Article
Environmental Sciences
Jianlong Feng, Delei Li, Jing Zhang, Liang Zhao
Summary: The Amundsen Sea in Antarctica is a region with high primary productivity. Understanding the variations and environmental controls of primary productivity is crucial to comprehend the role of the Southern Ocean in the global carbon cycle and climate regulation. Through cluster analysis, the Amundsen Sea was divided into nine bioregions, which helped to identify priorities for studying the temporal and spatial variations in primary production. Four nearshore bioregions with high primary productivity were selected for analysis, revealing significant seasonal and annual variations influenced by factors such as net solar radiation, sea ice, and dissolved iron. The findings highlighted the importance of sea surface temperatures and dissolved iron as limiting factors and their impact on phenology and long-term changes in primary productivity.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Wenqiang Zhang, Songjie Han, Dianwei Zhang, Baoqing Shan, Dongyang Wei
Summary: Coastal areas are crucial for biodiversity conservation, and maintaining good water quality is vital for this function. A study in China's coastal seas analyzed data from 2011 to 2020 and found an upward trend in dissolved oxygen (DO) levels, attributed to a reduction in terrestrial anthropogenic pollutant (TAP) input. The East China Sea had lower DO content due to higher TAP input, with over 60% of the total DO being <5 mg L-1. Different species of phytoplankton, zooplankton, and macrobenthos responded differently to changes in DO, with phytoplankton species numbers showing the strongest correlation. A better DO environment was found to contribute to increased density of macrobenthos. The study highlights the importance of maintaining good DO levels and controlling TAP input for coastal ecosystem health.
ENVIRONMENTAL RESEARCH
(2023)
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
Environmental Studies
Yanan Wen, Min Xiao, Zhaochuan Chen, Wenxi Zhang, Fujun Yue
Summary: Dissolved organic matter (DOM) in urban rivers was studied to reveal its spatiotemporal variations and influencing factors. The results showed significant seasonal differences in DOM concentration, with higher levels in urban suburbs due to anthropogenic inputs. Different land use types affected the composition of riverine DOM, with a higher abundance of protein-like DOM in urban rivers. DOM in the watershed was influenced by both terrestrial and autochthonous sources, with human activities playing a major role.
Article
Environmental Sciences
Steven F. Dimarco, Zhankun Wang, Piers Chapman, Lubna al-Kharusi, Leila Belabbassi, Hilal al-Shaqsi, Marion Stoessel, Stephanie Ingle, Ann E. Jochens, Matthew K. Howard
Summary: Long-term observations from a cabled ocean observatory in the Sea of Oman reveal that the recurrence of coastal hypoxia is associated with the seasonal monsoon winds. During the summer/fall southwest monsoon season, the winds generate coastal upwelling of low dissolved oxygen waters, while during the winter monsoon season, the winds lead to downwelling and ventilation in the coastal ocean.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Jean Marcais, Louis A. Derry, Luca Guillaumot, Luc Aquilina, Jean-Raynald de Dreuzy
Summary: The study found that the transit time distributions of streamwater in the watershed display different proportions of old waters, mainly due to groundwater contributions to the stream. Seasonal variations in transit time are influenced by the variable contributions of different flowpaths and the stratification of groundwater residence times. A parsimonious model is developed to capture the groundwater contribution and its effect on transient transit times. Calibration of hydraulic conductivity, porosities, and tracer data successfully reproduces the concentrations and dynamics of the stream. Groundwater flow contribution is controlled by the hydraulic conductivity, while its age is controlled by the porosities.
