Publication Date:
2021-11-04
Description:
The Black Sea bottom is well known to be earth’s largest anaerobic methane source,
hosting a huge amount of cold seeps releasing significant volumes of methane of both
thermogenic and biogenic origin. Taking into account the well-known effects of methane
concerning global warming, including the warming up of the oceans, an effective
monitoring of its output from the Black Sea is nowadays an essential target for
interdisciplinary studies. We discuss the results achieved during monitoring campaigns
aimed to detect and track methane flares from the seafloor of the Romanian sector of the
Black Sea, in order to better constrain the possible mechanisms responsible for its injection
from the marine sediments, through the water column, into the atmosphere. In the
mainframe of the ENVRI-Plus project, we deployed a multidisciplinary seafloor
observatory for short, mid and long time monitoring and collected samples of the
water column. The multidisciplinary seafloor observatory was equipped with probes for
passive acoustic signals, dissolved CH4 and chemical-physical parameters. The collected
data showed a high concentration of dissolved methane up to values of 5.8 micromol/L.
Passive acoustics data in the frequencies range 40–2,500 Hz allow us to discriminate
different degassing mechanisms and degassing styles. The acoustic energy associated
with gas bubbling is interpreted as a consequence of the gas dynamics along the water
column while the acoustic range 2–20 Hz reveals vibration mechanisms generated by gas
dynamic’s along the cracks and inside the sediments.
Description:
Published
Description:
678834
Description:
7A. Geofisica per il monitoraggio ambientale
Description:
JCR Journal
Keywords:
methane
;
greenhouse gas
;
hydrosphere
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
