title: Atmospheric rivers and the mass mortality of wild oysters: insight into an extreme future?
abstract: Climate change is predicted to increase the frequency and severity of extreme events. However, the biological consequences of extremes remain poorly resolved owing to their unpredictable nature and difficulty in quantifying their mechanisms and impacts. One key feature delivering precipitation extremes is an atmospheric river (AR), a long and narrow filament of enhanced water vapour transport. Despite recent attention, the biological impacts of ARs remain undocumented. Here, we use biological data coupled with remotely sensed and in situ environmental data to describe the role of ARs in the near 100% mass mortality of wild oysters in northern San Francisco Bay. In March 2011, a series of ARs made landfall within California, contributing an estimated 69.3% of the precipitation within the watershed and driving an extreme freshwater discharge into San Francisco Bay. This discharge caused sustained low salinities (less than 6.3) that almost perfectly matched the known oyster critical salinity tolerance and was coincident with a mass mortality of one of the most abundant populations throughout this species' range. This is a concern, because wild oysters remain a fraction of their historical abundance and have yet to recover. This study highlights a novel mechanism by which precipitation extremes may affect natural systems and the persistence of sensitive species in the face of environmental change.
authors.affiliation: Bodega Marine Laboratory, University of California, Davis, Bodega Bay, CA 94923, USA bscheng@gmail.com.|Smithsonian MarineGEO, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA.
authors.forename: Brian S
authors.identifier: 0000-0003-1679-8398
authors.initials: BS
authors.lastname: Cheng
authors.affiliation: San Francisco Bay National Estuarine Research Reserve, San Francisco State University, Tiburon, CA 94920, USA.|Smithsonian Environmental Research Center, Tiburon, CA 94920, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Chang
authors.affiliation: San Francisco Bay National Estuarine Research Reserve, San Francisco State University, Tiburon, CA 94920, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Deck
authors.affiliation: San Francisco Bay National Estuarine Research Reserve, San Francisco State University, Tiburon, CA 94920, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Ferner
mesh_terms: D000818:Animals; D001272:Atmosphere; D061006:Bays; D002140:California; D057231:Climate Change; D009026:Mortality; D010125:Ostreidae / Q000502:physiology*; D054712:Salinity; D013227:Steam
chemical_list: D013227:Steam
keywords: atmospheric river; climate change; extreme; flood; mass mortality event; oyster