Nitroge Nitrogen Poll n Pollutio ution: n: from the Sources to - - PowerPoint PPT Presentation

Nitroge Nitrogen Poll n Pollutio ution: n: from the Sources to from the Sources to the Sea the Sea

• C. Driscoll
• C. Driscoll, D

, D. .Wh Whital itall l, J. A , J. Ab be er r, E , E. .Boye Boyer, r,

• M. Cast
• M. Castro, C.

ro, C. Cronan Cronan, C. , C. Goodale Goodale, , P.

• P. Grof

Groffman fman, C. , C. Hopki Hopkinson nson, K , K. .Lambe Lamber rt, t,

• G. Law
• G. Lawr

ren ence ce, S. O , S. Ol ll li in ng ger er

What is Hubbard Brook? What is Hubbard Brook?

Hubbard Brook Experimental Forest Hubbard Brook Ecosystem Study

Hubbard Brook Research Foundation

USDA Forest Service -1955 Non-profit Action/Think- tank - 1993 University scientists

• 1963

Casco Bay Great Bay Merrimack Harbor Mass Bay Buzzards Bay Long Island Sound Narragansett Bay Raritan Bay

Study Area Study Area

No rth

1990 Lan d Cover Forest Agriculture Urban Water

Map by E. Boyer. HBRF 2003.

Fo For r fores forest ts an s and coa d coas sta tal wa l waters… ters…

• 1. What are the major sources of

anthropogenic nitrogen in the Northeastern U.S.?

• 2. What are the ecological effects?
• 3. What are the most effective strategies

for reducing anthropogenic nitrogen and its effects?

5 10 15 20 1850 1900 1950 2000 Population (million) New York New England 0% 20% 40% 60% 80% 1850 1900 1950 2000 Percent total land area Forest Farmland Other

A) U.S. Bureau of Census, 1996. B) USDA 1997, NASS 1999.

Northeast Population and Northeast Population and Land Use Trends Land Use Trends

Compiled by C. Goodale. HBRF 2003.

HBRF 2003.

HBRF 2003.

trate co entrat ns in

• ff by land use

t Ni nc io run Ni rate concentrations in runoff by land use

Driscoll et al. 2002. In review.

Global Population and

Global Population and Reactive Reactive Nitro Nitrogen Tr gen Trends ends

2 4 6 50 100 150 200

Human Population (billions) Tg N yr­1 Natural N Fixation

1850 1870 1890 1910 1930 1950 1970 1990 2010 Population Haber Bosch C-BNF Fossil Fuel Total Nr

From Galloway et al. 2002. In review.

5 10 15 20 1850 1900 1950 2000 Population (million) New York New England 0% 20% 40% 60% 80% 1850 1900 1950 2000 Percent total land area Forest Farmland Other

A) U.S. Bureau of Census, 1996; B) USDA 1997, NASS 1999.

Northeast Population and Land Northeast Population and Land Use Trends Use Trends

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA Fertilizer Production Feed Animal Food consumption & excretion Denitrification Greenhouse Effect Atmospheric Effects Forest Effects Groundwater Effects Surface Water Effects Coastal Effects Energy Production Ozone Formation Human Health/ Plant Damage Drinking water quality

NOx NH3 NH3 NO3

• NO3
• N2 to atm.

N2O NO3

• NO3
• NO3
• NO3
• NO3
• NO3
• Atmospheric Deposition

NH3 NO3

• Nitrogen Cascade

Nitrogen Cascade

NOx

Adapted from Galloway and Cowling, 2002.

Sou Sour rc ce es sof

• f Nitrog

Nitrogen en

In remote forested watersheds, such as the Hubbard Brook Experimental Forest, anthropogenic nitrogen sources are dominated by atmospheric emissions and deposition. In large watersheds and coastal systems anthropogenic nitrogen sources are more diverse and are dominated by food.

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLKJIHGFEDCBA

Sources of Atmospheric Nitrogen Emissions Sources of Atmospheric Nitrogen Emissions

Mobile NOx Point Source NOx Area NOx Ag NH3 Mobile NH3 Other NH3

150 100 50

Atmospheric N Emissions thousand kt N/yr

Legend

Primary airshed for LIS watershed (includes 65% of emissions to the watershed).

Driscoll et al. 2002. In review.

Map by G. Lawrence. HBRF 2001.

How have emissions changed over time?

