Article
Environmental Sciences
Ji-Hyung Park, Hyojin Jin, Tae Kyung Yoon, Most Shirina Begum, Chea Eliyan, Eun-Ju Lee, Seung-Cheol Lee, Neung-Hwan Oh
Summary: Water pollution from untreated wastewater significantly impacts organic matter biodegradation and CO2 pressure along the Mekong-Tonle Sap network near Phnom Penh. High-resolution measurements in the dry season show a large increase in pCO2 downstream in areas receiving urban sewage, while the monsoon survey reveals little spatial variation due to the reversal of water flow. This highlights the importance of considering wastewater-enhanced CO2 production in urbanized river basins to accurately estimate CO2 emissions.
Article
Environmental Sciences
Hao-Ran Guo, Yun Wu, Chao-Chen Hu, Xue-Yan Liu
Summary: This study measured nitrogen concentrations and stable isotopes in river water and aquatic plants along the Nanming River in Guiyang, China. The findings revealed the sensitivity of aquatic plants to riverine nitrogen loadings and their nitrogen assimilation processes. The study found that the total nitrogen content of aquatic plants increased as river nitrogen concentrations increased, but the increment decreased. The study also observed a distinct shift in the nitrogen preference of plants from ammonium to nitrate with increased sewage nitrogen loadings. The elevated nitrate preference and assimilation in plants were supported by higher levels of nitrate reductase activity in the downstream river section.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Environmental Sciences
C. E. Renshaw, E. N. Dethier, J. D. Landis, J. M. Kaste
Summary: The input of organic matter into stream channels is an important energy source for headwater ecosystems and plays a crucial role in the global carbon cycle. The study focuses on quantifying the mobilization, transport, and storage of organic-rich fine sediment in a Strahler fourth-order stream during intermediate-sized storm events. It is found that the channel bed is consistently a source of suspended load to the channel margins, and the trapping of suspended load by riparian margins limits sediment transport distance and decouples the channel from local terrestrial organic matter exchange.
WATER RESOURCES RESEARCH
(2022)
Article
Environmental Sciences
Jin Liu, Tiezhu Yan, Zhenyao Shen
Summary: This study investigated the sources and transformations of suspended particulate organic matter (POM) within the Beiyun River Watershed, as well as the influence of landscape patterns on POM, using stable carbon and nitrogen isotope techniques combined with multiple statistical analyses. The study found significant spatial fluctuations in POM variables under different urban development gradients, with different POM sources existing in the rainy season and dry season. The study also highlighted the importance of landscape metrics in correlating with POM variables over seasons, providing insights for urban river water quality improvement strategies.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Dong-Young Lee, Jung Hyun Kwak, Tae Hee Park, Hee Yoon Kang, Dongyoung Kim, Sungmin Hwang, Hyun Je Park
Summary: The geomorphology of coastal lagoons plays a crucial role in the hydrological balance and biogeochemical properties. This study found that seasonal variations in suspended particulate organic matter (POM) in different lagoon systems were influenced by environmental variability driven by hydrological dynamics. The differences in environmental conditions resulted in significant variations in POM composition between the two lagoon systems.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Xiaojing Zhang, Shengwei Zhang, Junping Lu, Ruishen Li, Xi Lin, Wenlong Gao
Summary: Studying the sources of suspended particulate organic matter (SPOM) in reservoirs located in desert grassland areas is crucial for understanding the carbon and nitrogen cycles. This study focused on the impact of atmospheric deposition on reservoirs in regions with little rainfall and a dusty climate. Using isotope techniques, the study analyzed the composition and sources of SPOM in the reservoir and its watershed during dry and wet seasons. The results revealed that atmospheric deposition and terrestrial C3 plants were the main sources of carbon in SPOM, while atmospheric nitrogen deposition and soil erosion were the primary sources of nitrogen.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Environmental Sciences
Heng Xiao, Changping Mao, Shuai Wang, Zhimin Jia, Wenbo Rao
Summary: The construction of the Three Gorges Dam has altered the hydrology and sediment trapping in the Three Gorges Reservoir, resulting in changes in the composition and export of organic matter in the Yangtze River. Surface sediment samples from the reservoir were analyzed to determine the seasonal variations and sources of organic matter, with results showing that soil organic matter, river plankton, and aquatic vascular plants are the main sources. The analysis of nitrogen isotopes further revealed the presence of external pollutants, mainly from nitrogen fertilizers and domestic sewage. This study highlights the need for fine nitrogen management to reduce pollution in the Three Gorges Reservoir.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Engineering, Environmental
