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Chu, Jackson W.F.; Curkan, Curtis; Tunnicliffe, Verena; Chu, Jackson W. F. 2018-03-14 Global expansion of oxygen deficient (hypoxia) waters will have detrimental effects on marine life in the Northeast Pacific Ocean (NEP) where some of the largest proportional losses in aerobic habitat are predicted to occur. However, few studies have accounted for the high environmental variability in this region while including natural community-assembly dynamics. Here, we present results from a 14-month deployment of a benthic camera platform tethered to the VENUS cabled observatory in the seasonally hypoxic Saanich Inlet. Our time series continuously-recorded, natural cycles of deoxygenation and reoxygenation that allowed us to test whether a community from the NEP showed hysteresis in its recovery compared to hypoxia-induced decline and to address the processes driving temporal beta diversity under variable states of hypoxia. Using high-frequency ecological time series we reveal (1) differences in the response and recovery of the epibenthic community are rate-limited by recovery of the sessile species assemblage, (2) both environmental and biological processes influence community assembly patterns at multiple time-scales, and (3) interspecific processes can drive temporal beta diversity in seasonal hypoxia. Ultimately, our results illustrate how different time scale dependent drivers can influence the response and recovery of a marine habitat under increasing stress from environmental change.
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Dryad
Chu, Jackson W.F.; Leys, Sally P. 2014-05-13 The dorid nudibranchs Peltodoris lentiginosa and Archidoris odhneri were found on glass sponges (Porifera, Hexactinellida) during remotely operated vehicle surveys of three reefs in the Strait of Georgia, British Columbia, Canada. Eight nudibranchs were sampled from 2009 to 2011. Identification of sponge spicules found in their gut and fecal contents confirmed the nudibranchs to be predators of the reef-forming hexactinellids Aphrocallistes vastus and Heterochone calyx, as well as of the demosponge Desmacella austini, which encrusts skeletons of the glass sponges. Four of five nudibranchs dissected for gut content analysis had stomachs containing sponge spicules. Counts from high-definition video footage taken during systematic surveys done in 2009 showed that nudibranchs were found in only two of the three glass sponge reefs. These data provide the first quantitative evidence of a molluscan predator on glass sponges found outside of Antarctica, and establish the first trophic link between glass sponges and their associated community of animals in a sponge reef ecosystem on the western Canadian continental shelf.
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Chu, Jackson W.F.; Matthews, Marie-Noël R.; Alavizadeh, Zahra; MacGillivray, Alexander O.; Therriault, Thomas W.; Schmill, Alejandro; Ban, Natalie C. 2021-12-17 This repository contains spatial data of modelled underwater noise levels at the benthic boundary layer due to vessel traffic in the Salish Sea. Received equivalent continuous noise levels (Leq) near the seabed were calculated using JASCO’s cumulative vessel noise model (Acoustic Real-Time Exposure Model for In-Motion Sources; ARTEMIS). The model incorporated detailed source-level data and accounts for the influence of speed and class on vessel noise emissions. Vessel traffic information was based on 2015 automatic identification system (AIS) data, scaled to compensate for yearly traffic increases through 2020 and to include non-AIS traffic. Seasonal variability in sound propagation conditions and vessel traffic was assessed by modelling noise levels during representative months in winter and summer (January and July, respectively).

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