5 TERRESTRIAL DISSOLVED ORGANIC MATTER (DOM) STRONGLY INFLUENCES COASTAL ECOSYSTEM PRODUCTION AND CARBON CYCLING BY REGULATING NUTRIENT AVAILABILITY, LIGHT PENETRATION AND TEMPERATURE. CHANGES IN BIOGEOCHEMICAL PROCESSES IN SOILS, AND RIVERS WHICH ARE SUSCEPTIBLE TO CHANGES INDUCED BY CLIMATE FACTORS CAN DRASTICALLY ALTER THE QUANTITY AND CHARACTER OF DOM AS IT IS DELIVERED TO LARGE LAKES AND COASTAL OCEANS, IN TURN ALTERING BIOGEOCHEMICAL PROCESSES AND CARBON CYCLING IN THESE SYSTEMS. RELATIONSHIPS BETWEEN CLIMATE CHANGE, FLUXES IN DOM DELIVERY TO AQUATIC SYSTEMS, AND LONG TERM SYSTEMIC CHANGE ARE NOT WELL-UNDERSTOOD. THIS STUDY AIMS TO DECREASE UNCERTAINTY IN THE CONNECTION OF TERRESTRIAL DOM POOLS AND THE COASTAL ZONE. OUR EFFORTS ARE FOCUSED ON LAKE SUPERIOR DUE TO THE LOW ANTHROPOGENIC IMPACT ON LAND USE AND SUBSEQUENTLY THE LAKE AS WELL AS AN EVIDENT GAP IN DATA REGARDING COASTAL BIOGEOCHEMICAL PROCESSES IN THE LAKE. TO DATE, LIMITED IN-SITU OBSERVATIONS AS WELL AS ITS SEASONAL SNOW AND ICE COVER, LEAVE MUCH UNCERTAINTY IN THE ROLE OF TERRESTRIALLY DERIVED DOM ON BIOLOGICAL PRODUCTION AS WELL AS CHANGES IN ICE DYNAMICS AND INCREASING WATER TEMPERATURES IN LAKE SUPERIOR. HOWEVER, RESEARCH HAS INDICATED SEASONAL AND INTRA-ANNUAL VARIABILITY IN DOM EXPORT AND MIXING IN THE LAKE. THIS STUDY IS COMPOSED OF THREE MAIN OBJECTIVES TO INVESTIGATE THE QUESTION: HOW DO ENVIRONMENTAL CONDITIONS SUCH AS LOCAL WEATHER, PRECIPITATION, AND WATER RESOURCES ALTER DOM QUALITY AND QUANTITY EXPORTED FROM FORESTED WATERSHEDS TO LAKE SUPERIOR S COASTAL ZONE? TASK 1) ON A LOCALIZED SCALE, INVESTIGATE THE EFFECT OF INCREASED RATE OF SNOWMELT AND WARMER SPRING SOIL AND AIR TEMPERATURES ON THE TERRESTRIAL ORIGINS OF DOM EXPORTED THE LAKE SUPERIOR. CHEMICAL CHANGES IN SOIL DOM SUCH AS LABILITY AND AROMATICITY VARY WITH SOIL DEPTH. VARIATIONS IN THE RATE, TIMING AND DURATION OF SNOWMELT HAVE BEEN SHOWN TO CAUSE VARIATION IN THE PERCENT OF MELTWATER FLOWING THROUGH VARIOUS DEPTHS OF SOIL. WE PROPOSE TWO MAIN CONSEQUENCES OF CHANGES IN THE DYNAMICS OF SNOWMELT. FIRST, INCREASED INTENSITY OF MELT DUE TO A MORE RAPID ONSET OF SPRING IS LIKELY TO INCREASE THE PERCENT OF RUNOFF ENTERING OVERLAND FLOW-PATHS, THUS CAUSING A HIGH INTENSITY AND BRIEF SPIKE IN MORE LABILE DOM CONCENTRATIONS ASSOCIATED WITH FLUSHING SNOWMELT. SECONDLY, A SLOWER ONSET TO SPRING CAUSING A SLOWER MELT WOULD PRODUCE A LARGER OVERALL SEASON FLUX OF LABILE DOM TO THE LAKE. A HILLSLOPE SCALE