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

Dag L. Aksnes, Anders Røstad, Stein Kaartvedt, Udane Martinez, Carlos M. Duarte, Xabier Irigoien

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring the pelagic open ocean ecosystem. It is formed by mesopelagic fishes and pelagic invertebrates. The DSL animals are an important food source for marine megafauna and contribute to the biological carbon pump through the active flux of organic carbon transported in their daily vertical migrations. They occupy depths from 200 to 1000 m at daytime and migrate to a varying degree into surface waters at nighttime. Their daytime depth, which determines the migration amplitude, varies across the global ocean in concert with water mass properties, in particular the oxygen regime, but the causal underpinning of these correlations has been unclear. We present evidence that the broad variability in the oceanic DSL daytime depth observed during the Malaspina 2010 Circumnavigation Expedition is governed by variation in light penetration. We find that the DSL depth distribution conforms to a common optical depth layer across the global ocean and that a correlation between dissolved oxygen and light penetration provides a parsimonious explanation for the association of shallow DSL distributions with hypoxic waters. In enhancing understanding of this phenomenon, our results should improve the ability to predict and model the dynamics of one of the largest animal biomass components on earth, with key roles in the oceanic biological carbon pump and food web.
Original languageEnglish (US)
Pages (from-to)e1602468
JournalScience advances
Issue number5
StatePublished - May 31 2017

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This is a contribution to the Malaspina 2010 Circumnavigation Expedition project, funded by the CONSOLIDER-Ingenio 2010 program from the Spanish Ministry of Economy and Competitiveness (ref. CSD2008-00077). Additional funding was provided by King Abdullah University of Science and Technology through the baseline program.


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