Response of Forest Carbon and Nitrogen Cycles to Decreasing - - PowerPoint PPT Presentation

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Response of Forest Carbon and Nitrogen Cycles to Decreasing - - PowerPoint PPT Presentation

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Response of Forest Carbon and Nitrogen Cycles to Decreasing Acidification NYSERDA-EMEP Biennial Conference November 15, 2011 Christine L. Goodale April M. Melvin Department of Ecology & Evolutionary Biology Cornell University Acid

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SLIDE 1

Response of Forest Carbon and Nitrogen Cycles to Decreasing Acidification

Christine L. Goodale April M. Melvin Department of Ecology & Evolutionary Biology Cornell University

NYSERDA-EMEP Biennial Conference November 15, 2011

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SLIDE 2

Acid Deposition Atmospheric CO2 Conc. DOC Release Calcium Depletion Nitrate Loss? Forest C Storage?

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Outline

  • 1. Deacidification, DOC

and Nitrate Export

  • 2. Interactions Among

Carbon, Nitrogen, and Calcium Cycles in an Adirondack Forest

Carbon Calcium Nitrogen

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SLIDE 4

Trends and Interactions: Sulfate, DOC and Nitrate

Monteith et al. 2007, Nature Driscoll et al. 2007, Applied Geochem.

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SLIDE 5
  • NO3 (µmol/L)

Northeast United States

40 35

Streams Streams

30

Lakes

25

Lakes Adirondacks

20

< 9 kg/ha/y

15

> 9 kg/ha/y

10 5

United Kingdom

40 35

Cairngorms North Wales Galloway

30

~8 kg/ha/y ~21 kg/ha/y ~18 kg/ha/y

25 20 15 10 5 5 10 5 10 5 10 15 20 25

DOC concentration (mg/L)

N Retention, DOC, and De-Acidification

  • Driven by variation in catchment soils?
  • Response to changes in acidification?

Goodale, CL, JD Aber, PM Vitousek, and WH McDowell. 2005. Long-term decreases in stream nitrate: successional causes unlikely; possible links to DOC? Ecosystems 8:334-337. Evans, CD, B Reynolds, A Jenkins, RC Helliwell, CJ Curtis, CL Goodale, RC Ferrier, BA Emmett, M Pilkington, SJM Caporn, JA Carroll, D Norriss, J Davies, and MC Coull. 2006. Soil carbon pool determines susceptibility of semi-natural ecosystems to nitrogen saturation. Ecosystems 9:453-462.

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SLIDE 6
  • DOC and NO3

Affected by changing acidification?

Description SO4

2-

(µeq/L) Target pH

Control Simulated current ADK

precipitation; based on Moss Lake NADP site (2004-07)

21 4.6

Low S

Mean H2SO4 for ADKs during the 1970s

75 4.0

High S

+3X the H2SO4 load of the low S treatment

225 3.6

NaOH

+NaOH, equimolar to high S treatment

21 7.0

CaCO3

+CaCO3, equimolar to high S treatment

21 7.0

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SLIDE 7

Soil Core Response to Weekly Leaching

Leaching shifted core pH – eventually. No significant effect

  • n (variable) DOC

concentrations

Week of extraction

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SLIDE 8

bDOC (mg/L) bDOC (% of DOC) δ13C-DOC

Initial DOC (mg/L) Initial pH Initial DOC (mg/L)

Acidification increases DOC bioavailability (week 34)

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SLIDE 9

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Outline

  • 1. Deacidification, DOC

and Nitrate Export

  • 2. Interactions Among

Carbon, Nitrogen, and Calcium Cycles in an Adirondack Forest

Carbon Calcium Nitrogen

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SLIDE 10

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Hypotheses

Increased Ca availability alters C and N cycling Tree Response Soil Response

  • Increased tree growth
  • Forest Floor:
  • Increased litter production

– Enhanced decomposition and N mineralization

  • Increased root production

– Reduced C and N stocks

  • Mineral soil

– Physical stabilization of organic matter – Increased C and N stocks

Mineral Soil Forest Floor

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Woods Lake Watershed

Adirondack Park, New York

Photos courtesy of Doug Burns

L1 C1 L2 C2

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Liming increased soil exchangeable Ca (cmolc kgsoil

  • 1).

~ 32% of added Ca is currently in the forest floor

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Liming increased surface soil pH.

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Live tree biomass decreased but was unaffected by liming.

