Hiroshima University 4 articles published in JoVE Environment A Standardized Procedure for Monitoring Harmful Algal Blooms in Chile by Metabarcoding Analysis Kyoko Yarimizu1, So Fujiyoshi1, Mikihiko Kawai2, Jacquelinne J. Acuña3, Joaquin-Ignacio Rilling3, Marco Campos3, Jonnathan Vilugrón4, Henry Cameron5, Karen Vergara6, Gonzalo Gajardo6, Oscar Espinoza-González4, Leonardo Guzmán4, Satoshi Nagai7, Carlos Riquelme5, Milko A. Jorquera3, Fumito Maruyama1 1Office of Research and Academia-Government-Community Collaboration, Hiroshima University, 2Graduate School of Human and Environmental Studies, Kyoto University, 3Scientific and Biotechnological Bioresource Nucleus, Universidad de La Frontera, 4Centro de Estudios de Algas Nocivas, Instituto de Fomento Pesquero, 5Ciencias del Mar y Recursos Biologicos, Universidad de Antofagasta, 6Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, 7Japan Fisheries Research and Education Agency, Fisheries Resources Institute This protocol introduces steps of metabarcoding analysis, targeting 16S rRNA and 18S rRNA genes, for monitoring harmful algal blooms and their associated microbiome in seawater samples. It is a powerful molecular-based tool but requires several procedures, which are visually explained here step-by-step. Behavior Calcium Imaging in Freely Behaving Caenorhabditis elegans with Well-Controlled, Nonlocalized Vibration Kazuki Shigyou*1, Haruka Maeoka*1, Ryuji Igarashi2,3,4, Takuma Sugi1 1Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, 2Institute for Quantum Life Science, National Institute for Quantum and Radiological Science and Technology, 3National Institute for Radiological Sciences, National Institute for Quantum and Radiological Science and Technology, 4JST, PRESTO Reported here is a system for calcium imaging in freely behaving Caenorhabditis elegans with well-controlled, nonlocalized vibration. This system allows researchers to evoke nonlocalized vibrations with well-controlled properties at nano-scale displacement and to quantify calcium currents during responses of C. elegans to the vibrations. Environment Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O Megumi Kuroiwa1, Keitaro Fukushima2,3, Kazuma Hashimoto2, Yukiko Senga4, Tsubasa Sato4, Chie Katsuyama5, Yuichi Suwa1 1Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 1Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 2Faculty & Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 3Center for Ecological Research, Kyoto University, 4Department of Chemistry, Faculty of Science, Toho University, 5Graduate School of Integrated Arts and Sciences, Hiroshima University A series of methods to determine the potential DNRA rate based on 14NH4+/15NH4+ analyses is provided in detail. NH4+ is converted into N2O via several steps and analyzed using quadrupole gas chromatography–mass spectrometry. Environment Removal of Arsenic Using a Cationic Polymer Gel Impregnated with Iron Hydroxide Syed Ragib Safi1, Takehiko Gotoh1, Takashi Iizawa1, Satoshi Nakai1 1Department of Chemical Engineering, Hiroshima University In this work, we prepared an adsorbent composed of the cationic N,N-dimethylamino propylacrylamide methyl chloride quaternary (DMAPAAQ) polymer gel and iron hydroxide for adsorbing arsenic from groundwater. The gel was prepared via a novel method designed to ensure the maximum content of iron particles in its structure.