Methodology and Results of Satellite Monitoring of Karenia Microalgae Blooms, That Caused the Ecological Disaster off Kamchatka Peninsula

Abstract

The environmental disaster in Kamchatka in the autumn of 2020 was caused by an extensive bloom of harmful microalgae of the genus Karenia. A spectral shape algorithm was used to detect algae on satellite imagery. The algorithm calibration of in situ species composition data made it possible to identify areas where harmful algae dominated in biomass. The algorithm allowed evaluation of the dynamics of the distribution of the algae. The state of phytoplankton was estimated based on images of the specific capacity of photosynthesis. Specific fluorescence is the ratio of the height of the fluorescence line (flh) to the concentration of chlorophyll-a (chl-a). The parameter was used to recognize the stages of the algal bloom: intensive growth, blooming, and change in the dominant algal species. In addition, an increase in the concentration of harmful substances in the coastal zone due to wind impact was analyzed. After analyzing the available data, the events that caused the ecological disaster can be summarized as follows. After the stage of intensive growth of microalgae, nutrient deficiency stimulated the production of metabolites that have a harmful effect on the environment. The change of the dominant alga species in the second half of September and the past storm contributed to a sharp increase in the concentration of metabolites and dead organic matter in the coastal zone, which caused an ecological disaster. The subsequent mass bloom of alga species of the same genus, and the regular wind impact leading to the concentration of harmful substances in the coastal zone, contributed to the development of this catastrophic phenomenon.

Studying Conditions of Intense Harmful Algal Blooms Based on Long-Term Satellite Data

“…The features of spatial distributions presented in Figure 4 agree with the data given in Table 4 and indicate that complex, spatially heterogeneous processes took place in the studied water areas before and during the intensive HABs. As is known, for example [6,17,19,79,80], attempts to analyze the sets of spatial distributions (similar to those shown in Figure 4) in detail help to make assumptions about the particularities of certain HABs' formation mechanisms.…”