WATER RESOURCES RESEARCH
(2022)
Article
Environmental Sciences
Wei-Jen Huang, Wei-Jun Cai, Xinping Hu
Summary: The study found that strong seasonal net DIC removal occurred in the near-surface water during summer on the northern Gulf of Mexico continental shelf, while the net DIC production peak in the near-bottom, subsurface waters was observed between July and September. The delayed coupling between eutrophic surface and hypoxic bottom waters suggests a similar pattern may be seen in other nutrient-rich, river-dominated ocean margins worldwide.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Meteorology & Atmospheric Sciences
Shineng Hu, Shang-Ping Xie, Richard Seager, Mark A. Cane
Summary: Tropical rainfall variations have direct societal relevance and influence global climate variations through tele-connections. We analyzed 40 years of monthly observations and found that sea surface temperature threshold (SSTthr) varies by up to 4°C in space and with season. Based on local convective instability, we developed a quantitative theory that explains the variations in SSTthr using the climatological state of the tropical atmosphere.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Xiaolei Chen, Xiao Ma, Xueji Gu, Sumei Liu, Guodong Song, Haiyan Jin, Guiling Zhang
Summary: Continental shelves and estuaries are important regions for the production and emission of N2O, with variations in distribution and emissions affected by temperature gradients, currents, and riverine inputs. N2O concentrations peak in spring and decrease sharply in summer and fall, with higher emissions in the ECS compared to the SYS. Sediments, especially around the Yangtze River Estuary, are identified as significant benthic N2O sources.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Oceanography
Angela A. Bahamondes Dominguez, Helen S. Macdonald, Graham Rickard, Matthew L. Hammond
Summary: Nutrient limitation is crucial for phytoplankton growth and ecosystem functioning in the Celtic Sea. This study demonstrates the importance of both nitrate and dissolved iron as limiting nutrients in the region, with iron playing a significant role in the spring bloom development. The findings highlight the need to consider dissolved iron as an important state variable in models of the Celtic Sea and other temperate shelf seas.
CONTINENTAL SHELF RESEARCH
(2022)
Article
Oceanography
Yongfei Deng, Zhiqiang Liu, Tingting Zu, Jianyu Hu, Jianping Gan, Yuxin Lin, Zhibing Li, Qi Quan, Zhongya Cai
Summary: This study comprehensively investigates the interannual variability of multi-scale motions in the northern South China Sea (NSCS) and the associated influences from terrestrial, atmospheric, and oceanic processes. The results show that the NSCS circulation and hydrographic properties are sensitive to the tropical climate variability represented by ENSO, and are influenced by various factors.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Multidisciplinary Sciences
Xu Lian, Shilong Piao, Anping Chen, Kai Wang, Xiangyi Li, Wolfgang Buermann, Chris Huntingford, Josep Penuelas, Hao Xu, Ranga B. Myneni
Summary: The study demonstrates that the carryover effect of vegetation growth has strong positive impacts on seasonal vegetation growth in the Northern Hemisphere, particularly in early growing-season vegetation growth, surpassing the influence of past and co-occurring climate factors. This carryover effect persists into the subsequent year but does not extend further, significantly contributing to the observed annual greening trend.
NATURE COMMUNICATIONS
(2021)
Article
Environmental Sciences
Tetsuya Matsunaka, Seiya Nagao, Mutsuo Inoue, Rodrigo Mundo, Saki Tanaka, Ning Tang, Masa-aki Yoshida, Masanori Nishizaki, Masaya Morita, Tetsutaro Takikawa, Nobuo Suzuki, Shouzo Ogiso, Kazuichi Hayakawa
Summary: This study monitored the concentrations of phase-partitioned polycyclic aromatic hydrocarbons (PAHs) in seawater off Oki Island, Japan, from 2015 to 2019, aiming to understand the seasonal variations, main sources, and transport pathways of PAHs in the southwestern Sea of Japan. The results showed that combustion products were the main sources of both dissolved and particulate PAHs. Higher concentrations of PAHs were observed in summer-autumn, and it was found that the area around southern Oki Island was impacted by PAH-rich summer continental-shelf water transported by the Tsushima Warm Current flowing from the East China Sea.