EXPERIMENT WILL LEVERAGE A STRONG NORTH-SOUTH ASPECT GRADIENT OF A SMALL LAKE SUPERIOR TRIBUTARY TO INVESTIGATE VARIATIONS IN EXPORTED DOM DURING VARIOUS SNOWMELT DYNAMICS. TASK 2) INVESTIGATE THE ACCURACY OF CDOM ABSORPTION FROM SATELLITE RADIOMETRY AND DEVELOP A RELATIONSHIP BETWEEN DOM LEVELS AND CDOM ABSORPTION IN THE COASTAL REGION. THIS TASK AIMS TO INVESTIGATE SEASONAL AND SPATIAL CHANGES IN OPTICAL CHARACTERISTICS OF DOM IN COASTAL LAKE SUPERIOR. IN-SITU CHEMICAL AND OPTICAL SAMPLING OF THE COASTAL ZONE WILL PROVIDE INFORMATION INTO THE PHYSICAL, CHEMICAL AND OPTICAL CHARACTERISTICS OF TERRESTRIAL DOM DELIVERED TO LAKE SUPERIOR. TASK 3) USE LEGACY OCEAN COLOR SENSOR RETRIEVALS OF COASTAL DOM CHARACTERISTICS TO INVESTIGATE THE LINK BETWEEN HISTORIC ENVIRONMENTAL CONDITIONS AND DOM VARIABILITY WITHIN COASTAL LAKE SUPERIOR. TASK 1 AND 2 BEGIN TO DISENTANGLE THE PHYSICAL VARIATIONS IN DOM CHARACTER ON A MORE LOCALIZED SCALE, HOWEVER THEY DO NOT OFFER A SPATIALLY EXPLICIT TOOL FOR MONITORING COASTAL DOM FOR THE ENTIRE LAKE. IN TASK 3, IN-SITU OPTICAL SAMPLING (TASK 2) WILL BE USED TO FURTHER ASSESS THE ACCURACY AND REFINE, AS NECESSARY, THE CDOM ABSORPTION RETRIEVAL OF A QUASI-ANALYTICAL INVERSION ALGORITHM IN LAKE SUPERIOR. A SYNTHESIS OF ENVIRONMENTAL, SNOWMELT AND HYDROLOGICAL DATA WILL BE USED IN CONJUNCTION WITH REMOTELY SENSED DOM CONCENTRATION RETRIEVALS TO ASSESS RELATIONSHIPS BETWEEN ENVIRONMENTAL FORCING AND DOM DYNAMICS IN THE LAKE. Funding Only Action ($178) 6/25/21 Not listed TERRESTRIAL DISSOLVED ORGANIC MATTER (DOM) STRONGLY INFLUENCES COASTAL ECOSYSTEM PRODUCTION AND CARBON CYCLING BY REGULATING NUTRIENT AVAILABILITY LIGHT PENETRATION AND TEMPERATURE. CHANGES IN BIOGEOCHEMICAL PROCESSES IN SOILS AND RIVERS WHICH ARE SUSCEPTIBLE TO CHANGES INDUCED BY CLIMATE FACTORS CAN DRASTICALLY ALTER THE QUANTITY AND CHARACTER OF DOM AS IT IS DELIVERED TO LARGE LAKES AND COASTAL OCEANS IN TURN ALTERING BIOGEOCHEMICAL PROCESSES AND CARBON CYCLING IN THESE SYSTEMS. RELATIONSHIPS BETWEEN CLIMATE CHANGE FLUXES IN DOM DELIVERY TO AQUATIC SYSTEMS AND LONG TERM SYSTEMIC CHANGE ARE NOT WELL-UNDERSTOOD. THIS STUDY AIMS TO DECREASE UNCERTAINTY IN THE CONNECTION OF TERRESTRIAL DOM POOLS AND THE COASTAL ZONE. OUR EFFORTS ARE FOCUSED ON LAKE SUPERIOR DUE TO THE LOW ANTHROPOGENIC IMPACT ON LAND USE AND SUBSEQUENTLY THE LAKE AS WELL AS AN EVIDENT GAP IN DATA REGARDING COASTAL BIOGEOCHEMICAL PROCESSES IN THE LAKE. TO DATE LIMITED IN-SITU OBSERVATIONS