유해조류 Akashiwo sanguinea 대발생에 따른 환경요인 및 박테리아 군집에 대한 변화

Abstract

To investigate changes in environmental factors and bacteria community during Akashiwo sanguinea blooms, we conducted daily monitoring for 41 days (Nov. 14, 2016 &#8211 Feb. 27, 2017), in Jangmok Bay, a semi-closed bay on the southern coast of South Korea. A. sanguinea was first observed on Oct. 31, 2016, and up to 2,935 cells mL-1 appeared on Nov.18, 2016, and A. sanguinea disappeared on Jan. 30, 2018. The mean temperature and salinity were 14.4℃ and 32.2 at the occurrence of A. sanguinea blooms, respectively. Dissolved inorganic phosphorus and dissolved inorganic nitrogen increased during the blooming period, while dissolved silica maintained. Dissolved organic carbon was similar pattern to that of A. sanguinea and showed a maximum of 7.56 mg L-1. The time-lag changes in bacteria abundances might be associated with fluctuation in A. sanguinea blooms. In particular, to analyze bacteria composition of attached to A. sanguinea and the free living bacteria in seawater, the most highest dominant attached bacterium in A. sanguinea was Rickettsia rhipicephali (Alphaproteobacteria) at proportion of 57.5%, also rickettsia rhipicephali (Alphaproteobacteria) was the most pre-dominant species in seawater. Thus, rickettsia rhipicephali is the specific-species bacterium when A. sanguinea was bloomed. However, we still don’t know what this bacterium plays a role of A. sanguinea blooms. Therefore, our next study will explore mst of South Korea. A. sanguinea was first observed on Oct. 31, 2016, and up to 2,935 cells mL-1 appeared on Nov.18, 2016, and A. sanguinea disappeared on Jan. 30, 2018. The mean temperature and salinity were 14.4℃ and 32.2 at the occurrence of A. sanguinea blooms, respectively. Dissolved inorganic phosphorus and dissolved inorganic nitrogen increased during the blooming period, while dissolved silica maintained. Dissolved organic carbon was similar pattern to that of A. sanguinea and showed a maximum of 7.56 mg L-1. The time-lag changes in bacteria abundances might be associated with fluctuation in A. sanguinea blooms. In particular, to analyze bacteria composition of attached to A. sanguinea and the free living bacteria in seawater, the most highest dominant attached bacterium in A. sanguinea was Rickettsia rhipicephali (Alphaproteobacteria) at proportion of 57.5%, also rickettsia rhipicephali (Alphaproteobacteria) was the most pre-dominant species in seawater. Thus, rickettsia rhipicephali is the specific-species bacterium when A. sanguinea was bloomed. However, we still don’t know what this bacterium plays a role of A. sanguinea blooms. Therefore, our next study will explore m