Dr. Jens Karstens
Phone: +49 431 600-2415
E-Mail: jkarstens(at)geomar.de
MOLA – the Modular Ocean Lander
The marine environment has a critical role to play in the energy transition from a carbon-based to a carbon-neutral society. This will require the development of offshore wind farms and marine carbon capture and storage, while protecting marine ecosystems. These tasks require detailed, ideally real-time, information on subsea and seafloor processes. However, most current subsea observation platforms are large, heavy, single-function devices that require significant infrastructure and financial investment, making them accessible to a very limited user base. MOLA aims to change this by opening up subsea observation technology to a much wider user base. MOLA is a compact, modular sensor platform for monitoring various geophysical, oceanographic and chemical parameters on the seabed and can be equipped with a variety of different sensors and accessory components depending on the area of application. We currently have seismometers, hydrophones, inclinometers, pressure gauges, thermometers and CO2 sensors modularly integrated into the system. Due to its compact size, MOLA can be deployed and retrieved from small boats, significantly reducing the logistics and mobilisation costs of the system, and can be mobilised within hours, making it an ideal tool for rapid response missions.
Smart Seafloor Monitoring
Multiple MOLA's can form a communicating underwater network using integrated acoustic modems to transmit measurement data, analysis results and commands. Together with the University of Kiel and the MarData Graduate School, we have developed machine learning based data analysis schemes that are resource efficient enough to run on microcontrollers. For example, LightEQ and SeismicSense are neural network-based data analysis pipeline that enables on-device earthquake detection. In addition, we currently develop automated acoustic underwater monitoring applications for the detection of marine mammals and to evaluate the health of marine ecosystems. Such applications, combined with resource-optimised network communication and distributed system analysis schemes, enable the design and implementation of intelligent seafloor monitoring and early warning systems that offer a significant advantage over today's passive and non-networked marine instrumentation to meet the demands of a growing sustainable blue economy.
Development and application of the MOLA system
Based on initial concept studies, MOLA has been funded by the Helmholtz validation project of the same name since May 2023. The MOLA system has been designed and tested in GEOMAR's workshops and test facilities and during several dedicated test cruises onboard FK Littorina in the Kiel Bay. In addition, individual MOLA devices and small networks were tested during the research cruises M198 onboard RV METEOR offshore Sicily and MSM132 onboard RV MARA S. MERIAN offshore Santorini. The MOLA system has already been used several times for various underwater measurements:
Application 1
- Measuring the soundscape in Kiel harbour:
In June 2023, two MOLA landers were deployed for three weeks in the harbour basin of the Naval Arsenal to characterise the soundscape of Kiel Harbour using hydroacoustic and seismic measurements. These first measurements, which lasted several weeks, demonstrated the potential of the system for long-term passive acoustic measurements.
Application 2
- Seismic monitoring of underwater blasting by the German navy
In September 2023, the German Navy carried out a series of underwater detonations in the Baltic Sea. The aim was to determine the noise pollution caused by underwater explosions, particularly during the controlled detonation of munitions (UXO). Five MOLAs provided hydroacoustic and seismic recordings of 20 blasts and were able to contribute to the determination of sound propagation in the water column and the seabed.
Application 3
- Rapid-response mission during the 2025 earthquake crisis on Santorini:
As part of the MULTI-MAREX project, MOLA landers were installed in the Santorini caldera at the request of the Greek partners in order to supplement the existing seismological network of underwater stations and investigate the seismic crisis of February 2025 in more detail. The MOLA landers were ready for use within a few days, while the other underwater stations could only be installed over a month later.
