Article
Environmental Sciences
Xi Wang, Hui Xu, Ruyuan Jiao, Gefei Ma, Dongsheng Wang
Summary: The study focused on the effect of coagulation on dephosphorization in reservoir water, comparing the performances of Al-based and Fe-based coagulants. Results showed that aluminum salts had stable advantages in dephosphorization, especially in the initial stage of algal blooms. Factors such as pH, P content, and extracellular organic matter were found to significantly affect the efficiency of dephosphorization.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Rong Xiang, Binghui Zheng, Haifeng Jia
Summary: Algal blooms negatively impact reservoir water quality, and the role of dissolved organic matter (DOM) in bloom formation in reservoirs has not been investigated. The compositions of sediment- and soil-derived DOM and their effects on the growth, physiology, and photosynthetic activity of four bloom-forming species were assessed. Sediment DOM promoted the growth of all algal species, while soil DOM significantly promoted the growth of two species and slightly inhibited the growth of one species. The main DOM components affecting algal growth were identified. This study provides a theoretical foundation for the development of bloom-prevention strategies for river-type reservoirs.
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
(2023)
Article
Engineering, Environmental
Jia Pu, Shengrui Wang, Fuqiang Fan, Chunyang Zhou, Zhezhe Liu
Summary: The bioavailability of sediment-bound organic phosphorus (Po) varies significantly between high risk-periods and low risk-periods of algal blooms (HRP-ABs and LRP-ABs), and this variation is important for understanding the biogeochemical processes of phosphorus and controlling lake eutrophication.
Article
Marine & Freshwater Biology
Alicia M. Hendrix, Kathi A. Lefebvre, Lori Quakenbush, Anna Bryan, Raphaela Stimmelmayr, Gay Sheffield, Gabriel Wisswaesser, Maryjean L. Willis, Emily K. Bowers, Preston Kendrick, Elizabeth Frame, Thomas Burbacher, David J. Marcinek
Summary: The study investigated the potential increase in exposure risks of Alaskan ice seals to domoic acid and saxitoxin, with both toxins detected in bearded, ringed, and spotted seals, especially with a higher prevalence in bearded seals. The findings suggest that ice seals, particularly bearded seals, are suitable sentinels for monitoring harmful algae bloom prevalence in the Pacific Arctic and subarctic regions.
MARINE MAMMAL SCIENCE
(2021)
Article
Engineering, Environmental
Moshan Chen, Carter A. Rholl, Shane L. Persaud, Zixuan Wang, Zhen He, Kimberly M. Parker
Summary: During harmful algal blooms (HABS), permanganate can be used as a preoxidant to improve drinking water quality by removing algal cells and degrading algal toxins. However, permanganate oxidation also alters the precursors of disinfection byproducts (DBPs) from intracellular algal organic matter (AOM), affecting DBP formation during disinfection. This study evaluated the impacts of permanganate preoxidation on DBP generation during chlorination and chloramination of AOM. The results showed that permanganate preoxidation increased the formation of certain DBPs and decreased others, indicating a complex interaction between permanganate and AOM.
Article
Environmental Sciences
Chelsea Nicole Lopez, Dennis Arthur Hansell
Summary: This study provides evidence of deep particle export and enhanced dissolved organic carbon concentrations beneath the Pacific's Subarctic Front and Northern Subtropical Front. These phenomena are controlled by latitude-specific biogeochemical and hydrographic conditions.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Zhou Liang, Robert T. Letscher, Angela N. Knapp
Summary: Surface ocean bulk and semi-labile dissolved organic matter (DOM) stoichiometry vary across ocean regions with global means of 387:26:1 and 179:20:1, respectively. Surface ocean DOC:DOP and DON:DOP concentration ratios are more variable than DOC:DON concentration ratios. Surface ocean gradients in P-depleted DOM stoichiometries in the Pacific and Atlantic basins reflect variable nutrient stress.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Multidisciplinary Sciences
Yoshiko Kondo, Rise Bamba, Hajime Obata, Jun Nishioka, Shigenobu Takeda
Summary: The research found uneven distribution of dissolved organic ligands between western and eastern stations in the subarctic Pacific, with higher concentration of organic ligands in the lower part of subarctic Pacific intermediate water at the western station. However, a more detailed size-fractionated treatment showed no significant difference in the distribution of soluble ligands between western and eastern stations. This suggests that organic and inorganic colloid formations are potentially essential for Fe transport mechanisms in the subarctic Pacific.
