Research ArticleMarine Ecology

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

See allHide authors and affiliations

Science Advances  31 May 2017:
Vol. 3, no. 5, e1602468
DOI: 10.1126/sciadv.1602468
  • Fig. 1 The Malaspina 2010 Circumnavigation Expedition.

    The stations along the cruise track (A). Dissolved oxygen concentration (B) and downwelling irradiance (C) in the visible spectrum (400 to 700 nm) in μmol quanta m−2 s−1 (logarithmic scale). Daytime DSL weighted median depths (blue line) with 25 and 75% quartiles (black lines) are indicated in (B) and (C). Downwelling irradiance was measured down to depths of 180 to 280 m and calculated according to a proxy model (see Materials and Methods) of light attenuation beyond. Distance is the distance traveled along the cruise track from the first station.

  • Fig. 2 Daytime distribution of acoustic backscatter in the mesopelagic (200 to 1000 m).

    Percentage acoustic backscatter as a function of depth (A), ambient dissolved oxygen concentration (B), and ambient irradiance (C) of the backscatter. Black dots are data from all stations, and each dot represents the acoustic backscatter of a 2-m depth interval at a particular station as a percentage of total backscatter between 200 and 1000 m at that station. The acoustic backscatter marked in colors are from three stations with different oxygen regimes: low oxygen (Pacific Ocean, 15.9°N, 124.5°W), medium oxygen (Atlantic Ocean, 11.7°S, 31.4°W), and high oxygen (Indian Ocean, 29.6°S, 89.4°E). The boxplots show median, quartiles, and the range of the DSL WMDs for all stations.

  • Fig. 3 DSL daytime depth in relation to light penetration.

    The WMD of the DSL plotted against the reciprocal light attenuation coefficient that is (A) modeled (KI) for the entire water column down to 1000-m depth and (B) estimated (K0.01%) from irradiance measurements conducted in the upper water masses down to 0.01% light depth.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/5/e1602468/DC1

    table S1. Model of the observed light attenuation coefficient.

    table S2. Linear regression analyses of the depth-specific light attenuation coefficient versus fluorescence or dissolved oxygen.

    fig. S1. The observed depth-specific light attenuation coefficient versus that approximated from the multiple regression model.

    fig. S2. DSL distribution along the cruise track.

    fig. S3. Association between the depth-specific light attenuation coefficient and the dissolved oxygen concentration.

    fig. S4. Observations of fluorescence, dissolved oxygen concentration, and depth-specific light attenuation coefficient.

  • Supplementary Materials

    This PDF file includes:

    • table S1. Model of the observed light attenuation coefficient.
    • table S2. Linear regression analyses of the depth-specific light attenuation coefficient versus fluorescence or dissolved oxygen.
    • fig. S1. The observed depth-specific light attenuation coefficient versus that approximated from the multiple regression model.
    • fig. S2. DSL distribution along the cruise track.
    • fig. S3. Association between the depth-specific light attenuation coefficient and the dissolved oxygen concentration.
    • fig. S4. Observations of fluorescence, dissolved oxygen concentration, and depth-specific light attenuation coefficient.

    Download PDF

    Files in this Data Supplement:

Navigate This Article