Monitoring of nitrate concentration using spectrophotometer and research on the trigger of population development the diatom in the winter season of the Ariake Sea

2015 Fiscal Year Final Research Report

• Project/Area Number: 25450259
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Tokyo University of Marine Science and Technology (2014-2015); Saga University (2013)
• Principal Investigator: katano toshiya 東京海洋大学, 学術研究院, 准教授 (00509820)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 珪藻赤潮 / ノリの色落ち / 有明海

Outline of Final Research Achievements

Nitrate concentrations determined by an ultraviolet specrtophotometer were corrected with data obtained with a conductivity, temperature, and depth profiler (CTD) equipped with turbidity sensor for the better estimation of nitrate in an embayment. Monitoring of nitrate concentration using the spectrophotometer revealed that nitrate concentration becomes high (e.g. >0.07 mM) at the low tide during spring tide.
The red tide developing process was monitored using CTD continuous monitoring and field observation using boats. Red tide occurred in late February during spring tide. Difference in the density of seawater in the water column was not important to develop the population. River discharge might be important to determine the size of the population. Nitrate concentration should be further monitored to clarify the developing process of the red tide. Data obtained with the spectrophotometer is released real time on the web site (http://www.ilt.saga-u.ac.jp/aripro/tower/nutrient.html).

Free Research Field

植物プランクトンの個体群動態