As we approach the Azores it is time to update the Challenger Society on our progress on the FRidge cruise (@Fridge_GA13). We have a whole host of old and new Challenger members on board the RRS James Cook including Honorary Life Member Malcolm Woodward who you will hear from later this month.
We are sailing south from the Azores along the mid-Atlantic Ridge sampling all of the known hydrothermal vent sites along the way as well at carrying out full ocean casts to strict GEOTRACES protocols to put these data into the global framework emerging from this exciting international program (http://www.geotraces.org/)
Al Tagliabue (Challenger Fellow 2016) is Chief Scientist and is leading this first ever nano-molar level evaluation of how the ridges impact on seawater trace metal distributions and their cycling. Al has pulled together a talented multi-national team crossing disciplinary boundaries from chemists to physicists to biologists. We have scientists from the UK, Ireland, US, France, Spain, Malaysia and China on board and we are all working together to track the hydrothermal inputs along the mid-Atlantic Ridge.
Maeve Lohan (Challenger Fellow 2008) co-wrote the proposal that funded this expedition. Her talent is measuring tiny amounts of metals in seawater. We are measuring dissolved iron and specifically the reduced iron on board as indicators of hydrothermal vents and are already seeing exciting results. We have to work in ultra-clean conditions, sampling in a clean container and enclosing the scientists inside a bubble of polythene to ensure nothing contaminates the samples. By being really careful we can measure down to picomolar levels – which means 1 part in a million, million – an amazing thing to be able to do on a rusty ship.
Azyyati Aziz joins us from the Universiti Malaysia Terengganu and is funded by the Partnership for Observation of the Global Oceans to join the expedition. She is responsible for undertaking the oxygen analyses on board which are crucial for interpreting the influence of organic matter regeneration on trace metal distributions and of course for calibrating the CTD sensor.
And why am I here? I’m collaborating with Koichi Nakamura from the National Institute of Advanced & Industrial Science & Technology in Japan who has provided us with one of his Eh sensors to deploy on the CTD frame. This detector allows us to sniff out the reduced chemical species such as hydrogen sulphide associated with the vents and thereby track the plume dispersion from each site. The Eh sensor is by far the most sensitive method we have for tracking plumes – the particle and temperature anomalies are difficult to pick out and surprisingly ephemeral in some areas where we know that vents are pumping out hot fluids on the seafloor. Once we have locked into the plume signal we work with our physics colleagues led by Challenger member Ric Williams to understand the mixing and dispersion of the signal into the deep ocean.
We have a great team of people here and over the next month I’ll persuade several of them to write for the Captain’s Blog and all of them to be Challenger Society members!
A very Happy New Year to all and hope to see many of you at our biennial conference in Newcastle in September 2018.
Professor Rachel Mills is the President of the Challenger Society for Marine Science and Dean of the Faculty of Natural and Environmental Sciences at the University of Southampton.