Tunnicliffe Verena

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Tunnicliffe
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Verena
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  • Article
    Groundfish overfishing, diatom decline, and the marine silica cycle : lessons from Saanich Inlet, Canada, and the Baltic Sea cod crash
    (American Geophysical Union, 2009-12-31) Katz, Timor ; Yahel, Gitai ; Yahel, Ruthy ; Tunnicliffe, Verena ; Herut, Barak ; Snelgrove, Paul V. R. ; Crusius, John ; Lazar, Boaz
    In this study, we link groundfish activity to the marine silica cycle and suggest that the drastic mid-1980s crash of the Baltic Sea cod (Gadus morhua) population triggered a cascade of events leading to decrease in dissolved silica (DSi) and diatom abundance in the water. We suggest that this seemingly unrelated sequence of events was caused by a marked decline in sediment resuspension associated with reduced groundfish activity resulting from the cod crash. In a study in Saanich Inlet, British Columbia, Canada, we discovered that, by resuspending bottom sediments, groundfish triple DSi fluxes from the sediments and reduce silica accumulation therein. Using these findings and the available oceanographic and environmental data from the Baltic Sea, we estimate that overfishing and recruitment failure of Baltic cod reduced by 20% the DSi supply from bottom sediments to the surface water leading to a decline in the diatom population in the Baltic Sea. The major importance of the marginal ocean in the marine silica cycle and the associated high population density of groundfish suggest that groundfish play a major role in the silica cycle. We postulate that dwindling groundfish populations caused by anthropogenic perturbations, e.g., overfishing and bottom water anoxia, may cause shifts in marine phytoplankton communities.
  • Article
    Axial Seamount
    (Oceanography Society, 2010-03) Chadwick, William W. ; Butterfield, David A. ; Embley, Robert W. ; Tunnicliffe, Verena ; Huber, Julie A. ; Nooner, Scott L. ; Clague, David A.
    Axial Seamount is a hotspot volcano superimposed on the Juan de Fuca Ridge (JdFR) in the Northeast Pacific Ocean. Due to its robust magma supply, it rises ~ 800 m above the rest of JdFR and has a large elongate summit caldera with two rift zones that parallel and overlap with adjacent segments of the spreading center.
  • Article
    Exploring the ecology of deep-sea hydrothermal vents in a metacommunity framework
    (Frontiers Media, 2018-02-21) Mullineaux, Lauren S. ; Metaxas, Anna ; Beaulieu, Stace E. ; Bright, Monika ; Gollner, Sabine ; Grupe, Benjamin ; Herrera, Santiago ; Kellner, Julie B. ; Levin, Lisa A. ; Mitarai, Satoshi ; Neubert, Michael G. ; Thurnherr, Andreas M. ; Tunnicliffe, Verena ; Watanabe, Hiromi K. ; Won, Yong-Jin
    Species inhabiting deep-sea hydrothermal vents are strongly influenced by the geological setting, as it provides the chemical-rich fluids supporting the food web, creates the patchwork of seafloor habitat, and generates catastrophic disturbances that can eradicate entire communities. The patches of vent habitat host a network of communities (a metacommunity) connected by dispersal of planktonic larvae. The dynamics of the metacommunity are influenced not only by birth rates, death rates and interactions of populations at the local site, but also by regional influences on dispersal from different sites. The connections to other communities provide a mechanism for dynamics at a local site to affect features of the regional biota. In this paper, we explore the challenges and potential benefits of applying metacommunity theory to vent communities, with a particular focus on effects of disturbance. We synthesize field observations to inform models and identify data gaps that need to be addressed to answer key questions including: (1) what is the influence of the magnitude and rate of disturbance on ecological attributes, such as time to extinction or resilience in a metacommunity; (2) what interactions between local and regional processes control species diversity, and (3) which communities are “hot spots” of key ecological significance. We conclude by assessing our ability to evaluate resilience of vent metacommunities to human disturbance (e.g., deep-sea mining). Although the resilience of a few highly disturbed vent systems in the eastern Pacific has been quantified, these values cannot be generalized to remote locales in the western Pacific or mid Atlantic where disturbance rates are different and information on local controls is missing.
