Mapping the Dynamics of Particulate Organic Carbon: Satellite Observations of Coastal to Shelf Variability in the Northeastern Gulf of Mexico: Mapping the Dynamics of Particulate Organic Carbon

Understanding the distribution and dynamics of particulate organic carbon (POC) is essential for assessing marine ecosystem health and carbon cycling. This study analyzed the spatial and temporal variability of POC in the northeastern coastal waters to the continental shelf of the Gulf of Mexico using satellite remote sensing data within the United States. Over 19 years, surface water POC averaged 155.57 ± 13.56 mg/m 3 , with values ranging from 127.17 to 188.81 mg/m 3 , and an insignificant annual increase of 0.78 mg/m 3 . Spatial analysis across five transects (T1–T5) revealed significant variability, with mean POC values ranging from 125.19 mg/m 3 (T5) to 169.23 mg/m 3 (T1) and standard deviations from 136.76 mg/m 3 (T5) to 193.64 mg/m 3 (T3). Transects near the estuaries of the Mississippi and Atchafalaya Rivers (T1–T4) exhibited elevated POC due to terrestrial organic matter and nutrient inputs, while the west Florida shelf (T5) had lower concentrations. Seasonal variations were influenced by wind-driven currents, sea surface temperature (SST), and mesoscale eddies. Analysis of Variance showed a significant seasonal effect on POC concentrations (F-value: 96.51, p