Control Limed

Lime effect P = 0.76

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Stand mortality driven by beech decline and was unaffected by liming.

C1 L1 L2 C2

Control Limed

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SLIDE 16

2

No effect of liming on litter production.

3.5 3.25 3 2.75 2.5 2.25

Lime effect P = 0.36

tons ha-1 yr-1 C1 C2 L1 L2 Control Limed

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Liming increased fine roots, but only in the Oe in one subcatchment.

Control Limed Control Limed

Lime effect: P = 0.01 Lime effect: P = 0.11

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SLIDE 18

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Liming increased

Oe

forest floor C stocks.

Oa

~37 t C ha-1 Lime effect: P < 0.0001

Control Limed

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SLIDE 19

Liming suppressed soil basal respiration.

17% 43%

Control Limed Control Limed

Lime effect: P = 0.04 Lime effect: P < 0.0001

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Why has respiration decreased?

Hypotheses

  • Increased chemical recalcitrance?
  • Change in the microbial community?
  • Increased physical stabilization?
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SLIDE 21

Liming suppressed net N mineralization.

Control Limed Control Limed

Lime effect P = 0.0003 Lime effect P = 0.0032

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SLIDE 22

Liming stimulated net nitrification.

Control Limed Control Limed

Lime effect P < 0.0001 Lime effect P = 0.95

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Increased Ca availability alters C and N cycling

Mineral Soil Forest Floor

Tree Response

  • Wood production

NO LIME EFFECT

  • Leaf litter production

NO LIME EFFECT

  • Root production

INCREASED Forest Floor

  • Respiration

DECREASED

  • N Mineralization

DECREASED

  • Nitrification

INCREASED

  • C and N stocks

INCREASED

  • Mineral Soil
  • C and N stocks

NO LIME EFFECT

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SLIDE 24

Annual CO2 respiration estimated from Fahey et al. 2005

C unaccounted for in measured pools 14.2

Net C balance

20 - year Increase in C stocks enhancement in C Source of C flux in limed soils stocks due to liming (t C ha-1 yr-1) (t C ha-1) Foliar litter nsd 0.32 6.4 Non - foliar litter nsd

  • 0.20
  • 4.0

< 2 mm roots* 0.07 1.4 Heterotrophic 0.95 19 respiration* Observed increase in 1.85 37 forest floor C stocks Net C balance of 1.14 22.8 measured fluxes

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SLIDE 25

Some Conclusions

  • (De-)acidification directly and indirectly affects

multiple forest C processes and pools

– Increases release of bio-available DOC.

  • Implications for catchment NO3 export?

– Decreases decomposition rates and yields additional C storage in some forest soils.

  • Exact mechanism and persistence uncertain.
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SLIDE 26

Thank-you!

Guin Fredriksen Max Kraft Chris Johnson Multiple undergrads The Woods Lake Co.

NYSERDA-EMEP Program & Grad. Student Fellowship NSF IGERT NSF CAREER

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SLIDE 27
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Spare Slides

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SLIDE 29

Sulfate Deposition

Sulfate Ion Concentrations 1986

NADP

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Leaching shifted core pH No effect on DOC Nitrate increase in acidified samples

Week of extraction

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Acidification increases DOC bioavailability (week 34)

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Why calcium?

  • Biologically important
  • Abiotic soil interactions
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SLIDE 33

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Woods Lake Watershed

Adirondack Park, New York

L1 C1 L2 C2

Photos courtesy of Doug Burns

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SLIDE 34

Tree response

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SLIDE 35

Annual litter production

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SLIDE 36

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Litter C and N inputs

Carbon Nitrogen

Lime effect: P = 0.60 Lime effect: P = 0.12

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SLIDE 37

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Litter Ca inputs

Lime effect P = 0.001

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SLIDE 38

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Increased Ca availability alters C and N cycling

Tree response

Increased:

  • tree growth: NO LIME EFFECT
  • leaf litter production: NO LIME EFFECT
  • root production: INCREASED

Mineral Soil Forest Floor

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SLIDE 39

Increased Ca availability alters C and N cycling

Mineral Soil Forest Floor

Soil response

  • Forest floor:
  • increased decomposition and net N

mineralization DECREASED

  • decreased C and N stocks INCREASED
  • Mineral soil:
  • increased C and N stocks NO EFFECT
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SLIDE 40