AS WELL AS ITS SEASONAL SNOW AND ICE COVER LEAVE MUCH UNCERTAINTY IN THE ROLE OF TERRESTRIALLY DERIVED DOM ON BIOLOGICAL PRODUCTION AS WELL AS CHANGES IN ICE DYNAMICS AND INCREASING WATER TEMPERATURES IN LAKE SUPERIOR. HOWEVER RESEARCH HAS INDICATED SEASONAL AND INTRA-ANNUAL VARIABILITY IN DOM EXPORT AND MIXING IN THE LAKE. THIS STUDY IS COMPOSED OF THREE MAIN OBJECTIVES TO INVESTIGATE THE QUESTION: HOW DO ENVIRONMENTAL CONDITIONS SUCH AS LOCAL WEATHER PRECIPITATION AND WATER RESOURCES ALTER DOM QUALITY AND QUANTITY EXPORTED FROM FORESTED WATERSHEDS TO LAKE SUPERIOR S COASTAL ZONE? TASK 1) ON A LOCALIZED SCALE INVESTIGATE THE EFFECT OF INCREASED RATE OF SNOWMELT AND WARMER SPRING SOIL AND AIR TEMPERATURES ON THE TERRESTRIAL ORIGINS OF DOM EXPORTED THE LAKE SUPERIOR. CHEMICAL CHANGES IN SOIL DOM SUCH AS LABILITY AND AROMATICITY VARY WITH SOIL DEPTH. VARIATIONS IN THE RATE TIMING AND DURATION OF SNOWMELT HAVE BEEN SHOWN TO CAUSE VARIATION IN THE PERCENT OF MELTWATER FLOWING THROUGH VARIOUS DEPTHS OF SOIL. WE PROPOSE TWO MAIN CONSEQUENCES OF CHANGES IN THE DYNAMICS OF SNOWMELT. FIRST INCREASED INTENSITY OF MELT DUE TO A MORE RAPID ONSET OF SPRING IS LIKELY TO INCREASE THE PERCENT OF RUNOFF ENTERING OVERLAND FLOW-PATHS THUS CAUSING A HIGH INTENSITY AND BRIEF SPIKE IN MORE LABILE DOM CONCENTRATIONS ASSOCIATED WITH FLUSHING SNOWMELT. SECONDLY A SLOWER ONSET TO SPRING CAUSING A SLOWER MELT WOULD PRODUCE A LARGER OVERALL SEASON FLUX OF LABILE DOM TO THE LAKE. A HILLSLOPE SCALE EXPERIMENT WILL LEVERAGE A STRONG NORTH-SOUTH ASPECT GRADIENT OF A SMALL LAKE SUPERIOR TRIBUTARY TO INVESTIGATE VARIATIONS IN EXPORTED DOM DURING VARIOUS SNOWMELT DYNAMICS. TASK 2) INVESTIGATE THE ACCURACY OF CDOM ABSORPTION FROM SATELLITE RADIOMETRY AND DEVELOP A RELATIONSHIP BETWEEN DOM LEVELS AND CDOM ABSORPTION IN THE COASTAL REGION. THIS TASK AIMS TO INVESTIGATE SEASONAL AND SPATIAL CHANGES IN OPTICAL CHARACTERISTICS OF DOM IN COASTAL LAKE SUPERIOR. IN-SITU CHEMICAL AND OPTICAL SAMPLING OF THE COASTAL ZONE WILL PROVIDE INFORMATION INTO THE PHYSICAL CHEMICAL AND OPTICAL CHARACTERISTICS OF TERRESTRIAL DOM DELIVERED TO LAKE SUPERIOR. TASK 3) USE LEGACY OCEAN COLOR SENSOR RETRIEVALS OF COASTAL DOM CHARACTERISTICS TO INVESTIGATE THE LINK BETWEEN HISTORIC ENVIRONMENTAL CONDITIONS AND DOM VARIABILITY WITHIN COASTAL LAKE SUPERIOR. TASK 1 AND 2 BEGIN TO DISENTANGLE THE PHYSICAL VARIATIONS IN DOM CHARACTER ON A MORE LOCALIZED SCALE HOWEVER THEY DO NOT OFFER A SPATIALLY EXPLICIT