Understanding the night ecology of poisonous blue-green algae and its application to good-quality water intake system

在8月和9月进行的夜间观察中，在凌晨2点至4点之间，小块的水华停留在固定的水深，没有任何特别的运动。从下午2点开始，水面上的水华开始分散，到下午4点才几乎看不到水面上的水华。直到9月下旬，每天都有这样的循环。这种循环的节奏表明，光合藻类的行为不能仅仅用趋光性来解释。我们可以发现，水华在夜间潜入水下，并在特定的时间停留在一定的深度。然而，我们无法创造出优质的取水系统来取用优质的原水。为实现这一目标，需要解决以下关键问题：垂直运动跨越几个月，从开花的初始阶段到下降阶段；2. 成华藻排泄代谢物毒性的测定3. 分解后的细胞行为。

In the nocturnal observation conducted during August and September, small lumps of bloom stayed at a fixed depth of water between 2 and 4 a.m. without any particular motion. Blooms on the water surface started to disperse starting around 2 p.m. and they are observed only scarcely on the surface by 4 p.m. Such cycle was observed every day until late September. The rhythm of this cycle indicates that behavior of photosynthetic algae cannot be explained only by photo-taxis. We could find that bloom goes down under water during night time and stays at a certain depth during certain period. However, we could not create good-quality water intake system to intake raw water of a good quality. To realize this, the following key issues need to be addressed: 1. Vertical motions spanning a few months through the initial phase to decline phase of bloom forming; 2. Determination of the toxicity of metabolite excreted by bloom forming algae; 3. Cell behavior after the decomposition of bloom.