The aim of our research - which relates to the SURETY project - is to understand the impact of natural marine and terrestrial organic matter (OM) in the sea on the enrichment of SML in OM, and most importantly to assess the role of SML as a barrier to gas exchange processes, CO2, between the sea and the atmosphere. Optical surveys of the European Arctic surface waters were conducted during three polar research cruises of RV Oceania, in 2018, 2019 and 2021. Sampling of the surface microlayer (SML) and subsurface water (ULW, 1m) allowed us to calculate the enrichment factor (EF) of the SML in organic matter (OM) and in phytoplankton pigments - based on absorption and fluorescence measurements and HPLC analyses of the collected samples. Additionally, the analysis of absorption and fluorescence indices (E2:E3, SR, aCDOM(l), fluorescence intensities of the main chromophoric fractions of DOM in the sea: A, C, M and T, the ratio (M+T)/(A+C), HIX index, composition and concentration of phytoplankton pigments) allow to describe the properties of organic molecules. The analyses of EEMs of sea samples reveals that: (1) concentration of OM fractions - both in the SML and SS – depend on a study-region and a year; (2) enrichment factor of fluorescing fractions of OM yielded higher values in M and T than A and C components. The results reveal the relationships between phytoplankton and the concentration of various optically active organic matter components in the surface layer (0-1m) and microlayer (0-1mm).

Primary Presenter: Violetta Drozdowska, Institute of Oceanology (drozd@iopan.pl)

Authors:

Violetta Drozdowska, IO PAN  (drozd@iopan.pl)

Joanna Ston-Egiert, IO PAN  (aston@iopan.pl)

Jacek Piskozub, IO PAN  (piskozub@iopan.pl)

Iwona Niedźwiecka, IO PAN  (iwrobel@iopan.pl)

Małgorzata Kitowska, IO PAN  (gosiak@iopan.pl)

Piotr Markuszewski, IO PAN  (pmarkusz@iopan.pl)

Przemysław Makuch, IO PAN  (makuch@iopan.pl)