Shift from Atmospheric Deposition to Climatic Regulation of Sulfur - PowerPoint PPT Presentation

Shift from Atmospheric Deposition to Climatic Regulation of Sulfur Budgets in Forested Watersheds By: Myron J. Mitchell SUNY ‐ ESF, Syracuse, NY

Collaborators • S. Bailey • S. Kahl • F. Beall • G. Likens • D. Burns • G. Lovett • D. Buso • P. McHale • T. Clair • M. Moran • F. Courchesne • C. Rogers • Z. Dong • K. Roy • C. Driscoll • D. Schwede • L. Duchesne • J. Shanley • C. Eimers • K. Weathers • D. Jeffries • R. Vet

Why should we care about sulfur budgets?

Why is this 18 North America important? Emissions Tg S yr -1 Sulfur atmospheric 4 emissions 1900 YEAR 1990 have decreased 30 in North America Europe and Europe 10 4

The Effects of Acidic Deposition 2 ‐ and NO 3 ‐ ) result in the • Acidic mobile, anions ( SO 4 mobilization of cations. • Nutrient cations (Ca 2+ , Mg 2+ , K + ) may be lost. Especially important for some tree species such as sugar maple. • Acidic cations (H + , Al +3 ) may be mobilized in soils and surface waters. • Al +3 may be toxic to aquatic (i.e., fish) and terrestrial vegetation (i.e., fine roots)

Effects of Mobile Anions on Cation Leaching in Soil Nutrients Toxic to Biota

Wet Dry Deposition Deposition Litter Inputs Largest S pool in most temperate forested Organic watersheds Uptake Sulfur Immobilization Mineralization Adsorbed Sulfate Sulfur Weathering Minerals Drainage Adsorption Desorption Waters Only important in highly Losses weathered soils

Sulfur Budget Wet Dry Discrepancy = Deposition Deposition Atmospheric Deposition (Wet+Dry) – Drainage Water Losses Litter Inputs Organic Uptake Sulfur Immobilization Mineralization Adsorbed Sulfate Sulfur Weathering Minerals Drainage Adsorption Desorption Waters Losses

Objectives • Analyze sulfur budgets for watersheds in southeast Canada and the northeast United States in areas known to highly sensitive to acidification from atmospheric inputs of S. • Examine changes in S budgets over time under conditions of decreasing S emissions. • Use a range of sites which have different amounts and types of information that can be used in evaluating sulfur budgets.

Three Case Studies Longer Period of Record I. Northeast U.S. and Southeast Canada (15 sites from ~1985 to 2002) II. Adirondack Mountains of New York State (15 sites, 15 watersheds from 1984 to 2010) III. Hubbard Brook Experimental Forest, White Mountains, New Hampshire (1 site, 4 watersheds from 1966 to 2008 ) Larger Spatial Scale

Case Study I: Northeast U.S. and Southeast Canada Mitchell, M.J., G. Lovett, S. Bailey, F. Beall, D. Burns, D. Buso. T. A. Clair, F. Courchesne, L. Duchesne, C. Eimers, D. Jeffries, S. Kahl, G. Likens, M.D. Moran, C. Rogers, D. Schwede, J. Shanley, K. Weathers and R. Vet. 2011. Comparisons of Watershed Sulfur Budgets in Southeast Canada and Northeast US: New Approaches and Implications. Biogeochemistry103:181 ‐ 207

Selected well studied forested watershed sites with data sets on sulfur budgets.

SO 2 Emissions Data (EPA) 35000 Regions 1-5 (East USA) Period Total US 30000 of SO2 (tons x 1000) Study 25000 20000 15000 10000 5000 0 1900 1920 1940 1960 1980 2000 Year

1985-2002 20 Without Dry Deposition 10 kg S ha -1 yr -1 0 Precipitation kg S ha-1 yr-1 -10 Discharge kg S ha-1 yr-1 Difference k 6 s y t r e e e s e d i e k r e o u e p e s W k k n i n o a m v o t s e a k s a i u o m o i l - r a a r s R L L C m F e B P b r o r L r B E r M c p i e a o s e T A t e i y r H l i B r r t k M f u a n e s e a a e a H H c o a k p e L k L s l r C e B a P u i e B e L T k l S a L Watershed

1985-2002 8 Deposition Equation 2 (CASTNET) Deposition Equation 3 (CAPMoN) 6 Discrepancy using Equation 2 Discrepancy using Equation 3 4 2 kg S ha -1 yr -1 0 -2 -4 -6 With Dry -8 Deposition -10 -12 k r e s e 6 s y t e e d e k e i r o e u e p k k s W n i m n v o a o k s t s e a a i o o u i m l r - r R a m a s L L C F r B P b e o L r B r M c p a i E r e s e o T A t e y i l r r H i B r t k M f u e a e n a s a e a H c p a H k o e L k L s e l r C B a P u e i e B L T k l S a L Watershed

