Our last day of science sampling and we are collecting water just above a site where we suspect there is low-temperature fluid flow at the seafloor 2.5km below the ship.   This is the site that in 1974 was named TAG after dredging hydrothermal deposits from the eastern rift-valley wall. I worked on these precious samples much later in the 1990’s and demonstrated that hydrothermal neodymium could be traced in these ferromanganese crusts demonstrating that they formed from low-temperature vent fluids rather than from seawater. We want to see what we can see in the deep water over this site and measure the input from the seafloor.

Over the last 38 days we have put our sampling rosette into the deep water 83 times and collected nearly 30,000 litres of seawater for processing, filtering, measuring and archiving. We have pumped over 45,000 litres of seawater through our deep sea cartridges to strip out natural radioactive isotopes that we use measure time in the deep sea. We have filled the container on the aft deck with over 100 crates of samples carefully wrapped for transport around the world to our labs in the UK, the US and elsewhere. Our physics team have made over 20 million measurements of turbulence through the water column and measured the plumes wafting through the deep waters in intricate detail.

We have steamed 4200 nautical miles since we left Southampton and have over 1000 to go to get to Guadaloupe. We have drunk over 7000 cups of coffee and eaten nearly a tonne of potatoes and over a 1000 rashers of bacon. We’ve hit the gym (perhaps because of the potatoes) and collectively rowed, run and cycled thousands of kilometres. We’ve played 350 games of cribbage, nearly 500 games of table football and some challenging games of darts when the ship is rolling.

All 52 people on the ship have worked (and played) really well together on this expedition – we have made new friends and close collaborations that will last a long time. On this long passage south to Guadaloupe we are drafting the ideas for the next proposals, practicing the talks for the big conferences coming up in 2018 and of course getting our fancy-dress costumes designed and made for the ‘RPC’.

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We still ‘sail’ in rather larger science teams for much shorter periods of time. The rhythm of work on a ship and the lowering and hauling of wires is very familiar. We collect water samples in large bottles that can be closed remotely at depth and are arranged around an array of in situ sensors that give us real time data of ocean properties as we sit in the lab. The samples are recovered at awkward times of day and night – these samples need to be processed immediately to catch the helium atoms that escape out of the sample, the oxygen samples that are compromised as soon as the tap is opened, the microbial and chemical measurements of trace amounts of rare elements that we use to understand the scale and timing of ocean processes. We pump tonnes of water through cartridges to strip out radioactive isotopes that help determine the timescales in the deep ocean.

All this happens in slick sequence time and time again as we progress South along the volcanic ridge towards the subtropics. After a couple of weeks we are a great team – called on deck at odd hours to process samples under ultra-clean conditions, careful not to contaminate that water from the deep. Make decisions, move on South.

The key to effective work on the ship is of course how well this team works. You would all recognise the dynamics – the Captain is in charge of the ship – the Chief Scientist is in charge of the programme and together they make decisions every day to curtail a bit of this, cut a bit of that, move on if this isn’t working. The rest of the team are here to get the most out of this fantastic opportunity to track all the known volcanic vents in this region.

Ocean expeditions are fabulous training grounds for the next generation of scientists. We have an undergraduate student from California, a POGO funded postgraduate student from Malaysia, a whole group of PhD students from Southampton and Liverpool and the graduate students from collaborating labs in the US and France aboard. They work relentlessly round the clock and still have the energy to have fun – friendships made at sea last a lifetime.

The ship is a melting pot for people from all sorts of backgrounds, all sorts of experiences, all sorts of life stories and these are shared during the night shift over cups of Maeve’s espresso. The bridge calls down to point out those things that we can only really appreciate out here – dolphins on the starboard bow, alignment of Jupiter and Mars off the port deck.

The best part of being at sea is the freedom to focus on the task at hand and nothing more, nothing less. Time slows down, problems are solved, solutions are found, new data is stuck to the walls, new ideas forged as we each contribute to the picture emerging of plumes of metals wafted deep along the ridge. I love the rhythm of the days and nights – the sunsets and sunrises, the slow passing of time. We love the singularity of purpose.

The worst part is the severing of connections with home over the first few days and the vague feeling of institutionalisation and repetition that takes over after several weeks – all lifestyle decisions are out of your hand – what you eat, what you drink, when you sleep, when you do laundry, how you exercise, who you mix with.

The FRidge team is exceptional. I have made new friends, really cemented some work relationships and am looking forward to working with these great scientists over the next few years to get these samples measured and our new ideas out into the community and beyond.

The post Fair winds and following seas appeared first on Exploring our Oceans .

 If you watched the Blue Planet II last night I hope you’ll agree that, if all the world’s a stage, the ocean is a pretty spectacular one!

Well, if the organic carbon coming out of rivers was a performer, I think it would be Houdini.