SCIENTIFIC REPORTS
(2021)
Article
Marine & Freshwater Biology
R. Eugene Turner, James M. Lee, Charles S. Milan, Erick M. Swenson
Summary: The study found that phosphorous entering the lake mainly comes from fertilizer use in the watershed, while the source of nitrogen is not related to the total nitrogen concentration in the lake. Half of the particulate P entering the lake is trapped within it, and the net accumulation of N in the lake appears to be from the stimulation of nitrogen fixation.
Article
Water Resources
Ryuichiro Shinohara, Kenji Tsuchiya, Ayato Kohzu
Summary: The study focused on the role of particulate organic phosphorus (POP) in the phosphorus cycle in the Sakura River, Japan. Findings indicated that concentrations of suspended particles and particulate phosphorus increased after rain events during irrigation, with POP accounting for 42.4% of PP concentrations. Changes in phosphorus composition were observed during decomposition experiments, with a decrease in organic phosphorus proportion as DNA-P disappeared from the PP. Additionally, the presence of suspended particles was found to increase DOP mineralization rates.
JOURNAL OF HYDROLOGY-REGIONAL STUDIES
(2022)
Article
Environmental Sciences
Tiantian Chen, Xi Chen, Huichen Sun, Han Zhang, Jie Bai
Summary: This study compared the growth, phosphorus utilization, toxin production, and gene expression of Alexandrium pacificum under different phosphorus supply conditions. The findings revealed that the utilization strategies of organic and inorganic phosphorus differ, and organic phosphorus utilization in low phosphorus conditions may be a crucial factor driving bloom formation.
SCIENCE OF THE TOTAL ENVIRONMENT
(2024)
Review
Engineering, Environmental
Kayla Piezer, Lei Li, Youchul Jeon, Anusha Kadudula, Youngwoo Seo
Summary: Climate change and eutrophication create favorable conditions for cyanobacterial growth and harmful algal blooms, posing a threat to society. Water utilities face challenges in treating cyanobacteria-laden water, but the use of potassium permanganate (KMnO4) may offer a potential solution for removing cyanotoxins.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Marine & Freshwater Biology
Wen-Yu Jin, Xiang-Wu Chen, Jin-Zhou Tan, Xin Lin, Lin-Jian Ou
Summary: This study investigated the intracellular polyP metabolism and its regulation in Karenia mikimotoi, a harmful algal bloom species, under varying external phosphorus conditions. The findings suggest that K. mikimotoi has a strong capability to mobilize the intracellular phosphorus pool for growth under phosphorus deficiency, and polyP may not play a crucial role in cellular phosphorus storage in phytoplankton, at least in dinoflagellates.
Article
Environmental Sciences
Qing-Chun Zhang, Yun-Feng Wang, Min-Jie Song, Jin-Xiu Wang, Nan-Jing Ji, Chao Liu, Fan-Zhou Kong, Tian Yan, Ren-Cheng Yu
Summary: This study documented the first occurrence of a Takayama bloom in the temperate coastal waters of China. The researchers found that the high eutrophication levels in Haizhou Bay, caused by intensive mariculture and terrestrial nutrient input, accelerated the proliferation of T. acrotrocha. The results suggest that Karenia blooms are becoming increasingly dominant in eutrophic temperate coasts with intensive mariculture activities, particularly under ocean warming.
MARINE POLLUTION BULLETIN
(2022)
Article
Engineering, Environmental
Mengjiao Wang, Junfeng Chen, Yushan Wei, Lijun Hu, Yuling Xu, Yanyan Liu, Renjun Wang
Summary: This study summarizes the application of metal-organic frameworks and covalent organic frameworks in photocatalytic inhibition of algae. The research provides theoretical support for further improving the photocatalytic efficiency of materials and enhancing environmental interactions.
JOURNAL OF WATER PROCESS ENGINEERING
(2023)
Article
Multidisciplinary Sciences
Youhei Yamashita, Motohiro Nakane, Yutaro Mori, Jun Nishioka, Hiroshi Ogawa
Summary: The study reveals the distribution of dissolved black carbon in the Pacific Ocean, indicating a negative correlation between its concentration and deep-ocean circulation. The removal process of black carbon to abyssal sediments is estimated to account for a small percentage of anthropogenic CO2 uptake by the ocean.