TOOL FOR MONITORING COASTAL DOM FOR THE ENTIRE LAKE. IN TASK 3 IN-SITU OPTICAL SAMPLING (TASK 2) WILL BE USED TO FURTHER ASSESS THE ACCURACY AND REFINE AS NECESSARY THE CDOM ABSORPTION RETRIEVAL OF A QUASI-ANALYTICAL INVERSION ALGORITHM IN LAKE SUPERIOR. A SYNTHESIS OF ENVIRONMENTAL SNOWMELT AND HYDROLOGICAL DATA WILL BE USED IN CONJUNCTION WITH REMOTELY SENSED DOM CONCENTRATION RETRIEVALS TO ASSESS RELATIONSHIPS BETWEEN ENVIRONMENTAL FORCING AND DOM DYNAMICS IN THE LAKE. ($178) 6/25/21 Not listed TERRESTRIAL DISSOLVED ORGANIC MATTER (DOM) STRONGLY INFLUENCES COASTAL ECOSYSTEM PRODUCTION AND CARBON CYCLING BY REGULATING NUTRIENT AVAILABILITY LIGHT PENETRATION AND TEMPERATURE. CHANGES IN BIOGEOCHEMICAL PROCESSES IN SOILS AND RIVERS WHICH ARE SUSCEPTIBLE TO CHANGES INDUCED BY CLIMATE FACTORS CAN DRASTICALLY ALTER THE QUANTITY AND CHARACTER OF DOM AS IT IS DELIVERED TO LARGE LAKES AND COASTAL OCEANS IN TURN ALTERING BIOGEOCHEMICAL PROCESSES AND CARBON CYCLING IN THESE SYSTEMS. RELATIONSHIPS BETWEEN CLIMATE CHANGE FLUXES IN DOM DELIVERY TO AQUATIC SYSTEMS AND LONG TERM SYSTEMIC CHANGE ARE NOT WELL-UNDERSTOOD. THIS STUDY AIMS TO DECREASE UNCERTAINTY IN THE CONNECTION OF TERRESTRIAL DOM POOLS AND THE COASTAL ZONE. OUR EFFORTS ARE FOCUSED ON LAKE SUPERIOR DUE TO THE LOW ANTHROPOGENIC IMPACT ON LAND USE AND SUBSEQUENTLY THE LAKE AS WELL AS AN EVIDENT GAP IN DATA REGARDING COASTAL BIOGEOCHEMICAL PROCESSES IN THE LAKE. TO DATE LIMITED IN-SITU OBSERVATIONS AS WELL AS ITS SEASONAL SNOW AND ICE COVER LEAVE MUCH UNCERTAINTY IN THE ROLE OF TERRESTRIALLY DERIVED DOM ON BIOLOGICAL PRODUCTION AS WELL AS CHANGES IN ICE DYNAMICS AND INCREASING WATER TEMPERATURES IN LAKE SUPERIOR. HOWEVER RESEARCH HAS INDICATED SEASONAL AND INTRA-ANNUAL VARIABILITY IN DOM EXPORT AND MIXING IN THE LAKE. THIS STUDY IS COMPOSED OF THREE MAIN OBJECTIVES TO INVESTIGATE THE QUESTION: HOW DO ENVIRONMENTAL CONDITIONS SUCH AS LOCAL WEATHER PRECIPITATION AND WATER RESOURCES ALTER DOM QUALITY AND QUANTITY EXPORTED FROM FORESTED WATERSHEDS TO LAKE SUPERIOR S COASTAL ZONE? TASK 1) ON A LOCALIZED SCALE INVESTIGATE THE EFFECT OF INCREASED RATE OF SNOWMELT AND WARMER SPRING SOIL AND AIR TEMPERATURES ON THE TERRESTRIAL ORIGINS OF DOM EXPORTED THE LAKE SUPERIOR. CHEMICAL CHANGES IN SOIL DOM SUCH AS LABILITY AND AROMATICITY VARY WITH SOIL DEPTH. VARIATIONS IN THE RATE TIMING AND DURATION OF SNOWMELT HAVE BEEN SHOWN TO CAUSE VARIATION IN THE PERCENT OF MELTWATER FLOWING THROUGH VARIOUS DEPTHS OF