MARINE POLLUTION BULLETIN
(2022)
Article
Engineering, Environmental
Linjie Zhang, Lilan Zhang, Yue Shi, Zhihui Yang, Qijun Gong, Dong Sun
Summary: This study developed a method to quantify the variability of oceanic PAHs based on wind frequency and wind-speed-weighted wind frequency. The validity of this method was tested using in-situ survey data and publicly available data from other monsoonal open oceans. The results showed that wind frequency and wind-speed-weighted wind frequency could better explain the variation of dissolved and particulate PAHs in the surface ocean, respectively. This study suggests that the influence of seasonal atmospheric transport is important in describing and interpreting the distribution patterns of PAHs in monsoon-influenced low and mid-latitude open oceans, and provides a reference method for understanding the global-scale distribution patterns of PAHs in the ocean.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Geosciences, Multidisciplinary
Matthew T. Jenkins, Aiguo Dai
Summary: In this study, seasonal variations in Arctic climate feedbacks and their relationship to sea-ice loss were investigated using ERA5 reanalysis data. The results showed that spring and summer experienced significant sea-ice loss, strong surface albedo feedback, and large oceanic heat uptake. Arctic clouds had a small net cooling effect in May-June-July but a moderate warming effect during the cold season, particularly in areas with substantial sea-ice loss. Arctic water vapor feedback reached its peak in summer but was weak and unrelated to sea-ice loss. Arctic positive lapse rate feedback (LRF) was strongest in winter over regions with significant sea-ice loss and weak inversion but was uncorrelated with atmospheric stability, indicating that oceanic heating from sea-ice loss led to enhanced surface warming and positive LRF.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Jin-Yu Terence Yang, Ting-Chang Hsu, Ehui Tan, Kitack Lee, Michael D. Krom, Sijing Kang, Minhan Dai, Silver Sung-Yun Hsiao, Xiuli Yan, Wenbin Zou, Li Tian, Shuh-Ji Kao
Summary: Coastal oceans are increasingly suffering from eutrophication and hypoxia, which significantly affect the nitrogen cycle. This study found that estuarine surface sediments are the major source of N2O production, while nitrification and denitrification have a minimal contribution. Furthermore, the coupling of nitrification and denitrification at the sediment-water interface, under the presence of abundant organic matter, is the main driver of N2O release in this region.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Zuozhu Wen, Thomas J. Browning, Yihua Cai, Rongbo Dai, Ruifeng Zhang, Chuanjun Du, Ruotong Jiang, Wenfang Lin, Xin Liu, Zhimian Cao, Haizheng Hong, Minhan Dai, Dalin Shi
Summary: Nitrogen fixation is vital for ocean productivity, but the exact mechanisms controlling this process are still unclear. This study shows that the supply ratio of iron:nitrogen is the most important factor in regulating N-2 fixation distribution in the tropical ocean.
Review
Astronomy & Astrophysics
Minhan Dai, Jianzhong Su, Yangyang Zhao, Eileen E. Hofmann, Zhimian Cao, Wei-Jun Cai, Jianping Gan, Fabrice Lacroix, Goulven G. Laruelle, Feifei Meng, Jens Daniel Mueller, Pierre A. G. Regnier, Guizhi Wang, Zhixuan Wang
Summary: This review examines the current understanding of the global coastal ocean carbon cycle and provides a new quantitative synthesis of air-sea CO2 exchange. The study highlights the importance of coastal and open ocean carbon sinks in mitigating climate change and meeting the target set by the Paris Agreement. The review also identifies challenges and knowledge gaps in projecting future changes in the coastal ocean carbon cycle.
