Recovery artefacts associated to sampling at the extreme pressure and cold temperature at hadal depths confound onboard investigations of microbial performance and biogeochemical processes.
Thus, the HADAL team deploys instruments for investigations directly at the sea-bed. These so-called landers are 3-4 m tall, and weigh about 1 tonne. Depending on the specific research question, each lander is equipped with customized instrumentation for performing measurements, conducting experiments and/or recovering samples.
Landers are typically deployed for 1- 3 days days. Once released from the ship, they sink with about 40 m/min until they touch down at the ocean bed. Here, they realize their pre-programed mission before receiving an acoustic signal from the research vessel, prompting the release of their ballast. Buoyant material ensures a landers return to the ocean surface where it is located with radiotransmitters and GPS tracking and taken onboard the ship.
Upcoming exhibition
The next HADAL expedition will go to the Tonga and the Kermadec Trenches in February 2027. We will revisit the Kermadec Trench after 8 years to examine changes after heavy seismic activity. From Fiji we will sail to the Tonga Trench where different in situ landers will be deployed and sediment and water samples will be collected for later analysis.
Approximately 5 different stations will be examined. Afterwards we steam to the Kermadec Trench close to New Zealand, where we will use an array of moored instruments to explore the seasonal material deposition and water movements during one year of deployment. This will enable us to understand how material transport is linked to seismic activity and surface production. In this trench we also deploy in situ landers and collect sediment and water.
