This project partners a US team working on Ocean World astrobiology with international polar scientists to investigate a hydrogen-rich seafloor hydrothermal system in the ice-covered Arctic Ocean at seafloor pressures that are intermediate between those projected for submarine vents on Enceladus and the deeper seafloor of Europa.

PI Team at WHOI:

Chris German (lead), Jeff Seewald, Mike Jakuba, Andy Bowen

Co-I’s at JPL:

Andrew Branch, Andy Klesh, Steve Chien, Kevin Hand

International partners:

V.Schlindwein (AWI, Bremerhaven, Germany)

W.Bach & M.Walter (MARUM, Bremen, Germany)

N.Dubilier (MPI-MM, Bremen, Germany)

 

Science:

The Aurora vent field (82°N, Gakkel Ridge) lies beneath the most persistent multi-year ice in the Arctic Ocean.  It also shows clear evidence of ultramafic-influenced venting despite prior work that showed the site to be hosted in young basaltic volcanism.  This represents a novel geologic setting for submarine venting anywhere on Earth, but with particular potential to host abiotic organic synthesis.  We hypothesize that the ultra-slow spreading Gakkel Ridge generates volcanism in such low volumes that only a thin veneer of basalt is extruded as a crust overlying uplifted mantle rocks.  Thus, fracturing of the lithosphere allows seawater to circulate through both this young basaltic ocean crust and uppermost component of the underlying mantle.  To test this, our colleague at AWI have proposed a 2 cruise program for seismic studies aboard their new icebreaker FS Polarstern and have invited PI German to sail as Co-Chief Scientist for the 2nd cruise (shiptime already secured for June-July 2023) to lead an international team that will study the seafloor vents at Aurora field using WHOI’s purpose built and now 5000m-rated Nereid Under Ice vehicle. Our interdisciplinary project will integrate geological, geochemical and micro-biological investigations of the high temperature venting already photographed at Aurora but pay particular attention to associated low-temperature venting because that is where our most recent NASA funded work has revealed that the greatest potential for both (a) abiotic organic synthesis in ultramafic-influenced submarine vents and (b) availability of chemical energy release to be exploited by microbial metabolisms (at temperatures <120°C) are expected to arise.

Technology:

Our use of Nereid Under Ice to dive to ≥4000m deep vents in the ice-covered Arctic Ocean will immediately meet two PSTAR goals: testing and application of a mobile science platform that will be used to conduct in situ sensing, and sample acquisition and handling at pressures in excess of those inferred for seafloor venting at Enceladus and approaching those anticipated for Europa.  Our work will also focus on two further PSTAR goals: techniques for autonomous operations and intelligent systems and human/robotic interfaces.  Building on our prior PSTAR research (autonomous water-column localization of hydrothermal fields), we will develop methods for autonomous localization of low-temperature flow sites within a vent field, once it has been located (these low-T sites are now recognized as a high priority for astrobiology). Our work will compare single and multiple vehicle approaches to autonomous exploration for site localization, identification, and selection. We will conduct this work in shadow mode during Y1 Arctic field operations, and target full testing in partnership with NOAA OECI cruises in subsequent years. Once a (seafloor) target of interest has been identified, the next operational issue is how to land a mobile platform (location, orientation) to enable sample collection, manipulation and/or sensing.  This challenge maps from present day deep ocean to future ocean world operations.  Repositioning at the seafloor is costly (time, energy) and can compromise sampling sites.  Here, therefore, we will combine terrain relative navigation with 3D projection to transform sparse seafloor data into enhanced situational awareness for vehicle operators that will improve efficiency at Earth’s seafloor and retire risks for landed operations on other Ocean Worlds.

 

Progress to-date:

Our research expedition to the Gakkel Ridge was highly successful despite particularly challenging ice conditions.