Marcelo is on expedition in the Mediterranean Sea to study how gas in the ocean floor can trigger a tsunami
Since a few weeks back, researcher Marcelo Ketzer from Linnaeus University takes part in the Mediterranean Sea expedition Mission Albacore, together with researchers from, among others, Sorbonne University. His mission is to study the presence of methane gas in the ocean floor, which is one of several contributing factors to the formation of submarine landslides and tsunamis.
Hi Marcelo! Where are you right now?
We are in the western part of the Mediterranean Sea, more precisly in the Alboran Sea. It’s located between Spain and Morocco. We left Toulon in southern France in mid-October and will spend one month at sea.
Why are you in the Alboran Sea?
The Alboran Sea is one of the most geologically active areas in the Mediterranean Sea, and earthquakes, submarine landslides and tsunamis are commonly occurring here. The idea of the project is to improve our understanding of the occurrence of these phenomena and to be able to assess the risk of them happening. We collect samples from the ocean floor sediment, which we then analyse to get information about how climate changes and submarine landslides ocurred in the past.
What is it that you study?
I study the presence of methane gas below the ocean floor, that is to say, its composition, how it has been formed, and how it migrates in the sediment and eventually out into the water. And also whether it can trigger submarine landslides. Why methane gas? Because it affects the stability of the ocean floor and makes it weaker, which increases the risk of submarine landslides and tsunamis to occur. The higher quantity of gas, the weaker the ocean floor. Thus, the idea is that by gaining more knowledge about the gas, we will gain a better understanding of how submarine landslides are created and what the risk is of them occurring in this area, which is quite densely populated.
How do you collect the methane gas samples?
We use an instrument called piston corer to obtain the samples. It is a long and heavy tube that penetrates deep into the ocean floor to collect sediment. On the inside of the tube, there is a piston that helps get sediment into the tube. The gas from the ocean floor is kept in the tube. We then bring the tube up and take out the sediment core. We analyse the sediment samples partly on the ship, but the more in-depth analyses of the chemical composition of the gas, its quantity and origin we conduct in our laboratory at Linnaeus University.
To learn more, check out Mission Albacore’s own blog. It in French, but contains many more photos from the expedition.