Antarctic ocean carbon absorption study reveals manganese mystery affecting climate predictions
Climate and Ecosystem Concerns: The Southern Ocean absorbs about 40% of human carbon dioxide emissions, aided by phytoplankton and krill. However, climate change threatens this process, with declining krill populations and uncertain phytoplankton growth challenging carbon absorption predictions.
IronMan Project Goals: Led by Alessandro Tagliabue, the £4m IronMan project aboard the RRS Sir David Attenborough aims to study the roles of iron and manganese in phytoplankton growth and carbon cycling – elements overlooked in climate models but potentially critical for global climate regulation.
Extreme Sampling Challenges: Researchers face harsh Antarctic conditions while measuring trace metals at concentrations as low as a teaspoon in the River Thames. They use specialized titanium equipment, clean labs, and advanced techniques to avoid contamination and gather over 1000 litres of seawater samples.
Broader Scientific Impact: The project combines chemical, biological, and genetic analyses to understand nutrient recycling, organism metabolism, and gene expression. Findings could reshape climate models and reveal how rapid sea ice loss and ecosystem changes affect global climate resilience.
Blue Whales and Krill in the Southern Ocean: In the Southern Ocean near Antarctica, blue whales, the largest animals on Earth, have recovered since hunting reduced their numbers. BAS researchers measure whale numbers and krill consumption, with plans to study the impact of climate change on krill populations.
Climate Models and Nutrient Absorption: Climate models predict that phytoplankton should prosper as temperatures rise, acting as a brake on global heating. However, observations show the opposite, indicating that creatures in the Southern Ocean may absorb less of humanity's carbon emissions as the planet heats up.
Manganese Mystery: Iron has been considered the key nutrient driving phytoplankton growth, but manganese could be equally critical in many parts of the ocean. The IronMan project aims to explore the role of manganese in the Southern Ocean, considering the unique adaptations of Antarctic organisms.
Measuring Trace Metals in Extreme Conditions: Researchers use specialized equipment, including a rosette with Niskin bottles, to measure trace metals in the sea. They must contend with harsh Antarctic conditions, including strong winds and freezing temperatures, to ensure accurate measurements.
Clean Lab Procedures: In a clean lab, researchers filter out particles larger than 0.2µm from seawater, separating living creatures from dissolved elements. This process is laborious and requires careful handling to prevent contamination.
Genetic Analysis and Nutrient Recycling: The project will also study the creatures filtered out, including zooplankton and krill, to understand nutrient recycling. Researchers will measure excretion to see if it recycles nutrients, with implications for the food chain and carbon absorption.
Algal Enzymes and Manganese Recycling: Algae use enzymes containing iron and manganese for photosynthesis and metabolism. The IronMan project aims to understand how algae and consumers use these elements, with a focus on manganese recycling.
Psychological Challenges and Ship Operations: The project faces psychological challenges, with 40 people trapped in a metal ship for seven weeks. Researchers must also contend with equipment malfunctions and the unpredictability of Antarctic conditions, including sea ice and icebergs, which can delay ship operations.