  • Article
    sFDvent: a global trait database for deep-sea hydrothermal-vent fauna
    (Wiley, 2019-07-30) Chapman, Abbie S. A. ; Beaulieu, Stace E. ; Colaço, Ana ; Gebruk, Andrey V. ; Hilario, Ana ; Kihara, Terue C. ; Ramirez-Llodra, Eva ; Sarrazin, Jozée ; Tunnicliffe, Verena ; Amon, Diva ; Baker, Maria C. ; Boschen‐Rose, Rachel E. ; Chen, Chong ; Cooper, Isabelle J. ; Copley, Jonathan T. ; Corbari, Laure ; Cordes, Erik E. ; Cuvelier, Daphne ; Duperron, Sébastien ; Du Preez, Cherisse ; Gollner, Sabine ; Horton, Tammy ; Hourdez, Stephane ; Krylova, Elena M. ; Linse, Katrin ; LokaBharathi, P. A. ; Marsh, Leigh ; Matabos, Marjolaine ; Mills, Susan W. ; Mullineaux, Lauren S. ; Rapp, Hans Tore ; Reid, William D. K. ; Rybakova, Elena Goroslavskaya ; Thomas, Tresa Remya A. ; Southgate, Samuel James ; Stöhr, Sabine ; Turner, Phillip J. ; Watanabe, Hiromi K. ; Yasuhara, Moriaki ; Bates, Amanda E.
    Motivation Traits are increasingly being used to quantify global biodiversity patterns, with trait databases growing in size and number, across diverse taxa. Despite growing interest in a trait‐based approach to the biodiversity of the deep sea, where the impacts of human activities (including seabed mining) accelerate, there is no single repository for species traits for deep‐sea chemosynthesis‐based ecosystems, including hydrothermal vents. Using an international, collaborative approach, we have compiled the first global‐scale trait database for deep‐sea hydrothermal‐vent fauna – sFDvent (sDiv‐funded trait database for the Functional Diversity of vents). We formed a funded working group to select traits appropriate to: (a) capture the performance of vent species and their influence on ecosystem processes, and (b) compare trait‐based diversity in different ecosystems. Forty contributors, representing expertise across most known hydrothermal‐vent systems and taxa, scored species traits using online collaborative tools and shared workspaces. Here, we characterise the sFDvent database, describe our approach, and evaluate its scope. Finally, we compare the sFDvent database to similar databases from shallow‐marine and terrestrial ecosystems to highlight how the sFDvent database can inform cross‐ecosystem comparisons. We also make the sFDvent database publicly available online by assigning a persistent, unique DOI. Main types of variable contained Six hundred and forty‐six vent species names, associated location information (33 regions), and scores for 13 traits (in categories: community structure, generalist/specialist, geographic distribution, habitat use, life history, mobility, species associations, symbiont, and trophic structure). Contributor IDs, certainty scores, and references are also provided. Spatial location and grain Global coverage (grain size: ocean basin), spanning eight ocean basins, including vents on 12 mid‐ocean ridges and 6 back‐arc spreading centres. Time period and grain sFDvent includes information on deep‐sea vent species, and associated taxonomic updates, since they were first discovered in 1977. Time is not recorded. The database will be updated every 5 years. Major taxa and level of measurement Deep‐sea hydrothermal‐vent fauna with species‐level identification present or in progress. Software format .csv and MS Excel (.xlsx).
  • Article
    Resuspension by fish facilitates the transport and redistribution of coastal sediments
    (Association for the Sciences of Limnology and Oceanography, 2012-07) Katz, Timor ; Yahel, Gitai ; Reidenbach, Matthew A. ; Tunnicliffe, Verena ; Herut, Barak ; Crusius, John ; Whitney, Frank ; Snelgrove, Paul V. R. ; Lazar, Boaz
    Oxygen availability restricts groundfish to the oxygenated, shallow margins of Saanich Inlet, an intermittently anoxic fjord in British Columbia, Canada. New and previously reported 210Pb measurements in sediment cores compared with flux data from sediment traps indicate major focusing of sediments from the oxygenated margins to the anoxic basin seafloor. We present environmental and experimental evidence that groundfish activity in the margins is the major contributor to this focusing. Fine particles resuspended by groundfish are advected offshore by weak bottom currents, eventually settling in the anoxic basin. Transmittance and sediment trap data from the water column show that this transport process maintains an intermediate nepheloid layer (INL) in the center of the Inlet. This INL is located above the redox interface and is unrelated to water density shifts in the water column. We propose that this INL is shaped by the distribution of groundfish (as resuspension sources) along the slope and hence by oxygen availability to these fish. We support this conclusion with a conceptual model of the resuspension and offshore transport of sediment. This fish-induced transport mechanism for sediments is likely to enhance organic matter decomposition in oxygenated sediments and its sequestration in anoxic seafloors.