1. 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.gov 1

2. Funded by NWCAA Co-sponsored by NWCAA, NPS, USFS, and USGS Focus on NW WA but applicability for most of R10 2 Science Workshop

3. Researchers with expertise in nitrogen and sulfur effects on: –Lichens –Soil chemistry –Vegetation –Water chemistry –Mycorrhizae –Diatoms –Deposition monitoring –Deposition modeling –Setting critical loads 3 Participants

4. NPS Science Staff USFS NWCAA PSCAA Ecology Tribes 4 Participants

5. “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?

6. 6 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)

7. 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 7 Critical Loads in Action http://www.cdphe.state.co.us/ap/rmnp.html

8. 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 8 Current Knowledge – Deposition Monitoring

9. 9 Current Knowledge – NADP N Deposition Monitoring

10. Throughfall Monitoring –Low under canopy Lichens absorbing N? –High in bulk deposition –Inconsistent with NADP or CG Snowfall –Comparable to NADP 10 Current Knowledge – N Deposition Monitoring Research

11. 11 Current Knowledge – Deposition Modeling Research WSU CMAQ preliminary work based on 36 km grid

12. Modeling –Overpredicts dry –Underpredicts wet –No cloud –Limited sensitivity analysis 12 Current Knowledge – Deposition Modeling Research

13. 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 13 Current Knowledge – Ecological Effects

14. 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) 14 Current Knowledge – Ecological Effects

15. 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 Priorities

16. 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) 16 Research Priorities

17. Terrestrial Ecosystems –Alpine meadows Fertilization effects research using RMNP as model –Mycorrhizal diversity Similar to lichens in terms of PNW ecological importance and diversity. 17 Research Priorities

18. Quantifying actual deposition Adequate to “index” to NADP or other standard monitor 18 Not a Research Priority

19. 19 Questions?