Article
Environmental Sciences
Hanna M. Kauko, Tore Hattermann, Thomas Ryan-Keogh, Asmita Singh, Laura de Steur, Agneta Fransson, Melissa Chierici, Tone Falkenhaug, Elvar H. Hallfredsson, Gunnar Bratbak, Tatiana Tsagaraki, Terje Berge, Qin Zhou, Sebastien Moreau
Summary: Understanding the dynamics of phytoplankton bloom phenology in the Atlantic sector of the Southern Ocean revealed the importance of sea ice retreat and zooplankton grazing in driving bloom initiation and termination, respectively. The study also highlighted the spatial correlation between primary productivity and topographic features, suggesting natural fertilization as a contributing factor. Further investigation into the identified bloom regimes in the area may help inform spatial management strategies and anticipate potential shifts in bloom timing due to environmental changes.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
S. Mcclish, S. M. Bushinsky
Summary: The Southern Ocean seasonal sea ice zone in spring is characterized by sea ice retreat and the development of phytoplankton blooms. Studies using biogeochemical profiling floats have found that higher net community production (bNCP) occurs when sea ice breakup happens early in the year, especially near topographic features that may increase micronutrient supply. This suggests that changes in Southern Ocean sea ice will influence future bNCP.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Esmee M. van Wijk, Stephen R. Rintoul, Luke O. Wallace, Natalia Ribeiro, Laura Herraiz-Borreguero
Summary: The Denman Glacier, a major ice river in East Antarctica, has the potential to contribute significantly to global sea level rise due to its large ice volume. Recent observations suggest that warm ocean water is reaching deep troughs beneath the glacier, potentially causing unstable retreat and melting of the ice from below. These findings highlight the vulnerability of the Denman Glacier to climate change and the importance of understanding the dynamics of warm water intrusion in the region.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Christine Dybwad, Philipp Assmy, Lasse M. Olsen, Ilka Peeken, Anna Nikolopoulos, Thomas Krumpen, Achim Randelhoff, Agnieszka Tatarek, Jozef M. Wiktor, Marit Reigstad
Summary: The study reveals clear seasonal patterns in the development and fate of phytoplankton blooms in the Arctic Ocean's seasonal sea ice zone, with low phytoplankton stocks and carbon fluxes in winter and pre-bloom periods, a short but intense productive season in May and June, and moderate carbon export fluxes in the autumn post-bloom conditions. The taxonomic composition of protist assemblages, large grazers, distance to open water, and Atlantic water advection play crucial roles in determining the fate of the blooms and the magnitude of organic carbon exported out of the surface water column. Intense blooms and high export events were observed in ice-covered waters, challenging previous assumptions about the productivity of the marginal ice zone in the area.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Bo Yang
Summary: This study utilized satellite and Argo data to determine the seasonal variations of e-ratio in subtropical gyres, showing significant seasonal changes in NCP and e-ratio in the North Pacific, North Atlantic, and South Pacific. The e-ratio was significantly lower in the South Pacific subtropical gyre, attributed to stronger sub-annual variations in NCP.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Leilei Bai, Xin Liu, Yuanqiang Wu, Hongyu Cheng, Changhui Wang, Helong Jiang, Aijie Wang
Summary: This study investigated the composition and stability of dissolved organic matter (DOM) in two large freshwater lakes in China, Poyang Lake and Lake Taihu. The findings showed that floodplain-derived organics and river-lake interaction increased the input of terrestrial aromatic and humic-like DOM in Poyang Lake, while autochthonous production during phytoplankton bloom enriched the semi-labile and biodegradable DOM in Lake Taihu. The seasonality of DOM lability profiles in these lakes was regulated by flow-related variation and phytoplankton production.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Geosciences, Multidisciplinary
C. W. Lester, T. J. W. Wagner, Dylan E. McNamara, M. R. Cape
Summary: The study suggests that the spring blooms of phytoplankton in the Arctic Ocean are highly dependent on sea-ice meltwater for horizontal mixing and maintaining the stratified upper ocean. When meltwater concentration is sufficient, it allows phytoplankton to be confined near the surface, exposed to enough sunlight for optimal growth. The findings support the central role of sea-ice meltwater in shaping the spatial patterns of Arctic phytoplankton blooms.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Oceanography
Jens M. Nielsen, Noel A. Pelland, Shaun W. Bell, Michael W. Lomas, Lisa B. Eisner, Phyllis Stabeno, Colleen Harpold, Scott Stalin, Calvin W. Mordy
Summary: This study quantifies primary production rates in the southeastern Bering Sea from 2016 to 2019 and finds that the majority of gross primary production (GPP) and net community production occur during the spring phytoplankton bloom. After the bloom, the water column experiences low GPP and net biological carbon consumption. Phytoplankton growth rates are commonly suppressed in late summer due to nitrogen limitation. This research provides important insights into seasonal variations of biogeochemical cycles, phytoplankton community growth rates, and carbon availability in the southeastern Bering Sea using high-temporal-resolution measurements.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Microbiology
Rui Zhang, Pavla Debeljak, Stephane Blain, Ingrid Obernosterer
Summary: Iron plays a crucial role in the cycling of organic carbon in the Southern Ocean, but the strategies of diverse microbes in acquiring different forms of iron under seasonally changing organic carbon regimes are poorly understood. High-resolution seasonal metagenomic observations near Kerguelen Island revealed distinct seasonal patterns in the abundance of genes related to iron and organic substrate transport, siderophore biosynthesis, and carbohydrate-active enzymes. This study provides insights into the ecological strategies of iron acquisition and their potential impact on the microbial community composition and organic matter transformations in the Southern Ocean.
ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Qi Liu, Yulu Tian, Yang Liu, Ming Yu, Zhaojiang Hou, Kejian He, Hui Xu, Baoshan Cui, Yuan Jiang
Summary: This study investigated phytoplankton communities at 110 sites in the Dongjiang River basin, China, and found that dissolved organic matter (DOM) is closely related to phytoplankton biomass and taxonomic composition, with different types of DOM having varying effects on phytoplankton community dynamics. The results suggest that DOM may serve as a potential warning of phytoplankton blooms.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Microbiology
Jesse M. Wilson, Emelia J. Chamberlain, Natalia Erazo, Melissa L. Carter, Jeff S. Bowman
Summary: Seasonality and nutrient availability were found to be the primary factors contributing to changes in microbial community structure in coastal ecosystems. Network analysis revealed distinct subsets within the microbial community that varied on different timescales and were associated with unique biotic and abiotic factors.
ENVIRONMENTAL MICROBIOLOGY
(2021)
Article
Environmental Sciences
Haakon Hop, Anette Wold, Amelie Meyer, Allison Bailey, Maja Hatlebakk, Slawomir Kwasniewski, Peter Leopold, Piotr Kuklinski, Janne E. Soreide
Summary: The impact of the rapidly changing Arctic on zooplankton community structure and seasonal behavior is not yet understood. Zooplankton in the Arctic region is more dependent on surrounding water mass characteristics, such as salinity and depth, rather than geographical location. Seasonal changes in the community are closely linked to algal food availability and seasonal changes from winter to spring.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Multidisciplinary Sciences
Brandon Kieft, Zhou Li, Samuel Bryson, Robert L. Hettich, Chongle Pan, Xavier Mayali, Ryan S. Mueller
Summary: This study found that different heterotrophic populations selectively assimilate exudates from common marine phytoplankton, with unique metabolic adaptations. The carbon assimilation rates calculated from SIP data provide a deeper mechanistic understanding of consumer succession and carbon use during marine bloom events.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Marine & Freshwater Biology
Claudia Sabine Bruhn, Sylke Wohlrab, Bernd Krock, Nina Lundholm, Uwe John
Summary: Harmful algal blooms (HABs) are increasingly occurring in the world's oceans possibly due to climate change, and a lack of information on their occurrence in the Arctic makes assessing future changes challenging. A study found that Arctic waters provide a suitable habitat for various toxin producers, with changing toxin abundances reflecting the strong seasonality of the environment, posing a potential threat to the ecosystem and its beneficiaries.
Article
Environmental Sciences
Xiansheng Zhang, Guangming Zhen, Xiaoru Cui, Yulan Zeng, Weimin Gao, Kunlong Yu, Keqiang Li
Summary: Blooms of Prorocentrum donghaiense occur annually in the East China Sea coastal waters, causing damage to the ecosystem and hindering economic development. Dissolved organic nitrogen and phosphorus are found to be the key factors influencing the bloom and phytoplankton community structure.
MARINE ENVIRONMENTAL RESEARCH
(2023)
Article
Environmental Sciences
K. Misumi, J. Nishioka, H. Obata, D. Tsumune, T. Tsubono, M. C. Long, K. Lindsay, J. K. Moore
Summary: Continental shelf sediments are an important source of iron in the oceans, with a large amount of Fe laterally transported mainly through interactions with slowly sinking particles in the North Pacific. This biogeochemical linkage between marginal seas and ocean basins has implications for understanding the global Fe cycle.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Review
Oceanography
Jun Nishioka, Hajime Obata, Toru Hirawake, Yoshiko Kondo, Youhei Yamashita, Kazuhiro Misumi, Ichiro Yasuda
Summary: The most significant breakthrough in oceanography in the past 30 years has been the discovery of iron (Fe) as a micronutrient controlling biological production. Our understanding of iron and nutrient dynamics in the ocean has greatly advanced. The review focuses on the natural iron supply processes and nutrient dynamics in the subarctic Pacific, discussing the impact on biological production and proposing explanations for the biological response in these waters.
JOURNAL OF OCEANOGRAPHY
(2021)
Review
Oceanography
Daiki Nomura, Hiroto Abe, Toru Hirawake, Atsushi Ooki, Youhei Yamashita, Aiko Murayama, Kazuya Ono, Jun Nishioka
Summary: The study analyzed temperature, salinity data, and oxygen isotope ratios in the northwestern Bering Sea in summer 2018 to quantify the formation of dense shelf water (DSW) associated with sea ice freezing. The results indicated continued DSW formation in the Gulf of Anadyr despite historically low sea ice extent in the Bering Sea in winter 2018.
PROGRESS IN OCEANOGRAPHY
(2021)
Article
Chemistry, Multidisciplinary
Mitsuhide Sato, Jun Nishioka, Kazuyuki Maki, Shigenobu Takeda
Summary: The study revealed differences in the distributions of DFe and L-Fe between the Kuroshio Current and its neighboring waters, with unique characteristics observed in the surface waters of the Kuroshio. The neighboring waters were classified into two types: East China Sea water and coastal water, each with distinct vertical gradients of DFe concentration. These findings suggest that different processes contribute to the iron dynamics in the Kuroshio area and its surrounding waters.
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)
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
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
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
Oceanography
Takenobu Toyota, Noriaki Kimura, Jun Nishioka, Masato Ito, Daiki Nomura, Humio Mitsudera
Summary: The sea ice in the southern Sea of Okhotsk has significant impacts on freshwater input and primary production, but its interannual variability is not well understood yet. Long-term field observations and satellite data analysis revealed that the sea ice in this region is uncorrelated with that in the northern and central regions, and its thickness and volume are mainly controlled by dynamical pile-up processes, rather than the thermodynamical freezing conditions.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
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)