SOIL. WE PROPOSE TWO MAIN CONSEQUENCES OF CHANGES IN THE DYNAMICS OF SNOWMELT. FIRST INCREASED INTENSITY OF MELT DUE TO A MORE RAPID ONSET OF SPRING IS LIKELY TO INCREASE THE PERCENT OF RUNOFF ENTERING OVERLAND FLOW-PATHS THUS CAUSING A HIGH INTENSITY AND BRIEF SPIKE IN MORE LABILE DOM CONCENTRATIONS ASSOCIATED WITH FLUSHING SNOWMELT. SECONDLY A SLOWER ONSET TO SPRING CAUSING A SLOWER MELT WOULD PRODUCE A LARGER OVERALL SEASON FLUX OF LABILE DOM TO THE LAKE. A HILLSLOPE SCALE EXPERIMENT WILL LEVERAGE A STRONG NORTH-SOUTH ASPECT GRADIENT OF A SMALL LAKE SUPERIOR TRIBUTARY TO INVESTIGATE VARIATIONS IN EXPORTED DOM DURING VARIOUS SNOWMELT DYNAMICS. TASK 2) INVESTIGATE THE ACCURACY OF CDOM ABSORPTION FROM SATELLITE RADIOMETRY AND DEVELOP A RELATIONSHIP BETWEEN DOM LEVELS AND CDOM ABSORPTION IN THE COASTAL REGION. THIS TASK AIMS TO INVESTIGATE SEASONAL AND SPATIAL CHANGES IN OPTICAL CHARACTERISTICS OF DOM IN COASTAL LAKE SUPERIOR. IN-SITU CHEMICAL AND OPTICAL SAMPLING OF THE COASTAL ZONE WILL PROVIDE INFORMATION INTO THE PHYSICAL CHEMICAL AND OPTICAL CHARACTERISTICS OF TERRESTRIAL DOM DELIVERED TO LAKE SUPERIOR. TASK 3) USE LEGACY OCEAN COLOR SENSOR RETRIEVALS OF COASTAL DOM CHARACTERISTICS TO INVESTIGATE THE LINK BETWEEN HISTORIC ENVIRONMENTAL CONDITIONS AND DOM VARIABILITY WITHIN COASTAL LAKE SUPERIOR. TASK 1 AND 2 BEGIN TO DISENTANGLE THE PHYSICAL VARIATIONS IN DOM CHARACTER ON A MORE LOCALIZED SCALE HOWEVER THEY DO NOT OFFER A SPATIALLY EXPLICIT TOOL FOR MONITORING COASTAL DOM FOR THE ENTIRE LAKE. IN TASK 3 IN-SITU OPTICAL SAMPLING (TASK 2) WILL BE USED TO FURTHER ASSESS THE ACCURACY AND REFINE AS NECESSARY THE CDOM ABSORPTION RETRIEVAL OF A QUASI-ANALYTICAL INVERSION ALGORITHM IN LAKE SUPERIOR. A SYNTHESIS OF ENVIRONMENTAL SNOWMELT AND HYDROLOGICAL DATA WILL BE USED IN CONJUNCTION WITH REMOTELY SENSED DOM CONCENTRATION RETRIEVALS TO ASSESS RELATIONSHIPS BETWEEN ENVIRONMENTAL FORCING AND DOM DYNAMICS IN THE LAKE. $0 8/29/19 4 TERRESTRIAL DISSOLVED ORGANIC MATTER (DOM) STRONGLY INFLUENCES COASTAL ECOSYSTEM PRODUCTION AND CARBON CYCLING BY REGULATING NUTRIENT AVAILABILITY, LIGHT PENETRATION AND TEMPERATURE. CHANGES IN BIOGEOCHEMICAL PROCESSES IN SOILS, AND RIVERS WHICH ARE SUSCEPTIBLE TO CHANGES INDUCED BY CLIMATE FACTORS CAN DRASTICALLY ALTER THE QUANTITY AND CHARACTER OF DOM AS IT IS DELIVERED TO LARGE LAKES AND COASTAL OCEANS, IN TURN ALTERING BIOGEOCHEMICAL PROCESSES AND CARBON CYCLING IN THESE SYSTEMS. RELATIONSHIPS BETWEEN CLIMATE