of Cs + 8.0 mg/L of I 2 , and 8.0 mg/L of Cs + 2.7 mg/L of I 2 ) were adjusted and
loaded 16 days after culturing began. The addition concentrations were set on the
basis of the m-NOECs of Cs and I 2 . The endpoints were abundance (structural
parameter) and the concentration of DO (functional parameter), and the population
was measured using an optical microscope and counted from the start of culturing on
days 0, 2, 4, 7, 14, 16, 18, 20, 23, and 30; it was evaluated from the results of B 16–30
(days 16–30), which was the ratio of the abundance and population density (N 30 ) on
the 30th day. The DO concentration was measured continuously from the 16th day,
and the P/R ratio was calculated from the amounts of production (P) and respiration
(R). As a result, the m-NOEC of the structural parameter was estimated to be 1.0 mg/
L of Cs + 3.0 mg/L of I 2 . In comparison with the I 2 -only addition system, the
Aeolosoma hemprichi population was recognized as having a tendency to increase.
7.10.14 Sr
Strontium was supplied for assessment, and a no-addition system (control) and
addition systems (0.1, 0.3, 0.4, 0.5, 1, 4, 6, 7, 8, and 10 mg/L) were adjusted and
added 16 days after culturing began. The endpoints were abundance (structural
parameter) and the concentration of DO (functional parameter), and the population
was measured using an optical microscope and counted from the start of culturing on
days 0, 2, 4, 7, 14, 16, 18, 20, 23, and 30; it was evaluated from the results of B 16–30
(days 16–30), which was the ratio of abundance and population density (N 30 ) on the
30th day. The DO concentration was measured continuously from the 16th day, and
the P/R ratio was calculated from the amounts of production (P) and respiration (R).
As a structural parameter, after the addition of Sr, all of the microorganisms in the
microcosm existed at a Sr concentration of 0.3 mg/L, but Cyclidium glaucoma
perished with the addition of 0.4 mg/L. Additionally, other zooplanktons were
observed to decrease in abundance with increased Sr concentrations. The population
of the phytoplankton, Scenedesmus quadricauda, increased, and Tolypothrix sp. also
increased from double to ~3.5 times its initial abundance. These species increased
with higher concentrations of Sr. It was thought that Sr worked to decrease the
abundance of zooplankton and to multiply phytoplankton. As a functional parameter
(the P/R ratio), the activity increased and was not disturbed at concentrations of
7 mg/L, but it was unbalanced with the addition of 8 mg/L of Sr near the end of the
25th day. For the N30 of the 7 mg/L and 8 mg/L concentrations, phytoplankton
increased in both concentrations. It was thought that there was a mechanism that
caused reduction in zooplankton activity at high concentrations. Additionally, the
P/R ratio collapsed on the consumption side at a concentration of 8 mg/L (Fig. 7.29).
Because the abundance of zooplankton decreased, the multiplication of phytoplankton was affected and decreased in its activity, and it is thought that phytoplankton
consumed more than they produced. From these outcomes, the m-NOEC of the
structural parameter was estimated to be 0.3 mg/L, and the m-NOEC of the
126
K. Murakami et al.
loaded 16 days after culturing began. The addition concentrations were set on the
basis of the m-NOECs of Cs and I 2 . The endpoints were abundance (structural
parameter) and the concentration of DO (functional parameter), and the population
was measured using an optical microscope and counted from the start of culturing on
days 0, 2, 4, 7, 14, 16, 18, 20, 23, and 30; it was evaluated from the results of B 16–30
(days 16–30), which was the ratio of the abundance and population density (N 30 ) on
the 30th day. The DO concentration was measured continuously from the 16th day,
and the P/R ratio was calculated from the amounts of production (P) and respiration
(R). As a result, the m-NOEC of the structural parameter was estimated to be 1.0 mg/
L of Cs + 3.0 mg/L of I 2 . In comparison with the I 2 -only addition system, the
Aeolosoma hemprichi population was recognized as having a tendency to increase.
7.10.14 Sr
Strontium was supplied for assessment, and a no-addition system (control) and
addition systems (0.1, 0.3, 0.4, 0.5, 1, 4, 6, 7, 8, and 10 mg/L) were adjusted and
added 16 days after culturing began. The endpoints were abundance (structural
parameter) and the concentration of DO (functional parameter), and the population
was measured using an optical microscope and counted from the start of culturing on
days 0, 2, 4, 7, 14, 16, 18, 20, 23, and 30; it was evaluated from the results of B 16–30
(days 16–30), which was the ratio of abundance and population density (N 30 ) on the
30th day. The DO concentration was measured continuously from the 16th day, and
the P/R ratio was calculated from the amounts of production (P) and respiration (R).
As a structural parameter, after the addition of Sr, all of the microorganisms in the
microcosm existed at a Sr concentration of 0.3 mg/L, but Cyclidium glaucoma
perished with the addition of 0.4 mg/L. Additionally, other zooplanktons were
observed to decrease in abundance with increased Sr concentrations. The population
of the phytoplankton, Scenedesmus quadricauda, increased, and Tolypothrix sp. also
increased from double to ~3.5 times its initial abundance. These species increased
with higher concentrations of Sr. It was thought that Sr worked to decrease the
abundance of zooplankton and to multiply phytoplankton. As a functional parameter
(the P/R ratio), the activity increased and was not disturbed at concentrations of
7 mg/L, but it was unbalanced with the addition of 8 mg/L of Sr near the end of the
25th day. For the N30 of the 7 mg/L and 8 mg/L concentrations, phytoplankton
increased in both concentrations. It was thought that there was a mechanism that
caused reduction in zooplankton activity at high concentrations. Additionally, the
P/R ratio collapsed on the consumption side at a concentration of 8 mg/L (Fig. 7.29).
Because the abundance of zooplankton decreased, the multiplication of phytoplankton was affected and decreased in its activity, and it is thought that phytoplankton
consumed more than they produced. From these outcomes, the m-NOEC of the
structural parameter was estimated to be 0.3 mg/L, and the m-NOEC of the
126
K. Murakami et al.