THE OCEANS PLAY A VITAL ROLE IN THE GLOBAL CARBON CYCLE AND RELATIVE TO THEIR SIZE COASTAL WATERS AND CONTINENTAL SHELF SEAS ARE ESTIMATED TO CONTRIBUTE DISPROPORTIONATELY TOWARDS OCEANIC CARBON EXCHANGE AND UPTAKE OF CARBON DIOXIDE. INCREASING LEVELS OF ATMOSPHERIC CARBON DIOXIDE LEADS TO AN INCREASE IN ACIDITY OF COASTAL AND OCEANIC WATERS WHICH CAN POTENTIALLY HAVE A DETRIMENTAL EFFECT ON CALCIFYING PLANTS AND ANIMALS. CARBON CYCLING SUPPORTS THE BASE OF MARINE ECOSYSTEMS HENCE MONITORING CARBON STOCKS AND FLUXES IN SHELF SEAS IS VITAL FOR COASTAL COMMUNITIES AS THESE WATERS ARE OF GREAT ECONOMIC IMPORTANCE IN TERMS OF FISHERIES AQUACULTURE AND TOURISM. THE OVERARCHING GOAL OF THIS PROJECT IS TO CHARACTERIZE AND QUANTIFY THE CARBON STOCKS AND FLUXES IN THE GULF OF MAINE A DYNAMIC CONTINENTAL SHELF SEA. WE WILL (1) EVALUATE DEVELOP REFINE AND VALIDATE REMOTE SENSING METHODS FOR MONITORING DIFFERENT FORMS OF CARBON AND CARBON FLUXES AND (2) APPLY THESE METHODS TO SATELLITE IMAGERY TO ANALYZE THE SPATIAL AND TEMPORAL VARIABILITY OF CARBON STANDING STOCKS AND FLUXES. SPECIFICALLY THE OBJECTIVES OF THIS PROPOSAL ARE TO: (1) QUANTIFY THE STANDING STOCKS OF THE FOUR DIFFERENT CARBON POOLS (PARTICULATE ORGANIC CARBON PARTICULATE INORGANIC CARBON DISSOLVED ORGANIC CARBON DISSOLVED INORGANIC CARBON) VIA REMOTE SENSING METHODS AND WITH WELL-CONSTRAINED ERRORS (2) EXTEND SATELLITE SURFACE MEASUREMENTS TO DETERMINE EUPHOTICINTEGRATED STANDING STOCKS WITH QUANTIFIED UNCERTAINTIES FOR THE DIFFERENT CARBON POOLS (3) UNDERSTAND AND QUANTIFY THE DIFFERENT CARBON FLUX TERMS AND THEIR ASSOCIATED ERRORS VIA REMOTE SENSING METHODS AND (4) CHARACTERIZE THE ABILITY OF THE GULF OF MAINE TO ACT AS A NET CARBON SOURCE OR SINK VIA REMOTE SENSING OBSERVATIONS. THE OBJECTIVES OF THIS PROJECT WILL BE ACHIEVED BY USING IN SITU STANDING STOCK AND RATE OBSERVATIONS FROM THE GULF OF MAINE NORTH ATLANTIC TIME SERIES (GNATS) AS A MEANS TO EVALUATE AND DEVELOP REMOTE SENSING METHODS FOR CARBON STANDING STOCKS AND ASSOCIATED FLUXES. WE WILL LEVERAGE THE GNATS PROGRAM DATA TO PROVIDE WELL-CONSTRAINED UNCERTAINTIES ON THE CARBON MONITORING PRODUCTS. GNATS IS A UNIQUE COASTAL TIME SERIES WHICH HAS BEEN RUNNING SINCE 1998 MEASURING ALL PARTS OF THE CARBON CYCLE. WE WILL APPLY THE VALIDATED REMOTE SENSING METHODS TO SATELLITE DATA FROM 1997 TO PRESENT (SPANNING THE CONTINUOUS OCEAN COLOR SATELLITE RECORD). TO CALCULATE CARBON STANDING STOCKS WE WILL DEVELOP A METHOD TO EXTEND THE SATELLITE SURFACE MEASUREMENTS TO DEPTH. WE WILL USE SATELLITE OBSERVATIONS TO ESTIMATE CARBON FLUXES ASSOCIATED WITH: PRIMARY PRODUCTION CALCIFICATION DISSOLVED ORGANIC CARBON TRANSFER FROM RIVERS-TO-SEA CARBON DIOXIDE AIR-SEA FLUXES AND CARBON EXPORT FROM SURFACE WATERS TO DEPTH. THE SPATIAL AND TEMPORAL VARIABILITY OF STANDING STOCKS AND CARBON FLUXES WILL BE ANALYZED TO SYNTHESIZE THE OBSERVATIONS OF DIFFERENT PARTS OF THE CARBON CYCLE AND DETERMINE THE GULF OF MAINE S ROLE AS A NET CARBON SOURCE OR SINK. THE METHODS DEVELOPED IN THIS PROJECT TO CHARACTERIZE CARBON WILL RESULT IN PARAMETERS THAT ARE RELEVANT NOT ONLY TO CARBON MONITORING BUT FOR MONITORING OCEAN ACIDIFICATION AS WELL. COASTAL AND OCEAN ACIDIFICATION IS OF CONCERN IN THE GULF OF MAINE REGION; HENCE WE WILL COLLABORATE WITH STAKEHOLDERS TO ENSURE THE SCIENCE OUTPUTS OF THIS PROJECT ARE WHAT ARE REQUIRED BY THEIR NETWORK OF STATE AND FEDERAL RESOURCE MANAGERS AND INDUSTRY PARTNERS. THIS PROJECT ALIGNS WITH KEY FINDINGS AND RECOMMENDATIONS FROM THE SECOND STATE OF THE CARBON CYCLE REPORT AS WE WILL (1) EXPAND THE GNATS PROGRAM BY CREATING REMOTE SENSING METHODS TO CHARACTERIZE THE EXCHANGE OF CARBON AND EXTEND THIS UNDERSTANDING ACROSS THE WHOLE REGION (2) SYNTHESIZE OBSERVATIONS FROM ALL FOUR CARBON POOLS AND KEY FLUX TERMS EXCHANGING CARBON ACROSS THE SYSTEM AND (3) PROVIDE DATA PRODUCTS ESSENTIAL FOR MONITORING OCEAN ACIDIFICATION A NEED FOR STAKEHOLDERS AROUND THE GULF OF MAINE.