Multi-scale responses of scattering layers to environmental variability in Monterey Bay, California

摘要: Abstract A 38 kHz upward-facing echosounder was deployed on the seafloor at a depth of 875 m in Monterey Bay, CA, USA (36° 42.748′N, 122° 11.214′W) from 27 February 2009 to 18 August 2010. This 18-month record acoustic backscatter compared oceanographic time series nearby data buoy investigate responses animals sound-scattering layers oceanic variability seasonal and sub-seasonal scales. Pelagic animals, as measured by backscatter, moved higher water column decreased abundance during spring upwelling, attributed avoidance shoaling oxycline advection offshore. Seasonal changes were most evident non-migrating scattering layer near 500 m that disappeared reappeared summer, building maximum fall. At scales, similar observed after individual upwelling events, though they much weaker than relationship. Correlations with also differed depth. Backscatter upper immediately following then increased approximately 20 days later. Similar correlations existed deeper column, but increasing lags, suggesting near-surface productivity propagated down 10–15 m d −1 , consistent sinking speeds marine snow Bay. Sub-seasonal best correlated sea-surface height, passive physical transport important these