carbon, part 3, • carbon balance of ecosystems • …nature.berkeley.edu/biometlab/espm111/espm...

4/5/2013

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ESPM 111 Ecosystem Ecology

Carbon, Part 3,Net Ecosystem Production

• Carbon Balance of Ecosystems

• NEP,NPP, GPP

• Seasonal Dynamics of Ecosystem Carbon Fluxes

• Carbon Flux Partitioning

• ‘Chain-saw’ and ‘Shovel’ Ecology

Dennis BaldocchiESPMUC Berkeley


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Law and Ryan, Biogeochemistry, 2005

Carbon Cycle:Above and Below Ground Links


Active Carbon/Water Flux Measurement Sites

www.fluxdata.org

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Published Data, April, 2011

GPP (gC m-2 y-1)

0 500 1000 1500 2000 2500 3000 3500 4000

pdf

0.00

0.01

0.02

0.03

0.04

0.05

0.06

What is the Range of Gross Primary Productivity?


2

max gg

PAR gC mGPP R LUE fpar

R mole C

7000 * MJ m-2 y-1 * (4.6/2) * 0.02 * 0.9 * 12 = 3477 gC m-2 y-1

Rg: incoming short wave radiationPAR: photosynthetically active radiation, 0.4 to 0.7 micronLUE: light use efficiencyfpar: fraction of absorbed PAR

Upper Limits of GPP

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FLUXNET 2007 Database

GPP at 2% efficiency and 365 day Growing Season

Potential and Real Rates of Gross Carbon Uptake by Vegetation:Most Locations Never Reach Upper Potential

tropics

GPP at 2% efficiency and 182.5 day Growing Season

How much Carbon do Ecosystems take up?Probability Distribution of Published NEE Measurements, Integrated Annually

Published Data, April, 2011

NEE (gC m-2 y-1)

-1000 -500 0 500 1000

pdf

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

0.016

n = 973mean = -165 +/- 253 gC m-2 y-1

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Luyssaert et al. 2007, GCB


NEP is the balance between two large fluxesGPP and ecosystem respiration

Chapin et al.

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Harvard Forest: 1991-2000

Day

0 50 100 150 200 250 300 350 400

NE

E (

kg h

a-1 d

-1)

-100

-50

0

50

100

Data of Wofsy et al; Urbanski et al 2007 JGR

Seasonal change in daily NEE for a temperate deciduous forest


d a y

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0

Rec

o (

kgC

ha-1

d-1)

0

2 0

4 0

6 0

8 0

1 0 0

H a r v a r d F o r e s t , 1 9 9 2 - 2 0 0 2

d a y

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0

GP

P (

kgC

ha-1

d-1

)

- 1 4 0

- 1 2 0

- 1 0 0

-8 0

-6 0

-4 0

-2 0

0

Data of Wofsy et al; Urbanski et al. JGR 2008

Season Course in Daily GPP and Reco for a temperate deciduous forest

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Day

0 50 100 150 200 250 300 350

FN (

gC

m-2

d-1

)

-8

-6

-4

-2

0

2

4

Deciduous forest Evergreen forest Macchia Perennial grassland Annual grassland Crop (wheat)Tundra

Seasonal Patterns Vary with Plant Functional Type

Length of Growing Season, days

50 100 150 200 250 300 350

FN (

gC

m-2

yr-1

)

-1000

-800

-600

-400

-200

0

200

Temperate and Boreal Deciduous Forests Deciduous and Evergreen Savanna

Baldocchi, Austral J Botany, 2008

Net Ecosystem Carbon Exchange of Deciduous Forests Scales with Length of Growing Season

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Does Net Ecosystem Carbon Exchange Scale with Photosynthesis?

FA (gC m-2 y-1)

0 500 1000 1500 2000 2500 3000 3500 4000

FN (

gC

m-2

y-1

)

-1000

-750

-500

-250

0

250

500

750

1000

Ecosystems with greatest GPP don’t necessarily experience greatest NEE

FA (gC m-2 y-1)

0 500 1000 1500 2000 2500 3000 3500 4000

FR (

gC m

-2 y

-1)

0

500

1000

1500

2000

2500

3000

3500

4000

UndisturbedDisturbed by Logging, Fire, Drainage, Mowing


Ecosystem Respiration Scales with Ecosystem Photosynthesis,But with an Offset by Disturbance

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Interannual Variability in FN

d FA/dt (gC m-2 y-2)

-750 -500 -250 0 250 500 750 1000

d F

R/d

t (g

C m

-2 y

-2)

-750

-500

-250

0

250

500

750

1000Coefficients:b[0] -4.496b[1] 0.704r ² 0.607n =164


Interannual Variations in Photosynthesis and Respiration are Coupled

ESPM 111 Ecosystem EcologyLuyssaert et al. 2007, GCB

GPP and Climate Drivers

Climate explains 70% of variation in GPP

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NPP and Climate Drivers


Climate explains 35% of variation in NPP


NEP and Climate Drivers


Climate explains 5% of variation in NEP

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Magnani et al 2007 Nature

Disentangling roles of Age, Climate and N deposition


Harvard Forest

Year

1990 1992 1994 1996 1998 2000 2002 2004 2006

Car

bo

n F

lux

(gC

m-2

y-1

)

