Iron and Manganese Impacts on the Future of Southern Ocean Ecosystems (Iron-Man)
Lead Research Organisation:
University of Liverpool
Department Name: Earth, Ocean and Ecological Sciences
Abstract
Context
The Southern Ocean plays a critical role in the Earth system. It hosts emblematic components of global biodiversity that motivate international conservation efforts. It is also the flywheel of the ocean circulation and climate system, where it plays a critical role in the carbon sequestration and supplies nutrients to lower latitudes where they support global productivity. These key ecosystem services are supported by the activity of photosynthetic phytoplankton and zooplankton that underpin food-webs and biogeochemical cycling.
We need accurate climate-model projections to assess the response of Southern Ocean ecosystems and biogeochemical cycles to climate change. But our best models cannot even correctly reproduce the direction of ongoing change. This suggests fundamental problems with projections, undermining efforts to protect and conserve ecosystems and lowering confidence in our understanding of how carbon and nutrient cycling will respond, both in the future and in the geological past. Iron-Man will develop a new paradigm that integrates the processes regulating Southern Ocean productivity by addressing critical knowledge gaps. This is urgent given the rapid ongoing changes to the region and the timescales of policy action that require robust science.
Challenge we address
Over past decades, extensive research has focused on the role of the micronutrient iron (Fe) in the Southern Ocean. However, recent work, spanning observations, experiments and models (mostly led by our team), now shows that accounting for manganese (Mn) as a limiting nutrient and the associated unique ecophysiology of the resident phytoplankton community is also critical to the ecological-biogeochemical function of the Southern Ocean. Importantly, these issues are neglected by current models.
Iron-Man is focused on unravelling how the supply and cycling of Fe and Mn affects the net primary productivity (NPP) and biomass of Southern Ocean ecosystems. In doing so, we will deliver 'fit for purpose' assessments of how future change will affect this critical system.
Aims and objectives
We have assembled a team of world leading scientists, operating across multiple disciplines, using state-of-the-art observational, experimental and modelling tools in an integrated and co-designed manner. Iron-Man must address three questions:
1. How the relative supply of Fe and Mn varies to set the resource limitation regime?
2. How phyto- and zoo-plankton in different regions respond to changes in Fe and Mn?
3. Whether integrating Mn and regional ecology alters future projections?
These are mapped onto three objectives:
1. Quantify the relative supply and abiotic recycling and removal of Fe and Mn to the upper ocean varies in different regimes, using ship-based and autonomous platforms.
2. Assess biological cycling of Fe and Mn, alongside the adaptive and acclimatory responses via integrated measurements across natural gradients and manipulative experiments.
3. Produce improved model projections of NPP and ecological change in the Southern Ocean and test the importance of newly identified knowledge gaps.
Potential applications and benefits
International experts acting as partners will maximise our ability to upscale and engage stakeholders with our results. We focus specifically on key international initiatives (e.g. CCAMLR, CMIP7 etc) and science-to-society challenges, including co-financing of stakeholder facing events and outputs throughout the project duration. In this way, Iron-Man will make critical contributions to the scientific knowledge base around the response of the Southern Ocean in a changing climate, but also make a difference by translating science for the policy makers grappling with a rapidly changing system.
The Southern Ocean plays a critical role in the Earth system. It hosts emblematic components of global biodiversity that motivate international conservation efforts. It is also the flywheel of the ocean circulation and climate system, where it plays a critical role in the carbon sequestration and supplies nutrients to lower latitudes where they support global productivity. These key ecosystem services are supported by the activity of photosynthetic phytoplankton and zooplankton that underpin food-webs and biogeochemical cycling.
We need accurate climate-model projections to assess the response of Southern Ocean ecosystems and biogeochemical cycles to climate change. But our best models cannot even correctly reproduce the direction of ongoing change. This suggests fundamental problems with projections, undermining efforts to protect and conserve ecosystems and lowering confidence in our understanding of how carbon and nutrient cycling will respond, both in the future and in the geological past. Iron-Man will develop a new paradigm that integrates the processes regulating Southern Ocean productivity by addressing critical knowledge gaps. This is urgent given the rapid ongoing changes to the region and the timescales of policy action that require robust science.
Challenge we address
Over past decades, extensive research has focused on the role of the micronutrient iron (Fe) in the Southern Ocean. However, recent work, spanning observations, experiments and models (mostly led by our team), now shows that accounting for manganese (Mn) as a limiting nutrient and the associated unique ecophysiology of the resident phytoplankton community is also critical to the ecological-biogeochemical function of the Southern Ocean. Importantly, these issues are neglected by current models.
Iron-Man is focused on unravelling how the supply and cycling of Fe and Mn affects the net primary productivity (NPP) and biomass of Southern Ocean ecosystems. In doing so, we will deliver 'fit for purpose' assessments of how future change will affect this critical system.
Aims and objectives
We have assembled a team of world leading scientists, operating across multiple disciplines, using state-of-the-art observational, experimental and modelling tools in an integrated and co-designed manner. Iron-Man must address three questions:
1. How the relative supply of Fe and Mn varies to set the resource limitation regime?
2. How phyto- and zoo-plankton in different regions respond to changes in Fe and Mn?
3. Whether integrating Mn and regional ecology alters future projections?
These are mapped onto three objectives:
1. Quantify the relative supply and abiotic recycling and removal of Fe and Mn to the upper ocean varies in different regimes, using ship-based and autonomous platforms.
2. Assess biological cycling of Fe and Mn, alongside the adaptive and acclimatory responses via integrated measurements across natural gradients and manipulative experiments.
3. Produce improved model projections of NPP and ecological change in the Southern Ocean and test the importance of newly identified knowledge gaps.
Potential applications and benefits
International experts acting as partners will maximise our ability to upscale and engage stakeholders with our results. We focus specifically on key international initiatives (e.g. CCAMLR, CMIP7 etc) and science-to-society challenges, including co-financing of stakeholder facing events and outputs throughout the project duration. In this way, Iron-Man will make critical contributions to the scientific knowledge base around the response of the Southern Ocean in a changing climate, but also make a difference by translating science for the policy makers grappling with a rapidly changing system.
