The devastating algal blooms that plagued the west coast of Florida in 2020 had far-reaching consequences. From massive marine life die-offs to increased asthma cases and significant economic losses, the harmful effects were undeniable. While satellites have been an invaluable tool for detecting algal blooms from space, their effectiveness has been limited to clear sky conditions. However, a recent study led by scientists at NASA’s Jet Propulsion Laboratory has revealed how one instrument, TROPOMI, has the ability to see through thin clouds and shed light on the microscopic algae responsible for these blooms. This enhanced satellite technology has the potential to improve forecasting and management of harmful outbreaks, providing crucial insights for federal agencies and local communities.
The West Florida Shelf
The scientists focused their study on the West Florida Shelf, a region vulnerable to algal blooms due to its nutrient-rich and warm conditions fueled by runoff, fertilizer, and climate change. This stretch of continental crust, stretching from the Panhandle to the Keys, experiences the transport of the microscopic algae, Karenia brevis (K. brevis), towards the coastline through strong winds and ocean currents. Understanding the behavior and patterns of these blooms is essential for developing effective monitoring and forecasting systems.
Harmful algal blooms, particularly those caused by K. brevis, present a significant threat to marine and human life. These blooms produce a potent neurotoxin that can result in massive fish kills and impact marine animals such as turtles, manatees, and birds. The toxin can also have respiratory effects on humans when inhaled and cause gastrointestinal illness when shellfish containing the toxin are consumed. Identifying and tracking these blooms is crucial for protecting both ecological and human health.
TROPOMI, an instrument onboard the European Sentinel 5P spacecraft, was originally designed to measure air pollution. However, through its advanced imaging capabilities, including four spectrometers that capture a wide range of light wavelengths, TROPOMI has proven to be a valuable tool for monitoring algal blooms. By detecting the solar-induced fluorescence emitted by K. brevis, TROPOMI provides double the fluorescence information compared to previous methods that rely on ocean color measurements. Additionally, TROPOMI’s ability to penetrate thin cloud cover allows for more frequent measurements and a deeper understanding of the ocean surface.
Combining Technologies for Enhanced Monitoring
While TROPOMI has demonstrated its effectiveness in detecting algal blooms, combining it with other satellite instruments can further enhance monitoring efforts. MODIS (Moderate Resolution Imaging Spectroradiometer), aboard the Aqua and Terra satellites, is currently used to detect algae on clear days in Florida and other areas. The upcoming launch of NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) mission will introduce a new ocean color instrument that will study marine ecosystems in unprecedented detail. By observing phytoplankton and other ocean biology, atmospheric aerosols, and clouds in multiple wavelengths, PACE will significantly improve the forecasting of harmful algal blooms and the overall understanding of marine ecosystems.
The Benefits of Early Warning Systems
The ability to detect and forecast algal blooms via satellite has tangible benefits in terms of cost savings and public health. A case study involving the early detection of cyanobacteria in Utah Lake showed significant savings on healthcare expenses, lost work hours, and other economic losses. With just a few days of advance warning, prompt action can be taken, including issuing public alerts and closing beaches. By leveraging the power of satellite technology, early warning systems can minimize the impact of harmful algal blooms on communities and ecosystems.
Satellite technology, particularly instruments like TROPOMI, offers immense potential in uncovering the secrets of harmful algal blooms. Through its advanced capabilities in detecting solar-induced fluorescence and ability to penetrate cloud cover, TROPOMI provides valuable insights into the behavior and extent of these blooms. When combined with other satellite instruments, such as MODIS and future missions like PACE, monitoring efforts can be further enhanced, leading to more accurate forecasts and better management of outbreaks. Early warning systems powered by satellite technology can result in significant cost savings and improved public health outcomes. By understanding the complex dynamics of algal blooms, we can take meaningful steps towards protecting our oceans and communities from their harmful effects.
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