western mountains at risk: when do we know enough to limit emissions?
TRANSCRIPT
WESTERN MOUNTAINS AT RISK:WHEN DO WE KNOW ENOUGH TO LIMIT EMISSIONS?
OVERVIEW
– Nitrate– Snow: Process-level controls– Flowpaths– Dissolved organic nitrogen (DON)– DIN and DON story– Telluride case study
PROBLEM:N DEPOSITION INCREASES
STRATEGIES FOR BRINGING INDUSTRY AND TREE-HUGGERS TOGETHER
• Process-level understanding of the N cycle
• Indicators of ecosystem N-status
• Management help
ABER SPAGHETTI DIAGRAM
Alpine areas: early warning indicators
• Organisms on edge of environmental tolerance
• Same processes as downstream forested and grassland ecosystems
• Less capacity! Less “buffering”
• Snow: moderates soil temperature, stores water and chemical, released at once
NIWOT RIDGE NADP
STREAM WATER RESPONSEGL4-220 ha
ACIDIFICATION
Navajo-42 ha
Long Term Changes
GL4-sediment profile: McKnight group
NUTRIENT ENRICHMENT PRISTINE LAKE
NUTRIENT ENRICHMENT ENHANCES Hg IN LAKES
NITRATE SUMMARY
• Atmospheric deposition of inorganic N is increasing
• Nitrate concentrations in surface waters during growing season increasing
• C:N ratio in sediments decreasing
• C:N ration decreases correlated with Hg
• Should we set critical loads for N dep?
CRITICAL LOADS
• 5-7 kg/ha-yr
• Episodic vs chronic
• Ecological Applications: 3-5 kg/ha-yr
• Reviews wanted only one value
• Williams and Tonnessen, 2000
CRITICAL LOADS
• 5-7 kg/ha-yr
• Episodic vs chronic
• Ecological Applications: 3-5 kg/ha-yr
• Reviews wanted only one value
4 kg/ha-yr
WHAT IS THE SOURCE OF NITRATE IN STREAMS?
FLOWPATHS ANDSOURCE WATERS
Martinelli Catchment
Stream Flow Chemistry (1)
(a) Martinelli
0
20
40
60
80
100
120
125 155 185 215 245 275
Calendar Day (1996)
Ions
(uq
L-1
)ANCCalcium
NitrateSulphate
(c) Green Lake 4
0
30
60
90
120
130 190 250 310 370
Calendar Day (1996)
Ions
(uq
L-1
)
(d) Green Lake 4
0
10
20
30
40
130 190 250 310 370
Calendar Day (1996)
Q (
103 m
3 day
-1)
(b) Martinelli
0
10
20
30
40
50
125 155 185 215 245 275
Calendar Day (1996)
Q (
102 m
3 day
-1)
18O in Snowpack, Snowmelt and Stream Flow
(a) Martinelli
-25
-20
-15
-10
-5
100 150 200 250 300
18O
(‰)
Stream FlowSnowmeltSnow CoreSoil Water
(c) Green Lake 4
-20
-15
-10
-5
100 150 200 250 300
18O
(‰)
Stream Flow
Soil Water
(d) Green Lake 4
0
10
20
30
40
100 150 200 250 300
Calendar Day (1996)
Q (1
03 m
3 day
-1)
(b) Martinelli
0
10
20
30
40
50
125 155 185 215 245 275
Calendar Day (1996)
Q (
102 m
3 day
-1)
New Water and Old Water Using 18O (1)
(a) Martinelli
0
10
20
30
40
50
60
137 167 197 227 257
Calendar Day (1996)
Q (1
02 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Perc
enta
ge (%
)
New WaterOld WaterNew WaterOld Water
(c) Green Lake 4
0
10
20
30
40
50
60
135 165 195 225 255 285
Calendar Day (1996)
Q (1
03 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Perc
enta
ge (%
)
New WaterOld WaterNew WaterOld Water
• New water by snowmelt 18O & old water by base flow;
• Time series of snowmelt 18O used.
New Water and Old Water Using 18O (2)
• New water by snowmelt 18O & old water by base flow;
• Median of snowmelt 18O used.
