Call of Duty - Receiving a distress call

 By Lucie Munns

This week we were all reminded that RRS Discovery is more than just a research ship. On the open ocean, every vessel has a responsibility to play their part in the safety of the rest of the sea-going community.

Sampling activities at our first process station; Central Celtic Sea (CCS), were drawing to a close. All on board were starting to get into the swing of things. Most operations had run smoothly so far, including two pre-dawn sampling points, which at this time of year begin at 02.00 am!

At approximately 13.00 pm many scientists and technicians were on deck sampling seawater from the midday CTD; the piece of equipment which is deployed over the side of the ship to collect water from many different depths. Although sampling at CCS was not yet complete we noticed the ships engines rumble to life and the ship beginning to move. Soon after, Captain Jo appeared on deck with some somewhat startling news, at least for those of us who are not seasoned seamen.

RRS Discovery had received a distress call. The hull of an upturned vessel had been sighted from an aircraft, and we were in close vicinity and were required to respond immediately. The steam west to the site of the incident took approximately 3 hours, and it was all eyes on deck to keep a look out for anything unusual. Needless to say the atmosphere was tense, but the crew were incredibly calm and professional.

Cargo Ship and spotter plane look on as the boat from Discovery investigates
upturned hull.

When recovered Goose Barnacles indicate that the rusty old open boat has
clearly been at sea for a considerable time!

At around 16.00 we spotted a tiny brownish speck bobbing in the swell; the hull of a very small upturned boat. A light aircraft from the Irish coast guard was surveying from above, and a large container ship had reached the scene first, but neither had the means to move in for a closer look. 

With a readily deployable rib, RRS Discovery is better prepared than most vessels for the situation. Three brave crew members rose to the challenge of boarding the rib; 2nd Officer Vanessa, 3rd Engineer Angus and Petty Officer Willie. Watched anxiously by the rest of us they motored out to make an inspection, where to everyone’s great relief they found that the boat had clearly been adrift for quite some time, and was not a recent capsize. It was reddish-orange with rust, spattered with white bird poo, and hundreds of barnacles clung to its submerged surfaces. Some skilful manoeuvring by both the crew on the rib and on board the Discovery brought the old wreck alongside, and it was carefully winched aboard, in order that it would not cause an alarm to be raised in the future. The biologists among us ogled the stalked goose barnacles; beautiful yet slightly repulsive as their fleshy parts struggled and groped in vain for cool seawater. Meanwhile, the trace metal group shuddered at the amount of rust on the deck, and gave it a wide berth. 

The boat has been carefully stowed atop Alex and Chris’s container lab. They look forward to the stench of rot that will inevitably ensue if the sun decides to make an appearance.

SSB Cruise DY033: Leaving Southampton

This is first blog entry from Cruise DY033, which is the latest in the series of Shelf Sea Biogeochemistry (SSB) cruises. My name is Mark Moore and I am the principal scientist on this final pelagic focused cruise of the SSB programme.

We are all excited to see what has been happening since the last pelagic cruise in spring and will be looking forward to finding out how the characteristics of the water column have developed following the spring phytoplankton bloom, alongside performing a whole series of measurements and experiments aimed at developing a better understanding of what is going on in the post bloom summer period.

I was really impressed with how smoothly mobilisation for the cruise went.

The RRS Discovery leaving port in Southampton

Thanks to the hard work of all the scientists and crew, all the equipment was loaded, boxes unpacked and instruments set up in just 2 days, partly reflecting the fact that many of the people on board are now very well rehearsed having been on a series of these cruises. Indeed, I personally feel a bit like the newcomer, this being my first cruise within the SSB programme. So I am looking forward to finally being able to ‘get wet’ and be involved in the at sea work. The cruise is also a bit of a personal journey for me as we will be working in the Celtic Sea where I performed much of my PhD work (quite a few years ago now…).

Having left Southampton on Saturday evening (see picture), we have now transited down through the English Channel and are on route to our first working area around our array of moorings, many of which have been in place for more than 18 months collecting unique data which will form a central part of the programme. Although we already have a few underway systems running and recording data, the major science operations will commence early tomorrow with us adding some additional shorter duration moorings to the array alongside the deployment of some gliders.

Docked!

And that’s it.  A big thank you to all of you for all your hard work during the cruise and for making DY030 an extremely successful component of the SSB programme.

DY030 Team.Credit: Torben Stichel

Tracing metals

By Torben Stichel, University of Southampton

When Prof. Rachel Mills (Head of Department in Ocean and Earth Science, University of Southampton) asked me if I’m willing to help out on one of the Shelf Sea Biogeochemistry Programme’s benthic cruises and carry out some own research, I didn’t hesitate to say yes. I love the ocean, studying it, and before joining the University of Southampton as a Research fellow, I had already thought about the particular role of shelf seas in the global marine system.

In previous years I have put my focus on the deep ocean. I have been analysing trace metals in seawater to look at the big picture – how water masses with billions of litres per second are distributed along the ocean conveyor belt. I have looked at different tracers to understand where water masses come from and how they mix with each other. One particular tracer, neodymium, has been my focus for more than five years now – a study that involves collecting and processing thousands of litres of seawater. 

Recovery of our trace metal clean rosette that collected seawater at various depths. It is equipped with a conductivity, temperature and pressure, i.e. depth, sensor (CTD). Credit: Torben Stichel

Neodymium is a lithogenic element, which means it comes from land into the ocean via various weathering sources. The cool thing about neodymium is that its composition in water masses gives direct information about their formation regions. For example North Atlantic Deep Water has a distinct isotope composition because its surrounding landmasses mix their isotope signal into the source region where this water mass forms. We can also reconstruct past ocean circulation to a certain degree with neodymium isotopes archived in marine sediments. The problem with this isotope system is that the observed values not always meet the expected ones. In other words: water mass mixing is not the only process that governs trace metal isotope composition of seawater. Even though we have quite a good understanding on how water masses move and how they mix thanks to the help of reliable proxies, such as salinity, temperature and nutrients, there are processes involved, which we haven’t quite understood about neodymium, particular when it comes to sources and sinks of this element. 

RRS Discovery. Image: Torben Stichel

For this reason I’m looking at ocean boundaries to better understand source and sink mechanisms that imprint the neodymium isotope signal on the water masses we are tracing. The shelf seas like the Celtic Sea are potentially significant sources of neodymium into the ocean. So connecting shelf seas’ processes with the global ocean conveyor belt will help us to better understand the cycle of neodymium and trace metals in general in the ocean. 

Why is that important for us? The climate of our planet has been changing on large (glacial to inter-glacial) and smaller scales (modern climate change). Much of these changes are closely linked with ocean circulation. Understanding proxies that trace water masses are therefore vital to reconstruct past, assess present, and predict future ocean conditions.