So, just as onlookers could watch Houdini make his way out from the wings and take position centre stage, we can measure the presence of organic carbon and track its movements, allowing us to ‘see’ it flow out of rivers as it makes its grand entrance into the coastal ocean.

And just like Houdini, one minute it’s right in front of us and the next, it’s vanished without a trace. Or has it?

(Before we go any further, if you haven’t read my last blog post, you can catch up here. Caught up? Then let’s go!)

For marine scientists, nothing ever really vanishes. Ever improving scientific techniques and equipment mean that we are continually getting better and better at being able to track the movement of things beyond what you might expect possible. You just need to know what to look for!

At the most basic level, everything is made up of atoms which make up molecules which make up compounds which make up substances which make up, well, everything. So, like every other living thing, the chemicals and compounds which make up microorganisms have to come from somewhere. We use isotopic tracking to find out where…

We think of carbon as being a singular thing, but it actually comes in 3 different forms. These different forms are called isotopes, and they work a bit like smarties (stick with me!)

Say there are two bowls of smarties, one at each end of a hallway – one is mostly blue, with some red and yellow, and the other is mostly yellow, with some blue and red. If you took a handful of smarties from one of the bowls and walked into another room, I could likely tell which bowl you had taken your smarties from (or which end of the hallway you were at when you picked them up), based on the mix of smarties you had in your hand.

If a plant grows on land, it will pick up a different ‘handful of smarties’ compared to one that grows in the ocean. This is that plants isotopic signature, and it’s like a chemical fingerprint specific to that species and location.

We can take a sample of water from anywhere – a lake, a river, the ocean – and filter everything else out until we are left with just the organic material dissolved in it. From there, we can use a technique called mass spectrometry to determine what that material is made up of. Using this technique, we can separate molecules based on their mass, including 3 different forms of carbon. It’s our way of looking to see what smarties the plant is holding – or the isotopic signature of the organic carbon in the sample, which gives us the fingerprint of where it came from.

And this is how we know that riverine organic carbon is going missing – when we look at samples from rivers, we find an isotopic fingerprint full of land-derived organic carbon,  but when we look at samples from the ocean, we find much, much less.

Still with me? Great!

In my next posts, I’ll talk about some of the leading theories around why we don’t find as much riverine organic carbon in the ocean as we expect to, and how my research is trying to understand where it is going. In the meantime, if you have any questions please ask!

The post The ‘Missing’ Carbon Conundrum… Part 2 appeared first on Exploring our Oceans .

Imagine you have some fish in a tank, and you feed them a mixture of small, easy to digest flakes and larger, more difficult to digest flakes. Assuming you feed enough of each type of food to satisfy their hunger, what would you expect to happen?

You’d expect the fish to take the easy option and eat the smaller, easier to digest flakes, whilst the larger, more difficult to digest flakes are mostly left to sink out and end up on the bottom of the tank, right?

Well, that’s basically what happens in coastal waters when microorganisms have a choice between different kinds of food – they pick the easiest option.  

(Let’s just say that anything which is alive and so small you need a microscope to see it is a microorganism, for anyone who wasn’t sure. And because we are scientists and have to be careful with the meaning of words, when we talk about microorganisms we’ll say that they metabolise (or break down) organic matter rather than saying that they digest food, and we’ll use labile and recalcitrant instead of easy to break down and difficult to break down. Don’t worry, you’ll get the hang of it!)

So, coastal waters tend to be incredibly productive places. The surface waters in these regions are teeming with life, and the phytoplankton and algae which live there turn light and carbon dioxide into lovely, fresh, labile organic matter for other organisms to enjoy.  

At the same time tho, huge amounts of recalcitrant organic matter, mostly produced by land plants, flows out of the rivers that feed into these coastal waters. A lot of this river material is old, having been broken down and recycled by river microorganisms so many times as it travels downstream that it has become nutrient deplete and extremely difficult to metabolise by the time it reaches the sea.

With plenty of fresh food being produced in the surface waters, coastal microorganisms don’t need to spend precious energy breaking down this old river material. So what happens to it? Does it sink out and end up on the bottom, just like the fish food did?

No – and that’s the mystery!

Around 50% of the land-plant-derived organic matter which flows out of rivers and into the ocean goes ‘missing’. It’s not floating around in the water column, it’s not sitting in the sediments, and the scientific literature tells us that microorganisms aren’t eating it. So where does it go? 

This might not seem hugely important at first, but for scientists who study the global carbon cycle, solving this conundrum is vital. You see, a large portion of organic matter is made up of carbon, and we know that carbon is linked to climate. 

So let’s think about it! What could be happening to all that organic matter?  

Some of the biggest scientific breakthroughs have come about because people from different fields of expertise and backgrounds got together and threw around some ideas, so have a go!

In my next blog post, I’ll talk about how we know the organic carbon is going missing. In the mean time, over to you!

The post The ‘Missing’ Carbon Conundrum… Part 1 appeared first on Exploring our Oceans .