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES
(2022)
Article
Oceanography
Jin-Yu Terence Yang, Jin-Ming Tang, Sijing Kang, Minhan Dai, Shuh-Ji Kao, Xiuli Yan, Min Nina Xu, Chuanjun Du
Summary: This study utilizes sedimentary N records in the South China Sea to reconstruct past changes in the oceanic nitrate inventory and provides insights into nitrate dynamics in the region. The findings suggest that the changes in nitrate isotopic ratios in the euphotic zone of the South China Sea are influenced by both nitrate assimilation and nitrification. In subsurface and thermocline waters, disproportional decreases in nitrate isotopes and elevated nitrate anomalies indicate the accumulation of external nitrogen. The study also reveals increased benthic denitrification at the western North Pacific Ocean margins, leading to consistent nitrate isotopic compositions but lower nitrate anomalies in the deep water of the South China Sea.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Environmental Sciences
Xianhui S. Wan, Hua Lin, Bess B. Ward, Shuh-Ji Kao, Minhan Dai
Summary: The coastal ocean and marginal sea are important sources of nitrous oxide (N2O) emissions into the atmosphere, but the spatial and temporal distribution of N2O in these regions is still uncertain due to lack of measurements. This study presents a large dataset of N2O concentrations and fluxes obtained from 10 cruises in the Northern South China Sea (NSCS). The results show that the NSCS is a net source of atmospheric N2O, with variations in fluxes across different regions and seasons. The study also highlights the influence of riverine discharge and the intrusion of the Kuroshio Current on N2O distribution in the NSCS.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Geosciences, Multidisciplinary
Wei Yang, Xianghui Guo, Zhimian Cao, Jianzhong Su, Liguo Guo, Lifang Wang, Yi Xu, Tao Huang, Yan Li, Yanping Xu, Zhe Wang, Guizhi Wang, Minhan Dai
Summary: This study investigated carbonate dynamics in the northwestern South China Sea, where upwelling, river plumes, and submarine groundwater discharge intersect. The study revealed complex spatial and year-to-year variations and demonstrated the joint modulations of upwelling, river plumes, and submarine groundwater discharge on the carbonate system.
SCIENCE CHINA-EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Xianhui S. S. Wan, Hua-Xia Sheng, Minhan Dai, Karen L. L. Casciotti, Matthew J. J. Church, Wenbin Zou, Li Liu, Hui Shen, Kuanbo Zhou, Bess B. B. Ward, Shuh-Ji Kao
Summary: The removal of carbon dioxide from the atmosphere by the marine biological pump is counteracted by the production of nitrous oxide in the subtropical ocean, which weakens the radiative benefit of carbon removal. Nitrous oxide production is promoted by enhanced biological activity, leading to substantial emissions that offset part of the greenhouse warming mitigation achieved by the biological pump.
Article
Environmental Sciences
Zhixuan Wang, Guizhi Wang, Xianghui Guo, Jianyu Hu, Minhan Dai
Summary: Salinity is an essential physical property of seawater and plays a key role in differentiating water masses in the ocean. However, high-resolution salinity data is often limited by the coverage of direct observations, which hinders its fine application in ocean processes and modeling. To overcome this limitation, researchers used a machine learning algorithm based on remote sensing data and cruise observations to reconstruct sea surface salinity (SSS) in the South China Sea. The reconstructed SSS showed good accuracy compared to observations and revealed a spatial and seasonal distribution pattern influenced by various factors.
Review
Geochemistry & Geophysics
Minhan Dai, Ya-Wei Luo, Eric P. Achterberg, Thomas J. Browning, Yihua Cai, Zhimian Cao, Fei Chai, Bingzhang Chen, Matthew J. Church, Dongjian Ci, Chuanjun Du, Kunshan Gao, Xianghui Guo, Zhendong Hu, Shuh-Ji Kao, Edward A. Laws, Zhongping Lee, Hongyang Lin, Qian Liu, Xin Liu, Weicheng Luo, Feifei Meng, Shaoling Shang, Dalin Shi, Hiroaki Saito, Luping Song, Xianhui Sean Wan, Yuntao Wang, Wei-Lei Wang, Zuozhu Wen, Peng Xiu, Jing Zhang, Ruifeng Zhang, Kuanbo Zhou
Summary: Subtropical gyres cover a significant portion of the world's ocean and are typically considered as ocean deserts due to their permanent stratification, depleted surface nutrients, and low biological productivity. Despite advancements in understanding biogeochemistry, subtropical gyres remain understudied. This review focuses on the North Pacific Subtropical Gyre and compares it with other subtropical gyres. It highlights the spatial variability and its impact on community structure and export production. The review also identifies knowledge gaps and research challenges in these unique systems that warrant future studies.
