Natalia Restrepo-Coupe, Brad Christoffersen, Daniel F. Amaral, Plínio B. de Camargo; Scott R. Saleska

Carbon loss on the other side of drought:  excess wet season precipitation during La Niña suppresses Amazon forest photosynthesis

Motivation: will Amazon forest die-back with future climate change?

Adapted from: Cox et al., 2003, Amazon Dieback under Climate-Carbon Cycle Projections for the 21st Century

1 2 3 4 5 6 7 8 Mean daily temperature

change(K)

-3 -2 -1 -0.5 0.5 1 2 3Precipitation change (mm day-1)

-8 -4 -2 -1 1 2 4 8Change in Vegetation Carbon (kg C m-2)

180 90W 090 N

45 N

0

45 S

90S

Differences relative to 1990 - 2090 mean

180 90W 0

180 90W 0

Motivation: August 2008 – June 2008 La Niña Event

El Niño

La Niña

neutral

La Niña ONI value for ASO 2007 – AMJ 2008 is -1.4oCThe most recent ONI value (July – September 2009) is +0.8oC.

Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/

Oceanic Nino Index, ONI (ERSST.v3b ONI)Upper ocean heat anomalies (1991 -2009)

Se

a S

urf

ac

e T

em

pe

ratu

reA

no

mli

es

(C

)

4

3

2

1

0

-1

-2

-3

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Motivation: 2008 – June 2008 La Niña Event

La Niña

neutral

Source: http://www.cpc.ncep.noaa.gov/

Oceanic Nino Index, ONI (ERSST.v3b ONI)Upper ocean heat anomalies (1991 -2009)

Se

a S

urf

ac

e T

em

pe

ratu

reA

no

mli

es

(C

)

4

3

2

1

0

-1

-2

-3

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

NOV JAN MAR MAY JUL 2008 2009

Se

a S

urf

ac

e T

em

pe

ratu

reA

no

mli

es

(C

)

1.5

1

0.5

0

-0.5

-1

-2

Tropical Rainfall Measuring Mission (TRMM) data, at 0.25 spatial resolution 1998 – 2009 [NASA, 2006]

Motivation: South America precipitation 2008 – 2009La

t

Lon

2009 prec anomaly:Jan

-79 -74 -69 -64 -59 -54 -49 -44 -39

8

3

-2

-7

-12

Lat

Lon

2009 prec anomaly:Feb

-79 -74 -69 -64 -59 -54 -49 -44 -39

8

3

-2

-7

-12

Lat

Lon

2009 prec anomaly:Mar

-79 -74 -69 -64 -59 -54 -49 -44 -39

8

3

-2

-7

-12

Lat

Lon

2009 prec anomaly:Apr

-79 -74 -69 -64 -59 -54 -49 -44 -39

8

3

-2

-7

-12

Lat

Lon

2009 prec anomaly:May

-79 -74 -69 -64 -59 -54 -49 -44 -39

8

3

-2

-7

-12

-3

-2

-1

0

1

2

3

No

rmili

zed

an

om

aly

Lat

Lon

2009 prec anomaly:Jan-Mar

-85-80-75-70-65-60-55-50-45-40-35

15

10

5

-0

-5

-10

-15La

t

Lon

2009 prec anomaly:Apr-Jun

-85-80-75-70-65-60-55-50-45-40-35

15

10

5

-0

-5

-10

-15

Lat

Lon

2009 prec anomaly:Jul-Sep

-85-80-75-70-65-60-55-50-45-40-35

15

10

5

-0

-5

-10

-15

Lat

Lon

2009 prec anomaly:Oct-Dec

-85-80-75-70-65-60-55-50-45-40-35

15

10

5

-0

-5

-10

-15

Lon

K67

Lon

K67

Apr-May

… on the other side of drought …

Tapajós K67 tropical forest

A S O N D J F M A M J J23

26

29

Tai

r ( C

)

Tapajós K67 tropical forest: Climate

Hydrological year: Dry season – Wet seasonHY2002: Aug 1, 2002 – Jul 31, 2003 HY2003: Aug 1, 2003 – Jul 31, 2004HY2004: Aug 1, 2004 – Jul 31, 2005 HY2005: Aug 1, 2005 – Jan 6, 2006HY2008: Aug 1, 2008 – Jul 31, 2009

A S O N D J F M A M J J0

125

250

Pre

cip

(m

m w

ee

k-1

)

A S O N D J F M A M J J400

800

1200

PA

R ( m

ol m

-2 s

-1)

Aug 2008 – Jul 2009

dry season wet season

dry season wet season

dry season wet season

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

Result 1: La Niña Event corresponds to C Forest Loss

Net ecosystem exchangeForest C losses

Forest C uptake

dry season wet seasonAug 2008 – Jul 2009

A S O N D J F M A M J J-4

0

4

NE

E (

gC

m-2

d-1

)