CHANGE, FLUXES IN DOM DELIVERY TO AQUATIC SYSTEMS, AND LONG TERM SYSTEMIC CHANGE ARE NOT WELL-UNDERSTOOD. THIS STUDY AIMS TO DECREASE UNCERTAINTY IN THE CONNECTION OF TERRESTRIAL DOM POOLS AND THE COASTAL ZONE. OUR EFFORTS ARE FOCUSED ON LAKE SUPERIOR DUE TO THE LOW ANTHROPOGENIC IMPACT ON LAND USE AND SUBSEQUENTLY THE LAKE AS WELL AS AN EVIDENT GAP IN DATA REGARDING COASTAL BIOGEOCHEMICAL PROCESSES IN THE LAKE. TO DATE, LIMITED IN-SITU OBSERVATIONS AS WELL AS ITS SEASONAL SNOW AND ICE COVER, LEAVE MUCH UNCERTAINTY IN THE ROLE OF TERRESTRIALLY DERIVED DOM ON BIOLOGICAL PRODUCTION AS WELL AS CHANGES IN ICE DYNAMICS AND INCREASING WATER TEMPERATURES IN LAKE SUPERIOR. HOWEVER, RESEARCH HAS INDICATED SEASONAL AND INTRA-ANNUAL VARIABILITY IN DOM EXPORT AND MIXING IN THE LAKE. THIS STUDY IS COMPOSED OF THREE MAIN OBJECTIVES TO INVESTIGATE THE QUESTION: HOW DO ENVIRONMENTAL CONDITIONS SUCH AS LOCAL WEATHER, PRECIPITATION, AND WATER RESOURCES ALTER DOM QUALITY AND QUANTITY EXPORTED FROM FORESTED WATERSHEDS TO LAKE SUPERIOR S COASTAL ZONE? TASK 1) ON A LOCALIZED SCALE, INVESTIGATE THE EFFECT OF INCREASED RATE OF SNOWMELT AND WARMER SPRING SOIL AND AIR TEMPERATURES ON THE TERRESTRIAL ORIGINS OF DOM EXPORTED THE LAKE SUPERIOR. CHEMICAL CHANGES IN SOIL DOM SUCH AS LABILITY AND AROMATICITY VARY WITH SOIL DEPTH. VARIATIONS IN THE RATE, TIMING AND DURATION OF SNOWMELT HAVE BEEN SHOWN TO CAUSE VARIATION IN THE PERCENT OF MELTWATER FLOWING THROUGH VARIOUS DEPTHS OF SOIL. WE PROPOSE TWO MAIN CONSEQUENCES OF CHANGES IN THE DYNAMICS OF SNOWMELT. FIRST, INCREASED INTENSITY OF MELT DUE TO A MORE RAPID ONSET OF SPRING IS LIKELY TO INCREASE THE PERCENT OF RUNOFF ENTERING OVERLAND FLOW-PATHS, THUS CAUSING A HIGH INTENSITY AND BRIEF SPIKE IN MORE LABILE DOM CONCENTRATIONS ASSOCIATED WITH FLUSHING SNOWMELT. SECONDLY, A SLOWER ONSET TO SPRING CAUSING A SLOWER MELT WOULD PRODUCE A LARGER OVERALL SEASON FLUX OF LABILE DOM TO THE LAKE. A HILLSLOPE SCALE EXPERIMENT WILL LEVERAGE A STRONG NORTH-SOUTH ASPECT GRADIENT OF A SMALL LAKE SUPERIOR TRIBUTARY TO INVESTIGATE VARIATIONS IN EXPORTED DOM DURING VARIOUS SNOWMELT DYNAMICS. TASK 2) INVESTIGATE THE ACCURACY OF CDOM ABSORPTION FROM SATELLITE RADIOMETRY AND DEVELOP A RELATIONSHIP BETWEEN DOM LEVELS AND CDOM ABSORPTION IN THE COASTAL REGION. THIS TASK AIMS TO INVESTIGATE SEASONAL AND SPATIAL CHANGES IN OPTICAL CHARACTERISTICS OF DOM IN COASTAL LAKE SUPERIOR. IN-SITU CHEMICAL AND OPTICAL SAMPLING OF THE COASTAL ZONE WILL PROVIDE