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 the Sea from the Sources to the Sea C. Driscoll C. Driscoll, D , D. Whital itall l, J. A , J. Ab be er r, E , E. Boyer, r, .Wh .Boye M. Cast ro, C. Cronan , C. Goodale , M. Castro, C. Cronan, C. Goodale, P. Grof Groffman , C. Hopki Hopkinson nson, K , K. Lamber rt, t, P. fman, C. .Lambe G. Lawr ren ence ce, S. O , S. Ol ll li in ng ger er G. Law

What is Hubbard Brook? What is Hubbard Brook? Hubbard Hubbard Hubbard Brook Brook Brook Experimental Research Ecosystem Forest Foundation Study USDA Forest University scientists Non-profit Service -1955 - 1963 Action/Think- tank - 1993

Study Area Study Area No rth 1990 Lan d Cover Forest Agriculture Urban Water Casco Bay Great Bay Merrimack Harbor Mass Bay Buzzards Bay Narragansett Bay Long Island Sound Map by E. Boyer. HBRF 2003. Raritan Bay

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

Northeast Population and Northeast Population and Land Use Trends Land Use Trends 20 80% Percent total land area Population (million) New York 15 60% Forest 10 40% Farmland New England 5 20% Other 0 0% 1850 1900 1950 2000 1850 1900 1950 2000 A) U.S. Bureau of Census, 1996. B) USDA 1997, NASS 1999. Compiled by C. Goodale. HBRF 2003.

HBRF 2003.

HBRF 2003.

Ni rate concentrations in runoff by land use t Ni trate co nc entrat io ns in run off by land use Driscoll et al. 2002. In review.

Global Population and Reactive Reactive Nitro Nitrogen Tr gen Trends Global Population and ends 200 6 Human Population (billions) 150 Tg N yr ­1 4 Natural N Fixation 100 2 50 0 0 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.

Northeast Population and Land Northeast Population and Land Use Trends Use Trends 20 80% Percent total land area Population (million) New York 15 60% Forest 10 40% Farmland New England 5 20% Other 0 0% 1850 1900 1950 2000 1850 1900 1950 2000 A) U.S. Bureau of Census, 1996; B) USDA 1997, NASS 1999.

Nitrogen Cascade Nitrogen Cascade Fertilizer Energy Production Production Atmospheric NO x NO x NH 3 Effects Ozone NH 3 Formation Atmospheric Deposition zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA Feed Animal - NH 3 NO 3 - Human Health/ NO 3 Forest Plant Damage Effects Food consumption & - NO 3 excretion - NO 3 - NO 3 Groundwater N 2 to atm. Drinking Effects water quality Denitrification - NO 3 - NO 3 Surface Water N 2 O - NO 3 Effects - NO 3 Greenhouse Effect Adapted from Galloway and Coastal Cowling, 2002. Effects

Sou Sour rc ce es of Nitrog en sof Nitrogen 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 Primary airshed for LIS watershed (includes 65% of emissions to the watershed). Atmospheric N Emissions thousand kt N/yr 150 100 Legend 50 Ag NH 3 Mobile NH 3 Mobile NO x Other NH 3 Area NO x Point Source NO x Driscoll et al. 2002. In review.

Map by G. Lawrence. HBRF 2001.

How have emissions changed over time? (Total U.S. NO x emissions) Source: EPA National Air Pollution Emission Trends.

Ni Nitrog trogen Wet en Wet Depo ositi sition on Dep Wet Nitrate Wet Ammonium 1983- 1985 1992- 1994 1995- 1997 +- /ha/yr kg NH 4 - /ha/yr kg NO 3 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.

• zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA Wh What en at envi viro ronm nmen ental tal is iss su ue es are e li link nke ed sar d to nitrog to nitrogen en po pollu llution ? tion? Grou Ground- nd-level ozo level ozon e ne • • Acid rain rain and forest ef fects rest effects Acid and fo • Reduced visibility • Groundwater contamination • Climate change

G Gr rou ound nd- -l le ev ve el l ozon one e oz • • Ozo Ozone for ne form ma ati tion is dep on is depend ent on endent on ni nitr troge ogen o n ox xid es. ides. • • D De ecr creases net eases net ph photo otosynth synthesis and esis and r reduce educes fo or re st pr product oducti ivi ty. sf est vity. • La Large area eas i s in he No Nort rtheast xceed • rgear nt the heaste exceed EP EPA h A heal ealth standar ds for oz zone one. thsta ndards foro . Slide by S. Ollinger.

Foliar Ozone Injury Foliar Ozone Injury Ozone injury on white pine: Tip necrosis. Source: NC Cooperative Extension. 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 olat ting the Effe fec ct s o of Nitroge ogen De n Depos posit ition ing theEf ts fNitr ion Ha Har rv va ar rd For d Fore es t, M MA st, 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.

PnET BGC (Biogeochemical) Model Wet Dry Climatic data Deposition Deposition • Solar radiation PnET • Precipitation W ater balance • Temperature Ph otosynthesis Livi ng biomass Litt erfall Net Mineralization Uptake S h a l l BGC o w w • A queous reactions a t e r • S urface reactions f l o w ation exchange • dsorption C • BGC – Surface water umic binding A • Aqueous reactions luminum dissolution/precipitation H • A Deep water flow Weathering Slide by C. Driscoll.

Thr Thres esh ho olds fo lds for Positive Ch r Positive Chemical C emical Conditio ondition 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.

Em Emission Red ission Redu uction ction Scenarios Scenarios • Base = 1990 Clean Air Act. 2. 75% reduction in electric utility NO x from current levels. 3. 60­90% reduction in passenger vehicle NO x (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 zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLIHGFEDCBA NH 3 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 over­enrichment. • Over­enrichment can lead to low oxygen events that can cause fishkills. • Over enrichment can lead to the loss of seagrass habitats.

zyxwvutsrqponmlkjihgfedcbaYWVUTSRPONMLKJIHGFEDCBA Low Oxygen Events in Long Island Sound Low Oxygen Events in Long Island Sound 80 1200 70 1000 Length of Hypoxic Event Maximum area of hypoxia 60 800 50 40 600 (days) (km 2 ) 30 400 20 200 10 0 0 2000 1991 1992 1993 1994 1995 1996 1997 1998 1999 Days Max. Area Courtesy of Connecticut Depart ment of Environmental Protection. 2001.

From Driscoll et al. 2003.

od Cycle d the Food Cycle HBRF 2003. ogen and the Fo rogen an Nitr Nit

Where do oes the n ni itro trog ge en n tha t Whered esthe that en enters waters tershed s go ? terswa heds go? ¾ Returned to atmosphere ¾ Stored in biomass ¾ Stored in soil ¾ Exported to groundwater ¾ Expor Exported to es st tu aries ted toe uaries ¾ From Howarth et al. 2002.

From Driscoll et al. 2003.

Daily Nitrogen Consumption in Food New England and New York, 1909-1997 600 FATS & OILS FRUIT 500 VEGETABLES Nitrogen (kilograms) LEGUMES 400 OTHER DAIRY CHEESE 300 LOWFAT MILK WHOLE MILK GRAIN 200 EGGS FISH 100 POULTRY MEAT 0 1909 1917 1925 1933 1941 1949 1957 1965 1973 1981 1989 1997 HBRF 2002. Year