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 .

It all began way back in 2004 when I took up a place to Study a BSc in Marine Biology at the University of Aberdeen. Once I finished my studies I went to work for the Majestic Line as a Wildlife Guide/Bosun. I sailed around the west coast of Scotland for a year or so, saw some wonderful sights.

I then moved south of the boarder to take up a place at the University of Southampton on the Oceanography MSc Programme – little did I know then that I would still be here 8 years later. While I was studying for my masters, I decided that I would like to stay within the department once my studies were over. Therefore I needed to find a job! It wasn’t easy but I managed to convince a few people to take me on part-time to make up a full time role. I spend half my time working as crew on the University’s Research Vessel Callista and the rest of the week working for the SERPENT Project.  I was a video analyst at SERPENT, I would spend most of may day cataloguing species from footage around the world. My favourite entry was this Pyrosoma found off the coast of Angola.

Then a different job as research Assistant came up within the department working with Professor Steven Hawkins. I then went from deep sea cataloguing to Rocky shore ecology. My entire working life was centred around the tide timetable – frequent 4am starts but it was a huge amount of fun and for me a personal honour to be traversing the coasts of the UK counting and monitoring all that could be found or not found as the case maybe.

                                                          Limpet survey in the Isle of Man.

After this post came to end, I was lucky enough to secure permanent employment within the department. I am now a Research Technician – which is a simply a job title and doesn’t really explain my wonderfully crazy job. I love working within Ocean and Earth Science, I’m not sure where I really begin to describe what I do. This week for example I am busy trying to organize a sea survival course on Thursday I’ll be off to the Natural History Museum to measure historic limpets. Tomorrow I will be briefing our first years on the upcoming Easter Field Course. In the interest of brevity I shall stop here.  I have a few more blog posts to write about my current role which will give you a better insight into the department.

Cheers

Moira

The post How did you get a job like that? appeared first on Exploring our Oceans .

I’m Felicity Williams and I study how sea level changes when the amount of ice on land either grows or melts.

It is very tempting to think of our earth as one large bath tub in which the water level goes up and down uniformly across the entire surface. The real world is far more interesting!

Every location around the world experiences a different sea level for the same amount of water being added to or taken away from the oceans.

Figure 1: Mountainside scoured by a retreating glacier –the Moiry Glacier – which can be seen to the left of the image.

Figure 2: A view down the valley scoured by the Moiry Glacier. Here you can see the edge moraines formed by the ice when it surged down the valley.

This is because when ice grows it squishes down the land underneath it. This causes sea level to effectively rise in that location even though ice is building up on land and so taking water out of the ocean. Conversely when the ice melts, the land springs back and sea level falls, even though more water is being added to the ocean. This process is called Glacial Isostatic Adjustment – and we feel it even today in the British Isles as a result of the great British and Irish Ice Sheet that was centered over Scotland around twenty thousand years ago.

Figure 3: Beautiful corals on the Great Barrier Reef in Australia. We can reconstruct past sea levels using fossil corals that were once alive.

We have some clues as to how sea level changed in the past gained from evidence like fossil corals, and we have some clues as to how much ground the ice sheets covered in past times as the ice sheets can push huge mounds of earth and rubble in front of them as they advance – these are known as moraines.

My job is to pull these clues together, so that we get a better idea of just how variable sea level was in past times – with the intention of applying it to the present day. If we know how fast sea level changed in the past, we have a better idea as to just how variable sea level could be in the future.

Flic.

The post My Research: Flic Williams appeared first on Exploring our Oceans .

My name is Josie Robinson and I’m excited to be a facilitator on the “Exploring our Oceans” MOOC. I’m just entering the 3^rd 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.

Josie

The post My Research: Josie Robinson appeared first on Exploring our Oceans .