Temporal dynamics of the deep-sea pink urchin Strongylocentrotus fragilis on the Northeast Pacific continental margin

dc.contributor.authorCommand, Rylan J.
dc.contributor.authorDe Leo, Fabio C.
dc.contributor.authorRobert, Katleen
dc.descriptionWe are thankful for the support from ONC’s marine and digital operations staff for servicing and maintaining the NEPTUNE observatory and for the curation and quality control of all oceanographic data streams used in this study. We also thank the Department of Fisheries and Oceans (DFO) and the Institute of Ocean Sciences (IOS), in Sidney, BC, Canada, for the publicly and freely available data from the long-term Line P monitoring program.en_US
dc.description.abstractThe Northeast Pacific continental margin is characterized by strong seasonal upwelling, which drives high primary productivity, and supports high diversity and biomass of benthic megafauna. The recent occurrence of a marine heat wave (“The Blob”, sensu Kintisch, 2015) in 2013–2016 resulted in changes to phytoplankton community composition and loss of coastal kelp abundance and diversity, reducing gross primary productivity in the region. However, cumulative effects of marine heat waves and ongoing basin-scale deoxygenation in deepsea ecosystems remain poorly understood. Here, we use a 7-year time series of physicochemical and video imagery data from Ocean Networks Canada’s NEPTUNE observatory to investigate temporal dynamics of the deepsea pink urchin Strongylocentrotus fragilis in relation to multi-year environmental variability. Using generalized additive models, we show that local S. fragilis density at Barkley Upper Slope (420 m) fluctuated over time and was partially explained by changes in dissolved oxygen concentration and suspended particulate matter in the benthic boundary layer (ADCP backscatter), with high urchin density corresponding to high oxygen and low backscatter. Seafloor dissolved oxygen ranged from 0.80 to 1.89 mL/L and varied seasonally, exhibiting a clear negative correlation with sea surface primary productivity (MODIS satellite Chl-a data), corresponding with the onset of yearly upwelling conditions. However, during the anomalously warm years affected by ‘The Blob’, dampened upwelling maintained higher dissolved oxygen conditions near the seafloor. S. fragilis density declined during ‘Blob’ conditions, likely in response to reduced kelp and phytodetritus subsidies from coastal waters. We propose a foraging-respiration trade-off hypothesis, whereby S. fragilis forages in deeper water during weak upwelling and migrates to shallower habitats during low oxygen conditions. S. fragilis is an important bioturbator and detritivore; changes in the density and distribution of this species may directly affect sediment turnover rates and nutrient cycling on the continental margin, with consequences for surface and coastal productivity.en_US
dc.description.sponsorshipOcean Networks Canada is funded through the Canada Foundation for Innovation-Major Science Initiative (CFI-MSI) fund 30199. RC was supported by an Early Career Faculty Award Grant to Dr. Katleen Robert from the Marine Environmental Observation, Prediction and Response Network (MEOPAR) and a Canada Research Chair (Ocean Mapping) to PI KR.en_US
dc.identifier.citationCommand, R. J., De Leo, F. C., & Robert, K. (2023). Temporal dynamics of the deep-sea pink urchin Strongylocentrotus fragilis on the Northeast Pacific continental margin. Deep Sea Research Part I: Oceanographic Research Papers, 193, 103958. https://doi.org/10.1016/j.dsr.2022.103958.en_US
dc.publisherDeep Sea Research Part I: Oceanographic Research Papersen_US
dc.subjectMarine heatwavesen_US
dc.subjectContinental marginen_US
dc.subjectDeep seaen_US
dc.subjectTime seriesen_US
dc.titleTemporal dynamics of the deep-sea pink urchin Strongylocentrotus fragilis on the Northeast Pacific continental marginen_US


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