Augmenting estuary monitoring from space: New retrievals of fine-scale CDOM quality and DOC exchange
Year: 2025
Type: article
Abstract: • New MSI and OLI algorithms are developed to retrieve CDOM, spectral slope, and DOC. • Random forest regression performed best, with R rs and month as input features. • Algorithms applied show strong urban estuary seasonality in CDOM amount and quality. • Post-storm and low-tide imagery highlight terrigenous and wastewater CDOM inputs. Fueled by both terrestrial and marine inputs, estuaries worldwide are important biogeochemical reactors, strongly susceptible to natural and anthropogenic, episodic, or compounding disturbances. Satellite sensors provide a unique vantage point to capture estuarine processes at scales not feasible with in situ sampling alone; yet, remote sensing retrievals of estuarine biogeochemical dynamics remain challenging. Here, we developed new algorithms for high spatial resolution satellite retrievals of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC)—two key indicators of estuarine water quality and biogeochemical state. CDOM algorithms were optimized for Long Island Sound—one of the world’s most heavily urbanized estuaries—and included retrievals of CDOM absorption at 300 nm (a CDOM (300)), a proxy for CDOM amount, as well as absorption spectral slope in the 275–295 nm range (S 275-295 ), a proxy for CDOM quality. Algorithms were specifically designed for Sentinel-2A/2B MSI and Landsat-8/9 OLI, a constellation of high spatial resolution sensors that provides coverage of the most dynamic zones for estuary exchange. MSI and OLI a CDOM (300) and S 275-295 were most successfully retrieved using machine learning (ML) random forest regression, with the input features of remote sensing reflectance bands, band ratios, and month of acquisition. Satellite retrieval of DOC concentrations relied on a tight, widely applicable relationship between a CDOM (300) and S 275-295 . Timeseries generated for Long Island Sound, and its most impaired water quality region in the Western Narrows, revealed strong CDOM spatiotemporal dynamics associated with seasonal freshwater discharge, tidal wetland carbon export, recurring wastewater pollution, and episodic extreme events. Results highlight the value of these new ecosystem-scale observations for enhanced, sustainable estuarine management.
Authors: Alana Menendez, Maria Tzortziou
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,550
Funders: National Aeronautics and Space Administration, Connecticut Department of Energy and Environmental Protection, NOAA Center for Earth System Sciences and Remote Sensing Technologies, National Oceanic and Atmospheric Administration, New York Sea Grant, State University of New York, McCormick Science Institute
