Meteor-Blog 20. July 2008: Tracking for methane
Meteor-Blog: The Peruvian Geophysician César John Caparachin Villaverde explains why marine scientists investigate the sea-floor an how they detect methane seeps.
More informationen of Meteor-Blog and expedition M76/3B
20. July 2008 (Author: César John Caparachin Villaverde)
"Hola! My name is Cesar John Caparachin Villaverde and I just finished my bachelor studies in Geophysics Engineering at the National University of San Agustin in Arequipa/Peru. I absolutely love my profession. I have been invited by the University of Bremen to participate in this research cruise and being a Peruvian I will try to do my best!"
Tracking for methane
Geophysics and methane seeps
Many people can describe something only when they look at it, however, a geophysicist needs to describe something without seeing it but instead measuring physical properties of the material such as acoustic properties. Therefore, during M76-3b I will be in charge of the acoustic echosounder and parasound systems that I learned to handle during my participation in the previous cruise section M76-3a.
Picture 1: Multibeam echosounder measurements unravel the complex geomorphology of the Diapir area. The circle shows the place where the first gas flare was found
What kind of information can we retrieve from acoustic systems? The multibeam echosounder is used to get a real time visualization of the seafloor, whereas the parasound delivers information of sediments below the seafloor. It thus helps to understand different kind of complex sedimentary structures below the sea bottom. Apart from that, with the parasound measurements we are also able to identify gas flares in the water column down to 4000 meter depth, fantastic! The very first time I saw a gas flare was really amazing. Unbelievable how this strong signal in the water column could correspond to the small gas bubbles on their way up to the sea surface. The question of gas escape from the seafloor is very important because methane, the major component of the gas bubbles acts as an aggressive greenhouse gas when it finally reaches the atmosphere.
Picture 2: Gas flares have been detected by the parasound system in the Diapir area. On the left the seafloor structure is shown, on the right the gas flare above the seafloor within the water column is visible.
During the last cruise many places with pockmarks, which are depressions in the seafloor, and gas flares were identified by acoustic methods. Now, specialized German, French and scientists of many other countries aim to get samples and high resolution images of gas hydrates and different kinds of microbial communities associated to cold seepages. During the following days their task will be to find the sources of gas flares in the sea bottom of the Diapir and Regab Pockmarks, which represent the major areas of interest. My friend and colleague Frederic Tardeck and I will provide maps and positions of every interesting feature around the research area.
Picture 3: The seafloor can be accurately characterized by means of parasound recordings. Often much younger sediment layers cover old sedimentary structures within the seafloor, so called paleo channels. The complexity of the deformation can be easily identified by the high resolution of parasound measurements.
Dreams can come true
Just a few months ago, I used to watch marine documentation series in the TV programs but now I am part of a real scientific research group onboard of a research vessel. I have to confess that I feel really lucky to be part of this community and able to see things that I never thought of. Do you really think that you will never make your dreams true? Reconsider, I am sure you can do it!
Les deseo a todos uds. buena suerte y muchos éxitos!
Su amigo, César
Picture 4: Enthusiastic at work: Cesar, author of the blog, with the acoustic systems in the Lotzentrale.