situ experiments lack reproducibility, it is difficult to understand the precise phenomena at work due to the uncertainties associated with subjects in nature.
When targeting an ecosystem for evaluation, it is necessary to know that the
following four characteristics are needed for its recognition: “diversity,” “heterogeneity,” “microscopic,” and “reactivity.” Additionally, it is difficult to recognize the
response of an ecosystem without understanding its “operability.” Among these
characteristics, diversity and heterogeneity are caused by the open nature of the
ecosystem. Next, microscopic characteristics provide a macroscopic impression of
an ecosystem, but, in order to see the effects of these characteristics on an ecosystem,
it is desirable to consider the changes in the ecosystem, such as through the use of
microorganisms as indices. Due to the movement of bacteria, algae and protozoa
occupy fundamental positions in the overall function of ecosystems. The reactions of
microorganisms are faster than those of animals and plants. Moreover, they respond
to pure chemical substances so vigorously that they can record changes in the
environment sensitively and promptly.
In order to use microscopic phenomena in an ecosystem to evaluate the influence
of chemicals and genetically modified organisms, it is indispensable to manipulate
the “expansion” as a matter of course. “Drawing” the ranges of targeted ecosystems
remains an important problem. It is impossible to cover the entirety of nature that we
perceive. Even though understanding the natural environment is the ultimate purpose
of environmental research, it cannot be the actual target of investigation. The
subdivision and simplification of ecosystems are inevitable steps that cannot be
avoided. However, when trying to simplify environmental components and biota
to the scope of an impact assessment, two important problems arise. One is the
arbitrariness with which one extracts different kinds of environmental data from
natural ecosystems; the second results from having simplified the system to the
extent that one loses sight of the connection between the model and the natural
environment. We often try to simplify ecosystems by developing mathematical
models of them, but real ecosystems not only are composed of diversity but also
vary depending upon location and season. Therefore, there is often a non-negligible
gap between the model and reality. Indeed, it is unlikely that we can develop a model
capable of describing natural diversity in a unified way. As a next measure then, an
entity model of a given ecosystem should become a standard. As such, a model
reflects the general attributes of the ecosystem; even if there is no structural correspondence with the actual ecosystem, it is reproducible, is rich in operability,
responds promptly to external forces, and is easy to measure and recognize. Positioning the phenomena described by such standardized entities as a filter for impact
assessment will provide valuable information when incorporating risks to ecosystems into regulatory policies. Research using such information at a given locality
would then be the next step.
In this manual, a microcosm test was performed in which microcosms consisting
of bacteria as decomposers, micro-animals as consumers, and microalgae as producers were used to evaluate the ecosystem-level effects of chemical agents and
wastewater consisting of micropollutants on an aquatic ecosystem. Reproducibility
vi
Preface
When targeting an ecosystem for evaluation, it is necessary to know that the
following four characteristics are needed for its recognition: “diversity,” “heterogeneity,” “microscopic,” and “reactivity.” Additionally, it is difficult to recognize the
response of an ecosystem without understanding its “operability.” Among these
characteristics, diversity and heterogeneity are caused by the open nature of the
ecosystem. Next, microscopic characteristics provide a macroscopic impression of
an ecosystem, but, in order to see the effects of these characteristics on an ecosystem,
it is desirable to consider the changes in the ecosystem, such as through the use of
microorganisms as indices. Due to the movement of bacteria, algae and protozoa
occupy fundamental positions in the overall function of ecosystems. The reactions of
microorganisms are faster than those of animals and plants. Moreover, they respond
to pure chemical substances so vigorously that they can record changes in the
environment sensitively and promptly.
In order to use microscopic phenomena in an ecosystem to evaluate the influence
of chemicals and genetically modified organisms, it is indispensable to manipulate
the “expansion” as a matter of course. “Drawing” the ranges of targeted ecosystems
remains an important problem. It is impossible to cover the entirety of nature that we
perceive. Even though understanding the natural environment is the ultimate purpose
of environmental research, it cannot be the actual target of investigation. The
subdivision and simplification of ecosystems are inevitable steps that cannot be
avoided. However, when trying to simplify environmental components and biota
to the scope of an impact assessment, two important problems arise. One is the
arbitrariness with which one extracts different kinds of environmental data from
natural ecosystems; the second results from having simplified the system to the
extent that one loses sight of the connection between the model and the natural
environment. We often try to simplify ecosystems by developing mathematical
models of them, but real ecosystems not only are composed of diversity but also
vary depending upon location and season. Therefore, there is often a non-negligible
gap between the model and reality. Indeed, it is unlikely that we can develop a model
capable of describing natural diversity in a unified way. As a next measure then, an
entity model of a given ecosystem should become a standard. As such, a model
reflects the general attributes of the ecosystem; even if there is no structural correspondence with the actual ecosystem, it is reproducible, is rich in operability,
responds promptly to external forces, and is easy to measure and recognize. Positioning the phenomena described by such standardized entities as a filter for impact
assessment will provide valuable information when incorporating risks to ecosystems into regulatory policies. Research using such information at a given locality
would then be the next step.
In this manual, a microcosm test was performed in which microcosms consisting
of bacteria as decomposers, micro-animals as consumers, and microalgae as producers were used to evaluate the ecosystem-level effects of chemical agents and
wastewater consisting of micropollutants on an aquatic ecosystem. Reproducibility
vi
Preface