Possible controls of particle flux in the Weddell Gyre

• Main Author: Geibert, Walter
• Format: Conference Object
• Language: unknown
• Published: 2020
• Subjects: Weddell Sea
• Online Access: https://epic.awi.de/id/eprint/53170/; https://hdl.handle.net/10013/epic.819ef93f-531b-44b2-a8ca-b1073ee3dfe9

Seen from space, the Weddell Gyre (WG) is a high chlorophyll region. The controls of biological productivity in the WG differ from most other oceanic regions. The major nutrients nitrate, phosphate and silicate occur in abundance and are usually not limiting. Instead, trace elements and light availability control plankton blooms, and ice cover modulates local concentrations. The ultimate sources of trace elements that can support the high productivity have still not been identified- the deep WG has amongst the lowest iron concentrations of any part of the ocean. Also, the fate of the surface blooms is not clear. Following export from the surface, shallow remineralization seems to dissolve most organic material, and the abyssal Weddell Sea sediments contain almost no trace of the surface productivity. Sedimentation rates are on the order of millimeters per kiloyear. This contribution will follow some possible reasons for the anomalous characteristics of the biogeochemistry of the WG.