Nitrogen cycle

BiogeochemistryOctober 17, 2005

Maria Moskalenko, Gretchen Miles, Emily Paduano, Jaconette Mirck

OutlineOutline Background Information on N Papers: Kaiser, 2001. The Other Global Pollutant

Agriculture: fertilizer & food Mitsch, 2001. Reducing N loading to Gulf

Mississippi River-hypoxia Solutions to N-pollution

Driscoll, 2003. N Pollution in Northeast US Atmospheric Inputs Estuaries Models

Discussion

Background Information on N Papers: Kaiser, 2001. The Other Global Pollutant

Agriculture: fertilizer & food Mitsch, 2001. Reducing N loading to Gulf

Mississippi River-hypoxia Solutions to N-pollution

Driscoll, 2003. N Pollution in Northeast US Atmospheric Inputs Estuaries Models

Discussion

Nitrogen Forms, Phases and Oxidation States

Nitrogen Forms, Phases and Oxidation States

* *

* NOx, greenhouse gases

Nitrogen the other global pollutant (Kaiser, 2001)

Nitrogen the other global pollutant (Kaiser, 2001)

Essential element for growth/primary production

Surplus nitrogen = pollutantSources:

FertilizerFossil fuels

Results in various problems:Algal bloomGreenhouse gasOzone

Essential element for growth/primary production

Surplus nitrogen = pollutantSources:

FertilizerFossil fuels

Results in various problems:Algal bloomGreenhouse gasOzone

SolutionsSolutions

Increase requirements for fossil fuelsSmaller carsHybrids

Eat less meat to reduce food of live stockLess manure

Food control, precise amino acid ratioReduce runoffIncrease price of fertilizer

Increase requirements for fossil fuelsSmaller carsHybrids

Eat less meat to reduce food of live stockLess manure

Food control, precise amino acid ratioReduce runoffIncrease price of fertilizer

Reducing Nitrogen Loading to the Gulf of Mexico from the

Mississippi River Basin: Strategies to Counter a

Persistent Ecological Problem-Mitsch, et al. 2001

Reducing Nitrogen Loading to the Gulf of Mexico from the

Mississippi River Basin: Strategies to Counter a

Persistent Ecological Problem-Mitsch, et al. 2001

ProblemsProblems

Anthropogenic Additions of N to aquatic systems cause Increased ProductivityEutrophicationHypoxiaFish Kills

Anthropogenic Additions of N to aquatic systems cause Increased ProductivityEutrophicationHypoxiaFish Kills

Sources Sources

AgricultureWaste Water Draining Wetlands

AgricultureWaste Water Draining Wetlands

Drained wetlands converted to agricultural land

Solutions: Controlling N in Miss. River Basin

Solutions: Controlling N in Miss. River Basin

Modifying Agricultural Practice- use less fertilizer- apply fertilizer in spring- account for N sources present

Riparian and Wetland Buffers- effective nitrogen sinks due to

high levels of denitrification

Modifying Agricultural Practice- use less fertilizer- apply fertilizer in spring- account for N sources present

Riparian and Wetland Buffers- effective nitrogen sinks due to

high levels of denitrification

Example of Riparian BufferExample of Riparian Buffer

Solutions cont.Solutions cont.

Urban & Suburban Non-point Source Control

Point Source Control Controls on Atmospheric NOx

Mississippi River Diversions

Urban & Suburban Non-point Source Control

Point Source Control Controls on Atmospheric NOx

Mississippi River Diversions

Creation of Wetlands

Benefits of Reducing Nitrogen Levels in the Mississippi River

Basin

Benefits of Reducing Nitrogen Levels in the Mississippi River

BasinPredicted 40% reduction of nitrogen

loading to the Gulf through implementation of these practices

In addition to reduced hypoxia- reduced river pollution- reduced wetland loss- improved river ecosystems- improved control of floods

Predicted 40% reduction of nitrogen loading to the Gulf through implementation of these practices

In addition to reduced hypoxia- reduced river pollution- reduced wetland loss- improved river ecosystems- improved control of floods

Northeast U.S. Brief History

Northeast U.S. Brief History

Population ChangesLand Use ChangesCapacity of 2nd Growth

Forests for N-retention

Population ChangesLand Use ChangesCapacity of 2nd Growth

Forests for N-retention

N-pollution Sources in Northeast U.S. (Driscoll et

al. 2003)

N-pollution Sources in Northeast U.S. (Driscoll et

al. 2003)Atmospheric N SourcesFood ImportsFertilizer & Farming PracticesFeed ImportsWastewater EffluentMycorrhizae & Legumes

Atmospheric N SourcesFood ImportsFertilizer & Farming PracticesFeed ImportsWastewater EffluentMycorrhizae & Legumes