(b) Martinelli
0
10
20
30
40
50
60
137 167 197 227 257Calendar Day (1996)
Q (1
02 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cent
age
(%)
New WaterOld WaterNew WaterOld Water
(d) Green Lake 4
0
10
20
30
40
50
60
135 165 195 225 255 285
Calendar Day (1996)
Q (1
03 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cent
age
(%)
New WaterOld WaterNew WaterOld Water
Mixing Diagram: Paired Tracers
(a) Martinelli
0
30
60
90
120
150
180
0 20 40 60 80 100
ANC (meq L-1)
Ca2
+ (eq
L-1
) Stream Flow
Snowpit
Snow Lysimeter
Soil Water
Base Flow
(b) Green Lake 4
0
10
20
30
40
50
60
-24 -20 -16 -12 -8
18O(‰)
Si (
mol
L-1
)
Stream Flow
Snowpit
Snowmelt
Talus EN1-L
Talus EN1-M
Talus EN1-U
Talus EN2-LM
Talus EN2-UM
Talus EN4-V
Talus EN4-L
Talus EN4-U
Soil Water
Base Flow
Flowpaths: TMM
(a) Martinelli
0
10
20
30
40
50
60
137 167 197 227 257
Calendar Day (1996)
Q (
102 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cen
tage
(%
)
Near SurfaceHillslope SubsurfaceRiparian Subsurface
(b) Green Lake 4
0
20
40
60
135 165 195 225 255 285
Calendar Day (1996)
Q (
103 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cen
tage
(%
)
Near SurfaceHillslope SubsurfaceRiparian Subsurface
Burns et alnomenclature
Mixing Diagram: U-Space Defined by 8 Tracers
(a) Martinelli
-7
-5
-3
-1
1
3
5
-12 -7 -2 3 8
U1
U2
Stream Flow
Snowpit
Snowmelt
Base Flow
Soil Water
(b) Green Lake 4
-3
-1
1
3
5
-8 -3 2 7 12
U1
U2
Stream Flow
Snowpit
Snowmelt
Talus EN1-L
Talus EN1-M
Talus EN1-U
Talus EN2-LM
Talus EN2-UM
Talus EN4-V
Talus EN4-L
Talus EN4-U
Base Flow
Soil Water
Flowpaths: EMMA
(a) Martinelli
0
10
20
30
40
50
60
137 167 197 227 257
Calendar Day (1996)
Q (
102 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cen
tage
(%
)
Near SurfaceHillslope SubsurfaceRiparian Subsurface
(b) Green Lake 4
0
20
40
60
135 165 195 225 255 285
Calendar Day (1996)
Q (
103 m
3 day
-1)
0
40
80
120
160
200
240
280
320
Per
cen
tage
(%
)
Near SurfaceUpslope Subsurface
Riparian Subsurface
Prediction of Nitrate in Stream: Martinelli
EMMA
0
10
20
30
40
120 150 180 210 240 270 300
Calendar Day (1996)
NO
3- (eq
L-1
)
Oberved
Predicted
EMMA
0
10
20
30
40
50
120 150 180 210 240 270 300
Calendar Day (1996)
NH
4+ +
NO
3-
(meq
L-1
)
TMM
0
10
20
30
40
120 150 180 210 240 270 300
Calendar Day (1996)
NO
3- (m
eq L
-1)
Oberved
Predicted
TMM
0
10
20
30
40
50
120 150 180 210 240 270 300
Calendar Day (1996)
NH
4+ +
NO
3-
(meq
L-1
)
Prediction of Nitrate in Stream: GL4
EMMA
0
10
20
30
40
5 65 125 185 245 305 365
Calendar Day (1996)
NO
3- (eq
L-1
)
ObervedPredicted
EMMA
0
10
20
30
40
5 65 125 185 245 305 365
Calendar Day (1996)
NH
4+ +
NO
3-
(eq
L-1
)
TMM
0
10
20
30
40
5 65 125 185 245 305 365
Calendar Day (1996)
NO
3- (m e
q L
-1) Oberved
Predicted
TMM
0102030405060
5 65 125 185 245 305 365
Calendar Day (1996)
NH
4+ +
NO
3-
(eq
L-1
)
Nitrate 18O
10
20
30
40
50
60
70
80
130 150 170 190 210 230 250 270
Calendar Day (1997)
Nit
rate
18
O (
‰)
SnowpackStream Water: MartinelliStream Water: GL4Talus WaterRain
Sources of Nitrate: Martinelli
Atmospheric
0
20
40
60
80
100
125 155 185 215 245 275
Calendar Day (1996/1997)
Sour
ces
(%)
Nitrate O18 (1997)
EMMA (1996)
TMM (1996)
Terrestrial
0
20
40
60
80
100
125 155 185 215 245 275
Calendar Day (1996/1997)
Sour
