Using the Red Band Difference Algorithm to Detect and Monitor a Karenia spp. Bloom Off the South Coast of Ireland, June 2019

Abstract

During the months of May, June, July and August 2019 the Red Band Difference algorithm was tested over Irish waters to assess its suitability for the Irish harmful algal bloom alert system. Over the 4 weeks of June an extensive localised surface phytoplankton bloom formed in the Celtic Sea, south of Ireland. Satellite imagery from the Sentinel-3a’s Ocean and Land Colour Instrument, processed using the Red Band Difference algorithm detected the bloom in surface shelf waters and helped monitor its movement. Daily satellite images indicated that the bloom appeared at the sea surface on the 2nd June 2019 and peaked in size and surface abundance in offshore shelf waters within 4 weeks, remnants remained at the surface into July. A particle tracking approach was used to replicate oceanic circulation patterns in the vicinity of the observed algal bloom and estimate its trajectory. The initial horizontal distribution of particles in the tracking model were based on a satellite imagery polygon of the bloom when it first appeared in surface waters. Good agreement was observed between satellite imagery of the bloom and the particle tracking model. In situ sampling efforts from a research cruise and the national inshore phytoplankton monitoring programme confirmed that Karenia mikimotoi was the causative organism of the bloom. This pilot study shows great potential to use the Red Band Difference algorithm in the existing Irish harmful algal bloom alert system. In addition, satellite ocean colour data combined with particle tracking model estimates can be a useful tool to monitor high biomass harmful algal bloom forming species, such as Karenia mikimotoi, in surface coastal waters around Ireland and elsewhere.

Novel Methodologies for Providing In Situ Data to HAB Early Warning Systems in the European Atlantic Area: The PRIMROSE Experience

“…Improving the coordination of oceanographic vessel operators can facilitate the acquisition of samples if the HAB alert happens to coincide with an oceanographic cruise. An illustration of this coordination is reported in Jordan et al, (2021), this issue. Karenia spp.…”

“…High biomass blooms can be carried by advection from offshore areas to the coast. For these near surface bloom events, satellite detection is possible with algorithms developed to discriminate some HAB species from benign phytoplankton Kurekin et al, 2014;Jordan et al, 2021). Such HAB detection approaches are particularly powerful if coupled to a numerical model that can predict the likely trajectory of the bloom over the following days and hence provide an early warning for at risk aquaculture sites (Davidson et al, 2016;Maguire et al, 2016).…”

Distribution of Harmful Algae (Karenia spp.) in October 2021 Off Southeast Hokkaido, Japan

“…One method directly estimated Karenia spp. abundances through a combination of reflectance-based red band difference (RBD; Jordan et al, 2021) and in-situ Karenia spp. abundance.…”

“…Red band difference is frequently used for detecting and monitoring Karenia spp. blooms (e.g., Amin et al, 2009;Wolny et al, 2020;Jordan et al, 2021). LH(λ), which is similar to fluorescence line height (Gower et al, 1999), with a baseline formed by the reflectance between 665 and 753 nm, was applied to all spectra (Smith and Bernard, 2020).…”

Proteome Analysis of Whole-Body Responses in Medaka Experimentally Exposed to Fish-Killing Dinoflagellate Karenia mikimotoi

“…Blooms of the species Karenia mikimotoi have caused death of fish and marine invertebrates in various seas and coastal waters of many different countries, although a few were not associated with massive mortality. Over the past half century, from 1966 to 2019, cases were documented in Japan; South Korea; Australia; Alaska; the Gulf of Mexico; the Atlantic coast of the United States; and European countries, including Denmark, France, Germany, Ireland, Norway, Spain, Sweden, and the United Kingdom [5][6][7][8][9][10][11][12][13][14][15]. The first report of K. mikimotoi in China was in Xiamen coastal waters [16].…”