Bio-optical characterization and light availability parameterization in Uummannaq Fjord and Vaigat-Disko Bay (West Greenland)

This study investigated the bio-optical conditions of Uummannaq Fjord and Vaigat Disko Bay, two neighboring, semi-enclosed coastal systems in West Greenland. Though close to each other, the systems differ in their hydrographic structure influencing the bio-optical conditions and, subsequently, the biological activities. Both systems showed high inorganic suspended particulate matter (SPMi) concentrations near river runoff or meltwater influxes (max. of 15.28 mg L-1 at the surface) and low colored dissolved organic matter (aCDOM@350nm, < 1.50 m(-1)) abundance throughout the systems. High chlorophyll levels (as an indicator of phytoplankton biomass) were measured in the Vaigat (max. of 11.44 Kg L-1), which represents the outflow arm of Disko Bay. Light penetration depth as indicated by the 1 % depth of photosynthetically available radiation (PAR) was dominated by chlorophyll and SPMi alike, ranging from 12.2 to 41.2 m. Based on these characteristics, an effective two component parameterization for the diffuse attenuation coefficient kpAR was developed in order to model light penetration depth as a relevant factor for bio-optical studies in Arctic environments under glacial meltwater influence.