Sydney C. Clark, Rebecca T. Barnes, Isabella A. Oleksy, Jill S. Baron, Meredith G. Hastings
Summary: Despite declining trends in atmospherically deposited nitrate since 2000, nitrate concentrations in high-elevation lakes of the Colorado Front Range remain elevated. The sources of elevated nitrate in surface waters include atmospheric deposition, glacial inputs, and nitrification within the catchment. The study results suggest that during the summer open-water season, alpine lakes receive a consistent contribution of uncycled atmospheric nitrate and nitrification plays a significant role in nitrate production within the catchment.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Zenglei Han, Min Xiao, Fujun Yue, Yuanbi Yi, K. M. G. Mostofa
Summary: Fluorescence spectroscopy and PARAFAC modeling were used to study the sources, distribution, and transformation of dissolved organic matter (DOM) in the Duliujian River catchment, identifying four main fluorescent components. Results showed higher dissolved organic carbon and chromophoric dissolved organic matter in summer compared to other seasons, suggesting a significant impact of rainfall events on the input of terrestrial-derived DOM.
Article
Environmental Sciences
Maksymilian Ciesla, Renata Gruca-Rokosz, Lilianna Bartoszek
Summary: Having a comprehensive understanding of the process by which suspended sediment in water is aggregated and deposited is crucial for the proper management and use of storage reservoirs. This study investigated the varied granulometric composition of accumulated sediment and examined the amounts and origins of organic matter. The results showed that the aggregation of sediment is not only dependent on the amount of organic matter but also its origin, with greater production of autochthonous organic matter intensifying the process of suspended sediment flocculation.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Marine
Wenxun Dong, Zhengguo Cui, Mengjuan Zhao, Junfeng Li
Summary: In this study, the relationship between environmental factors and bacterial community structure in the estuary of the Bailang River was analyzed using high-throughput sequencing. The results showed that seasonal variations significantly affected the diversity and composition of bacterial communities. pH, salinity, and inorganic nitrogen were identified as key factors shaping the bacterial community composition. In addition, nitrogen-cycle-related processes played important roles in the bacterial community.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Environmental Sciences
Xiaoqiang Li, Guilin Han, Man Liu
Summary: This study investigated the water chemistry, DIC contents, and delta C-13(DIC) values in a tropical agricultural river in northeast Thailand. The results show significant seasonal variations in the DIC concentrations and delta C-13(DIC) values, with the wet season having lower values. Riverine biologic effects and CO2 outgassing play important roles in the evolution of DIC and delta C-13(DIC) in this agriculturally-dominated watershed.
Article
Microbiology
Xiangyu Guan, Ruoxue He, Biao Zhang, Chengjie Gao, Fei Liu
Summary: The physicochemical properties and microbial communities in karst aquifers undergo significant annual and seasonal changes. Water samples were collected from a typical karst river to investigate the changes in microbial communities and their relationships with environmental factors. The microbial communities were stable during winter but varied between different years in summer. The assembly of microbial communities in winter was more influenced by deterministic processes, likely due to environmental pollution.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Environmental Sciences
Matthew G. Marshall, Anne M. Kellerman, Jemma L. Wadham, Jon R. Hawkings, Giovanni Daneri, Rodrigo Torres, Helena Pryer, Alexander Beaton, Hong Chin Ng, Alejandra Urra, Laura F. Robinson, Robert G. M. Spencer
Summary: Biogeochemical processes in fjords are influenced by changes in glacier meltwater input, affecting dissolved organic matter composition. Seasonal variations in riverine and marine inputs impact the supply of biolabile peptides and organic nitrogen cycling. Differences in DOM composition with increasing salinity reflect patterns in estuaries and suggest riverine DOC is a significant carbon subsidy to bacterial communities in the fjord.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Engineering, Civil
Shiqi Liu, Ping Wang, Qiwei Huang, Jingjie Yu, Sergey P. Pozdniakov, Ekaterina S. Kazak
Summary: This study analyzed the concentration, ages, and seasonality of riverine dissolved organic carbon (DOC) in the estuaries of six major Arctic rivers. It found that DOC concentration increased with streamflow, decreased during the freezing period, and increased during the flood pulse period. In river basins with large continuous permafrost areas, the release of older DOC into rivers was restricted. However, riverine DOC exports likely respond positively to changes in water temperature during the ice-free period, especially in basins with more sporadic permafrost, thicker active layers, more precipitation, and less soil organic carbon.
