No abstract

We surveyed the spatial and temporal distribution of Japanese sea nettle jellyfish Chrysaora pacifica in Omura Bay, Japan, using an environmental DNA (eDNA) method. In 2018, the C. pacifica eDNA concentration increased from March-May at all depths. The seasonal pattern of C. pacifica eDNA was consistent with previous reports based on visual observations along the Japanese coast. Thus, the eDNA method might have advantages to follow the seasonal pattern of C. pacifica while being less time-consuming and less laborious compared with traditional methods. The eDNA concentrations tended to reach a maximum near and/or below the pycnocline throughout this study. Therefore, the vertical distribution of C. pacifica medusae may have been restricted by strong pycnocline formation in July and August 2018. However, even with a weak pycnocline, which C. pacifica should be able to swim across, the apparent distribution of C. pacifica eDNA seems to be restricted by the pycnocline. Therefore, the eDNA method cannot, currently, accurately assess the absolute vertical distribution pattern of C. pacifica, especially when a pycnocline is formed.

Colloidal photonic crystals, which are three-dimensional periodic structures of monodisperse submicron-sized particles, are expected to be suitable for novel photonic applications and color materials. In particular, nonclose-packed colloidal photonic crystals immobilized in elastomers exhibit significant potential for use in tunable photonic applications and strain sensors that detect strain based on color change. This paper reports a practical method for preparing elastomer-immobilized nonclose-packed colloidal photonic crystal films with various uniform Bragg reflection colors using one kind of gel-immobilized nonclose-packed colloidal photonic crystal film. The degree of swelling was controlled by the mixing ratio of the precursor solutions, which used a mixture of solutions with high and low affinities for the gel film as the swelling solvent. This facilitated color tuning over a wide range, enabling the facile preparation of elastomer-immobilized nonclose-packed colloidal photonic crystal films with various uniform colors via subsequent photopolymerization. The present preparation method can contribute to the development of practical applications of elastomer-immobilized tunable colloidal photonic crystals and sensors.

No abstract

Knowledge of the effects of local-and landscape-scale environmental factors is indispensable for the conservation of wetland biodiversity. We surveyed the distribution and abundance of two spring-dependent invertebrates, the Japanese freshwater crab Geothelphusa dehaani and larvae of dragonfly Anotogaster sieboldii, at 37 spring-fed wetlands in the Lake Inba watershed, Japan.The relationships among local factors (water temperature, channel-water velocity, substrate type, and abundance of the red swamp crayfish Procambarus clarkii), a landscape-scale factor (the percentage of permeable surface in catchment; PPSC), and catch per unit effort (CPUE) of each species were analyzed using path analyses. PPSC indirectly affected the CPUE of both G. dehaani and A. sieboldii via different processes. For G. dehaani, PPSC affected the CPUE via a positive effect on channel-water velocity and substrate composition in the wetland. On the other hand, PPSC positively affected the CPUE of A. sieboldii by decreasing the summer water temperature. Red swamp crayfish had no significant direct effects on either species, although we found a significant negative effect of channel-water velocity on the distribution of red swamp crayfish. For conservation of these spring-dependent species, we suggest preserving the area of permeable surface in the watershed in order to maintain flow velocity and low water temperature in wetlands.