Automated gas bubble imaging at sea floor – a new method of in situ gas flux quantification
- 1University of Applied Sciences Bremerhaven, An der Karlstadt 8, 27568 Bremerhaven, Germany
- 2MARUM Center for Marine Environmental Sciences, University of Bremen, Klagenfurter Str., 28359 Bremen, Germany
- 3IMARE Institute for Marine Resources, Bussestr. 27, 27570 Bremerhaven, Germany
Abstract. Photo-optical systems are common in marine sciences and have been extensively used in coastal and deep-sea research. However, due to technical limitations in the past photo images had to be processed manually or semi-automatically. Recent advances in technology have rapidly improved image recording, storage and processing capabilities which are used in a new concept of automated in situ gas quantification by photo-optical detection. The design for an in situ high-speed image acquisition and automated data processing system is reported ("Bubblemeter"). New strategies have been followed with regards to back-light illumination, bubble extraction, automated image processing and data management. This paper presents the design of the novel method, its validation procedures and calibration experiments. The system will be positioned and recovered from the sea floor using a remotely operated vehicle (ROV). It is able to measure bubble flux rates up to 10 L/min with a maximum error of 33% for worst case conditions. The Bubblemeter has been successfully deployed at a water depth of 1023 m at the Makran accretionary prism offshore Pakistan during a research expedition with R/V Meteor in November 2007.