(Total U.S. NOx emissions)

Source: EPA National Air Pollution Emission Trends.

Ni Nitrog trogen Wet en Wet Depo

• siti

sition

• n

Dep

Wet Nitrate Wet Ammonium

1983- 1985 1992- 1994 1995- 1997

kg NH4

+-/ha/yr

kg NO3

• /ha/yr

Lynch and Grimm, 1997.

Likens and Bormann 1995.

A recent analysis of 24 NADP sites in the Northeast and mid­Atlantic quantified the relationship between NOx emissions and concentrations of nitrate in precipitation. Butler, Likens, et al. Atmospheric Environment, 2003.

Total Nitrogen Deposition

Ollinger et al. 1993.

Wh What en at envi viro ronm nmen ental tal is iss su ue es sar are e li link nke ed d to nitrog to nitrogen en po pollu llution tion? ?

• zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA

Grou Ground- nd-level ozo level ozon ne e

• Acid rain

rain and forest ef rest effects fects Acid and fo

• Reduced visibility
• Groundwater contamination
• Climate change

• Ozo

Ozone for ne form ma ati tion is dep

• n is depend

endent on ent on ni nitr troge

• gen o

n ox xid ides. es.

• D

De ecr creases net eases net ph photo

• tosynth

synthesis and esis and r reduce educes sf fo

• r

re est st pr product

• ducti

ivi vity. ty.

• La

Large rgear area eas i s in nt the he No Nort rtheast heaste exceed xceed EP EPA h A heal ealth thsta standar ndards ds for foro

• z

zone

• ne.

.

G Gr rou

• und

nd-

• l

le ev ve el l ozon

• ne

e

• z

Slide by S. Ollinger.

Ozone injury on white pine: Tip necrosis. Source: NC Cooperative Extension.

Foliar Ozone Injury Foliar Ozone Injury

Visible Ozone injury to ash: Purple stipling on upper leaf surface is due to ambient ozone. Source: National Park Service, Acadia National Park, ME.

Slide by S. Ollinger.

From Ollinger et al. 1997. In HBRF 2003.

Is Isola

• lat

ting the ing theEf Effe fec ct ts s

• f

fNitr Nitroge

• gen De

n Depos posit ition ion Ha Har rv va ar rd For d Fore es st, t, M MA A

Clockwise from left: High treatment (150 kg N/Ha) Low treatment (50 kg N/Ha) Control

Slide by J. Aber.

Acidic deposition depletes nutrient cations and acidifies soils; these processes can be accompanied by increased plant stress from aluminum toxicity.

HBRF 2001.

36% of forestland From J. Aber et al. 2003 and S. Ollinger. In HBRF 2003.

Climatic data

• Solar radiation
• Precipitation
• Temperature

PnET W ater balance Ph otosynthesis Livi ng biomass Litt erfall Net Mineralization BGC – Surface water Aqueous reactions Uptake Deep water flow S h a l l

• w

w a t e r f l

• w

Weathering

Wet

Deposition

Dry

Deposition BGC

• A queous reactions
• S urface reactions
• C

ation exchange

• A

dsorption

• H

umic binding

• A

luminum dissolution/precipitation

PnET BGC (Biogeochemical) Model

Slide by C. Driscoll.

Thr Thres esh ho

• lds fo

lds for Positive Ch r Positive Chemical C emical Conditio

• ndition

ns s

Nitrogen deposition < 8 kg/ha­yr Soil base saturation > 20% Acid neutralizing capacity > 50 µeq/L Stream pH > 6.0 Stream aluminum <2.0 µmol/L

From Aber et al. 2003 and Driscoll et al. 2001.

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA

Em Emission Red ission Redu uction ction Scenarios Scenarios

• Base = 1990 Clean Air Act.
• 2. 75% reduction in electric utility NOx from current

levels.

• 3. 60­90% reduction in passenger vehicle NOx

(consistent with EPA Tier 2 regulations).

• 4. Aggressive vehicle reduction (90% reduction in

passenger car emissions beyond Tier 2).

• 5. All of the above with a 34% reduction in agricultural

NH3 emissions by animal waste treatment.

Also, run with a 75% reduction in sulfur emissions from electric utilities beyond 1990 Clean Air Act requirements.

Improvement in Indicators at Hubbard Brook, NH

Driscoll et al. 2003.

From Driscoll et al. 2003.

New slide showing PnET results

Results at year 50.

Slide by C. Driscoll.

