the protozoan ciliate Cyclidium glaucoma) in the microcosm increased. Pseudomonas fluorescens IID5115 has been shown to be a suitable food source for constituent
heterotrophic groups. By comparison, in N 30 , no significant difference was observed
between the system with Pseudomonas fluorescens IID5115 added and the system
without it (control system).
Pseudomonas fluorescens IID5115, as a bacterial pesticide, was added in 10
7 N/
mL; it decreased slightly after suddenly falling to 10
3 N/mL on the 30th day and
disappeared finally. Meanwhile, the population density of the ciliate, Cyclidium
glaucoma, increased from 10
2 N/mL to 10
4 N/mL. It was suggested that the
predation pressure of microorganisms has a strong influence on the proliferation
and decay of indigenous bacteria introduced into the ecosystem, and the results of
the predator-prey interaction monoxenic culture test was lined.
7.12.4 Beauveria bassiana F18-4B
Beauveria bassiana F18-4B, as a fungal pesticide, was added at one and ten times
the abundance of indigenous bacteria in the microcosm, and its influence on the
structure and function of the ecosystem was examined. Beauveria bassiana F18-4B
slowly decreased at 1- or 10-times inoculation concentrations in viable counts using
the selective media method, after microcosm inoculation, and the number of microorganisms in the microcosm increased. Beauveria bassiana F18-4B has been shown
to be a suitable food source for Philodina erythrophthalma and Aeolosoma
hemprichi, in predator-prey interaction tests, which was considered to be dominated
by these predatory actions. By comparison, in N 30 , no significant difference was
observed between the system with Beauveria bassiana F18-4B added and the
system without it (control system). Moreover, nearly identical behavior of the
introduced Beauveria bassiana F18-4B, as a fungal microbial pesticide, was
observed in a natural lake model ecosystem, that is, a naturally derived microcosm,
which was made from natural lake water, including natural microorganisms and
nutrients. Irrespective of the kind of natural environmental water, all fungal pesticides decreased and disappeared in the system finally after it was added at 10
5 N/mL.
The individual number of micro flagellates, such as Chlamydomonas sp. and Monas
sp., in the fungal pesticide addition system increased from 10
2 N/mL to 10
3 N/mL;
compared with the control system, the influence of the predation pressure by
heterotrophs was confirmed. Microbial pesticides, both fungal and bacterial,
exhibited a decreasing trend in the systems from which an organismal factor was
removed through filtration processing, but the survivorship period was clearly
lengthy, and the influence of the interaction between the microbes and the indigenous microorganisms was also confirmed. For indigenous microorganisms to
become so varied in the eutrophied aquatic environment, a survivorship period of
microbial pesticide tended to become short, so that the degree of water pollution was
high, and a small amount of chemicals which caused the water contamination
restrained the life and reproduction of the microbial pesticide. Organic matter also
7 Example Assessments of the Microcosm N-System
137
heterotrophic groups. By comparison, in N 30 , no significant difference was observed
between the system with Pseudomonas fluorescens IID5115 added and the system
without it (control system).
Pseudomonas fluorescens IID5115, as a bacterial pesticide, was added in 10
7 N/
mL; it decreased slightly after suddenly falling to 10
3 N/mL on the 30th day and
disappeared finally. Meanwhile, the population density of the ciliate, Cyclidium
glaucoma, increased from 10
2 N/mL to 10
4 N/mL. It was suggested that the
predation pressure of microorganisms has a strong influence on the proliferation
and decay of indigenous bacteria introduced into the ecosystem, and the results of
the predator-prey interaction monoxenic culture test was lined.
7.12.4 Beauveria bassiana F18-4B
Beauveria bassiana F18-4B, as a fungal pesticide, was added at one and ten times
the abundance of indigenous bacteria in the microcosm, and its influence on the
structure and function of the ecosystem was examined. Beauveria bassiana F18-4B
slowly decreased at 1- or 10-times inoculation concentrations in viable counts using
the selective media method, after microcosm inoculation, and the number of microorganisms in the microcosm increased. Beauveria bassiana F18-4B has been shown
to be a suitable food source for Philodina erythrophthalma and Aeolosoma
hemprichi, in predator-prey interaction tests, which was considered to be dominated
by these predatory actions. By comparison, in N 30 , no significant difference was
observed between the system with Beauveria bassiana F18-4B added and the
system without it (control system). Moreover, nearly identical behavior of the
introduced Beauveria bassiana F18-4B, as a fungal microbial pesticide, was
observed in a natural lake model ecosystem, that is, a naturally derived microcosm,
which was made from natural lake water, including natural microorganisms and
nutrients. Irrespective of the kind of natural environmental water, all fungal pesticides decreased and disappeared in the system finally after it was added at 10
5 N/mL.
The individual number of micro flagellates, such as Chlamydomonas sp. and Monas
sp., in the fungal pesticide addition system increased from 10
2 N/mL to 10
3 N/mL;
compared with the control system, the influence of the predation pressure by
heterotrophs was confirmed. Microbial pesticides, both fungal and bacterial,
exhibited a decreasing trend in the systems from which an organismal factor was
removed through filtration processing, but the survivorship period was clearly
lengthy, and the influence of the interaction between the microbes and the indigenous microorganisms was also confirmed. For indigenous microorganisms to
become so varied in the eutrophied aquatic environment, a survivorship period of
microbial pesticide tended to become short, so that the degree of water pollution was
high, and a small amount of chemicals which caused the water contamination
restrained the life and reproduction of the microbial pesticide. Organic matter also
7 Example Assessments of the Microcosm N-System
137