INFORMATION INTO THE PHYSICAL, CHEMICAL AND OPTICAL CHARACTERISTICS OF TERRESTRIAL DOM DELIVERED TO LAKE SUPERIOR. TASK 3) USE LEGACY OCEAN COLOR SENSOR RETRIEVALS OF COASTAL DOM CHARACTERISTICS TO INVESTIGATE THE LINK BETWEEN HISTORIC ENVIRONMENTAL CONDITIONS AND DOM VARIABILITY WITHIN COASTAL LAKE SUPERIOR. TASK 1 AND 2 BEGIN TO DISENTANGLE THE PHYSICAL VARIATIONS IN DOM CHARACTER ON A MORE LOCALIZED SCALE, HOWEVER THEY DO NOT OFFER A SPATIALLY EXPLICIT TOOL FOR MONITORING COASTAL DOM FOR THE ENTIRE LAKE. IN TASK 3, IN-SITU OPTICAL SAMPLING (TASK 2) WILL BE USED TO FURTHER ASSESS THE ACCURACY AND REFINE, AS NECESSARY, THE CDOM ABSORPTION RETRIEVAL OF A QUASI-ANALYTICAL INVERSION ALGORITHM IN LAKE SUPERIOR. A SYNTHESIS OF ENVIRONMENTAL, SNOWMELT AND HYDROLOGICAL DATA WILL BE USED IN CONJUNCTION WITH REMOTELY SENSED DOM CONCENTRATION RETRIEVALS TO ASSESS RELATIONSHIPS BETWEEN ENVIRONMENTAL FORCING AND DOM DYNAMICS IN THE LAKE. Other Administrative Action $0 8/29/19 3 TERRESTRIAL DISSOLVED ORGANIC MATTER (DOM) STRONGLY INFLUENCES COASTAL ECOSYSTEM PRODUCTION AND CARBON CYCLING BY REGULATING NUTRIENT AVAILABILITY, LIGHT PENETRATION AND TEMPERATURE. CHANGES IN BIOGEOCHEMICAL PROCESSES IN SOILS, AND RIVERS WHICH ARE SUSCEPTIBLE TO CHANGES INDUCED BY CLIMATE FACTORS CAN DRASTICALLY ALTER THE QUANTITY AND CHARACTER OF DOM AS IT IS DELIVERED TO LARGE LAKES AND COASTAL OCEANS, IN TURN ALTERING BIOGEOCHEMICAL PROCESSES AND CARBON CYCLING IN THESE SYSTEMS. RELATIONSHIPS BETWEEN CLIMATE CHANGE, FLUXES IN DOM DELIVERY TO AQUATIC SYSTEMS, AND LONG TERM SYSTEMIC CHANGE ARE NOT WELL-UNDERSTOOD. THIS STUDY AIMS TO DECREASE UNCERTAINTY IN THE CONNECTION OF TERRESTRIAL DOM POOLS AND THE COASTAL ZONE. OUR EFFORTS ARE FOCUSED ON LAKE SUPERIOR DUE TO THE LOW ANTHROPOGENIC IMPACT ON LAND USE AND SUBSEQUENTLY THE LAKE AS WELL AS AN EVIDENT GAP IN DATA REGARDING COASTAL BIOGEOCHEMICAL PROCESSES IN THE LAKE. TO DATE, LIMITED IN-SITU OBSERVATIONS AS WELL AS ITS SEASONAL SNOW AND ICE COVER, LEAVE MUCH UNCERTAINTY IN THE ROLE OF TERRESTRIALLY DERIVED DOM ON BIOLOGICAL PRODUCTION AS WELL AS CHANGES IN ICE DYNAMICS AND INCREASING WATER TEMPERATURES IN LAKE SUPERIOR. HOWEVER, RESEARCH HAS INDICATED SEASONAL AND INTRA-ANNUAL VARIABILITY IN DOM EXPORT AND MIXING IN THE LAKE. THIS STUDY IS COMPOSED OF THREE MAIN OBJECTIVES TO INVESTIGATE THE QUESTION: HOW DO ENVIRONMENTAL CONDITIONS SUCH AS LOCAL WEATHER, PRECIPITATION, AND WATER RESOURCES ALTER DOM QUALITY AND QUANTITY