Interannual variability in biogeochemical cycling around the island of South Georgia: insights from a new database of macronutrients from productive regions of the Southern Ocean

A key challenge in understanding carbon cycling in the Southern Ocean is disentangling long-term responses from significant spatial and temporal variability in physical and biogeochemical parameters. As such, there is a critical need for regional long-term observations for the model validation and testing needed for a better mechanistic understanding of primary production drivers. We present a new macronutrient data product for the South Atlantic sector of the Southern Ocean, including depth profiles and underway surface measurements of nitrate, nitrite, ammonium, phosphate, silicic acid, temperature and salinity, collected from 1980 to 2009 and covering most months of the year (https://doi.org/10/h3qr). Using this data product, we explore the differences in shallow and deep-water nutrients around the island of South Georgia that are observed between years. We discuss both the biological and physical driving mechanisms behind this variability, which are interconnected with climate feedbacks. The new data product provides an unprecedented view of biogeochemical cycling in biologically productive regions of the Southern Ocean across a critical period in recent climate history, and illustrates the importance of building these scientifically valuable and FAIR (findability, accessibility, interoperability, and reusability) observational datasets.