From silk to satellite: half a century of ocean colour anomalies in the Northeast Atlantic

Authors

  • Dionysios E. Raitsos,

    Corresponding author
    1. Plymouth Marine Laboratory (PML), Plymouth, UK
    • Correspondence: Dionysios E. Raitsos, tel. +44 01752 633406, fax +44 01752 633 101, e-mail: dra@pml.ac.uk

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  • Yaswant Pradhan,

    1. Met Office, Exeter, UK
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  • Samantha J. Lavender,

    1. Pixalytics Ltd, Plymouth, Devon, UK
    2. School of Marine Science & Engineering/Marine Institute, University of Plymouth, Plymouth, UK
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  • Ibrahim Hoteit,

    1. King Abdullah University for Science and Technology, Thuwal, Saudi Arabia
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  • Abigail McQuatters-Gollop,

    1. Sir Alister Hardy Foundation for Ocean Science (SAHFOS), The Laboratory, Plymouth, UK
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  • Phillip C. Reid,

    1. School of Marine Science & Engineering/Marine Institute, University of Plymouth, Plymouth, UK
    2. Sir Alister Hardy Foundation for Ocean Science (SAHFOS), The Laboratory, Plymouth, UK
    3. Marine Biological Association of the UK, The Laboratory, Plymouth, UK
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  • Anthony J. Richardson

    1. Centre for Applications in Natural Resource Mathematics (CARM), School of Mathematics and Physics, University of Queensland, St Lucia, Queensland, Australia
    2. Climate Adaptation Flagship, CSIRO Marine and Atmospheric Research, Ecosciences Precinct, Dutton Park, Queensland, Australia
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Abstract

Changes in phytoplankton dynamics influence marine biogeochemical cycles, climate processes, and food webs, with substantial social and economic consequences. Large-scale estimation of phytoplankton biomass was possible via ocean colour measurements from two remote sensing satellites – the Coastal Zone Colour Scanner (CZCS, 1979–1986) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, 1998–2010). Due to the large gap between the two satellite eras and differences in sensor characteristics, comparison of the absolute values retrieved from the two instruments remains challenging. Using a unique in situ ocean colour dataset that spans more than half a century, the two satellite-derived chlorophyll-a (Chl-a) eras are linked to assess concurrent changes in phytoplankton variability and bloom timing over the Northeast Atlantic Ocean and North Sea. Results from this unique re-analysis reflect a clear increasing pattern of Chl-a, a merging of the two seasonal phytoplankton blooms producing a longer growing season and higher seasonal biomass, since the mid-1980s. The broader climate plays a key role in Chl-a variability as the ocean colour anomalies parallel the oscillations of the Northern Hemisphere Temperature (NHT) since 1948.

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