Submersible operated peepers for collecting porewater from deep-sea sediments

Peepers are a common alternative to push cores for collecting porewater from shallow aquatic environments such as lakes, streams, and wetlands but are infrequently used to sample deep-sea sediments due to design limitations. In this study, a peeper was developed to obtain porewater from precisely located positions on the deep-sea floor using remotely operated or manned submersibles. The sample cells of the peepers can be sealed closed after they are deoxygenated on board a ship to ensure that they remain anoxic until peepers are deployed at the deepsea sampling location. Similarly, peeper cells can be closed at the end of an incubation period to maintain sample integrity during submersible recovery and until sample processing. Each peeper can be used to collect samples from 10 cm above the sediment water interface and at 10 cm intervals down to 60 cm depth in the sediment, and can provide sufficient volume for multiple chemical analyses, including stable isotope ratio determinations.