carbon sequestration in coastal freshwater peatlands: a ... · carbon sequestration in coastal...

Carbon Sequestration in Coastal Freshwater

Peatlands: A Market Credit Tool for Restoration

Funded by

U.S. Fish and Wildlife Service, Region 4

&

The Nature Conservancy, NC Chapter

Curtis Richardson1, Neal Flanagan1, Hongjun Wang1, & Mengchi Ho1

&

Sara Ward2, and Tom Augspurger2

1Duke University Wetland Center, Nicholas School of the Environment

2U.S. Fish and Wildlife Service, Region 4

Outline

• Importance of restoring agricultural peatlands and drained wetlands

• Conceptual C credit accounting plan USFWS

• Experimental site description

• Questions

– Does hydrologic restoration increase GHG flux?

– Does restoration increase C and N Sequestration?

– What controls C sequestration ?

• Conclusions

(325 Tg C)

Drained and converted organic soils in agriculture that have potential for increased greenhouse gas losses

(unpublished map from NC RAMSAR working group)

PLNWR

Utrient

Wetland Restoration

Recommended expansion of restoration at Pocosin Lakes NWR

Why?

• Peatland restoration allows

substantive C and N

sequestration benefits

• Refuge habitat improvement

• Reduces nutrient runoff to estuaries

Photo: S.Ward, USFWS

(Peat Fire June –September 2008)

(How much C was lost?)

(NC Pocosin Fire 2008)

9.9 Tg C lost

16,814 ha Burned

Mickler and Welch 2012

Large Scale Hydrology-Carbon

Sequesration Experiment

Pocosins Lake National Wildlife

Refuge

in

Coastal NC

Reference

Restored

Restored

Restored

Drained

Drained (F1)

Experimental Design

Fire

Boundary

Gordonia lasianthus

Pinus serotina

Zenobia pulverulenta

Pinus taeda

Ilex glabra

Morella cerifera

Pteridium aquilinum0

500

1000

1500

2000

2500

Litt

er

acc

um

ula

tion

ra

te (

kg C

hr-1

yr-1

)

Reference

Restored

Drained

Litter Accumulation Rates in Pocosins by Species & Hydrology Treatments

40

50

60

70

80

90

100

0 0.2 0.4 0.6 0.8 1 1.2

Ma

ss r

em

ain

ing

(%

ori

gin

al)

Time (yr)

SPDNLTPREFB7

C2

C14

Morella

50

55

60

65

70

75

80

85

90

95

100

0 0.2 0.4 0.6 0.8 1 1.2

Ma

ss r

em

ain

ing

(%

ori

gin

al)

Time (yr)

SPDNLTPREFB7

C2

C14

Ilex

Decomposition rates in drained, restored and reference pocosins

(Preliminary data from Tim Moore, McGill)

0.0

5.0

10.0

15.0

20.0

25.0

REF C2_REST C14_DRAIN

mg

/l

DIC

REF

C2_REST

C14_DRAIN

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

REF C2_REST C14_DRAIN

mg

/l

TOC

REF

C2_REST

C14_DRAIN

50% 80%

- -8x

Incomplete C Budget

100 Years left

Does Hydrologic Restoration Alone Control GHG Flux?

& Which GHG is the

Dominant Contributor?

Average By Treatment

-160

-140

-120

-100

-80

-60

-40

-20

0

20

01

/20

11

02

/20

11

04

/20

11

06

/20

11

07

/20

11

09

/20

11

11

/20

11

12

/20

11

RESTORED

DRAINED

REFERENCE

Sep.2011 Nov. 2011 Jan. 2012

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

CO

2 (m

g m

-2 h

-1)

Month

Drained sites

Reference sites

Restored sites

Sep.2011 Nov. 2011 Jan. 2012

0

100

200

300

400

500

600

700

800

CO

2 e

qu

iva

len

ts (

mg

m-2 h

-1)

Month

N2O

CH4

CO2

Drained sites

Sep.2011 Nov. 2011 Jan. 2012

0

100

200

300

400

500

600

700

CO

2 equ

ival

ents

(m

g m

-2 h

-1)

Month

N2O

CH4

CO2

Restored sites

Wet Dry Comparison of GHG

-200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0

0

200

400

600

800

1000

1200

1400

Drained sites

Reference sites

Restored sites

CO

2 (

mg

m-2 h

-1)

Water level (cm)

y = 3.9591x + 257.77

R2 = 0.6001

Dry Aug.

