22 JUNE 2022 • WORLD AQUACULTURE • WWW.WA S .ORG Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA), the USGS, and the Environmental Protection Agency (EPA). This project detects and quantifies algal blooms using satellite data and then disseminates these data through a mobile application developed by the EPA to provide a web-based tool that can help identify when a HABmay be forming in lakes and reservoirs. • S-3 EUROHAB is developing a web-based HAB and water quality alert system that uses satellite data to improve HABmonitoring methods in the French-English Channel and is capable of species-level identification of phytoplankton. These services are not yet commercially available. • The Algal Bloom Monitoring System operated by NOAA’s National Center for Coastal Ocean Science (NCCOS) routinely delivers near real-time products for use in locating, monitoring and quantifying algal blooms in lakes and coastal regions of the US using satellite imagery. Drones Remote sensing technologies such as a hyperspectral camera can also be deployed from drones. Drones can provide higher resolution images (up to 1 cm) than satellites but on a much smaller scale. Therefore, drones may be a more efficient means of tracking and monitoring HABs when there is a smaller area of interest, such as a small lake or pond, rather than a larger coastal area. Drones have advantages over satellites in that they are not hampered by cloud cover, can collect data on a more user-defined timescale and can be less costly to operate. Additionally, drones can be used with other sensors that satellites cannot use, such as water quality meters and equipment for collecting physical water samples. The combination of hyperspectral data from a water body and physical water samples allows ground-truthing of bloom composition, including phytoplankton species and toxin levels. This adds an additional level of accuracy and can aid in identifying more effective mitigation strategies. Use of a drone is driven in most cases by the required level of spatial resolution and economic needs. based on light reflectance (Nazirova et al. 2021). Higher turbidity values, in conjunction with other remotely sensed data, may indicate an increase in phytoplankton biomass; however, there are depth limitations as these sensors can only penetrate surface waters (~10 m deep). To determine turbidity values in deeper waters, supplemental algorithms must be used in conjunction with remotely sensed data and direct in-situ measurements, such as a turbidity sensor mounted on a Conductivity, Temperature, Depth (CTD) instrument. Satellite Data Analytics Service Providers Given the challenges of managing large datasets, facility operators may rather choose to use a service provider. Service providers supply the satellite data and the most current (and often custom-designed) data analytics software to properly interpret it. In some cases, satellites are owned by service providers who offer subscription services to data users. In return, the subscriber receives realtime continuous monitoring of specific parameters of interest to the facility. The output of the data analysis will often be displayed in a convenient graphical user interface (Fig. 3) that displays real-time HAB data and allows the user to quickly and easily monitor and track HABs. The data can be accessed from laptops, cell phones or other remote devices. Most providers integrate various data streams to provide a reliable EWS using site-specific parameters. Alerts can be sent when anomalies are detected and mitigation recommendations can be provided. This allows subscribers to take action before experiencing negative impacts from an HAB on their facility. Examples of such satellite service providers include: • ColomboSky’s Aqua XMonitoring provides satellite technology for water quality monitoring and risk management in marine aquaculture. • Satelytics Environmental Health Monitoring Program remotely measures phycocyanin, chlorophyll a, phosphorus and other contaminants. • UMITRON Pulse provides a worldwide high-resolution satellite ocean data map for aquaculture farmers. • CyANweb is a multi-agency project of the National FIGURE 2. Example of a satellite-derived image showing areas of elevated chlorophyll a (in red and orange) in the Gulf of Mexico taken using a MODIS sensor aboard the Aqua satellite (oceanservice.noaa.gov/podcast/may16/os17hab-forecast.html). FIGURE 3. A graphical user interface from ColomboSky’s Aqua X Monitoring showing chlorophyll a concentrations on 18 October 2021 (image), as well as chlorophyll a concentrations over a four-month period (graph) in the northern Adriatic Sea. These interfaces provide convenient, real-time data that allow subscribers to better manage environmental threats to their facilities (Image: ColomboSky).
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