Quantification of Environmental Changes by Benthic Animals

为了实现实验室的原位环境，开发了一种特殊的水族箱（limorium）。目的要求是：(1)在水族箱中完整地拍摄沉积物；(2)能够通过放大摄像机从水族箱外观察；(3)能够控制水温和水流速度，并对其进行监测等。据目前所知，这些要求在水族馆中还没有得到满足。因此，开发了新的特殊水族馆。为了测量悬浮喂料机的摄食率，构建了用于测量水流流速精细分布的微传感器热流量计和用于精细观察鱼体运动的微高示波器系统。由于悬浮喂养不仅会受到食物浓度的影响，还会受到水流速度的影响，因此我们还构建了一个24小时以上的观测系统，用于观察和控制食物浓度和水流速度。对悬浮摄食双壳贝（Tapes phillippinarum）的观察超过160小时，可以通过测量点流速度来估计摄食速度。在一种沉淀物饲养动物和一种管栖动物Maldane sp.上，通过长时间观察排便和粪便颗粒超过50小时，该系统可以估计排便率。已知非选择性沉积物取食动物的摄食率和排便率基本相似，表明Maldane sp.的摄食率与体重呈正相关。人均平均排便率估计为360 mm^3天^<-1>。假设在1 m^2的海底存在100条蚯蚓，估计该物种对0.036 mm^2 day^<-1>的海底沉积物进行了再加工，并重新沉积在海底表面。

To realize in situ environments in laboratory, a specific aquarium (limorium) was developed. Requirements for the aim were (1) to be taken intact sediments in the aquarium, (2) to be able to observe from outside of aquarium by an enlarging video camera, (3) to be able to control water temperature and water flow velocity, and monitor them, etc. These requirements have not been satisfied in aquaria as known as far. Thus, new special aquaria was developed.To measure food intake rate of suspension feeders, a micro-sensored thermo-flow meter for measurement of fine distribution of water flow velocity and a micro-hi-scope system for fine observation of betnos movements were constructed. A observation system available for more than 24 hours to watch and for controlling food concentrations and flow velocity was also constructed, because of suspension feeding would be affected not only by food concentration and but also water flow velocity. The observation of a suspension-feding bivalve, Tapes phillippinarum, which were taken more than 160 hours, made possible to estimate feeding rate from mesurements of point flow velocities.On a deposit-feeder and a tube-dweller, Maldane sp., defecation rate could be estimated by the system with long time observation more than 50 hours of defecation and fecal pellets. As known that feeding and defecation rates in non-selective deposit feeders are almost similar, it was appeared that the feeding rate of Maldane sp.was positively correlated to body weight. Mean defecation rate per capita was estimated as 360 mm^3 day^<-1>. If existence of 100 worms in a m^2 sea bottom were assumed, that sublayr sediments of 0.036 mm^2 day^<-1> was reworked by this species and resedimentated on the surface of sea bottom, was estimated.