Exploring the Relationship Between Diatom Productivity and AMOC Variability Over the Past 40,000 Years: records from the Drake Passage and the Subtropical North Atlantic

Diatoms are photosynthetic siliceous algae and major contributors to the marine biological pump. Their fossil record provides insight into the environmental conditions that alter its performance, particularly during major climatic events. Defining the past oceanographic settings that favored diatom productivity improves the understanding of the biological pump efficiency and can ultimately enhance climate projection accuracy.

Nowadays, due to its rich silica waters, the Southern Ocean (SO) offers optimal conditions for diatom production, whereas diatoms are in general poorly or not even preserved in the North Atlantic sediments. During periods when the Atlantic Meridional Overturning Circulation (AMOC) was disrupted, such as during Heinrich events, the adjustment of ocean currents may have allowed silica-rich waters from the Southern Ocean to reach the North Atlantic, enhancing diatom productivity. Diatoms records for the last 40 000 years from the subtropical North Atlantic and the Drake passage will be compared to evaluate the possible leaking of southern sourced water and its impact on the efficiency of the biological pump will be discussed.