POSTER SESSION 3
15:30–17:30, Wednesday, September 16
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1186 | POSTER 175
PHYSICAL CONTROLS ON OCEAN COLOR BIOGEOCHEMISTRY: A 27-YEAR SATELLITE STUDY OF CHLOROPHYLL, PARTICULATE ORGANIC CARBON DYNAMICS
Chlorophyll-a (Chl-a) and particulate organic carbon (POC) are complementary indicators of biogeochemical variability in the Baltic Sea, an optically complex system with strong hydrographic gradients. Chl-a is widely used as a proxy for phytoplankton biomass, whereas POC represents the total carbon pool, including phytoplankton, detritus, and mineral organic matter. The POC:Chl-a ratio thus serves as an integrative indicator of plankton variability and carbon partitioning. Using a 27-year satellite dataset, we quantified the spatio-temporal variability of POC, Chl-a, and their ratio across the Baltic Sea. Distinct seasonal patterns were observed, with spring and summer phytoplankton blooms characterized by elevated Chl-a and relatively low POC:Chl-a ratios. Mean Chl-a concentrations exhibited a summer maximum (2.7 mgm–3), whereas high POC concentrations in fall (309 mgm–3). This seasonal decoupling accompanied increased POC:Chl-a ratios indicates enhanced detrital accumulation and cyanobacterial dominance under stratified conditions. Significant interannual variability and regionally heterogeneous trends were detected across the sub-basins. Variability in POC and POC:Chl-a was predominantly controlled by physical and optical drivers, including photosynthetically active radiation (PAR), sea surface temperature (SST), wind, salinity, and mixed layer depth. PAR is the primary driver, accounting 38% of variance to Chl-a, 54% to POC, and 51% to the ratio variability across the area. SST exerted a regionally significant influence, particularly in the central Baltic, with a pronounced effect in the Gotland Basin. These findings underscore the importance of multi-parameter satellite observations to resolve ecosystem dynamics and emphasize the sensitivity of carbon cycling to climate-driven changes in light and thermal regimes.
Chandanlal Parida, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), [email protected]
Madhusmita Dash, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), [email protected]
Bronwyn Cahill, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