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

dry season wet season

Result 1: La Niña Event corresponds to C Forest Loss

dry season wet season

Aug 2008 – Jul 2009

Instantaneous C-flux

Cumulative C-flux and Precipitation

A S O N D J F M A M J J-4

0

4

NE

E (

gC

m-2

d-1

)

What is the cause of C-loss? (split into photosynthesis & respiration)

NEE: Net Ecosystem ExchangeR: Ecosystem RespirationGEE: Gross Ecosystem Productivity

~ Photosynthetic activity

Hig

her

C u

ptak

eH

ighe

r C

loss

es

NEE = R + GEE

dry season wet season

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

A S O N D J F M A M J J-12

-6

0

GE

E (

gC

m-2

d-1

)

A S O N D J F M A M J J-4

0

4

NE

E (

gC

m-2

d-1

)

A S O N D J F M A M J J0

6

12

R (

gC

m-2

d-1

)

Result 2: Forest C Loss is due to reduced photosynthesis

NEE: Net Ecosystem ExchangeR: Ecosystem RespirationGEE: Gross Ecosystem Productivity

~ Photosynthetic activity

Hig

her

C u

ptak

eH

ighe

r C

loss

es

dry season wet season

dry season wet season

dry season wet season

Reduced photosynthesis (less negative)

NEE = R + GEE

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

A S O N D J F M A M J J-12

-6

0

GE

E (

gC

m-2

d-1

) A S O N D J F M A M J J0

6

12

R (

gC

m-2

d-1

)

Hig

her

C u

ptak

eH

ighe

r C

loss

es

dry season wet season

dry season wet season

What is the cause of reduced photosynthesis?

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

A S O N D J F M A M J J-12

-6

0

GE

E (

gC

m-2

d-1

) A S O N D J F M A M J J0

6

12

R (

gC

m-2

d-1

)

Hig

her

C u

ptak

eH

ighe

r C

loss

es

dry season wet season

dry season wet season

What is the cause of reduced photosynthesis?

Lower PAR and…

A S O N D J F M A M J J400

800

1200

PA

R ( m

ol m

-2 s

-1)

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

A S O N D J F M A M J J-12

-6

0

GE

E (

gC

m-2

d-1

) A S O N D J F M A M J J0

6

12

R (

gC

m-2

d-1

)

Hig

her

C u

ptak

eH

ighe

r C

loss

es

dry season wet season

dry season wet season

Result 3: decreased photosynthetic response

0 800 16000

25

50

PAR (mol m-2 s-1)

GE

P (

mo

l m

-2 s

-1)

Jan

0 800 16000

25

50

PAR (mol m-2 s-1)G

EP

(m

ol

m-2

s-1

)

Feb

Decreased photosynthetic response

Jan

Feb

GE

P =

-G

EE

NE

E (

kgC

ha-1

)

K67

-1000

0

1000

2000

3000

4000

5000

pre

c (m

m)

K67

A S O N D J F M A M J J0

500

1000

1500

2000HY2002HY2003HY2004HY2005HY2008HY2009

What is the cause of reduced photosynthetic response? Earlier onset of the wet season? High soil moisture? ….

Summary:at Tapajós K67 tropical forest Result 1: La Niña Event (wet wet season and

earlier onset of the wet season, corresponds to C Forest Loss.

Result 2: Forest C Loss is due to reduced photosynthesis.

Result 3: decreased photosynthetic response.

Future work: Investigaion on the cause of reduced photosynthetic response?

Acknowledgments

This research was funded by the National Science Foundation’s Partnerships for International Research and Education (PIRE) and the National Aeronautics and Space Administration (NASA) LBA investigation CD-32.

Thank you

0:00 12:00 0:00-150

350

850

1350

Aug

0:00 12:00 0:00-150

350

850

1350

Sep

0:00 12:00 0:00-150

350

850

1350

Oct

0:00 12:00 0:00-150

350

850

1350

Nov

0:00 12:00 0:00-150

350

850

1350

Dec

PA

R ( m

ol m

-2 s

-1)

0:00 12:00 0:00-150

350

850

1350

Jan

0:00 12:00 0:00-150

350

850

1350

Feb

0:00 12:00 0:00-150

350

850

1350

Mar

0:00 12:00 0:00-150

350

850

1350

Apr

0:00 12:00 0:00-150

350

850

1350

May

Local Time0:00 12:00 0:00

-150

350

850

1350

Jun

0:00 12:00 0:00-150

350

850

1350

Jul

Local Time

NE

E (

kgC

ha-1

)

K67

-500

0

500

1000

pre

c (m

m)

K67

A S O N D0

100

200

300HY2002HY2003HY2004HY2005HY2008HY2009

PAR)) *(+(GEP

GEP*PAR*=GEP

sat

sat