Wide-spread Occurrence and Increasing Trend of Biogenic Aerosol Precursors in the Arctic Ocean Simulated by an Ocean Biogeochemical Model

• Main Authors: Zeising, Moritz, Oziel, Laurent, Gürses, Özgur, Hauck, Judith, Heinold, Bernd, Losa, Svetlana, Thoms, Silke, Pinxteren, Manuela van, Völker, Christoph, Zeppenfeld, Sebastian, Bracher, Astrid
• Format: Other/Unknown Material
• Language: unknown
• Published: Authorea, Inc. 2023
• Subjects: Arctic; Arctic Ocean; Barents Sea; Kara Sea; Canadian Archipelago; Fram Strait; Phytoplankton
• Online Access: http://dx.doi.org/10.22541/essoar.168332181.16821948/v1

Biogenic aerosol precursors from phytoplankton production can affect cloud properties, especially in remote regions such as the Arctic Ocean. Reliable estimates on variability and trend of these precursors are required as extensive measurements in the Arctic are still scarce. We present a setup of the coupled ocean biogeochemical model FESOM2.1-REcoM3 where we integrated dissolved carboxylic acid containing polysaccharides (PCHO) and Transparent Exopolymer Particles (TEP) to describe these precursors in the upper ocean. We define PCHO as one part of the excreted organic carbon, which can then aggregate to form larger particles, TEP. Compared to observations, the simulation provides a valid TEP estimate with mean concentrations of 200-400 µg C L-1 on the continental shelves and 10-50 µg C L-1 in the central basins (0-30 m depth range). Further, the simulation for 1990-2019 reveals a significant positive trend of TEP of 0.5-3 µg C L-1 yr-1 during July-September in the Amerasian Basin (+3.5% yr-1), the Canadian Archipelago (+1.2% yr-1) and the Kara Sea (+0.8% yr-1), in contrast to the eastern Fram Strait (-0.4% yr-1), the Barents Sea (-0.3% yr-1), and parts of the Eurasian Basin with a significant decrease of -0.5-2 µg C L-1 yr-1. Our study provides for the first time an integration of TEP formation, aggregation and remineralization processes into a global ocean biogeochemical model. This simulation assembles valuable data on biogenic aerosol precursors, and as such, fills a gap on which Earth System Models can greatly benefit to improve the understanding of aerosol feedbacks within the Arctic climate.