Temperate Forest Watersheds: Responses to Atmospheric

Pollutants and Climate Change Myron J. Mitchell

Distinguished ProfessorSUNY College of Environmental Science and

ForestrySyracuse, New York, USA

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)

• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)

• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

Processes Involved in Acid DepositionSources

The Effects go beyond on that of Acid Deposition

• Acidic mobile, anions (SO42- and NO3

-) result in the mobilization of cations.

• Nutrient cations (Ca2+, Mg2+, K+) may be lost.• Acidic cations (H+, Al+3) may be mobilized in

soils and surface waters.• Al+3 may be toxic to aquatic (i.e., fish) and

terrestrial vegetation (i.e., fine roots)

Effects of Mobile Anions on Cation Leaching in Soil

Nutrients

Toxic to Biota

Other Problems Related to Acidic Deposition

• Degradation of materials.• Interactions with other air pollutants including

O3, NOx and hydrocarbons.• Fixed N inputs are causing eutrophication of

coastal waters that are N limited.• Interrelationships with global change including,

climate alteration, biotic diversity and carbon budgets.

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)• Historical Patterns of SO2 emissions

• North America• Europe• Asia

• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

SO2 Emissions inU.S.APeakedMid-1970’sU.S. EPA

Figure 1. Historical development of sulfur dioxide emissions in Europe (Unit: Tg SO2) from Vestreng et al.  2007. Emissions Peaked in 1980’s

SO2 Emissions in Europe peaked in 1980’s

In Asia emissions are still increasing.From Streets et al. (2000) Atmospheric Environment

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets

– Central European watershed case studies– North American watershed case studies

• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

Intensive study watersheds in Central Europe for examining sulfur budgets.  Black Triangle: area of pollutants from lignite coal 

BlackTriangle

*Syracuse

Location and YearSouth-1986 South-1993 North-1986 North-1993

μeq

L-1

0

50

100

150

200

250

300

350

Acid Rain in China

pH

4.0

4.5

5.0

5.5

6.0

6.5

7.0

SO42-

NO3-

NH4+

Ca2+

Highest inputs of S and N in northern China, but pH also high due to high [base cations] e.g. Ca2+. From: Wang, W. and T. Wang. 1996. Atmospheric Environment 30:4091-4093.

Acidity

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen

– Changes in relative contribution of sulfur and nitrogen– Nitrogen Cascade– Nitrogen concentrations in Japanese surface waters

• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

Wet-Only Preciptation Huntington ForestRelative contribution of NO3 increasing

Year1985 1990 1995 2000

μeq

L-1

0

20

40

60

80

100SO4 NO3Cl

Mitchell et al. unpublished data(New York State)

NOx

NH4+

HNO3

Acidification

Coastal Eutrophication

Changes inBiotic Diversity

Atmosphere

TerrestrialEcosystems

Freshwater Ecosystems

Smog formationVisability

NH3

N O2

Global Warming

NO3-

Nitrogen Cascade

From: Galloway et al. (2003) BioScience

●●

●

●

●

●●

●

●●●

●

●●

●

●

●

●

1.0 mg N L-1

0.5 mg N L-1

Nitrate concentration in forest stream

water during base flow (Shibata et al.

2001)

High NO3-

in area of high N deposition

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change

– Linkage of climate change with changes in chemistry of alpine lakes in Europe

– Nitrate loss linked with snow melt in forested watershed in North America

– Linkage of sulfur watershed budgets and climatic events

• Importance of climate change in East Asia• Concluding Statements

Changein

Albedo

Time series. (a) River and stream water temperatures (RWT) measured in Switzerland from 1965 to 2002 (b) Air temperature in Switzerland, Hurrell’s (1995) winter NAO index (NAOwin) and the brown trout catch in the 87 river sections. From Hari et al. (2006). Global Change Biology

Linkage of water temperature and fish survival in Switzerland

Water Chemistry and Climate Change Linked:Conductivity, sulfate, calcium, and magnesium in two high alpine lakes in of Rasass See in Italy (black triangles) and Schwarzsee ob Solden in Austria (open circles) (1985-2005). From Thies et al. (2007) ES&T

