Text and photos: Mauro Pau, Postdoc on Hopendjupet CAGE21-4 cruise
August 5th, 2021.
We are in an area of the central Barents Sea not (yet?) reached by the oil industry, but where oil slicks have consistently been identified on the sea surface from satellite images. The escape of oil through the seabed is a known natural phenomenon, and is controlled by climate and geological factors. Improving knowledge on how geological structures and seabed morphology affect hydrocarbon release here in Hopendjupet may be beneficial to better understand how some areas are more vulnerable than others to global climate warming.
André Jensen (NPD), cruise leader Monica Winsborrow and master’s student Abidemi Akinselure.
A team of CAGE scientists who visited the area a year ago reported a surprisingly high methane seepage activity. Our first priority is to have a more extensive picture of where the seepage occurs. We do so by complementing the previous sparse, but revealing, multibeam echosounder lines with the homogeneous survey of a rectangular area of over 400 square kilometres (or around 20 times the size of Tromsøya, for the connoisseurs).
Ship’s engineer Truls Holm.
Water depths range between 280 and 330 m, and a beautiful meltwater channel system appears below us, carved under the ice sheet that once covered the entire Barents shelf. Importantly, the multibeam data of the water column shows where the gas seeps are. Although we knew we would have found several, we remain equally amazed at the amount of seeps we encounter, in the thousands, and at the magnitude of many of them. Some may well reach the sea surface, possibly delivering methane to the atmosphere. Oil may travel upwards in the water column as a film covering the gas bubbles.