Increased Ca availability alters C and N cycling

Mineral Soil Forest Floor

Soil response

  • Forest floor:
  • increased decomposition and

net N mineralization

  • decreased C and N stocks
  • Mineral soil:
  • increased C and N stocks
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SLIDE 41

Increased Ca availability alters C and N cycling

Mineral Soil Forest Floor

Soil response

  • Forest floor:
  • increased decomposition and net N

mineralization DECREASED

  • decreased C and N stocks INCREASED
  • Mineral soil:
  • increased C and N stocks
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SLIDE 42

Increased Ca availability alters C and N cycling

Mineral Soil Forest Floor

Soil response

  • Forest floor:
  • increased decomposition and net N

mineralization DECREASED

  • decreased C and N stocks INCREASED
  • Mineral soil:
  • increased C and N stocks
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SLIDE 43

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA The Forest Floor

Oe Oa

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SLIDE 44

Liming increased forest floor N stocks

Lime effect: P < 0.0001

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SLIDE 45

Why a difference in forest floor mass?

  • Increased:
  • Litter production
  • Root production

37 t C ha-1

  • Decreased:
  • decomposition
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SLIDE 46

Forest floor C and N cycling

  • Soil basal respiration
  • Net N mineralization and nitrification
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SLIDE 47

Belowground response

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SLIDE 48

Nitrogen

Lime effect P = 0.03

Mineral soil C and N stocks

Carbon

Lime effect P = 0.33

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Soil basal respiration

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In situ net N mineralization

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zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Why have C and N cycling rates changed?

Hypotheses

  • Increased chemical recalcitrance
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SLIDE 52

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA

Why have C and N cycling rates changed?

Hypotheses

  • Increased chemical recalcitrance

Lime effect P = 0.01

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SLIDE 53

zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Why have C and N cycling rates changed?

Hypotheses

  • Increased chemical recalcitrance
  • Change in the microbial community
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SLIDE 54

Annual CO2 respiration estimated from Fahey et al. 2005

Net C balance

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SLIDE 55

Annual CO2 respiration estimated from Fahey et al. 2005

Foliar litter nsd 0.32 6.4 Non - foliar litter nsd

  • 0.20
  • 4.0

< 2 mm roots* 0.07 1.4 Heterotrophic respiration* 0.95 19 Enhanced C retention in measured pools 1.14 22.8 C unaccounted for in measured pools 14.2

Net C balance

20 - year Increase in C stocks enhancement in C Source of C flux in limed soils stocks due to liming (t C ha-1 yr-1) (t C ha-1) Observed increase in 1.85 37 forest floor C stocks

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SLIDE 56

Annual CO2 respiration estimated from Fahey et al. 2005

< 2 mm roots* 0.07 1.4 Heterotrophic respiration* 0.95 19 Enhanced C retention in measured pools 1.14 22.8 C unaccounted for in measured pools 14.2

Net C balance

20 - year Increase in C stocks enhancement in C Source of C flux in limed soils stocks due to liming (t C ha-1 yr-1) (t C ha-1) Foliar litter nsd 0.32 6.4 Non - foliar litter nsd

  • 0.20
  • 4.0

Observed increase in 1.85 37 forest floor C stocks

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SLIDE 57

Annual CO2 respiration estimated from Fahey et al. 2005

Heterotrophic respiration* 0.95 19 Enhanced C retention in measured pools 1.14 22.8 C unaccounted for in measured pools 14.2

Net C balance

20 - year Increase in C stocks enhancement in C Source of C flux in limed soils stocks due to liming (t C ha-1 yr-1) (t C ha-1) Foliar litter nsd 0.32 6.4 Non - foliar litter nsd

  • 0.20
  • 4.0

< 2 mm roots* 0.07 1.4 Observed increase in 1.85 37 forest floor C stocks

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SLIDE 58

Annual CO2 respiration estimated from Fahey et al. 2005

Enhanced C retention in measured pools 1.14 22.8 C unaccounted for in measured pools 14.2

Net C balance

20 - year Increase in C stocks enhancement in C Source of C flux in limed soils stocks due to liming (t C ha-1 yr-1) (t C ha-1) Foliar litter nsd 0.32 6.4 Non - foliar litter nsd

  • 0.20
  • 4.0

< 2 mm roots* 0.07 1.4 Heterotrophic 0.95 19 respiration* Observed increase in 1.85 37 forest floor C stocks