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Remote Sensing of Algal Blooms: An Overview with Case Studies

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KLEMAS, V., 2012. Remote sensing of algal blooms: an overview with case studies. Journal of Coastal Research, 28(1A), 34–43. West Palm Beach (Florida), ISSN 0749-0208. High concentrations of nutrients from agricultural and urban runoff, or those produced by coastal upwelling, are causing algal blooms in many estuaries and coastal waters. Algal blooms induce eutrophic conditions, depleting oxygen levels needed by organic life, limiting aquatic plant growth by reducing water transparency, and producing toxins that can harm fish, benthic animals, and humans. The magnitude and frequency of phytoplankton blooms have increased globally in recent decades, as shown in data from ocean-color sensors on-board satellites. Satellite and airborne measurements of spectral reflectance (ocean color) represent an effective way for monitoring phytoplankton by its proxy, chlorophyll-a, the green pigment that is present in all algae. This article reviews the use of remote sensing techniques for detecting phytoplankton and mapping algal blooms. Two case studies are presented, illustrating the advantages and limitations of satellite and airborne remote sensing. www.JCRonline.org ADDITIONAL INDEX WORDS: Harmful algal blooms, remote sensing, eutrophication, phytoplankton blooms.
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... They are the foundation of food chains and webs in aquatic environments. When nutrient loading occurs from agricultural and urban runoff, the abundance of nutrients causes the concentrations of these microorganisms to grow uncontrollably, resulting in HABs [19]. Blooms typically occur in the spring when longer days provide stronger sunlight. ...
... Water warms and becomes less dense, allowing stratification. The upper stratified layer retains the bacteria where the sun is bright, and nutrients are plentiful [19]. ...
... It is estimated that freshwater algal blooms cost the nation nearly $4.8 billion annually [21]. Magnitude and frequency of HABs are increasing globally [19]. Early detection and comprehensive monitoring of HABs is needed to effectively manage and mitigate detrimental impacts [11]. ...
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... Algal blooms, which are abnormal marine phenomena, have become a global problem in recent decades (Anderson et al., 2012;Klemas, 2011;Grattan et al., 2016;Sakamoto et al., 2021). Some of the related phytoplankton species can cause toxicity to sea products and human health (Wells et al., 2015;Sanseverino et al., 2016). ...
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