Post on 08-Jan-2016
description
Critical Load Development for
Nitrogen and Sulfur Deposition
Elizabeth Waddell
Air Resources Specialist
Pacific West Region
206 220 4287
Elizabeth_waddell@nps.gov
Critical Load Development for
Nitrogen and Sulfur Deposition
Elizabeth Waddell
Air Resources Specialist
Pacific West Region
206 220 4287
Elizabeth_waddell@nps.gov1
• Funded by NWCAA
• Co-sponsored by NWCAA, NPS, USFS, and USGS
• Focus on NW WA
but applicability for
most of R10
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Science WorkshopScience Workshop
Researchers with expertise in nitrogen and sulfur effects on:– Lichens– Soil chemistry– Vegetation– Water chemistry– Mycorrhizae– Diatoms– Deposition monitoring– Deposition modeling– Setting critical loads
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ParticipantsParticipants
• NPS Science Staff
• USFS
• NWCAA
• PSCAA
• Ecology
• Tribes
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ParticipantsParticipants
“the quantitative estimate of an exposure to one or more
pollutants below which significant harmful effects on specified
sensitive elements of the environment do not occur
according to present knowledge.” 5
What is a Critical Load?What is a Critical Load?
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What is a Critical Load?What is a Critical Load?
N Deposition (kg/ ha /yr)
Natural background N deposition
Increased NO3 in lakes
Changes in tree and soil chemistry
Change in alpine plant species
Change in algal species
Effects on aquatic and terrestrial biota (episodic or chronic acidification)
• Critical load work proceeding at Rocky Mountain NP – 1.5 kg N/ha/yr for eutrophication effects of
alpine lakes– Current deposition is 3-4 kg N/ha/yr
• Partnering with CDPHE to identify sources and
reduce emissions
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Critical Loads in ActionCritical Loads in Action
http://www.cdphe.state.co.us/ap/rmnp.html
• NADP Monitoring– S deposition – declining– N deposition – no trend
• Between 1 and 2 kg/ha/yr
• Does not include dry or occult deposition
• All low elevation sites
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Current Knowledge – Deposition MonitoringCurrent Knowledge – Deposition Monitoring
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Current Knowledge – NADP N Deposition MonitoringCurrent Knowledge – NADP N Deposition Monitoring
0
0.5
1
1.5
2
2.5
3
pre-1880 ONP MRNP NCNP
Low
2004
High
• Throughfall Monitoring– Low under canopy
• Lichens absorbing N?– High in bulk deposition– Inconsistent with NADP or CG
• Snowfall– Comparable to NADP
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Current Knowledge – N Deposition Monitoring ResearchCurrent Knowledge – N Deposition Monitoring Research
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Current Knowledge – Deposition Modeling ResearchCurrent Knowledge – Deposition Modeling Research
WSU CMAQ preliminary workbased on 36 km grid
• Modeling – Overpredicts dry– Underpredicts wet – No cloud – Limited sensitivity analysis
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Current Knowledge – Deposition Modeling ResearchCurrent Knowledge – Deposition Modeling Research
Lichens– Sensitive to air pollution– N sensitive lichens absent
in areas of “high” nitrogen deposition
– Preliminary work with Columbia Gorge throughfall monitoring data yields a CL of 2.4 kg/ha/yr
• 2.0 dry deposition• 0.4 wet deposition
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Current Knowledge – Ecological EffectsCurrent Knowledge – Ecological Effects
Acidification effects– Nutrient effects of N expected
to occur at lower deposition rates than acidification effects
– MAGIC model yielded an “upper bound” CL of 10 kg S/ha/yr for acidification of Lake Eunice (Mt. Rainier)
– (Recent documentation of episodic acidification at Lake Eunice due to snowmelt pulse)
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Current Knowledge – Ecological EffectsCurrent Knowledge – Ecological Effects
• Aquatic Ecosystems– Mine existing water quality
databases to identify:• Areas which may already be
affected by N or S deposition• Areas which may be
sensitive to additional N
– Establish CL for eutrophication of aquatic ecosystems using RMNP work as a model (diatoms)15
Research PrioritiesResearch Priorities
• Terrestrial Ecosystems– Lichens
• Collect lichens from NADP and “throughfall” sites;
• Refine deposition modeling and/or conduct additional monitoring to better establish a deposition gradient and/or use PRISM
– Natural Resources Conservation Service (NRCS) soils mapping effort
• Identify sensitive areas (N and Al)
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Research PrioritiesResearch Priorities
• Terrestrial Ecosystems– Alpine meadows
• Fertilization effects research using RMNP as model
– Mycorrhizal diversity • Similar to lichens in terms of
PNW ecological importance and diversity.
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Research PrioritiesResearch Priorities
• Quantifying actual deposition
• Adequate to “index” to NADP or other standard monitor
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Not a Research PriorityNot a Research Priority
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Questions?Questions?