8 mins read | Creating Change

Underwater Avalanches with Natasha Chapplow

Natasha Chapplow Ocean scientist

Hi Natasha, thank you so much for agreeing to talk to us today!

Please can you introduce yourself and tell us about your work.

Of course, happy to talk with you today. My name is Natasha Chapplow, and I am an Earth Scientist. My work involves the study of the Earth, and it’s 4 systems – land (lithosphere), water (hydrosphere), living things (biosphere), and air (atmosphere).

Earth scientists observe how natural processes create and shape the planet we see today. Natural landforms and features such as mountains, rivers, fossils etc can serve as clues to what the environment looked like millions of years ago. Alternatively, we can often observe natural phenomena that we’ve never seen before, and use existing features on Earth to help us learn more about how they occur. For example, much of my current research is focused on the deep ocean, in particular, the study of underwater avalanches. Until recently no measurements existed of these events occurring in our oceans. The only way scientists were able to try to understand them was by simulating them in a laboratory or by adapting studies from rivers. But in 2017 the first detailed measurements of underwater avalanches was recorded in Monterey California, over the course of a 2 year fieldwork campaign, that was an international collaboration between research institutes across the USA, UK and China. It’s a project that I am very proud to be a part of and one that I am still actively working on at the moment.


So let’s talk underwater avalanches, they sound totally fascinating. Please can you summarise what they are and their significance for those of us who have never heard of them!

They really are as fascinating as they sound. Underwater avalanches look similar to snow avalanches, and they occur in underwater canyon systems (think the grand canyon completely submerged by seawater). Instead of snow, however, underwater avalanches contain a mixture of sand, mud, and seawater. They travel along the seafloor picking up sand (erosion) from the seafloor and/or dropping sand (deposition) during their course. Underwater avalanches can accelerate if they pick up material or slow down when losing material, and so this process is basically the engine that drives these events. The scientific term for underwater avalanches is Turbidity currents.

Turbidity currents are important due to their sheer size, so the volume of these events, is what makes them the most important process for transporting sediment (ie. Sand) across our planet, only rivers carry similar volumes of sand. Amazingly, a single underwater avalanche event can sometimes transport more sediment than all the world’s rivers combined in a year (Talling et al. 2007). These events are also very fast and powerful which means that understanding them is important as they pose a risk to seafloor infrastructure such as fibre optic cables that supply internet worldwide.

Fragments of micro-plastics floating in the ocean

Fragments of micro-plastics floating in the ocean

They are also important in understanding the harmful impact of microplastics on the ocean right?

Yes that’s correct. In addition to sand, a range of other ‘stuff’ gets transported, such as organic carbon, nutrients, and even microplastics. Overall research on microplastics in the deep sea is still very new and there’s a lot more work needed, however, preliminary data has shown microplastics present in deep sea sediment deposits, which is basically the aftermath of turbidity currents. These results are interesting because turbidity currents travel along the seafloor up to100s of km, from shallow depths all the way to the deep ocean. They are therefore a way of identifying the fate of microplastics, after they are broken up at the surface of hotspots where plastic floats in concentrated locations commonly mentioned in the media as the Great Pacific Garage Patches. But, the plastic we see floating on the ocean surface is thought by scientists to account for only 1% of the total marine plastic budget. Understanding more about underwater avalanches is very necessary in this context, because these events could provide one of the missing puzzle pieces as to where the 99% majority of marine plastic ends up.


How did you first find out about underwater avalanches and what made you want to dedicate your time to researching them?

Firstly, because my early science background was a good starting point for understanding these events. I initially, heard about underwater avalanches when applying for a PhD Scholarship at Durham University, where I met with a Professor called Dr. Peter Talling who leads the research team there. At the time I had just finished my Bachelor’s degree at Plymouth University, where I studied Geology with Ocean science which was a joint honours course, meaning that the content from two separate degrees had been combined. I believe it’s very important to take a multi-disciplinary approach to learning, because when studying natural processes on Earth, multiple areas of science often overlap.

Exposure to this area of science for the first time presented me with possibility of new purpose and motivation, something I am sure we all can relate to at key points in our lives. Joining the research team would also mean that I would be working alongside exceptionally talented scientists who pioneered the field. I found the opportunity far too compelling for me to see any alternative for myself after that initial meeting in Durham. It’s been over four years since then and these reasons still hold true for me today – also helps to keep me focused on the value of my scientific goals during long research days and fieldwork campaigns!


Do you have any advice for people who want to reduce their impact on the oceans and any simple steps they can take?

Yes, in my opinion one of the most effective way to reduce our individual impacts on the oceans is to prevent synthetic fibres such as Polyester from polluting the oceans. Synthetic fibres used in the production of clothing are one of the largest sources of primary microplastic that enter the oceans each year. An easy way to prevent this is by installing a microfibre filter on the wastewater pipe of your washing machine, which can reduce our individual contributions of microfibre entering the ocean by ~90%, a number that will only improve as the technology advances over time. Or you can forgo synthetic fibres all together by buying 100% cotton clothing, admittedly this is more difficult to do, so I usually suggest the first option as it’s a low effort long-term solution.


I’m sure your professional environmental values must somewhat extend to your wider lifestyle – in what ways do you try to live sustainably?

Since microfibre pollution in the oceans is an issue that’s very concerning to me, I’m a big believer in slow fashion. I purchase new clothing rarely, some years I buy only one piece of new or used clothing. I also try to buy second-hand when possible, especially when something I like is manufactured by a major clothing brand – 9 times out of 10 I’ve been able to find the exact item online in almost new condition, usually because someone no longer wanted it, or it didn’t fit properly. Buying clothing in this way can cost far less than if the purchase was made in-store and helps to reduce waste overall. I think it’s great that the stigmas associated with second-hand clothing are gradually being shed in many countries too.


So when you’re not at your desk, what do you get up to switch off?

Typically, I’m trying to snowboard as soon there’s barely enough snow to slide my board around. I really enjoy it, because its great either alone with a great music playlist or with friends. Never had any bad days during a snow day. When there isn’t enough snow I’m out riding my electric skateboard which can go up to 25mph. Carving at those speeds feels pretty similar to snowboarding, but falling onto concrete at those speeds is a different story! I also enjoy kitesurfing, although I haven’t been able to find the time in far too long, but I’m definitely looking to add that back into my summer rotation.

Scientist Natasha Chapplow out in the snow

Natasha Chapplow out snowboarding


Finally, where is your research heading next and where can we go to follow it?

Well, we are still only just scratching the surface of what we know about underwater avalanches, which means I need to keep working away at the large amounts of data that we collected during our offshore fieldwork campaigns in California (USA) and our one last last year in The Congo. Sifting through all that data is a classic needle in a haystack situation. Except there are often times, in frontier science, when you have absolutely no idea where the haystack is, or even what it should look like to begin with. But to me that’s half the fun!

I actually just started an Instagram account @earth.scientist where I will be posting about my own research. But more importantly, I also write posts breaking down the key points from scientific studies that have discovered or solved globally important issues. I am doing this to make high level science research understandable to audiences outside of the scientific community, because I believe we need to push further than simply saying we need to make science more easily available/accessible to audiences.


Pala speaks with the chief scientist of the barrier reef foundation >