IRIS´s benthic chamber lander is a unique piece of infrastructure and is capable of carrying out experiments at the seafloor at depths down to 6000m. The lander houses 3 benthic respirometers that are driven into the sediment at pre-programmed times where changes in solute concentrations (e.g., dissolved inorganic carbon, nutrients) are measured over time by collecting water samples from each chamber with a syringe sampler. Oxygen concentrations through time are measured by Contros hydroflash O2 optodes mounted inside the chambers. Various substances (e.g., isotopically labeled algae, fish farm feed, oil dispersent) can be added into each chamber at specific times and the uptake of these tracers can then be traced into various components of the benthic ecosystem allowing one to assess how ecosystems function under different scenarios (e.g., next to an oil and gas platform/ fish farm versus a control site).
The lander has been used extensively in the ABYSSSLINE project, which is assessing abyssal seafloor functioning in the manganese nodule province in the CCZ, and has regularly been deployed to depths exceeding 4km.
The picture above shows the POLIRIS lander on the fantail of the research vessel “Thomas G. Thompson” in San Diego harbor (USA) about to depart on a 7 week research expedition to the abyssal equatorial Pacific to undertake baseline ecosystem investigations in the manganese nodule province of the Clarion Clipperton Zone.