Monitoring toxic cyanobacteria Lyngbya majuscula (Gomont) in Moreton Bay, Australia by integrating satellite image data and field mapping

摘要: Large-scale blooms of Lyngbya majuscula (Gomont) have occurred throughout Moreton Bay (south-east Queensland) and been documented since 1997. L. is a toxic cyanobacteria which fixes nitrogen found attached to: seagrass, algae coral. The smothering nature has affected human environmental health in sensitive coastal ecosystems. To reduce these impacts, monitoring an essential component studying the origins development blooms. An accurate cost effective means to map extent bloom its biophysical properties needed. This study presents operational approach for mapping clear shallow water regions Bay, eastern Australia, from combination field remotely sensed data sets. ability discriminate other substrate types over range depths was first examined using detailed reflectance spectra, measured optical waters radiative transfer model (Hydrolight 4.1). A two-stage process then used majuscula. spatial major recorded boat-based survey by marine park authorities point-based GPS measurements. sampling timed coincide with overpass Landsat 7 ETM+ sensor. When results detected more than 25% cover area, cloud free image acquired that date. In second stage mapping, selected provided basis supervised classification Effort accuracy assessment both methods indicated trade-off between areal coverage accuracy. based procedure 100% 58% contrast, method covered only 0.5% but almost outlined this work adopted as standard operating Bay. illustrates how remote sensing can be combined monitoring, provide useful information understand manage