Hunting for treasure on the seafloor

by Paola Moffa Sanchez, Cardiff University

One week after setting off from Southampton I am finally able to look at my computer screen for longer than 15min. I found my sea legs!! For someone who gets extremely seasick on the shortest boat rides, this is a huge achievement. My friends can´t comprehend why I would put myself through sailing for three weeks across the North Atlantic in a rocking boat with my terrible motion sickness. I did also wonder last week: Why did I not to choose to study lakes or bogs instead? There is a simple explanation: the ocean is special and no matter how ill you feel, having the opportunity to be on a research cruise like this one is totally worth it, personally and scientifically!

This is my first time on a physical oceanography cruise. So far, I have met incredible people doing very exciting research and I have gotten to see all the gadgets that get used to measure the properties, chemistry, and movement of waters in the ocean. This is a bit different from my research, where I mainly focus on understanding how the ocean changed in the past and how this may have impacted past climate. To do this we use sediments from the bottom of the ocean, which means the cruises I would go on normally are very muddy. My aim on this cruise is to survey the sediments on the seafloor and find the most suitable ones for extending the recent ocean measurements back in time (to 1000´s of years).

Essentially, is a bit like a treasure hunt. To survey the sediments of the seafloor we use a very clever method, which works on the basis of sending sound to the bottom of the ocean and receiving it back on the ship. This, sounds a little bit like a bird chirp and can get annoying whilst trying to sleep in our downstairs cabins. The sound sent is at a specific frequency, which will penetrate up to 100m into the sediment depending on its properties and tell us something about the sediment and hence the processes involved in the deposition of the sediments and their potential for reconstructing past ocean conditions. This allows us to find the best spots and then send the multicorer down to collect these sediments. So far we had a successful recover at a site that we surveyed and it even came up with a starfish! It must be a sign!

I could keep writing for ages but my watch has already started (16-midnight!) and the CTD will be on the deck soon ready to be sampled!

Photos by Paola Moffa Sanchez

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