NO3-

12/95 1/96

2/96 3/96

4/96 5/96

NO

3- con

cent

ratio

n ( μ

mol

L-1

)

0

10

20

30

40

50

60

70

Dai

ly a

vera

ge a

ir te

mpe

ratu

re (o C

)-30

-20

-10

0

10

20

Run

off (

mm

day

-1)

0

10

20

30

Dai

ly a

vera

ge a

ir te

mpe

ratu

re (o C

)

-20

-10

0

10

20

30Sn

owpa

ck d

epth

(cm

)0

50

100

150

200

Temperature

Runoff

Snowpacka

c

Responses of snowpack depths, runoff amounts, and nitrate concentrations in drainage water from the Archer Creek catchment to temperature changes from December 1995 to May 1996. Adirondack Mountains, New York State)Park et al. Global Change Biol. (2003)

a. January - December R2 = 0.30, P = 0.018

3.5 4.0 4.5 5.0 5.5 6.0 6.5

Annu

al N

O3- e

xpor

t (m

ol h

a-1 y

r-1)

0

50

100

150

200

250

b. January - March R2 = 0.72, P < 0.001

-10 -8 -6 -4 -2

NO

3- exp

ort f

rom

Jan

- M

ar (m

ol h

a-1pe

riod-1

)

0

20

40

60

80

Relationships between average air temperatures andNO3

- export in Arbutus Lake outlet for either the entire year or the months preceding spring snowmelt from 1984 to 2001. Winter air temperature major driver of NO3

- export. Our current research is trying to evaluate what is causing this relationship. Average daily air temperature °C

Sulfur and Climate Change• High concentrations of S aerosols in the

atmosphere result in less warming.• High sulfur loading in the past has resulted in

sulfur storage in soils and wetlands.• Sulfur stored in wetlands is stored as sulfide.• When wetlands become oxidized (lowering of

water table) the stored sulfide is oxidized to sulfuric acid (similar to acid mine drainage):6FeS2 + 21O2 + 6H2O ---> 6FeSO4 + 6H2SO4

• Changes in hydrology predicted with global climate change.

Drier conditions result in higher SO42- concentrations

in Ontario, Canada (Eimers and Dillon, 2002)

Days with no discharge

[SO42-]

Late Summer/Fall Storms at Archer Creek

Storm # (Study) (LTM = Long-Term Avg.)

LTM 1 2 3 4 1 1 2 3

pH

4.5

5.0

5.5

6.0

6.5

7.0

7.5

Mitche

ll et a

l. (20

06)

Inamda

r et a

l. (20

04)

McHale

et al

. (200

2)Lowest pH

Long-Term Avg.

4.7

Mitchell et al.Biogeo. (2006)

Low pH related to SO42- mobilization

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia

– General impacts– Effects on monsoonal rain– Melting of Himalayan glaciers– Permafrost in Mongolia– Nitrogen and snow in northern Japan (Hokkaido)

• Concluding Statements

Major Risks in Asia from Climate Change-IPCC 2007 and certainty

Very High, High, Medium, Low, Very Low• Permafrost degradation from global warming will

increase the vulnerability of many climate-dependent sectors affecting the economy in boreal Asia. ***

• Surface runoff will increase during spring.• Summer periods will become more pronounced

in boreal Asia. ***• The frequency of forest fires will increase in

boreal Asia. • The large deltas and coastal low-lying areas of

Asia will be inundated by sea-level rise. ****

Major Risks in Asia from Climate Change (continued)

• Developing countries of temperate and tropical Asia are vulnerable to droughts and floods; climate change and its variability will make this worse. ****

• Increased precipitation intensity, particularly during the summer monsoon, will increase flood-prone areas in temperate and tropical Asia. There is a potential for drier conditions in arid and semi-arid Asia during summer and more severe droughts. ***

• Freshwater availability is expected to be highly vulnerable to climate change.. ****

• Tropical cyclones will become more intense. Combined with sea-level rise, this will result in loss of life and properties in coastal low-lying areas of cyclone-prone countries of Asia ***

Major Risks in Asia from Climate Change (Continued)