Results at year 50.

Slide by C. Driscoll.

Coastal Over-Enrichment

Photo W. Bennett

• Nitrogen is the primary nutrient that causes coastal
• ver­enrichment.
• Over­enrichment can lead to low oxygen events that

can cause fishkills.

• Over enrichment can lead to the loss of seagrass

habitats.

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLKJIHGFEDCBA

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

10 20 30 40 50 60 70 80

200 400 600 800 1000 1200

Length of Hypoxic Event (days)

Low Oxygen Events in Long Island Sound Low Oxygen Events in Long Island Sound

Maximum area of hypoxia (km2) Days

• Max. Area

Courtesy of Connecticut Depart ment of Environmental Protection. 2001.

From Driscoll et al. 2003.

Nit Nitr rogen an

• gen and the Fo

d the Food Cycle

• d Cycle

HBRF 2003.

Where Whered do

• es

esthe the n ni itro trog ge en n tha that t en enters terswa waters tershed heds s go go? ?

¾ Returned to atmosphere ¾ Stored in biomass ¾ Stored in soil ¾ Exported to groundwater ¾ ¾ Expor

Exported to ted toe es st tu uaries aries

From Howarth et al. 2002.

From Driscoll et al. 2003.

Daily Nitrogen Consumption in Food New England and New York, 1909-1997

600 500 400 300 200 100 1909 1917 1925 1933 1941 1949 1957 1965 1973 1981 1989 1997 FATS & OILS FRUIT VEGETABLES LEGUMES OTHER DAIRY CHEESE LOWFAT MILK WHOLE MILK GRAIN EGGS FISH POULTRY MEAT

Nitrogen (kilograms)

HBRF 2002.

Year

rtilizer x Tran 3 Utility and other WWTP and septic

Nitrogen

Human NH3 NH3 Industry NH3

sources to the

2% 2% 1%

Casco Bay

Domestic animals

watershed

NH3 2% Chemical fe NH3 5% Area sources NO sportation 7% NOx 37% Animal waste NH 20%

HBRF 2002.

point sources NOx 24%

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLKJIHGFEDCBA

Wh Where erei is sNi Nitr trog

• gen

enDep Depo

• si

sit te ed don

• nth

the L e La and nd? ?

Wet Nitrate

1995-1997

Wet Ammonium

• kg NO3 ha
• 1 yr-1

kg NH4

+ ha-1 yr-1

Lynch and Grimm, 1997.

Red Redu uced Nit ced Nitr rogen Lo

• gen Loading t

ading to

• Estuaries

Estuaries

• Reduced N emissions:

75% reduction in utilities NOx . EPA Tier 2 reductions in vehicle emissions. 90% reduction above Tier 2 in NOx from cars.34% reduction in agriculture NH 3.

• 2. Biological Nitrogen Removal for WWTPs.
• 3. Septic system improvements.
• 4. Offshore pumping of waste.
• 5. Agricultural BMPs (33% reduction in runoff N).

Hubbard Brook

20 40 60 80

2001-2003 2024-2026 2048-2050

20 40 60 80

NO3

• ( µmol/L)

20 40 60 80 20 40 60 80 20 40 60 80

1990 CAAA Utility Tier II Agressive Transportation Integrated Control

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Month

Biscuit Brook

20 40 60 80 100

2001-2003 2024-2026 2048-2050

20 40 60 80 100 20 40 60 80 100 20 40 60 80 100

1990 CAAA Utility Tier II Agressive Transportation

20 40 60 80 100

Integrated Control

/L) mol µ (

• 3

NO

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Month

Below Fall Line N Inputs

SWAT NPS Runoff Point and NPS Septic Systems

Nitrogen Inputs to Estuary

Inputs Outputs

Watershed and Riverine Losses N Fertilization N Fixation Atmospheric Deposition Livestock Waste Crop Harvest Animal Grazing Ammonia Volatilization Denitrification Soil Climate N Fertilization Land Cover Atmospheric Deposition Human Population Wastewater N Discharge Atmospheric Deposition Nitrogen Fixation

Agricultural Lands (Crops and Pastures) Upland Forests Above Fall Line N Inputs Atmospheric N Deposition

WATERSN MODEL WATERSN MODEL

From Driscoll et al. 2003.

