Development of the culture methods of marine ostracodes for the environmental indicator species and paleobiological research

为保证古生物学研究所需实验生物的连续供应，设计了两种培养体系。首先，尝试了具有近自然海洋环境的母养殖系统。这种文化，系统有多个物种生活在一起。第二个系统是在小型培养皿中培养单种介形类，在母培养系统中，进行了海岸岩石环境的实验，并观察了介形类的微生境。与一般认为介形类生活在钙藻中的观点相反，本研究结果表明不同的介形类有不同的生境。有些种类生活在叶子上，有些生活在杂草的根部周围，而其他种类则生活在沉积物中。然而，这种文化体系也存在一些问题。由于在实验过程中物种中的个体数量减少，因此必须经常从自然栖息地添加个体。如果有可能在培养系统中保持健康生长的海藻，则个体的数量可以保持恒定。在单养系统中，分析了花井拟石首鱼的Sr/Ca和Mg/Ca比值。结果表明，Sr/Ca比值与海水温度无关，Mg/Ca比值与海水温度有关。特别是对化学参数的个体发育观察证明，镁主要集中在甲壳的有机层中。这表明镁在甲壳的钙化过程中起着重要作用。在该系统中，不仅可以通过更换海水，还可以通过更换培养皿本身来减少细菌问题。此外，该系统的食物量应该非常少，因此易于培养。

Two kinds of culturing system were planned in order to obtain a continuous supply of experimental organisms for paleobiological research. Firstly, a mother culture system having a near natural marine environment was tried. This culture, system had multiple species living together. The second system involved culturing of single species isolated in small petri dishes within the incubator.In the mother culture system, a rocky shore environment was experimented, and microhabitat of ostracodes were observed. Contrary to the general belief that certain ostracodes species lives in the calcareaous algae, the present results show that different species have different habitats. Some species live on the leaves, some others live surrounding the root of the weeds whereas other species live in the sediments. However, there are certain problems related with this culture system. As the number of individuals in a species reduces during the experiment, frequent addition of individuals from the natural habitat is essential. If it is possible to maintain a healthy growing sea weeds in the culture system, the number of individuals can be kept constant. The possible other factors include ultraviolet irradation and fast circulation of sea water.In the monoculture system, the Sr/Ca and Mg/Ca ratios were analyzed for the species of Xestoleberis hanaii. The results show that Sr/Ca ratio is independent of sea water temperature, where as the Mg/Ca ratio is dependent on sea water temperature. Especially, the ontogenetical observation of the chemical parameters prove that Mg is concentrated in organic layer within the carapace. This indicates that Mg has an important role in calcification process of the carapace. In this system, the problem of bacteria can be reduced by replacing not only the sea water but also the petri dish itself. Further, the quantity of food should be very less for this system and hence easy to culture.