Journal of Oceanography
https://doi.org/10.1007/s10872-021-00619-0

SPECIAL SECTION: PREFACE
Coastal Ecosystem Change in Asia: Hypoxia, Eutrophication, and Nutrient Conditions

Coastal ecosystem change in Asia: hypoxia, eutrophication,and nutrient conditions
Xinyu Guo1 · Akihiko Morimoto1 · Feng Zhou2 · Naoki Yoshie1 · Ario Damar3,4 · Tetsutaro Takikawa5© The Oceanographic Society of Japan and Springer Nature Singapore Pte Ltd. 2021

This special section is a collection of papers from international symposium on coastal ecosystem change in Asia:
hypoxia, eutrophication, and nutrient conditions, which
was held on November 14–15, 2019 in Ehime University,Japan. This symposium was one of the events supported bya project named Leading Academia in Marine and Environment Pollution Research (LaMer), which is granted by
Ministry of Education, Culture, Sports, Science and Technology (MEXT) to Center for Marine Environmental Studies(CMES) for a period from 2016 to 2021 as one national Joint
Usage/Research Center in Japan.
The background for this symposium is the emergence ofmany nutrients-related environmental issues in the bays andshelf seas in Asia. For example, hypoxia water has been
observed in the Bohai Sea, Thailand Bay, and Jakarta Bay
in the past 10 years, and most of them have been associatedto the increased nutrient loads from land or aquaculture. On
the other hand, the hypoxia records have been revealed in
the East China Sea and many bays and inland seas in Japanfor more than 50 years. The reduction of nutrient load into
coastal water in Japan has been continuing for many years
but the hypoxia water is still observed now. Apparently, the* Xinyu Guoguo.xinyu.mz@ehime-u.ac.jp
1Center for Marine Environmental Studies, Ehime University,Matsuyama, Japan

2

State Key Laboratory of Satellite Ocean Environment
Dynamics, Second Institute of Oceanography, Ministryof Natural Resources, Hangzhou, China

3

Department of Aquatic Resources Management Facultyof Fisheries and Marine Sciences, IPB University, Bogor,Indonesia

4

Center for Coastal and Marine Resources Studies, IPB
University, Bogor, Indonesia

5

Graduate School of Fisheries and Environmental Sciences,
Nagasaki University, Nagasaki, Japanoccurrence of hypoxia condition is not only regulated bynutrient loads but also affected by many other factors suchas hydrodynamics of the bay. Severe symptoms related tohypoxia/eutrophication have been of societal concern inmany countries such as mass mortality of fishes. The symposium provided an opportunity to exchange our understanding on the occurrence of hypoxia water in the coastal
water in Asia, which can be used as further input for coastalmanagement.
About 60 scientists and students from Japan, Thailand,
Indonesia, Chinese Mainland, Hong Kong and Taiwan
attended this symposium and presented 22 oral presentations and 10 posters. The presentations cover several topics:(1) the hypoxia in several areas including off the Changjiang
Estuary and Pearl River mouth, along the coastal transitionzone off Hong Kong, in the Upper Gulf of Thailand, TokyoBay, Osaka Bay, Mikawa Bay, Ariake Sea, and Dokai Bay;(2) transport of water and nutrients in the East China Sea
shelf, Taiwan Strait, Upper Gulf of Thailand, Jakarta Bay;(3) harmful algal blooms in western Japan, engineering
effort for enhancing water exchange in an inner bay, longterm variations of nutrient concentration and fish abundancein the Seto Inland Sea, and human-induced marine ecological degradation. An abstract book is available from http://​lamer-​cmes.​jp/​news/​2446.​html.
In this special section, we received five submissions andaccepted three of them. These papers summarized the contents reported in the symposium and the progresses after
the symposium. Because of COVID-19, we have to delay
the opening of second symposium that was originally set tobe held in Hangzhou in 2021. We wish that we can gather
in Hangzhou next year and propose another special section in Journal of Oceanography after the symposium. We
thank the Oceanographic Society of Japan for providing
an opportunity to publish this special section, especially toProfessor Naoto Ebuchi, Editor-in-Chief of the Journal ofOceanography.

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