Award: OCE-2048774

Dissolved metals have an important role as micronutrients that influence the marine biota. Of these metals, cobalt is one of the scarcest elements and is strongly influenced by both nutrient uptake processes in the upper water column and scavenging removal processes in the mid-water and deep ocean. There is growing evidence of cobalt's importance within marine biological processes where different chemical forms of cobalt have been observed to influence primary productivity. Cobalt is used as the metal at the center of the vitamin B₁₂, making it central to the nutrition of marine ecosystems.

In this study, using samples collected from the GEOTRACES GP17 OCE and GP17 ANT expeditions, full depth cobalt distributions in the Pacific and Southern Oceans were generated. These sections revealed nutrient-like behavior in the oligotrophic Pacific, versus hybrid-scavenged type behavior south of the polar front. There were labile cobalt signals that corresponded to hydrothermal and export flux-related processes. There were also large changes in cobalt and phosphate stoichiometry throughout the ocean basin. Within the Amundsen Sea, depletion of cobalt was observed in the upper water column due photosynthetic activity. In addition, sedimentary and glacial signals were detected, implying sources of cobalt from these processes. Metaproteomic analyses were conducted that provide insight into the influences of environmental factors on microbial populations, including nutrient limitation processes particularly at the biogeochemical province interfaces, and those data are being incorporated into the Ocean Protein Portal for use in research and education. 

Last Modified: 04/11/2025
Modified by: Mak A Saito