ESA-MERIS 10-Year Mission Reveals Contrasting Phytoplankton Bloom Dynamics in Two Tropical Regions of Northern Australia

David Blondeau-Patissier, Thomas Schroeder, Vittorio Brando, Stefan Maier, Arnold Dekker, Stuart Phinn

    Research output: Contribution to journalArticle

    18 Downloads (Pure)

    Abstract

    The spatial and temporal variability of phytoplankton blooms was investigated in two tropical coastal regions of northern Australia using the MEdium Resolution Imaging Spectrometer (MERIS) full mission (2002-2012) reduced resolution dataset. Satellite-derived proxies for phytoplankton (Chlorophyll-a (Chl), Fluorescence Line Height (FLH), Maximum Chlorophyll Index (MCI)) and suspended sediment (Total Suspended Matter (TSM)) were jointly analyzed for two clusters of the Great Barrier Reef Wet tropics (GBRW; 15°-19.5°S; Queensland) and the Van Diemen Gulf (VDG; 9°-13°S; Northern Territory). The analysis of time-series and Hovmöller diagrams of the four MERIS products provided a unique perspective on the processes linking phytoplankton blooms and river runoff, or resuspension, across spatio-temporal scales. Both regions are characterized by a complex oceanography and seasonal inflows of sediment, freshwater and nutrients during the tropical wet season months (November to April). The GBRW is characterized by a great variability in water clarity (Secchi depth 0-25 m). A long history of agricultural land use has led to a large increase in the seasonal discharge of sediments and nutrients, triggering seasonal phytoplankton blooms (>0.4 mgm-3) between January and April. In contrast, the VDG is a poorly flushed, turbid (Secchi depth ≤5 m) environment with strong tidal-energy (4-8 m) and very limited land use. Phytoplankton blooms here were found to have higher Chl concentrations (>1.0 mgm-3) than in the GBRW, occurring up to twice a year between January and April. Over the 10-year MERIS mission, a weak decline in Chl and TSM was observed for the VDG (Sen slope:-2.85%/decade, τ =-0.32 and-3.57%/decade, τ =-0.24; p « 0.05), while no significant trend in those two satellite products was observed in the GBRW. Cyanobacteria surface algal blooms occur in both regions between August and October. The MCI and FLH products were found to adequately complement Chl, while TSM provided relevant insight for the assessment of sediment resuspension and river runoff.
    Original languageEnglish
    Pages (from-to)2963-2988
    Number of pages26
    JournalRemote Sensing
    Volume6
    Issue number4
    DOIs
    Publication statusPublished - 1 Apr 2014

    Fingerprint Dive into the research topics of 'ESA-MERIS 10-Year Mission Reveals Contrasting Phytoplankton Bloom Dynamics in Two Tropical Regions of Northern Australia'. Together they form a unique fingerprint.

    Cite this