JOURNAL OF HYDROLOGY
(2022)
Article
Oceanography
Sinjae Yoo, Christina Eunjin Kong, Young Baek Son, Joji Ishizaka
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2019)
Article
Oceanography
Satoshi Nakada, Shiho Kobayashi, Masataka Hayashi, Joji Ishizaka, Satoshi Akiyama, Masaki Fuchi, Masaki Nakajima
JOURNAL OF OCEANOGRAPHY
(2018)
Article
Oceanography
Qian Xu, Chiho Sukigara, Joaquim I. Goes, Helga do Rosario Gomes, Yuanli Zhu, Shengqiang Wang, Anglu Shen, Eligio de Raus Maure, Takeshi Matsuno, Watanabe Yuji, Sinjae Yoo, Joji Ishizaka
JOURNAL OF OCEANOGRAPHY
(2019)
Article
Environmental Sciences
Rong Bi, Xi Chen, Jing Zhang, Joji Ishizaka, Yanpei Zhuang, Haiyan Jin, Hailong Zhang, Meixun Zhao
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2018)
Article
Oceanography
Eko Siswanto, Yongjiu Xu, Joji Ishizaka
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2018)
Article
Environmental Sciences
Meng Meng Yang, Joji Ishizaka, Joaquim Goes, Helga do R. Gomes, Eligio de Raus Maure, Masataka Hayashi, Toshiya Katano, Naoki Fujii, Katsuya Saitoh, Takayuki Mine, Hirokazu Yamashita, Akiko Mizuno
Article
Oceanography
E. R. Maure, J. Ishizaka, H. Aiki, Y. Mino, N. Yoshie, J. I. Goes, H. R. Gomes, H. Tomita
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2018)
Article
Marine & Freshwater Biology
Anglu Shen, Joji Ishizaka, Mengmeng Yang, Longling Ouyang, Yane Yin, Zengling Ma
Article
Limnology
Zhongping Lee, Shaoling Shang, Yongchao Wang, Jianwei Wei, Joji Ishizaka
LIMNOLOGY AND OCEANOGRAPHY
(2020)
Article
Environmental Sciences
Chi Feng, Joji Ishizaka, Katsuya Saitoh, Takayuki Mine, Hirokazu Yamashita
Article
Environmental Sciences
Mengmeng Yang, Joaquim Goes, Hongzhen Tian, Eligio de R. Maure, Joji Ishizaka
Proceedings Paper
Geosciences, Multidisciplinary
Mitsuhiro Toratani, Kazunori Ogata, Koji Suzuki, Joji Ishizaka, Toru Hirawake, Takafumi Hirata, Tomonori Isada, Hiroto Higa, Victor S. Kuwahara, Stanford B. Hooker, Yoko Kiyomoto, Hiroshi Murakami, Yukio Kurihara, Masahiro Hori, Hisatomo Waga, Youhei Yamashita, Akihiko Tanaka
2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019)
(2019)
Article
Environmental Sciences
Yuanli Zhu, David J. Suggett, Chenggang Liu, Jianfeng He, Longshan Lin, Fengfeng Le, Joji Ishizaka, Joaquim Goes, Qiang Hao
FRONTIERS IN MARINE SCIENCE
(2019)
Article
Environmental Sciences
Helga do Rosario Gomes, Qian Xu, Joji Ishizaka, Edward J. Carpenter, Patricia L. Yager, Joaquim Goes
FRONTIERS IN MARINE SCIENCE
(2018)
Proceedings Paper
Oceanography
Genki Terauchi, Eligio de Raus Maure, Zhiming Yu, Zaixing Wu, Changkyu Lee, Vasilii Kachur, Joji Ishizaka
REMOTE SENSING OF THE OPEN AND COASTAL OCEAN AND INLAND WATERS
(2018)