Wet Sep.

Average By Treatment

-160

-140

-120

-100

-80

-60

-40

-20

0

20

01

/20

11

02

/20

11

04

/20

11

06

/20

11

07

/20

11

09

/20

11

11

/20

11

12

/20

11

RESTORED

DRAINED

REFERENCE

Drought Effects ?

Questions

• How does this peat exist under such low summer water tables?

• What controls CO2 production in unsaturated peatlands? Phenolic cpds possible microbial block (Bridgham and Richardson, 2003)

• What are the responses of these peatlands to drought and can they resist drought effects? (Wang Ho and Richardson 2012)

Drought Low precipitation,

drainage for agriculture and forest

Aerobic decay

More CO2

Fenner and Freeman, 2011

Drought unlocks carbon historically restored in boreal peatland

Fenner and Freeman, 2011

Generally, such phenomenon occurs in

saturated peatlands,

However, unsaturated

peatlands?

High nitrogen in natural site Low C quality (C/N low) in drained site

1/28 2/12 2/27 3/14 3/29 4/13 4/28 5/13 5/28 6/12 6/27

1

2

3

4

5

6

CO

2 e

mis

sio

n (m

ol m

-2 s-1

)

Date

Drained

Natural

Restored

Figure 3. Temporal variation of CO2 emission during drought incubation of peat monoliths from drained, natural and restored Pocosin peatland sites.

No effects

(Wang , Ho and Richardson in Prep, Poster 336)

10

20

30

40

50

60

70

80

90

B

a

B

bB

c

B

a

A

a

A

a

B

b

A

bA

b

AB

c

A

c

So

il M

ois

ture

(v

%)

drained

Natural

restored

A

c

A

200

300

400

500

600

700

800

900

1000

B A

a

A

a

A

aAB

a

B

a

AB

a

B

a

B

abB

b

AB

a

B

b

B

b

So

lub

le p

oly

ph

en

ol

(g

C g

-1 d

ry s

oil)

1-Mar 31-Mar 1-May 1-Jul0

100

200

300

400

500

600

700C

A

a

A

a

A

a

A

aA

aA

a

A

a

A

a

B

a

A

aA

a

B

a

La

bile

po

lysa

cch

ari

de

(g

C g

-1 d

ry s

oil)

Date

1-Mar 31-Mar 1-May 1-Jul

1.0

1.5

2.0

2.5

3.0

3.5

4.0D

A

b

A

b

A

bA

b

A

a

A

a

A

a

A

a

A

a

Ph

en

ol o

xid

ise

act

ivity

(mm

ol d

iqc

g-1 m

in-1 )

Date

n/a

Figure 1. Temporal variations of soil moisture (A), soluble and polyphenol (B), labile polysaccharide (C) and phenol oxidase activity(D) during the drought incubation of peat monolith from natural, drained & restored Pocosin sites.

(Wang , Ho and Richardson in Prep, poster 336)

2.5 2.6 2.7 2.8 2.9 3.0 3.1

0.5

1.0

1.5

2.0

2.5

3.0

0 20 40 60 80 100

B

CO

2 e

mis

sion (m

ol m

-2 s

-1)

Log (Soluble polyphenol (g g-1 dry soil))

r2 = 0.694

p < 0.0001

A

Inorganic nitrogen (g N g-1 dry soil)

r2 = 0.4488

p < 0.001

Figure 4. Soluble polyphenol (A) and inorganic nitrogen (B, NH4++ NOx

-) vs. CO2

emission during the initial 60-day drought incubation of all peat monoliths

(Wang , Ho and Richardson in Prep, poster 336)

Phenolics-latch for CO2 production

Properties of Soil and Plants in the Pocosin Study Sites in Coastal NC

(Wang , Ho and Richardson in Prep, Poster 336)

Conclusion and application Build-up polyphenol inhibit CO2 production under drought

(weakens drought effects)

Moderate drought might increase C accumulation (similar with restored site results)

Altered species composition caused by drainage or by severe drought results in decreased polyphenol in soil & increased CO2 flux

Nitrogen deposition stimulates CO2 flux

Major Peatlands in the SE Coastal

Plain of the U.S.

Potential Peatland Restoration sites

Any Questions?