Activity concentrations of radionuclides in lichens following the Fukushima nuclear accident

The activity concentration of 131I, 134Cs and 137Cs radionuclides in lichens was traced one and a half months after the Fukushima nuclear accident. The samples were collected in Tsukuba City, which is located c. 170 km south of the Fukushima Daiichi nuclear power plant (NPP). The activity concentrations differed depending on species and habitat. For example, the maximum activity concentration of 137Cs was 22596 Bq kg–1 dry weight in Physcia orientalis (collected from the trunk of Zelkova serrata on 30 June 2011), and 1928 Bq kg–1 in Hyperphyscia crocata (from the trunk of Quercus myrsinaefolia collected on 8 March 2012). The activity concentration of 137Cs in Dirinaria applanata and Phaeophyscia spinellosa growing on vertical habitats decreased by c. 50% within a year, indicating radionuclides might have been washed off by rain. The radionuclides were apparently derived from the Fukushima NPP accident because: 1) one specimen collected at the same place one year before the accident did not contain radionuclides, 2) high activity concentrations of radionuclides were detected after the accident, 3) 131I, which has a short half-life of 8 days, was detected one and a half months after the accident, and 4) the ratio of 134Cs/137Cs in lichens was 0·90–0·98 on 26 April 2011, which is consistent with the values reported for radiocesium from the Fukushima NPP accident.

Primary Research of Bionic Design on Tools with Mouthpart of Larvae Long Horned Beetles

Bionic design is a new method in engineering design. The mouthpart of the larva long horned beetle and its tunnel in wood are discussed in this article. To improve the cutting properties and tool life are always the main aim of cutting tool design. The foreground of cutting tool design using the larva long horned beetle is discussed on the bases of the mouthpart maxillae of Aphrodisium sauteri (Matsushita) and the tunnel in Quercus myrsinaefolia. The research can also make direction at new tool material and tool geometry parameter design.

Changes in fungal communities in evergreen broad-leaved forests across a gradient of urban to rural areas in JapanThis article is one of a selection of papers published in the Special Forum on Towards Sustainable Forestry — The Living Soil: Soil Biodiversity and Ecosystem Function.

We investigated the structure of the fungal community of evergreen broad-leaved forests dominated by evergreen oak ( Castanopsis sieboldii or Quercus myrsinaefolia ) through surveying sporocarps in urban, suburban, and rural areas of the Kanto District, Japan. In a 4 year census, 132 species of fungi were recorded and classified into five groups on the basis of growth substrate: 22 litter decomposers, 39 wood rotters, 10 rotted-wood decomposers, 23 humus decomposers, and 38 ectomycorrhizal species. A long-term survey of fungi revealed lower species richness and diversity of ectomycorrhizal fungi in the urban and suburban forest than in the rural forest. The low species diversity of ectomycorrhizal fungi in the urban forest was related to low species richness of Amanitaceae and a high frequency of some Russulaceae species such as Russula japonica . In contrast, species richness and abundance of litter decomposers and wood rotters were higher in the urban forest than in the rural forest. The uneven litter distribution on soil surfaces in the mountainous rural forest may have caused the lower species richness of litter decomposers. Rotted-wood decomposers and humus decomposers showed no significant differences among the three types of forest.