1 % a g 3 3 % a g A n i m a l w a s t e C

• a

s t a l B N R B a s i n

• w

i d e B N R

• Aggr. sewage

Offshore pumping Mobile Tier 2

• Aggr. Mobile

Moderate utilities

• Aggr. Utilities

Integrated

More WATERSN Results More WATERSN Results

10 20 30 40 50 60

Percent Reduction

Delaware Bay Chesapeake Bay Pamlico Sound

Whitall et al. in review.

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLKJIHGFEDCBA

zywvutsrponmlkihgfedcbaWSRONMLIHGFEDCB

Co Conclusion nclusions: N Inpu s: N Inputs ts

• Anthropogenic N inputs to upland forested watersheds

are dominated by atmospheric emissions and deposition

• f nitrogen from transportation (39%) and electric utilities

(26%).

• Atmospheric deposition of N to forests at the Hubbard

Brook Experimental Forest has not decreased since measurements began in the 1960s.

• N to loading to downstream estuaries in the Northeast

that were examined in this study is dominated by wastewater inputs (36­81%) derived from food and atmospheric deposition (14­35%).

• Runoff from agricultural and urban lands can be large

inputs in some Northeast watersheds (up to 20% each).

zywvutsrponmlkihgfedcbaWSRONMLIHGFEDCB

Conclusions: N Effects Conclusions: N Effects

• Ambient ozone is projected to reduce forest productivity

in the NE from 4­14%.

• 36% of forestland in the Northeast receive N deposition

above 8 kg/ha/yr – a level which tends to result in elevated nitrate leaching.

• Nitrate is an increasing component of the acidity in acid

rain and a key contributor to acid episodes that release Al to streams.

• Over­enrichment by nitrogen has caused low­oxygen,

loss of habitat and algal blooms in some Northeast estuaries (such as Waquoit Bay, MA).

N Manag N Manage emen ment t– Em – Emi issio ssion ns & Dep s & Depo

• sition

sition

• The 1990 Clean Air Act Amendments are not likely to

reduce nitrogen deposition below 8 kg/ha­yr at Biscuit Brook, NY or Hubbard Brook, NH.

• An additional 30% cut in total nitrogen emissions would

likely bring deposition to levels that would reduce nitrogen leaching to streams.

• The recovery thresholds for ANC, pH and soil base

saturation are not achieved at either site under any N­

• nly control scenarios.
• ANC turns positive at Hubbard Brook under the ^

scenario.

zywvutsrponmlkihgfedcbaWSRONMLIHGFEDCB

N NMa Man na age gem me ent nt– –E Emi mis ss si io

• n

ns s& & Dep Depo

• sition

sition

• Policies that include a 75% reduction in SO2 emissions

from electric utilities achieve all the chemical thresholds at Biscuit Brook within 50 years, and approaches them at Hubbard Brook.

• The PnET model does not evaluate effects of nitrogen

emissions reductions on ground­level ozone.

• Additional model runs show that seasonal reductions in

N emissions may help with summertime ozone, but year­round controls are more effective in mitigating ecosystem effects.

N N m ma an na age geme ment nt- Coa

• Coas

st tal al w wa at te er rs s

• Improved wastewater treatment results in the largest

reduction in nitrogen pollution in our two case studies (up to 57% for Long Island Sound).

• Emissions reductions of NOx from utilities and vehicles has

the added benefit of reducing nitrogen pollution to coastal waters (up to 14% for Casco Bay).

• An integrated management plan that includes nitrogen

controls on several sources achieves maximum reductions in nitrogen pollution.

HB HBRF Sci RF Scie ence Lin nce Links ks fu fundi nding ng pr provid

• vided b

ed by y: :

NYSERDA

Davis Conservation Foundation Geraldine R. Dodge Foundation Harold Whitworth Pierce Charitable Trust Jessie B. Cox Charitable Trust John Merck Fund McCabe Environmental Fund of NHCF Merck Family Fund Sudbury Foundation Switzer Environmental Fund of NHCF

www.hubbardbrook.org hbrook@hbresearchfoundation.org 16 Buck Road, Hanover, NH 03755

Hubbard Brook Hubbard Brook Research Foundation Research Foundation

Pub Public Po lic Policy Acti licy Activi vity ty

• 1. Power plant bills in Congress.
• 2. Tailpipe emissions standards at the state and

federal levels.

• 3. Federal funding bills for wastewater treatment.
• 4. Total maximum daily load planning.
• 5. Incentives for improved agricultural practices

in the U.S. Farm Bill.