EXPORTED FROM FORESTED WATERSHEDS TO LAKE SUPERIOR S COASTAL ZONE? TASK 1) ON A LOCALIZED SCALE, INVESTIGATE THE EFFECT OF INCREASED RATE OF SNOWMELT AND WARMER SPRING SOIL AND AIR TEMPERATURES ON THE TERRESTRIAL ORIGINS OF DOM EXPORTED THE LAKE SUPERIOR. CHEMICAL CHANGES IN SOIL DOM SUCH AS LABILITY AND AROMATICITY VARY WITH SOIL DEPTH. VARIATIONS IN THE RATE, TIMING AND DURATION OF SNOWMELT HAVE BEEN SHOWN TO CAUSE VARIATION IN THE PERCENT OF MELTWATER FLOWING THROUGH VARIOUS DEPTHS OF SOIL. WE PROPOSE TWO MAIN CONSEQUENCES OF CHANGES IN THE DYNAMICS OF SNOWMELT. FIRST, INCREASED INTENSITY OF MELT DUE TO A MORE RAPID ONSET OF SPRING IS LIKELY TO INCREASE THE PERCENT OF RUNOFF ENTERING OVERLAND FLOW-PATHS, THUS CAUSING A HIGH INTENSITY AND BRIEF SPIKE IN MORE LABILE DOM CONCENTRATIONS ASSOCIATED WITH FLUSHING SNOWMELT. SECONDLY, A SLOWER ONSET TO SPRING CAUSING A SLOWER MELT WOULD PRODUCE A LARGER OVERALL SEASON FLUX OF LABILE DOM TO THE LAKE. A HILLSLOPE SCALE EXPERIMENT WILL LEVERAGE A STRONG NORTH-SOUTH ASPECT GRADIENT OF A SMALL LAKE SUPERIOR TRIBUTARY TO INVESTIGATE VARIATIONS IN EXPORTED DOM DURING VARIOUS SNOWMELT DYNAMICS. TASK 2) INVESTIGATE THE ACCURACY OF CDOM ABSORPTION FROM SATELLITE RADIOMETRY AND DEVELOP A RELATIONSHIP BETWEEN DOM LEVELS AND CDOM ABSORPTION IN THE COASTAL REGION. THIS TASK AIMS TO INVESTIGATE SEASONAL AND SPATIAL CHANGES IN OPTICAL CHARACTERISTICS OF DOM IN COASTAL LAKE SUPERIOR. IN-SITU CHEMICAL AND OPTICAL SAMPLING OF THE COASTAL ZONE WILL PROVIDE INFORMATION INTO THE PHYSICAL, CHEMICAL AND OPTICAL CHARACTERISTICS OF TERRESTRIAL DOM DELIVERED TO LAKE SUPERIOR. TASK 3) USE LEGACY OCEAN COLOR SENSOR RETRIEVALS OF COASTAL DOM CHARACTERISTICS TO INVESTIGATE THE LINK BETWEEN HISTORIC ENVIRONMENTAL CONDITIONS AND DOM VARIABILITY WITHIN COASTAL LAKE SUPERIOR. TASK 1 AND 2 BEGIN TO DISENTANGLE THE PHYSICAL VARIATIONS IN DOM CHARACTER ON A MORE LOCALIZED SCALE, HOWEVER THEY DO NOT OFFER A SPATIALLY EXPLICIT TOOL FOR MONITORING COASTAL DOM FOR THE ENTIRE LAKE. IN TASK 3, IN-SITU OPTICAL SAMPLING (TASK 2) WILL BE USED TO FURTHER ASSESS THE ACCURACY AND REFINE, AS NECESSARY, THE CDOM ABSORPTION RETRIEVAL OF A QUASI-ANALYTICAL INVERSION ALGORITHM IN LAKE SUPERIOR. A SYNTHESIS OF ENVIRONMENTAL, SNOWMELT AND HYDROLOGICAL DATA WILL BE USED IN CONJUNCTION WITH REMOTELY SENSED DOM CONCENTRATION RETRIEVALS TO ASSESS RELATIONSHIPS BETWEEN ENVIRONMENTAL FORCING AND DOM DYNAMICS IN THE LAKE. Funding Only Action $45.0k 8/7/18