ces
(%)
Nitrate O18 (1997)
EMMA (1996)
TMM (1996)
Sources of Nitrate: Green Lake 4
Atmospheric
0
10
20
30
40
50
60
70
125 155 185 215 245
Calendar Day (1996/1997)
Sour
ces
(%)
Nitrate O-18 (1997)
EMMA (1996)
TMM (1996)
Terrestrial
2030405060708090
100
125 155 185 215 245Calendar Day (1996/1997)
Sour
ces
(%)
Nitrate O-18 (1997)
EMMA (1996)
TMM (1996)
FLOWPATH SUMMARY
• 4 parts per mil separation in the delta O18 values of snowmelt (Taylor et al., 2002)
• Baseflow 35% of annual Q at 220 ha
• Ionic pulse somewhat important
• EMMA only works if we use talus:– Geographic areas as important as riparian areas
for both water quantity and quality
Dissolved Organic Nitrogen in a Headwater Catchment, Colorado
Front Range
•Eran Hood, Mark Williams, and Eran Hood, Mark Williams, and Diane McKnightDiane McKnight •INSTAAR and Dept. of GeographyINSTAAR and Dept. of Geography•University of Colorado, BoulderUniversity of Colorado, Boulder
DON in Headwater Catchments
• N loss from terrestrial systems - “Leaky Faucet N loss from terrestrial systems - “Leaky Faucet Hypothesis”Hypothesis”
• Source of N for plants and aquatic biotaSource of N for plants and aquatic biota
• Affected by inorganic N deposition?Affected by inorganic N deposition?
APPROACH
• Nitrogen cycling in Alpine/Subalpine ecosystemNitrogen cycling in Alpine/Subalpine ecosystem
– Characterize DOM: stable isotopes, 13C-NMR, elemental Characterize DOM: stable isotopes, 13C-NMR, elemental analysis, fractionationanalysis, fractionation
– Temporal and longitudinal changes in the character and Temporal and longitudinal changes in the character and source of DONsource of DON
– Ecological controls on DONEcological controls on DON
IMPORTANCE of DON
0
4
8
12
16
20
24AlpineSubalpine
NH4+ NO3
- DON PN
µM
oles
/L
DON vs SOIL C:N
R2 = 0.97
0
1
2
3
4
5
6
5 15 25 35
Soil C:N
DON CONCENTRATIONS
Dis
char
ge (
m3 /
day
)
µM
oles
/L
0
10
20
30
Apr May Jun Jul Aug Sep Oct
0
10000
20000
30000SLP
GL4
Discharge
METHODS
• FractionationFractionation– Chromatographic Chromatographic
separationseparation
– Isolate hydrophobic Isolate hydrophobic acids (fulvic acids) from acids (fulvic acids) from hydrophilic acids and hydrophilic acids and low molecular weight low molecular weight compoundscompounds
Fu
lvic
Aci
d (
% o
f D
OC
)
20
30
40
50
60
70
80
May Jun Jul Aug Sep Oct Nov
GL4
SLP
DOM Fractions: Seasonal trends
GL4 - June
46%54%
SLP - June
44%56%
GL4 - September
73%
27%
SLP - September
58%42%
Red = non-humic
green = fulvic
Seasonal and longitudinal changes
DOM fractions: 13C Isotopes
-28
-27
-26
-25
-24
0 20 40 60
13 C
C:N Ratio
DOM fractions: 15N Isotopes
C:N Ratio
15 N
0
1
2
3
0 20 40 60
DOM Fractions: Aromatic carbon
0
10
20
30
0 20 40 60
C:N Ratio
Aro
mat
ic C
(%
)
SUMMARY
• Most DON is non-humic
• Changes in DON quality linked to sources
• Effects of climate or environmental change
DOC Concentrations
0
2
4
6
8
10
2-May 21-Jun 10-Aug 29-Sep
GL4
Albion
SLPI
CCMRS
DO
C (
mg/
L)
Percent Fulvic Acid
20
30
40
50
60
70
80
2-May 21-Jun 10-Aug 29-Sep
GL4
Albion
SLPI
CCMRS
% F
ulv
ic A
cid
METHODS
• FluorescenceFluorescence– All humic substances fluoresceAll humic substances fluoresce– At least 2 main fluorophoresAt least 2 main fluorophores– Provides information on precursor organic material Provides information on precursor organic material