NATURE COMMUNICATIONS
(2022)
Article
Oceanography
Kuo Hong Wong, Jun Nishioka, Taejin Kim, Hajime Obata
Summary: In this study, comprehensive distributions of dissolved manganese (dMn) in the subarctic Pacific were presented and compared with the data of dissolved iron (dFe) in the same region. The study revealed different vertical profiles for dMn and dFe and observed different forms in the size fractionation of these two micronutrients. The transport distances of dMn found in this study were the highest in the Pacific region, and this long-range transport could potentially impact phytoplankton growth through upwelling processes.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Ariana Chih-Hsien Liu, Feng-Hsun Chang, Jinny Wu Yang, Hiroaki Saito, Yu Umezawa, Chung-Chi Chen, Sen Jan, Chih-hao Hsieh
Summary: This study investigated the diversity and taxonomic composition of free-living bacterioplankton along the Kuroshio. The results showed that temperature, phosphate concentration, and chlorophyll-a concentration were important factors affecting the diversity and composition of bacterioplankton.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2022)
Article
Geochemistry & Geophysics
Yuta Isaji, C. Yoshikawa, N. O. Ogawa, K. Matsumoto, A. Makabe, S. Toyoda, N. F. Ishikawa, H. Ogawa, H. Saito, M. C. Honda, N. Ohkouchi
Summary: In this study, nitrogen isotopic analysis of chlorophylls in the eastern Indian Ocean revealed differences in nitrogen source assimilation by phytoplankton species, with specific chlorophylls providing insights into isotopic variability within the community. The results highlighted subtle variations in nitrate availability at the subsurface chlorophyll maximum along a meridional transect.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Review
Oceanography
Jun Nishioka, Ichiro Yasuda, Toru Hirawake, Tomohiro Nakamura, Yoshiko Kondo, Yuri N. Volkov
Summary: The memorial addresses for Mr. Alexey Fedorovich Shcherbinin and Captain Evgeniy Anikovich Sklizkov highlight their significant roles and leadership in Russian-Japanese collaborative expeditions, expressing deep condolences and honoring their achievements.
PROGRESS IN OCEANOGRAPHY
(2022)
Review
Oceanography
Siyu Jiang, Fuminori Hashihama, Yukio Masumoto, Hongbin Liu, Hiroshi Ogawa, Hiroaki Saito
Summary: This study measured surface phytoplankton growth and mortality rates using dilution experiments and sensitive nutrient analysis in the Eastern Indian Ocean, demonstrating that the region is not a stable oligotrophic marine ecosystem but dynamic, influenced by unique regional physical events.
PROGRESS IN OCEANOGRAPHY
(2022)
Review
Oceanography
Dong Yan, Jun Nishioka, Takenobu Toyota, Koji Suzuki
Summary: The Sea of Okhotsk plays a key role in the seawater circulation of the North Pacific Ocean. During winter, sea ice forms in the northern shelf and is transported to the southern part of the sea by the East Sakhalin Current. Diatoms are the dominant microalgae in the sea ice ecosystem, with Thalassiosira spp., Porosira glacialis, and Fragilariopsis cylindrus being the major species. The presence of the East Sakhalin Current influences the composition and abundance of microalgae in the seawater stations, with higher concentrations of dissolved Fe and ammonia. The study suggests that the winter phytoplanktonic communities in the southern Sea of Okhotsk are largely dependent on the presence of the East Sakhalin Current.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Hirofumi Tazoe, Hajime Obata, Takuya Hara, Mutsuo Inoue, Takahiro Tanaka, Jun Nishioka
Summary: For the first time, the vertical activity concentration distributions of radium isotopes, Ra-226 and Ra-228, were obtained in the western Subarctic Pacific Gyre (WSAG). The distributions were influenced by upwelling of deeper water, vertical mixing, and lateral transport.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Limnology
Shunyan Cheung, Kailin Liu, Kendra A. Turk-Kubo, Jun Nishioka, Koji Suzuki, Michael R. Landry, Jonathan P. Zehr, Szeki Leung, Lixia Deng, Hongbin Liu
Summary: Recent studies have found active nitrogen fixation in high-latitude waters, but the ecological controls on nitrogen-fixing organisms in such systems are still unclear. This study detected abundant UCYN-A, a nitrogen-fixing cyanobacteria, in the Gulf of Anadyr and identified a correlation between its abundance and the ratio of dissolved iron to dissolved inorganic nitrogen. The study also found selective grazing of UCYN-A in nitrogen-depleted waters and highlighted the importance of the Fe : DIN ratio in determining the abundance of UCYN-A in high-latitude waters.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2022)
