Light penetration structures the deep acoustic scattering layers in the global ocean

• DOI: 10.1126/sciadv.1602468
• Publication Date: 2017-09-14T20:21:24Z
• Authors: Dag L. Aksnes; Anders Røstad; Stein Kaartvedt; Udane Martinez; Carlos M. Duarte; Xabier Irigoien
• Keywords: Mesopelagic zone; Bathyal zone

The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring pelagic open ocean ecosystem. It formed by mesopelagic fishes invertebrates. DSL animals are an important food source for marine megafauna contribute to biological carbon pump through active flux of organic transported in their daily vertical migrations. They occupy depths from 200 1000 m at daytime migrate varying degree into surface waters nighttime. Their depth, which determines migration amplitude, varies global concert with water mass properties, particular oxygen regime, but causal underpinning these correlations has been unclear. We present evidence that broad variability oceanic depth observed during Malaspina 2010 Circumnavigation Expedition governed variation light penetration. find distribution conforms common optical correlation between dissolved penetration provides parsimonious explanation association shallow distributions hypoxic waters. In enhancing understanding this phenomenon, our results should improve ability predict model dynamics one largest animal biomass components on earth, key roles web.