A Bio-physical Assessment of Harmful Algal Bloom (HAB) Outbreak using Multi-dimensional Array Data during 1998-2017

Abstract

Harmful algal blooms (HABs), Cochlodinium polykrikoides, which related a devastating algal bloom, recently have caused the serious problems of fishery and aquaculture activities in the south coast of Korea (SCK). To understand the evolution of red tide and determine physical factors as a function of the bloom occurrence and disappearance, we used the multi -dimensional data (satellite and in-situ) during 1998-2017. Red tides generally have started with finishing the raining season and then increased with increasing the sea surface temperature and tidal range. To understand the general trend of red tide occurrence, we classify three different scales with cell density, area, and duration of red tides such as small, medium, and large scale red tides. Small and medium scale red tides started in the middle of August. The periods of the maximum cell density and extinction were shown in the early and end of September. SST in small and medium scale red tides was higher than in large scale red tides. Even though the tidal range was relatively small at the beginning of the outbreak, it was increased in the maximum cell density and decreased in the extinction period. Large scale red tides began in the early of August and the maximum cell density appeared at the end of August. SST was the lowest and the tidal range was the largest difference in the beginning outbreak and the lowest difference in the maximum cell density. In particular, the phenomenon of large-scale variation in the overall time series was that the SST and PAR in large scale red tides were relatively low compared to the small and medium scale red tides. Even though the tidal range was less difference before the beginning outbreak, it is analyzed that there was a growing difference in time.