Holmes Mark L.

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Holmes
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Mark L.
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  • Article
    Submarine volcanic morphology of the western Galapagos based on EM300 bathymetry and MR1 side-scan sonar
    (American Geophysical Union, 2007-03-21) Glass, Jennifer B. ; Fornari, Daniel J. ; Hall, Hillary F. ; Cougan, Allison A. ; Berkenbosch, Heidi A. ; Holmes, Mark L. ; White, Scott M. ; De La Torre, Giorgio
    A compilation of high-resolution EM300 multibeam bathymetric and existing MR1 side-scan sonar data was used to investigate the volcanic morphology of the flanks of the western Galápagos Islands. The data portray an assortment of constructional volcanic features on the shallow to deep submarine flanks of Fernandina, Isabela, and Santiago Islands, including rift zones and groups of cones that are considered to be the primary elements in constructing the archipelagic apron. Ten submarine rift zones were mapped, ranging in length from 5 to 20 km, comparable in length to western Canary Island rift zones but significantly shorter than Hawaiian submarine rift zones. A detailed analysis of the northwestern Fernandina submarine rift, including calculated magnetization from a surface-towed magnetic study, suggests that the most recent volcanism has focused at the shallow end of the rift. Small submarine volcanic cones with various morphologies (e.g., pointed, cratered, and occasionally breached) are common in the submarine western Galápagos both on rift zones and on the island flanks where no rifts are present. At depths greater than ∼3000 m, large lava flow fields in regions of low bathymetric relief have been previously identified as a common seafloor feature in the western Galápagos by Geist et al. (2006); however, their source(s) remained enigmatic. The new EM300 data show that a number of the deep lava flows originate from small cones along the mid-lower portion of the NW submarine rift of Fernandina, suggesting that the deep flows owe their origin, at least in part, to submarine rift zone volcanism.
  • Other
    Value beyond view: illuminating the human benefits of the ocean twilight zone
    (Woods Hole Oceanographic Institution, 2019-12-12) Hoagland, Porter ; Jin, Di ; Holland, Michael ; Kostel, Ken ; Taylor, Eric ; Renier, Natalie ; Holmes, Mark
    The twilight zone is a fundamental part of the ocean ecosystem, playing an important role in carbon sequestration and marine food webs and supporting the natural function of many planetary processes. Ecosystem services provided by the twilight zone are highly beneficial to humans, but they occur largely out of sight and they are undervalued by society as a result. To better evaluate the benefits that the twilight zone provides, an ecosystem service framework provides a way to organize our thinking about them and even to quantify their economic value. With this information at hand, leaders and policymakers can think more carefully about what we stand to gain or lose from actions that affect the twilight zone and the broader ocean environment to which it is tightly linked, particularly as we strive for the sustainable use of marine resources. The title was changed from "Ecosystem Services of the Mesopelagic" to "Value beyond view: illuminating the human benefits of the ocean twilight zone."