Improved monitoring of HABs using autonomous underwater vehicles (AUV)

Abstract

Abstractincreasing in magnitude and frequency around the globe, causing extensive economic and Blooms of toxic algae are environmental impacts. On the west coast of Florida, blooms of the toxic dinoflagellate Karenia brevis (Davis) have been documented annually for the last 30 years causing respiratory irritation in humans, fish kills, and toxin bioaccumulation in shellfish beds. As a result, methods need to be established to monitor and predict bloom formation and transport to mitigate their harmful effects on the surrounding ecosystems and local communities. In the past, monitoring and mitigation efforts have relied on visual confirmation of water discoloration, fish kills, and laborious cell counts, but recently satellite remote sensing has been used to track harmful algal blooms (HABs) along the Florida coast. Unfortunately satellite ocean color is limited by cloud cover, lack of detection below one optical depth, and revisit frequency, all of which can lead to extended periods without data. To address these shortcomings, an optical phytoplankton discriminator (OPD) was developed to detect K. brevis cells in mixed phytoplankton assemblages. The OPD was integrated into autonomous underwater vehicle (AUV) platforms to gather spatially and temporally relevant data that can be used in collaboration with satellite imagery to provide a 3D picture of bloom dynamics over time. In January 2005, a Remote Environmental Monitoring UnitS (REMUS) AUV with an OPD payload was deployed on the west coast of Florida to retrieve a similarity index (SI), which indicates when K. brevis dominates the phytoplankton community. SI was used to monitor a K. brevis bloom in relation to temperature, salinity, chlorophyll, and ocean currents. Current speed, SI, temperature, salinity, and chlorophyll a from the AUV were used to quantify a 1 km displacement of the K. brevis bloom front that was observed over the deployment period. The ability to monitor short term bloom movement will improve monitoring and predictive efforts that are used to provide warnings for local tourism and fishing industries. In addition, understanding the fine scale environmental conditions associated with bloom formation will increase our ability to predict the location and timing of K. brevis bloom formation. This study demonstrates the use of one autonomous platform and provides evidence that a nested array of AUVs and moorings equipped with new sensors, combined with remote sensing, can provide an early warning and monitoring system to reduce the impact of HABs.

Field applications of the second‐generation Environmental Sample Processor (ESP) for remote detection of harmful algae: 2006‐2007

“…1998; Olson and Sosik 2007), the optical plankton discriminator (Kirkpatrick et al 2000;Robbins et al 2006), the Autonomous Microbial Genosensor , and the Laser In Situ Scattering and Transmissometer (Rienecker et al 2008). These and related instruments can be used independently or integrated with larger scale observing systems (e.g., Ryan et al 2005;Paul et al 2007;Babin et al 2008).…”

Current Techniques for Detecting and Monitoring Algal Toxins and Causative Harmful Algal Blooms

“…Beyond the traditional visual confirmation of water discoloration, fish kills, and laborious cell counts, new technologies for bloom monitoring and tracking span a wide range from the large scale using satellite remote sensing to the smallest scale of "molecular probes" [1,[79][80][81][82][83][84][85][86][87]. These new technologies stem from the need for real-or near real-time simultaneous detection of HAB species and their toxins such that surface water and coastal resource managers can promptly mitigate their economic, ecological, and environmental impacts, including providing the timely warning of approaching HABs [33,88].…”

“…The satellite data may be limited by cloud cover, lack of detection below one optical depth, and revisit frequently, all of which can lead to extended period without data. These shortcomings can be overcame by the use of an autonomous underwater vehicle (AUV) platform that support an optical phytoplankton discriminator (OPD) [87]. Using a Remote Environmental Monitoring UnitS (REMUS) AUV with an OPD deployed on the west of Florida coast, this autonomous platform along with remote sensing data, provide an early warning and monitoring system to reduce the HAB impact.…”

AUV Benthic Habitat Mapping in South Eastern Tasmania

“…Recently, the related AUVs Puma and Jaguar searched for hydrothermal vents under the artic ice [7]. Other AUV systems have been used to explore biophysical coupling, including mapping harmful algal blooms [11] and characterising up-welling around canyons [12].…”