 42
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?