-600

-400

-200

0

1000

1200

1400

1600

1800

FNFAFR

Urbanski et al. 2007, JGR

Net Ecosystem C Exchange is a Function ofTime Since Disturbance

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ESPM 111 Ecosystem EcologyHe et al. 2012 GBC

Net Primary Production and Stand Age


On to Ecosystem Respiration

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Gifford, 1994, Australian J Plant Physiol

The Ratio between Plant Respiration and Photosynthesis is Constant:Regardless of Plant Size, Treatment etc

Emerging and Useful Ecological Rules


Kyuzakov

Fundamentals of Soil Respiration

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deForest et al 2006 IntJ Biomet

Soil Respiration and Temperature

Note how Variance increases with T, especially after Ps starts!


Xu and Qi, 2001, Global Change Biology

Soil Respiration, Temperature and Soil Moisture

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Xu and Qi, 2001, Global Change Biology

Soil Respiration and Soil Moisture


Roles of Drought and Temperature on Soil Respiration

Reichstein et al. 2003, GBC

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Environmental Controls on Respiration:Temperature, Soil Moisture, Growth/Reproduction, Rain-Induced

Microbial Activity

Soil volumetric water content (m3 m-3)

0.0 0.1 0.2 0.3 0.4

Rec

o/R

ref

0.0

0.5

1.0

1.5

2.0Fast growth period data

Rain pulse

Xu + Baldocchi, 2003 AgForMet


Respiration: Temperature and acclimation

Enquist et al. 2003, Nature

Respiration of a coldBoreal Ecosystem, at 10 C,Is similar to a warm TemperateEcosystem at 20 C

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Soil tempreture (oC)

30 35 40 45 50

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

14:50h

6h

Fo=0.037e0.0525T, Q10=1.69, R2=0.95

Tonzi Open areas

Soil temperature (oC)

25 30 35

1.1

1.2

1.3

1.4

1.5

1.6

1.7

Under treesDOY 211

Fu=0.337e0.0479T, Q10=1.61, R2=0.80

20h

6h

12:50h12h

16h

Tonzi Under trees

10h

24h

Tang, Baldocchi, Xu, 2005, GCB

Respiration and Temperature:A role for fast-photosynthesis


Raich 2000 Tellus

On Annual Scales Soil Respiration Scales with Photosynthesis

Janssens et al 2001 GCB

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Rain Pulses: Heterotrophic Respiration

Days After Rain Pulse

-10 -5 0 5 10 15 20 25 30

C E

fflux

(gC

m-2

d-1

)

0

1

2

3

4

5

8 mm 12.7 mm61 mm12 mm3 mm

Xu, Baldocchi, Tang, 2004, GBC

Photodegradation

ESPM 111 Ecosystem EcologyAustin et al 2010 PNAS

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Concluding Points

GPP scales with Available Sunlightso there are upper Limits to GPP, set by Length of Growing Season,Temperature and Water

Most (80%) Assimilated Carbon is lost byAutotrophic and HeterTrophic Respiration

Net Carbon Fluxes are a Function of Weather, Structure and FunctionAnd Time Since Disturbance

Soil Respiration tied to Temperature and Moisture, and recent Photosynthesis…Rain can Induce Pulses!


‘Chain-Saw’ Carbon Balance, 101

C

tGains Losses

Gains GPP

Losses spiration LitterFall

Herbivory RootTurnover

VOC Emissions Fire Harvest

Re

_ )

C

tWood Soilannual C C| ~

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ESPM 111 Ecosystem EcologyLitton et al., 2007

Carbon Allocation of Forests


But Partitioning of Carbon is Poorly related to Biomass

Litton et al., 2007

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NPP Biometry

• NPP=GPP-Ra

• NPP=Live mass increment (L) + Detritus (D) + Herbivory (H)

• NEP = (L + D +H)-Rhetero

• Soil Carbon Store=Detritus-Rhetero

• dCarbon = Wood Increment + Soil Carbon Store

• NEP ~ dCarbon– H=0


Caveat Emptor

• Few of the NPP components are measured, or measured well, in practice– Litterfall– Bole Increment– Labile Carbon is not measured in wood increment– ANPP– Convert bole increment to gC– Small diameter trees ignored, < 10 cm diameter– Below ground components often ignored

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Gough et al 2008 AgForMet

Biometry and Eddy Covariance NEP converges on Long Time Scales


Curtis et al, 2002, AgForMet

•NEP,ec=GPP-Reco NEP = (L + D +H)-Rhetero

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Chapin et al

carbon, part 3, • carbon balance of ecosystems • …nature.berkeley.edu/biometlab/espm111/espm...

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