Awards: INTERTWINED AT THE LAND-WATER INTERFACE HUMAN POPULATIONS COASTAL WETLANDS AND ESTUARIES SHAPE THE ECOLOGICAL CHARACTERISTICS OF BOTH THE COASTAL TERRESTRIAL AND AQUATIC LANDSCAPE. YET THESE SYSTEMS HAVE BEEN THE FOCUS OF RESEARCH PRIMARILY DRIVEN BY DISCIPLINARY OBJECTIVES AND METHODOLOGIES. AS A RESULT STUDIES OF TERRESTRIAL AND AQUATIC PROCESSES IN WETLAND-ESTUARY SYSTEMS HAVE REMAINED LARGELY DISCONNECTED. URBAN DEVELOPMENT POPULATION SHIFTS AND ANTHROPOGENIC POLLUTION HAVE BEEN SHOWN TO AFFECT COASTAL WETLAND BIODIVERSITY BIOGEOCHEMISTRY VEGETATION CHARACTERISTICS AND GEOMORPHIC STABILITY. THE LINKAGES HOWEVER BETWEEN THESE HUMAN- INDUCED ALTERATIONS OF WETLAND ECOLOGICAL CHARACTERISTICS AND ESTUARINE ECOLOGICAL PROCESSES AND VULNERABILITY TO COASTAL HAZARDS REMAIN LARGELY UNKNOWN AND DRIVE THE PROPOSED RESEARCH. THIS PROPOSAL BRINGS TOGETHER AN INTERDISCIPLINARY TEAM TO ADDRESS FOUR KEY SCIENCE OBJECTIVES THAT EXPLICITLY LINK COASTAL URBAN LANDSCAPES WETLANDS AND ESTUARIES: (I) MAP TIDAL MARSH AREA EXTENT AND PLANT COMMUNITY COMPOSITION IN A HEAVILY URBANIZED ESTUARY ASSESS THE STATUS AND CHANGE IN THESE WETLAND ECOLOGICAL CHARACTERISTICS OVER MULTI-DECADAL TIMESCALES AND EXAMINE LINKAGES TO COASTAL POPULATION CHANGE AND ASSOCIATED URBAN DEVELOPMENT. THIS WILL BE USEFUL FOR ASSESSING BOTH DEGRADATION OF WETLAND HABITATS (E.G. EXPANSION OF INVASIVE PHRAGMITES) AS WELL AS EFFECTIVENESS OF RECENT RESTORATION EFFORTS.(II) ASSESS HOW SHIFTS AND LANDSCAPE VARIABILITY IN WETLAND ECOLOGICAL CHARACTERISTICS (I.E. MARSH EXTENT AND PLANT COMMUNITY COMPOSITION) INFLUENCE THE QUANTITY AND QUALITY OF NUTRIENTS AND ORGANIC MATTER EXCHANGED BETWEEN TIDAL MARSHES AND ADJACENT ESTUARINE WATERS.(III) QUANTIFY IMPACTS OF HUMAN-INDUCED ALTERATIONS IN WETLAND ECOLOGICAL CHARACTERISTICS AND WETLAND-ESTUARINE TIDAL EXCHANGES ON ESTUARINE ECOLOGY SPECIFICALLY ADDRESSING ESTUARINE WATER QUALITY ORGANIC MATTER CYCLING PLANKTON COMMUNITY COMPOSITION AND LINKING TO DEVELOPMENT OF HYPOXIC CONDITIONS OCCURRENCE OF BLOOM OUTBREAKS AND CHANGE IN FISHERIES HABITAT.(IV) DETERMINE POTENTIAL INFLUENCES OF FUTURE NATURAL AND ANTHROPOGENIC PRESSURES ON THESE PROCESSES UNDER VARIOUS ENVIRONMENTAL AND HUMAN POPULATION CHANGE SCENARIOS. WE WILL ADDRESS THESE OBJECTIVES THROUGH DEVELOPMENT OF NEW REMOTE SENSING TOOLS FOR CHARACTERIZATION OF TIDAL MARSH AREA EXTENT VEGETATION COMMUNITIES AND INUNDATION REGIMES (SENTINEL-1 SAR PALSAR PALSAR-2 LANDSAT SENTINEL-2 ASTER) AND ADVANCED RETRIEVALS OF ESTUARINE BIOLOGICAL AND BIOGEOCHEMICAL PROCESSES (SENTINEL-2 LANDSAT HICO MERIS MODIS VIIRS). REMOTE SENSING WILL BE INTEGRATED WITH MULTI-DISCIPLINARY ECOLOGICAL PALEOECOLOGICAL AND SOCIOECONOMIC DATASETS SPATIAL ECONOMETRIC MODELS OF POPULATION GROWTH AND A NOVEL COUPLED HYDRODYNAMIC-PHOTO-BIOGEOCHEMICAL MODEL THAT WE SPECIFICALLY DESIGNED FOR THE MARSH- ESTUARINE CONTINUUM. HUMAN-IMPACTED TIDAL WETLANDS ARE UBIQUITOUS AND RESULTS FROM OUR STUDY AND THE DEVELOPED REMOTE SENSING AND MODELING TOOLS WILL BE BROADLY APPLICABLE TO VARIOUS URBAN-MARSH-ESTUARINE SYSTEMS., G3152953972, G3379449628, G3827801342, G5390910397
OpenAlex ID: W4407865247