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  • 1
    Publication Date: 2023-02-08
    Description: Along mid-ocean ridges, submarine venting has been found at all spreading rates and in every ocean basin. By contrast, intraplate hydrothermal activity has only been reported from five locations, worldwide. Here we extend the time series at one of those sites, Teahitia Seamount, which was first shown to be hydrothermally active in 1983 but had not been revisited since 1999. Previously, submersible investigations had led to the discovery of low-temperature (≤30°C) venting associated with the summit of Teahitia Seamount at ≤1500 m. In December 2013 we returned to the same site at the culmination of the US GEOTRACES Eastern South Tropical Pacific (GP16) transect and found evidence for ongoing venting in the form of a non-buoyant hydrothermal plume at a depth of 1400 m. Multi-beam mapping revealed the same composite volcano morphology described previously for Teahitia including four prominent cones. The plume overlying the summit showed distinct in situ optical backscatter and redox anomalies, coupled with high concentrations of total dissolvable Fe (≤186 nmol/L) and Mn (≤33 nmol/L) that are all diagnostic of venting at the underlying seafloor. Continuous seismic records from 1986-present reveal a ∼15 year period of quiescence at Teahitia, following the seismic crisis that first stimulated its submersible-led investigation. Since 2007, however, the frequency of seismicity at Teahitia, coupled with the low magnitude of those events, are suggestive of magmatic reactivation. Separately, distinct seismicity at the adjacent Rocard seamount has also been attributed to submarine extrusive volcanism in 2011 and in 2013. Theoretical modeling of the hydrothermal plume signals detected suggest a minimum heat flux of 10 MW at the summit of Teahitia. Those model simulations can only be sourced from an area of low-temperature venting such as that originally reported from Teahitia if the temperature of the fluids exiting the seabed has increased significantly, from ≤30°C to ∼70°C. These model seafloor temperatures and our direct plume observations are both consistent with reports from Loihi Seamount, Hawaii, ∼10 year following an episode of seafloor volcanism. We hypothesize that the Society Islands hotspot may be undergoing a similar episode of both magmatic and hydrothermal reactivation.
    Type: Article , PeerReviewed
    Format: text
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  • 2
    Publication Date: 2022-10-20
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Barker, L. D. L., Jakuba, M., V., Bowen, A. D., German, C. R., Maksym, T., Mayer, L., Boetius, A., Dutrieux, P., & Whitcomb, L. L. Scientific challenges and present capabilities in underwater robotic vehicle design and navigation for oceanographic exploration under-ice. Remote Sensing, 12(16), (2020): 2588, doi:10.3390/rs12162588.
    Description: This paper reviews the scientific motivation and challenges, development, and use of underwater robotic vehicles designed for use in ice-covered waters, with special attention paid to the navigation systems employed for under-ice deployments. Scientific needs for routine access under fixed and moving ice by underwater robotic vehicles are reviewed in the contexts of geology and geophysics, biology, sea ice and climate, ice shelves, and seafloor mapping. The challenges of under-ice vehicle design and navigation are summarized. The paper reviews all known under-ice robotic vehicles and their associated navigation systems, categorizing them by vehicle type (tethered, untethered, hybrid, and glider) and by the type of ice they were designed for (fixed glacial or sea ice and moving sea ice).
    Description: Barker and Whitcomb gratefully acknowledge the support of the National Science Foundation under Award 1319667 and 1909182, and support of the first author under a Graduate Fellowship from the Johns Hopkins Department of Mechanical Engineering. Jakuba, Bowen, and German gratefully acknowledge the support of the National Aeronautics and Space Administration under Planetary Science and Technology through Analog Research (PSTAR) award NNX16AL04G. Maksym was supported by National Science Foundation Award CMMI-1839063. Dutrieux was supported by his Center for Climate and Life Fellowship from the Earth Institute of Columbia University. Boetius acknowledges funding from the Helmholtz Association for the FRAM infrastructure, and from her ERC Adv. Grant ABYSS (294757). Mayer’s work is supported by NOAA Grant NA15NOS4000200.
    Keywords: Underwater robotic vehicles ; Under-ice navigation ; Tethered vehicles ; Hybrid vehicles ; Gliders ; Ocean science ; Ocean exploration
    Repository Name: Woods Hole Open Access Server
    Type: Article
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