1 to 6 kg S Contribution of Internal S Sources 10 ha ‐ 1 year ‐ 1 to Drainage Water Sulfate 1985 ‐ 2002 0 2- L -1 -10 μ mol SO 4 Category I -20 Category II Category III Category IV Category V -30 Equation 2 (CASTNET) More sulfur is Equation 3 (CAPMoN) being lost than -40 being added by atmospheric r e k s d e r e 6 k s y e t e e i i k o u n m k W o e e s n a p v a o t a o k s s i o l e m m i u C - L L a r a R r r s deposition when P F e B b B L r a o r E p e c M i r e e s l T o k A f i B y r r t r n H t a a a i M a e s e H u e normalized for o H e L L k p a k c C B l r e a e s P u e k i L B T l discharge a S L Watershed

Case Study II: Adirondack Mountains of New York State Mitchell, M.J., C.T. Driscoll, P.J. McHale, K. M. Roy and Zheng Dong. 2012. Lake ‐ Watershed Sulfur Budgets and Their Response to Decreases in Atmospheric Sulfur Deposition: Watershed and Climate Controls. Hydrological Processes (in press). Sub ‐ objective: Extrapolate sulfur budgets to those watersheds with limited direct measurements of hydrology and S deposition.

Adirondack Mountains of New York State

SO 2 Emissions Data (EPA) Period of study 35000 Regions 1-5 (East USA) 40000 Total US 30000 35000 SO2 (tons x 1000) 25000 30000 Mt x 1000 20000 25000 20000 15000 15000 10000 10000 5000 5000 0 0 1900 1920 1940 1960 1980 2000 Year

All Lakes (ALTM) 16 Watersheds 250 Seepage Drainage Rondaxe Constable Barnes Arbutus Squash Dart Big Moose Little Echo 200 West Heart Black Moss Windfall Bubb 2- μ mol c L -1 Otter Cascade 150 100 SO 4 50 0 1990 2000 2010 Monthly Concentrations Year

Procedures • Used measured monthly values for the discharge chemistry for all watersheds. • Used monthly directly measured wet deposition from Arbutus/Huntington (NADP/NTN). • Calculated spatial patterns among watersheds across the Adirondacks of wet S deposition and discharge using formulations from Ito et al. (2002, Atmospheric Environment). See next slide for examples of spatial patterns for precipitation and S deposition in the Adirondacks.

Procedures Continued • Calculated annual dry deposition from formulations of Mitchell et al. (2011, Biogeochemistry) for each watershed. • Used monthly temporal results for precipitation and discharge from direct measurements at Arbutus Watershed to extrapolate temporally for all sites. • Calculated annual S budgets and listed from greatest to least discrepancies in S budgets as shown in the next slide.

S Budgets Budget Discrepancy Discharge Total Deposition kg S ha -1 yr -1 -10 10 15 -5 0 5 Arbutus Black Windfall Constable Cascade Moss Watersheds Otter Big Moose Dart Rondaxe Bubb Heart West Squash

Examples of annual sulfur budgets for three watersheds over the range of sulfur budget discrepancies are given in the next three slides. Note that there is substantial variation in sulfur budget discrepancies among years.

12 y = -0.22x +445.2, r 2 =0.812 p<.0001 10 Total S Deposition 8 Arbutus 6 4 2 0 1985 1990 1995 2000 2005 2010 kg S ha -1 yr -1 20 y= -0.237x + 484, r 2 =0.345 2-) 18 Discharge (SO4 p=0.0013 16 14 12 10 8 6 4 2 0 1985 1990 1995 2000 2005 2010 2 Regression not significant 0 -2 -4 -6 -8 S Budget Discrepancy -10 -12 1985 1990 1995 2000 2005 2010 Year

16 y = -0.29x +582.4, r 2 =0.806 14 p<.0001 Total S Deposition 12 Plot 1 Regr 10 Big 8 6 Moose 4 2 0 1985 1990 1995 2000 2005 2010 kg S ha -1 yr -1 20 y= -0.295x + 601, r 2 =0.470 2-) 18 Discharge (SO4 p<0.0001 16 14 12 10 8 6 4 2 0 1985 1990 1995 2000 2005 2010 4 2 Regression not significant 0 -2 -4 -6 S Budget Discrepancy -8 -10 1985 1990 1995 2000 2005 2010 Year

18 y = -0.32x +655.2, r 2 =0.796 16 p<.0001 Total S Deposition 14 12 10 8 Squash 6 4 2 0 1985 1990 1995 2000 2005 2010 kg S ha -1 yr -1 18 y= -0.263x + 536, r 2 =0.444 2-) 16 Discharge (SO4 p<0.0001 14 12 10 8 6 4 2 0 1985 1990 1995 2000 2005 2010 6 Regression not significant 4 2 0 -2 S Budget Discrepancy -4 -6 1985 1990 1995 2000 2005 2010 Year

The annual variations in sulfur budget discrepancies normalized to discharge are significantly related to watershed wetness as a function of discharge as shown in the next slide.

Drainage Lakes 60 Arbutus Rondaxe Constable Arbutus Rondaxe Constable Big Moose Squash Dart Big Moose Squash Dart SO42- Discrepancy μ molc L-1 Black West Heart Black West Heart 40 Bubb Moss Windfall Bubb Moss Windfall Cascade Otter Cascade Otter 20 0 y= -88.1x + 48.8 -20 r ²=0.473 p<0.0001 -40 20 100 Discharge cm year-1 (log scale)

How important are these S budget discrepancies in the recovery from acidification in these Adirondack watersheds?