Article
Limnology
Mitsuhide Sato, Takuhei Shiozaki, Fuminori Hashihama, Taketoshi Kodama, Hiroshi Ogawa, Hiroaki Saito, Atsushi Tsuda, Shigenobu Takeda, Ken Furuya
Summary: Flow cytometric data from multiple stations in the Pacific and Indian Oceans were analyzed to determine the depth and magnitude of the subsurface abundance maximum of phytoplankton populations. The results showed a strong correlation between the peak depth of each population and the depth of the subsurface chlorophyll maximum. This correlation was consistent across different ocean provinces and was largely in line with the differences in their ability to acquire light and nutrients. However, the absolute light levels and nutrient concentrations varied dramatically among neighboring stations.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Meteorology & Atmospheric Sciences
Kaori Kawana, Yuzo Miyazaki, Yuko Omori, Hiroshi Tanimoto, Sara Kagami, Koji Suzuki, Youhei Yamashita, Jun Nishioka, Yange Deng, Hikari Yai, Michihiro Mochida
Summary: This study conducted a cruise observation in the western North Pacific to characterize atmospheric aerosols and gaseous air/seawater compounds. The results showed high variability in size distribution and cloud condensation nuclei (CCN) activity of aerosols from different sources.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Environmental Sciences
Naoya Kanna, Shin Sugiyama, Takuto Ando, Yefan Wang, Yuta Sakuragi, Toya Hazumi, Kohei Matsuno, Atsushi Yamaguchi, Jun Nishioka, Youhei Yamashita
Summary: An increasing body of work has shown the potential impacts of subglacial discharge from marine-terminating glaciers on the marine environment around Greenland. Upwelling of nutrients associated with rising buoyant plumes near the front of marine-terminating glaciers plays a key role in maintaining the high productivity of connected fjords. However, the response of protist communities to subglacial discharges into fjords remains poorly understood.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Limnology
Kailin Liu, Jun Nishioka, Bingzhang Chen, Koji Suzuki, Shunyan Cheung, Yanhong Lu, Huijun Wu, Hongbin Liu
Summary: This study investigates phytoplankton growth and microzooplankton grazing, two critical processes in marine food webs, in the subarctic western Pacific and the Bering Sea. Results show that phytoplankton growth is primarily determined by nutrient availability and temperature. In the high-nutrient, low-chlorophyll regions, iron availability is the limiting factor. In the Gulf of Anadyr and Kamchatka Strait, phytoplankton growth is mainly limited by inorganic nitrogen. Microzooplankton grazing rate is influenced by temperature and prey availability. The study reveals different food web structures in areas with and without riverine iron input.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Youhei Yamashita, Jun Nishioka
Summary: Through circulation of intermediate water, the marginal seas have been identified as important external sources of dissolved iron (Fe) in the North Pacific. This study presents comprehensive spatial distributions of dissolved Fe concentrations and Fe(III) solubilities over the North Pacific, including the marginal seas, the Sea of Okhotsk, and the Bering Sea. The results suggest that the major dissolved Fe chemical form derived from shelf and slope sediments in the marginal seas changed from colloidal Fe to FDOMH-Fe complexes.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Oceanography
Siyu Jiang, Fuminori Hashihama, Hongbin Liu, Kazutoshi Yoshitake, Hideto Takami, Koji Hamasaki, Idha Yulia Ikhsani, Hajime Obata, Hiroaki Saito
Summary: This study investigated the adaptation of Prochlorococcus to nutrient environments in the surface eastern Indian Ocean. The results showed distinct physiological patterns and abundance of functional gene modules related to nutrient utilization, indicating their adaptation to local nutrient environments.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Chemistry, Multidisciplinary
Morgane Leon, Pieter van Beek, Virginie Sanial, Marc Souhaut, Paul Henderson, Matthew A. Charette
Summary: The analysis of radium and actinium isotopes in seawater requires the collection of large volumes of water and the use of high sensitivity instruments. To concentrate these isotopes, filters impregnated with MnO2 are typically used. However, the extraction efficiency of these filters for the target isotopes needs to be determined.