• Crop production and aquaculture will be threatened by thermal and water stresses, sea level rise, increased flooding, and strong winds associated with intense tropical cyclones.***

• Warmer and wetter conditions will increase potential for the higher incidence of heat-related and infectious diseases in tropical and temperate Asia.*

• Climate change will make worse threats to biodiversity resulting from land-use/cover change and population pressure in Asia..*

RegCM3 simulated interannual variation in precipitationindex (mm/day) for two modeled periods. Precipitation index defined as the departure of rainfall from theclimatological mean (1961–1990), averaged over land points between 70–90E and 5–25N. From Ashfaq et al. (2009) GEOPHYSICAL RESEARCH LETTERS

Some recent results already show that southeast Asia is getting drier

From: Kulkarni et al. (2007) Current Science

Glaciers are melting in the Himalayas threatening water supplies to Asia

Lake Hovsgol Mongolia

Lake Hövsgöl, Mongolia (WWW.hovsgolecology.org)

Clive GouldenPhiladelphia Academy of Natural Sciences

http://www.ub-mongolia.mn/photos-mongolia/displayimage.php?album=9&pos=6

Khusvgul in winter

Long-Term Climate Change of the Hovsgol Basin Area

-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0.0

1963

1967

1971

1975

1979

1983

1987

1991

1995

1999

Year

Tem

pera

ture

,0C

-7.0-6.0-5.0-4.0-3.0-2.0-1.00.0

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

Year

Tem

pera

ture

,0C

-5.0-4.0-3.0-2.0-1.00.01.02.0

1940

1947

1954

1961

1968

1975

1982

1989

1996

Year

Tem

pera

ture

,0C

Murun

Hatgal

1.860C

Hanh

Gradual warming has occurredsince the 1970s in Hovsgol areathat is similar to reported changesthroughout the southern Siberianregion.

Hövsgöl is in transition zone for permafrost

Northern JapanHokkaido Island

Christopher et al.

Japan

Hokkaido

Tokyo

1300 km

Uryu

Shibecha

Long-term changes in maximum snowpack depth in Hokkaido University's Uryu Experimental forest located in northern Japan (Shibata et al., unpublished data, while mostly reported for data from 1956 to 1989 by Hokkaido University Forests 1990). The open circles represent data of each year. The line represents five year's mean which indicates significant decreasing with year (p<0.001).

Measured soil temp. and frost depth

Uryu

Shibecha

MoreSnow

Less Snow

Snow depth at sites in western versus eastern Hokkaido

MoreSnow

Less Snow

• Snowmelt important period of solute export west Hokkaido

• Biogeochemical processes occurring under the snowpack vary in Shibecha vs. Uryu

11/1/00 1/1/01 3/1/01 5/1/01 7/1/01 9/1/01 11/1/01

NO

3- µm

ol L

-1

0

5

10

15

20

25

30

11/1/01 1/1/02 3/1/02 5/1/02 7/1/02 9/1/02 11/1/02

NO

3- µm

ol L

-1

0

50

100

150

200

NO

3- µm

ol L

-1

020406080

100120140160180

Uryu Shi

Yearly Mean

Temporal Pattern

Uryu unpublished data (Hashiba et al. 2005) Shibecha unpublished data (Nakagawa et al. 2005)

Uryu

Lower

Conc.

Shibecha

Higher

Conc.

• Effects of “Acid Rain” (Atmospheric Acidic Deposition)

• Historical Patterns of SO2 emissions• Linkages to surface water chemistry• Watershed sulfur budgets• Effect of acidic deposition in China• Importance of nitrogen• Global Climate Change• Importance of climate change in East Asia• Concluding Statements

Concluding Statements• Acidic deposition has had major impacts on forested

watersheds in the northern hemisphere.– Emissions decreasing in Europe and North America.– Emissions increasing in Asia but at a lower rate than previously

predicted.• The relative importance of nitrogen versus sulfur in acidic

deposition is increasing.• Global climate change is clearly documented in Europe,

North America and Asia.• These climatic effects vary among regions but include

documented changes in both hydrology, chemistry and biota.

• Climatic changes and linkages with ecological changes will be very pronounced in Asia.

Domo arigato Xie xie

DanyavadGracias

Thank you!