In order to select plant species that have a high ability to remediate soil polluted with ¹³⁷Cs and ⁹⁰Sr, 14 species of 10 families were tested. During selection using stable Cs and Sr in place of these radionuclides, the absorption rate, transport ratio from root to shoot and the condensation to the shoot were evaluated. In phytoremediation of Cs-polluted soil, oilseed rape, livingstone daisy, iceplant and New Zealand spinach were found to be promising. In Sr-polluted soil, oilseed rape, iceplant, pumpkin and sunflower were promising. A candidate species for the phytoremediation of Cs-contaminated soil might not always be a candidate for the phytoremediation of Sr-contaminated soil. In phytoremediation of Cs- and Sr-polluted soil, not only the absorption ability, but also the characteristics of the species used should be considered and evaluated.

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Lagoon Notoro-ko is connected to the Okhotsk Sea by an artificial channel, and it has few incoming rivers. The lagoon is covered with sea ice during the winter and early spring. We investigated temporal changes in environmental variables in the sea ice and water column from February 6^th to March 18^th 2008. The integrated chlorophyll α in water column was remarkably high on every survey day, ranging from 8.7－119.1 mg·m^-2, whereas in the sea, it ranged from 2.5－11.6 mg·m^-2. In contrast, chlorophyll a concentrations (relative to unit volume) in the sea ice and water column were 8.3－40.1 mg·m^-3 and 0.4－6.0 mg·m^-3, respectively. Chlorophyll a concentration was therefore remarkably high in the sea ice, with the maximum concentration of chlorophyll a in sea ice detected in the lower layer. We suggest that the sea ice gathers chlorophyll a in the lower layers, and it is thus likely that sea ice provides the environment which small amount of chlorophyll a is available to primary consumers easily.

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There is a great need to establish a method for energy-saving environmental control using renewable energy resources for a stable, year-round production of greenhouse crops with high sustainability and profitability. Solar radiation is a widespread and accessible renewable energy resource. However, owing to the distribution gaps in time and space between the supply and demand of energy, the processes of collection, storage and release of energy need to be optimized for the effective utilization of solar energy in agriculture. The latent heat storage materials (LHSM) can store and release solar energy as latent heat by changing its phase, and can be expected to be used for temperature control for eliminating excessively high and low temperatures inside the greenhouse by adjusting the distribution gaps. In this study, conducted during the cold season (from January to May 2012), we installed 520 capsules of LHSM in a greenhouse, each weighing 2.5 kg, with 189 kJ kg^-1 of latent heat, and a phase change temperature of 25°C. The greenhouse was 42 m long, 24 m wide, and 3 m high, and was equipped with an oil heater which worked when the inside air temperature dropped below 18°C. During the sunny daytime, the LHSM stored a large amount of solar energy as latent heat, thus moderating the extremely high temperature inside the greenhouse. At night, the LHSM released the stored heat resulting in a decrease of 19% in the operation time of the oil heater. Therefore, the LHSM should be effective for energy-saving temperature control in greenhouse horticulture.

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