Search

We investigated the distribution of nitrogen compounds in Han River as well as two tributaries of Tancheon and Jungrangcheon. Particularly, we observed the significant releases of NH -N from effluent of wastewater treatment plants (WWTPs) in two tributaries that has resulted in the increases of ammonium nitrogen (NH -N) in Han River as well as in Tancheon and Jungrangcheon. Due to the increases of NH -N in two tributaries, the larger distribution of δN-NH was observed than those of δN-NO in downstream. We calculated the contribution rate of ammonium nitrogen and nitrate nitrogen from effluent to downstream according to the results of stable isotope. The contribution rates of δN-NH from effluent to downstream were significant that ranged between 53 and 100 % in Tancheon and between 27 and 100 % in Jungrangcheon. While the contribution of δN-NO was not significant in Tancheon, it was occasionally observed in Jungrangcheon. These results demonstrated that WWTPs are the major sources of NH -N in two tributaries, which caused the distinguishable stable isotope of δN-NH . Therefore, the stable isotope of δN-NH could be a useful parameter or tracer for the evaluation of NH-N released from WWTPs in rivers. [ABSTRACT FROM AUTHOR]

Monochamus alternatus Hope, 1842, is a major forest pest that hosts the pathogenic pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner and Buhrer, 1934) Nickle 1970. Taxonomically, M. alternatus is currently divided into two subspecies, based on morphology and geography: Monochamus alternatus alternatus Hope, 1842 in China, Taiwan, Tibet, Vietnam, and Laos and Monochamus alternatus endai Makihara, 2004 in South Korea and Japan. Despite their economic importance, the subspecies taxonomy of M. alternatus has never been tested after the first description. In this study, we aimed to reassess the subspecies taxonomy of M. alternatus using molecular and morphological data. For morphological analysis, we examined three major morphological characters (pronotal longitudinal band, granulation on humeri, and elytral proximomedial spine) from 191 individuals from China, Korea, and Taiwan. Population genetic structures were examined using 85 de novo sequences and 82 public COI sequences from China, Korea, Japan, Malaysia, Taiwan, and a few intercepted specimens from the United States. All the genetic data were aligned as three different multiple sequence alignments. Individuals from each subspecies were morphologically and genetically scattered, not clustered according to subspecies in any of the analyses. Therefore, a new synonymy is proposed: Monochamus alternatus Hope, 1842 = Monochamus alternatus endai, syn. n. This study suggests a more robust classification of M. alternatus for the first time and ultimately will pose a substantial impact on implementing quarantine or forestry policies., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)