REVIEWS OF GEOPHYSICS
(2023)
Article
Limnology
Zhongwei Yuan, Thomas J. J. Browning, Ruifeng Zhang, Chengwang Wang, Chuanjun Du, Yanmin Wang, Ying Chen, Zhiyu Liu, Xin Liu, Dalin Shi, Minhan Dai
Summary: In nitrogen limited low latitude ocean regions, phosphate depletion can induce stress responses in marine microbes. This study associates a broad region of phosphate depletion in the subtropical North Pacific with different levels of phosphorus stress, and demonstrates the primary nitrogen limitation of the phytoplankton community with the relief provided by aerosol supply. Enhanced alkaline phosphatase activities indicate elevated phosphorus stress in northern sites with depleted phosphate. Increased aerosol deposition, likely stimulated by aerosol iron supply, can drive the regional enhancement in phosphate depletion through elevated nitrogen fixation. These findings are crucial for predicting future biogeochemical responses in the subtropical North Pacific to changes in aerosol supply.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2023)
Editorial Material
Multidisciplinary Sciences
Wei-Lei Wang, Mar Fernandez-Mendez, Franziska Elmer, Guang Gao, Yangyang Zhao, Yuye Han, Jiandong Li, Fei Chai, Minhan Dai
NATURE COMMUNICATIONS
(2023)
Article
Oceanography
Xianghui Guo, Jianzhong Su, Liguo Guo, Zhiqiang Liu, Wei Yang, Yan Li, Zhentong Yao, Lifang Wang, Minhan Dai
Summary: A field survey in the Pearl River estuary showed that upwelling-induced high DIC, low pH, and low DO values led to acidification and hypoxia. The observed phenomena contradicted the predicted consumption of DIC and over-saturation of DO. Hypoxia, acidification, and DIC accumulation were observed in the bottom waters. The ventilation under the influence of downwelling winds during the second survey reduced hypoxia but enhanced acidification.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Ecology
Yifan Ma, Kuanbo Zhou, Weifang Chen, Junhui Chen, Jin-Yu Terence Yang, Minhan Dai
Summary: In this study, samplings were conducted in the South China Sea to examine the nutrient-dependent structures of export productivity. The results showed that nitrate concentrations sharply increased with depth in the nutrient-replete layer. By estimating POC export fluxes, it was found that the NDL could rapidly export POC, challenging the traditional view that it would not be a net exporter of POC.
Article
Geosciences, Multidisciplinary
Zhixuan Wang, Guizhi Wang, Xianghui Guo, Yan Bai, Yi Xu, Minhan Dai
Summary: This study reconstructed the monthly sea surface pCO2 in the South China Sea (SCS) using a machine-learning-based method. The results show that while the SCS is overall a weak source of atmospheric CO2, the northern SCS acts as a sink, with the strength of the sink increasing over the past 2 decades. This research is significant for understanding carbon cycling and climate change in the SCS.
EARTH SYSTEM SCIENCE DATA
(2023)
Article
Geochemistry & Geophysics
Zigeng Song, Shujie Yu, Yan Bai, Xianghui Guo, Xianqiang He, Weidong Zhai, Minhan Dai
Summary: The South China Sea is one of the largest marginal seas in the world, and estimating the air-sea CO2 flux in this region is challenging. In this study, a retrieval algorithm for sea surface pCO2 was developed using a combination of a mechanistic semianalytical method and machine learning. The algorithm was validated using independent cruise-based datasets and showed good accuracy and consistency.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)