However, the introduced ecosystem recovers to a state similar to that before the
introduction by keeping down the introduced microorganisms and the detritus when
the indigenous phytoplankton decreases within a system. It is necessary to remove
the introduced microorganisms and detritus out of the system through the on-site
biomanipulation. The microcosm was also effective as a tool for the environmental
risk assessments, which targeted ecosystem function.
7.14.5 Moina macrocopa (Alien Species)
Moina macrocopa is filter-feeding minute crustacean belonging to Daphnia, with a
physical size of 0.6–1.2 mm, and it is usually parthenogenetic (only in females), but
males appear with the deterioration of the environment, due to water pollution and
other stresses leading to the formation of resistant eggs. They are also useful as live
baits for ornamental fishes and toxicity testing of chemicals, and they have gained
attention as a biomanipulation-introduced species, among other applications. In this
section, focusing on the competitive relationship with Aeolosoma hemprichi, which
is the top predator in the microcosm, Moina macrocopa is added at one, five, and ten
times the introduction amount of Aeolosoma hemprichi individuals, and the structure
of the ecosystem and its effect on function are studied.
In any of the addition systems, the producers Chlorella sp. and Tolypothrix sp.
decreased immediately after the introduction of Moina macrocopa (Fig. 7.39). The
cause was thought to be that predation pressure increased from the Moina
macrocopa invasion and Tolypothrix sp. could not grow sufficiently long due to
amputation by the swimming behavior of Moina macrocopa. In predatory taxa,
Lecane sp. and Cyclidium glaucoma showed a decreasing tendency, and, in the
10-times addition system, extinction was confirmed on the 18th day immediately
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0
5
10
15
20
25
30
Number(N/mL)(cm/mL)
Time(day)
Chlorella
Scenedesmus
Tolypothrix
Lecane
Philodina
Aeolosoma
Cyclidium
Fig. 7.38 Population dynamics in ten times of Aeolosoma-added microcosm N-system
148
K. Murakami et al.
introduction by keeping down the introduced microorganisms and the detritus when
the indigenous phytoplankton decreases within a system. It is necessary to remove
the introduced microorganisms and detritus out of the system through the on-site
biomanipulation. The microcosm was also effective as a tool for the environmental
risk assessments, which targeted ecosystem function.
7.14.5 Moina macrocopa (Alien Species)
Moina macrocopa is filter-feeding minute crustacean belonging to Daphnia, with a
physical size of 0.6–1.2 mm, and it is usually parthenogenetic (only in females), but
males appear with the deterioration of the environment, due to water pollution and
other stresses leading to the formation of resistant eggs. They are also useful as live
baits for ornamental fishes and toxicity testing of chemicals, and they have gained
attention as a biomanipulation-introduced species, among other applications. In this
section, focusing on the competitive relationship with Aeolosoma hemprichi, which
is the top predator in the microcosm, Moina macrocopa is added at one, five, and ten
times the introduction amount of Aeolosoma hemprichi individuals, and the structure
of the ecosystem and its effect on function are studied.
In any of the addition systems, the producers Chlorella sp. and Tolypothrix sp.
decreased immediately after the introduction of Moina macrocopa (Fig. 7.39). The
cause was thought to be that predation pressure increased from the Moina
macrocopa invasion and Tolypothrix sp. could not grow sufficiently long due to
amputation by the swimming behavior of Moina macrocopa. In predatory taxa,
Lecane sp. and Cyclidium glaucoma showed a decreasing tendency, and, in the
10-times addition system, extinction was confirmed on the 18th day immediately
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0
5
10
15
20
25
30
Number(N/mL)(cm/mL)
Time(day)
Chlorella
Scenedesmus
Tolypothrix
Lecane
Philodina
Aeolosoma
Cyclidium
Fig. 7.38 Population dynamics in ten times of Aeolosoma-added microcosm N-system
148
K. Murakami et al.