Posters

Poster Session 3, Wednesday,  October  5, 16:00–18:00

Poster 59

Variability of inherent optical properties of seawater in relation to the concentration and composition of suspended particulate matter in the fjords of western Spitsbergen

Inherent optical properties (IOPs) and characteristics of suspended particles in surface seawater samples were measured in summer of 2021 in four fjords of western Spitsbergen: Hornsund, Kongsfjord, Krossfjord, and Isfjord. The measured IOPs included the spectral absorption coefficients of suspended particulate matter and its phytoplankton and non-algal particulate components, as well as the spectral scattering and backscattering coefficients of particles. The particulate assemblages were characterized by measuring the concentrations of suspended particulate matter (SPM), particulate organic matter (POM), particulate inorganic matter (PIM), and phytoplankton pigments including chlorophyll-a (Chla). The Spitsbergen fjords exhibit high variability of characteristics of particulate assemblages and associated IOPs. We observed more than two orders of magnitude variation in SPM and particulate IOPs, and Chla varied from below the detection limit to more than 3 mg m -3 . The contribution of organic fraction to SPM varied from 5% to 45%, and the Chla/SPM ratio spanned more than three orders of magnitude with a maximum value of the order of 10 -3 . Our measurements of optical and particulate properties also demonstrate significant variability of SPM, POM, and PIM mass-specific scattering and backscattering coefficients of particles and the mass-specific absorption coefficient of non-algal particles. In addition, we examined the influences of changes in composition of suspended matter parameterized in terms of POM/SPM and Chla/SPM ratios on IOPs. The dataset from the Spitsbergen fjords also provided a basis to formulate spectral parametrizations of inherent optical coefficients which are representative of this Arctic marine coastal environment.

*Dagmara Litwicka, Institute of Oceanology Polish Academy of Sciences, [email protected], 0000-0002-6701-8067

Sławomir B. Woźniak, Institute of Oceanology Polish Academy of Sciences, [email protected], 0000-0001-9757-5553

Joanna Stoń-Egiert, Institute of Oceanology Polish Academy of Sciences, [email protected], 0000-0002-4274-8979

Dariusz Stramski, Marine Physical Laboratory, Scripps Institution of Oceanography, University of California San Diego, [email protected], 0000-0002-8518-072X