UK_2026_Sir David Attenborough_IronMan

This project will deliver improved understanding of how key resources regulate primary production across the Southern Ocean to better constrain future impacts in this critical region for global biodiversity and carbon cycling. This will achieved by combining chemical and biological observations and experiments through the key Southern Ocean biological regimes that are closely tailored to deliver necessary constraints on the only suitable global ocean model that will upscale findings and deliver improved projections. The assembled team is unique in being capable to deliver this multi-disciplinary insight. This is important because confidence in projections of future Southern Ocean net primary production underpins regional biodiversity, ecosystem structure and carbon cycling – critical information for those seeking to manage and mitigate climate change impacts, including the development of marine protected areas. Primary production in the Southern Ocean is considered to the dominantly regulated by iron and climate models project increasing future primary production with relatively high across-model confidence. However, new findings from a combination of ocean survey, autonomous platforms, experimental and modelling work highlight three key complicating issues: (1) Climate models neglect the role of the micronutrient manganese, which has been shown to also be important in limiting Southern Ocean primary production. (2) The historical trends in Southern Ocean iron limitation are incorrectly represented by climate models and (3) Antarctic organisms possess unique adaptations to their environment and may therefore need to be explicitly represented by climate models. Iron and manganese are both predominantly associated with photosynthesis and the relative demand primary producers have for one resource over the other is critical. Unfortunately, the role of different iron and manganese supply and cycling pathways in the Southern Ocean is poorly constrained and regional acclimatory responses are ignored, hindering a complete inclusion in the ocean component of global climate models used for future projections. Objective 1 (O1): Quantify how the relative supply and abiotic recycling and removal of Fe and Mn to the upper ocean varies through different SO regimes, using ship-based and autonomous platforms. Objective 2 (O2): Quantify variability in biological cycling of Fe and Mn, alongside the adaptive and acclimatory responses to environmental change, via in situ gradients and manipulative experiments. Objective 3 (O3): Deliver improved model projections of SO PP change and test the importance of knowledge gaps, using the new constraints from observational and experimental efforts.

https://nerc.marinefacilitiesplanning.com/programme/timeline#