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ArticleTropical pacific observing system(Frontiers Media, 2019-02-18) Smith, Neville ; Kessler, William S. ; Cravatte, Sophie ; Sprintall, Janet ; Wijffels, Susan E. ; Cronin, Meghan F. ; Sutton, Adrienne J. ; Serra, Yolande L. ; Dewitte, Boris ; Strutton, Peter G. ; Hill, Katherine Louise ; Sen Gupta, Alexander ; Lin, Xiaopei ; Takahashi, Ken ; Chen, Dake ; Brunner, ShelbyThis paper reviews the design of the Tropical Pacific Observing System (TPOS) and its governance and takes a forward look at prospective change. The initial findings of the TPOS 2020 Project embrace new strategic approaches and technologies in a user-driven design and the variable focus of the Framework for Ocean Observing. User requirements arise from climate prediction and research, climate change and the climate record, and coupled modeling and data assimilation more generally. Requirements include focus on the upper ocean and air-sea interactions, sampling of diurnal variations, finer spatial scales and emerging demands related to biogeochemistry and ecosystems. One aim is to sample a diversity of climatic regimes in addition to the equatorial zone. The status and outlook for meeting the requirements of the design are discussed. This is accomplished through integrated and complementary capabilities of networks, including satellites, moorings, profiling floats and autonomous vehicles. Emerging technologies and methods are also discussed. The outlook highlights a few new foci of the design: biogeochemistry and ecosystems, low-latitude western boundary currents and the eastern Pacific. Low latitude western boundary currents are conduits of tropical-subtropical interactions, supplying waters of mid to high latitude origin to the western equatorial Pacific and into the Indonesian Throughflow. They are an essential part of the recharge/discharge of equatorial warm water volume at interannual timescales and play crucial roles in climate variability on regional and global scales. The tropical eastern Pacific, where extreme El Niño events develop, requires tailored approaches owing to the complex of processes at work there involving coastal upwelling, and equatorial cold tongue dynamics, the oxygen minimum zone and the seasonal double Intertropical Convergence Zone. A pilot program building on existing networks is envisaged, complemented by a process study of the East Pacific ITCZ/warm pool/cold tongue/stratus coupled system. The sustainability of TPOS depends on effective and strong collaborative partnerships and governance arrangements. Revisiting regional mechanisms and engaging new partners in the context of a planned and systematic design will ensure a multi-purpose, multi-faceted integrated approach that is sustainable and responsive to changing needs.
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ArticleCharacteristics and evolution of sill-driven off-axis hydrothermalism in Guaymas Basin - the Ringvent site(Nature Research, 2019-09-25) Teske, Andreas ; McKay, Luke J. ; Ravelo, Ana Christina ; Aiello, Ivano ; Mortera, Carlos ; Núñez-Useche, Fernando ; Canet, Carles ; Chanton, Jeffrey P. ; Brunner, Benjamin ; Hensen, Christian ; Ramírez, Gustavo A. ; Sibert, Ryan J. ; Turner, Tiffany ; Chambers, Christopher R. ; Buckley, Andrew ; Joye, Samantha B. ; Soule, S. Adam ; Lizarralde, DanielThe Guaymas Basin spreading center, at 2000 m depth in the Gulf of California, is overlain by a thick sedimentary cover. Across the basin, localized temperature anomalies, with active methane venting and seep fauna exist in response to magma emplacement into sediments. These sites evolve over thousands of years as magma freezes into doleritic sills and the system cools. Although several cool sites resembling cold seeps have been characterized, the hydrothermally active stage of an off-axis site was lacking good examples. Here, we present a multidisciplinary characterization of Ringvent, an ~1 km wide circular mound where hydrothermal activity persists ~28 km northwest of the spreading center. Ringvent provides a new type of intermediate-stage hydrothermal system where off-axis hydrothermal activity has attenuated since its formation, but remains evident in thermal anomalies, hydrothermal biota coexisting with seep fauna, and porewater biogeochemical signatures indicative of hydrothermal circulation. Due to their broad potential distribution, small size and limited life span, such sites are hard to find and characterize, but they provide critical missing links to understand the complex evolution of hydrothermal systems.