Operation on AL447
The DeepSea-Monitoring group is currently developing a multibeam based lander system for monitoring and quantifying marine gas flow (bubbles). The GasQuant II is built as the successor of the GasQuant I system (Greinert, 2008), that has been successfully used for monitoring temporal variability of gas flares in the past (Schneider von Deimling et al., 2010, 2011). With special focus on light weight and low-power consumption the system will have longer endurance and deployment capabilities and can even be deployed from small vessels or precisely placed on the seafloor by an ROV. GasQuant-II can operate autonomously for up to three days continuously. GasQuant-II has been successfully deployed during the Alkor cruise AL447 in September/November 2014, where it was operating stable during three 24 hour deployments
Some key features, like an integrated compass and motion sensor, are still missing however the data gained from Eckernförde Mittelgrund already show to be useful to detect single bubble release events. These can be analyzed in post-processing and compared with changes in sea-level to find possible correlations. Future work aims for direct flux estimates of marine gas release.
GasQuant II technical details:
- 40 kg
- range 50-100m
- swath opening angle: 120°
- base frequency 260 kHz
- autonomous operation time of up to three days; depth rating of up to 4000m.
Greinert, J., 2008. Monitoring temporal variability of bubble release at seeps: The hydroacoustic swath system GasQuant. J. Geophys. Res. Oceans Vol. 113 Issue C7 CiteID C07048 113, 7048. doi:10.1029/2007JC004704
Schneider von Deimling, J., Greinert, J., Chapman, N.R., Rabbel, W., Linke, P., 2010. Acoustic imaging of natural gas seepage in the North Sea: Sensing bubbles controlled by variable currents. Limnol. Oceanogr. Methods 8, 155. doi:10.4319/lom.2010.8.155