ProblemsProblems

Acidic Deposition Ground Level Ozone FormationCoastal EutrophicationAcidification & Overfertilization N-

enrichmentForest (N-saturation)Freshwater

(high flow)

Acidic Deposition Ground Level Ozone FormationCoastal EutrophicationAcidification & Overfertilization N-

enrichmentForest (N-saturation)Freshwater

(high flow)

Smog in LA & Chicago

Wet Deposition and Emissions

Wet Deposition and Emissions

a: nitrate, sulfate, b: nitrate & ammonium, c: sulfate, nitrate, chloride

Ozone FormationOzone Formation

For Formation: NOx & VOC’s (volitile organic compounds) Or NO from soil + Oxygen

VOC’s were thought to be limiting factorAutomobile VOC’s are regulated VOC’s are also produced naturally (isoprene)

In Northeast U.S. we now believe that NOx

regulates O3 formationGround Level O3 in many U.S. cities exceeds

National Ambient Air Quality Standards

For Formation: NOx & VOC’s (volitile organic compounds) Or NO from soil + Oxygen

VOC’s were thought to be limiting factorAutomobile VOC’s are regulated VOC’s are also produced naturally (isoprene)

In Northeast U.S. we now believe that NOx

regulates O3 formationGround Level O3 in many U.S. cities exceeds

National Ambient Air Quality Standards

Solution: Reductions in NSolution: Reductions in N

Management Options:Coastal Watersheds

Wastewater Treatment PlantsAgriculture

AtmosphereFossil fuel electric utilitiesTransportationAgriculture

Management Options:Coastal Watersheds

Wastewater Treatment PlantsAgriculture

AtmosphereFossil fuel electric utilitiesTransportationAgriculture

Purpose of ModelingPurpose of Modeling

Models were run to test proposed management options and determine their effectiveness

Atmospheric Model: PnET-BGCEstuary Loading: WATERSN

Models were run to test proposed management options and determine their effectiveness

Atmospheric Model: PnET-BGCEstuary Loading: WATERSN

ConclusionsConclusions

Estuary: Major N-sourceWastewater effluent:

Add biotic N-removal to wastewater treatment practices

Atmosphere: Source Specific Control

(due to numerous sources)

Estuary: Major N-sourceWastewater effluent:

Add biotic N-removal to wastewater treatment practices

Atmosphere: Source Specific Control

(due to numerous sources)

Discussion TopicsDiscussion Topics

Ecotechnology PhytoremediationWillow Project

Theoretical Models vs. Real Life Problems? Lifestyle Changes

No Meat = No NitrogenSUV’s, Hybrids,Public Transportation, Walk,

BikeOther Effects of N

Purely Atmospheric take on N- Aerosols

Ecotechnology PhytoremediationWillow Project

Theoretical Models vs. Real Life Problems? Lifestyle Changes

No Meat = No NitrogenSUV’s, Hybrids,Public Transportation, Walk,

BikeOther Effects of N

Purely Atmospheric take on N- Aerosols

Willow ApplicationsWillow Applications Set-aside arable land Bio-remediation of

contaminated soils, like brownfields (phytoremediation)

Nutrient and waste management systems

Windbreaks/snow fences

Buffer zones for clean water

Set-aside arable land Bio-remediation of

contaminated soils, like brownfields (phytoremediation)

Nutrient and waste management systems

Windbreaks/snow fences

Buffer zones for clean water

Incorporating willow biomass crops into riparian buffers produces clean water and renewable energy (Salix Maskiner 2000)

Soil ConservationSoil Conservation

•Very little soil erosion once the crop is established

•Negligible N leaching from established willow plantings, even with large applications nitrogen (Adegbidi 1999, Aronsson et al. 2000).

•Very little soil erosion once the crop is established

•Negligible N leaching from established willow plantings, even with large applications nitrogen (Adegbidi 1999, Aronsson et al. 2000).

One year old coppcie growth

Nitrogen MovementNitrogen Movement

NO3-N (kg/ha)

NH4-N (kg/ha)

Pots with willow growth

4.3 + 2.6 1.3 + 0.2

Pots without willow growth

140.8 +12.9 1.3 + 0.2

p-value <0.01 0.75

NO3-N (kg/ha)

NH4-N (kg/ha)

Pots with willow growth

4.3 + 2.6 1.3 + 0.2

Pots without willow growth

140.8 +12.9 1.3 + 0.2

p-value <0.01 0.75

Trial with organic amendments with nitrogen loads ranging from 200 – 1,880 TKN kg/ha (Adeigbidi 1999)

AerosolsAerosols

GCEP 2004 Orientation Presentation by Jeff Gaffney

What???

Aerosols absorb or scatter light

Ecological Effect

Photosynthesis

The EndThe End