of fulvic acidsof fulvic acids• Excitation emission matrices (EEMS) different for Excitation emission matrices (EEMS) different for
microbial vs terrestrial DOCmicrobial vs terrestrial DOC
METHODS
• Fluorescence IndexFluorescence Index– Simple interpretive toolSimple interpretive tool
– Ratio of 450 /500 nm Ratio of 450 /500 nm emission at 370 nm excitationemission at 370 nm excitation
1
1.2
1.4
1.6
1.8
2
Suwannee River Lake Fryxell
Fl u
o res
c enc
e In
dex
Fluorescence Index
1.2
1.3
1.4
1.5
1.6
1.7
1.8
6-May 25-Jun 14-Aug 3-Oct
Lake Fryxell
Suwannee River
GREEN LAKE 4MayMay SampleSample
JulyJuly SampleSample
SeptemberSeptember SampleSample
Flu
ores
cen
ce I
nd
ex
Fluorescence Index
1.2
1.3
1.4
1.5
1.6
1.7
1.8
6-May 25-Jun 14-Aug 3-Oct
GREEN LAKE 4
SILVER LAKE INLET
COMO CREEK
Flu
ores
cen
ce I
nd
ex
SUMMARY
• Fractionation Fractionation – Recalcitrant DOM during snowmeltRecalcitrant DOM during snowmelt– Labile DOM in fallLabile DOM in fall
• FluorescenceFluorescence– Source of source of dissolved organic materialSource of source of dissolved organic material– Terrestrial source during snowmeltTerrestrial source during snowmelt– Aquatic source in fallAquatic source in fall
• Insight into ecological controls on DOMInsight into ecological controls on DOM
THE DIN AND DON STORY: RATIO OF DIN TO DON IN ANNUAL RIVERINE FLUX
Mark Williams, Eran HoodAnd Bill McDowell
LTER X-site comparison
HYPOTHESIS
• DON export not related to N input
• Nitrate export responds to N input
• DON: DIN ratio thus an indicator of ecosystem N status
• Do not need long-term data sets
LEAKY FAUCET
• Persistent “leak” of DON from catchments
• DON is decoupled from microbial demand for N.
• DON export coupled to soil standing stock of C, N
• Lag between N inputs and DON export
FORESTED CATCHMENTS
MORE FORESTED CATCHMENTS
DIN: DON for ALPINE CATCHMENTS
FORESTED/ALPINE COMPARISON
DIN and DON: SUMMARY
• May be an indicator of ecosystem N status
• May provide an emotionally neutral starting point for regulating emissions and other N sources
• Looking for more data sets!
TELLURIDE: New West
LEGACY OF EXTRACTIVE INDUSTRIES
TROPHY HOMES: A NEW ERA
HOW TO PROTECT?
• Balance restrictions with reasonable economic and recreational activities
• Legal approach that is bulletproof– Good intentions not good enough
• Committed stakeholders
• Community consensus
INITIAL EFFORTS
• San Miguel Planning Department proposed “blue line” at 11,000’
• Developers said they would sue
• County attorney refused to back planning department
• “Blue line” was capricious and arbitrary
• Needed a new strategy
WATER QUALITY
• Mom and apple pie-no one against good water quality
• Streams are kidneys of an ecosystem
• Water quality provides diagnostic indicator of ecosystem health
• Indicators based on process-level research
RIPARIAN
TUNDRA
FOREST
TALUS
Nitr
ate
(mic
ro e
q/L)
18
16
14
12
10
8
6
4
2
LAND USE CODES
• Maximum building footprint of 800 sq ft
• No septic tanks
• No fertilization
• Maximum road width of 10 feet
• No winter plowing
3 June 1998
• Land use code amendments adopted by the Board of County Commissioners
• We could not pass those codes today; new BOCC