Aspects of the biological carbon pump in the Atlantic sector of the Arctic: Aggregation, vertical flux and pelagic-benthic coupling

• Main Author: Bodur, Yasemin V.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UiT The Arctic University of Norway 2024
• Subjects: Arctic shelves; Arctic Ocean; benthos; Barents Sea; Northeast Greenland; fjord; carbon cycle; carbon export; particulate organic matter; DOKTOR-002; Arctic; Greenland; Arktis; Arktis*; Climate change; Sea ice
• Online Access: https://hdl.handle.net/10037/33778

The biological carbon pump (BCP) is a major component of earth’s biogeochemical cycle. In the Arctic, increasing air temperatures, declining sea-ice cover, and increasing influence of boreal water masses and coastal runoff lead to changes in Arctic ecosystems, with consequences for the BCP. To get a holistic understanding of the BCP, it is important to integrate findings from disciplines that tackle different aspects of its functioning and possible response to climate change. In this thesis, the results from a benthic study on the Northeast Greenland shelf, a seasonal vertical flux study in the northwestern Barents Sea, and aggregation experiments in a sub-Arctic fjord are integrated to get a holistic understanding of some mechanisms of the BCP and pelagic-benthic coupling in the Arctic. The key findings of this thesis are: 1) on the Northeast Greenland shelf, benthic ecosystems depend on organic matter sinking from the pelagic, and pelagic-benthic coupling might have weakened since the 1990s; 2) in the northwestern Barents Sea; the composition of vertical flux between spring and summer differ highly from each other, with fresh, Chlorophyll-a-rich sinking particles dominated by diatoms during spring, and more regenerated particles sinking during summer, dominated by fecal pellets and flagellates. The efficiency of vertical flux is lower in summer compared to spring; 3) aggregation of dissolved organic matter (DOM) can be an important contributor to the particle pool, and this contribution changes seasonally, being higher in summer compared to spring. Integrating the findings of this thesis, some mechanisms of the BCP are summarized and pelagic-benthic coupling across different Arctic shelves are compared, concluding that the BCP will probably respond individually to climate change on the different Arctic shelves due to a range of mechanisms that control the BCP differently on regional levels. Den biologiske karbonpumpen er viktig for verdens biogeokjemiske syklus. I Arktis, økende lufttemperatur, avtagende ...