The Vertical Profile of Chlorophyll-a in the Waters of Submarine Volcano of Kawio Barat, Indonesia

The submarine volcano can release various materials into the waters and affect the distribution of chlorophyll. Nevertheless, studies in such kinds of exciting areas are rarely done. This study aims to determine the vertical profile of chlorophyll-a around the submarine volcano waters. A field survey was conducted in October 2018 in the photic zone (200 m) around the Kawio Barat submarine volcano waters, North Sulawesi Province, Indonesia. Chlorophyll fluorescence was measured using a sensor of WET Labs ECO-AFL/FL as a proxy of chlorophyll-a. The temperature, salinity, and depth were measured using a CTD. The nutrients, including nitrate, orthophosphate, and silicate, were measured using autoanalyzer Skalar SAN++. The average of chlorophyll-a values ranged between 0.098 - 0.175 mg/m3. The highest average chlorophyll-a was found around the waters of Kawio Barat submarine-volcano. The vertical profile of chlorophyll-a indicated a forming of Deep Chlorophyll Maxima (DCM), located at a depth of 69 - 90 meters. In the Kawio Barat submarine volcano waters, the DCM is found in a depth of 90 m. It has chlorophyll-a concentration four times higher than the surface (5 m). The Principal of Component Analysis (PCA) shows that the temperature and salinity have a more substantial influence on the value of chlorophyll-a. Meanwhile, the nutrients are more influence firmly on the depth of DCM. This current study may conclude that the Kawio Barat submarine volcano waters are more productive than the other stations.