My name is Josie Robinson and I’m excited to be a facilitator on the “Exploring our Oceans” MOOC. I’m just entering the 3rd year of my PhD at the National Oceanography Centre, Southampton, where I’ve been looking at ocean iron fertilisation.
By iron fertilisation I mean the addition of iron, which is a vital ingredient for life along with other essential nutrients, such as nitrogen and phosphorus. Phytoplankton are microscopic marine plants that form the base of the food chain across the world’s oceans, but they can only grow where nutrients are available to them. Large parts of the ocean lack either nitrogen and/or phosphorous, but the focus of my PhD is where phytoplankton growth is limited by the lack of iron, most notably the Southern Ocean. So far in my PhD I have looked at artificial iron fertilisation for the purposes of geoengineering and also natural iron fertilisation, occurring around Southern Ocean islands.
Geoengineering is a controversial last resort if we can’t get our CO2 emissions under control and reach a critical tipping point with our climate. It would involve the manipulation of nature to avert the worst of climate change. Proposed geoengineering methods range from orbiting space mirrors, to simply pumping CO2 into the ground. The aim of ocean iron fertilisation would be to increase the amount of CO2 absorbed by the ocean by artificially enhancing natural processes. This can be done by growing photosynthesising marine phytoplankton in areas it can’t ordinarily grow because of the lack of iron. Whether or not this would work has been an interesting topic for debate in the scientific community and was the focus of my first years study.
Natural iron fertilisation occurs around and down stream of landmass. Iron is found in the mud surrounding islands such as South Georgia and Crozet in the Southern Ocean and is scoured out of the sediment by ocean currents. As a result we see phytoplankton blooms around these islands, in an otherwise baron Southern Ocean. By studying this natural iron fertilisation we can learn a lot about the intricate interactions between the ocean iron and carbon cycles.
In order for me to study ocean iron fertilisation I use a simulation of the ocean, called the NEMO model, which I can experiment with to try and further our understanding of the real world ocean. I work with the … team at the National Oceanography Centre who are continually striving to improve the models representation of the ocean, capturing as much detail as possible and also the changes occurring during the passage of time and changing climate.
I hope you enjoy the Exploring our Oceans MOOC, and I am really looking forward to getting to know you and what interests you about the ocean.