Article
Environmental Sciences
Sayaka Yasunaka, Manfredi Manizza, Jens Terhaar, Are Olsen, Ryohei Yamaguchi, Peter Landschutzer, Eiji Watanabe, Dustin Carroll, Hanani Adiwira, Jens Daniel Muller, Judith Hauck
Summary: As a contribution to the RECCAP2 project, this study presents estimates of Arctic Ocean sea-air CO2 fluxes and their uncertainties. The results show that the Arctic Ocean has been a net sink of CO2 over the past few decades, with the uptake rate influenced by seasonal variations and climate change.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Environmental Sciences
Bing Yang, Po Hu, Yijun Hou
Summary: Based on analysis of in situ observations, remote sensing, and data, the characteristics of near-inertial waves induced by tropical storm Noul in the South China Sea were studied. It was found that the near-inertial waves were influenced by a southwestward moving anticyclonic eddy and had comparable spectral density with internal tides. The downward propagation of near-inertial energy was concentrated in smaller wavenumber bands and influenced by mesoscale eddies.
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
Ecology
Meike Becker, Are Olsen, Peter Landschuetzer, Abdirhaman Omar, Gregor Rehder, Christian Roedenbeck, Ingunn Skjelvan
Summary: A simple method was developed to refine existing open-ocean maps, extending them towards different coastal seas using multi-linear regression. Monthly maps of surface ocean fCO(2) from 1998 to 2016 in northern European coastal seas were produced, showing smaller fCO(2) trends compared to atmospheric trends in most regions, with exceptions in the western North Sea. Surface oceans in most areas were found to be net sinks for CO2, except for the southern North Sea and the Baltic Sea.
Article
Environmental Sciences
Zhidan Wen, Yingxin Shang, Lili Lyu, Sijia Li, Hui Tao, Kaishan Song
Summary: This paper reviews the temporal and spatial variability of pCO(2) in inland waters, showing significant daily and seasonal variations in lakes, higher pCO(2) levels in rivers and streams compared to lakes and reservoirs in the same climatic zone, and higher pCO(2) levels in tropical waters versus temperate, boreal, and arctic waters. The estimation of CO2 fluxes in global inland waters shows large uncertainties, highlighting the need for more reliable remote sensing models for mapping pCO(2) variations.
Article
Environmental Sciences
Xiaorun Hong, Lusheng Chen, Shaojie Sun, Zhen Sun, Ying Chen, Qiang Mei, Zhichao Chen
Summary: Petroleum extraction, transportation, and consumption in the marine environment contribute to a large portion of anthropogenic oil spills into the ocean. This study used optical imagery to detect oil slicks in the northern South China Sea and identified their sources. The results demonstrate the capability of medium-resolution optical imagery in monitoring regional oil spills.
Article
Oceanography
Jing Liu, Richard G. J. Bellerby, Qing Zhu, Jianzhong Ge
Summary: This study developed a multiple non-linear regression model to estimate pCO(2) in different regions of the East China Sea using various data. The comparison between observations and model results showed a high reliability of the model. The study also analyzed the seasonal and interannual variations of pCO(2) and air-sea CO2 flux in the East China Sea in recent years.
CONTINENTAL SHELF RESEARCH
(2023)
Article
Environmental Sciences
Young Ho Ko, Min-Woo Seok, Jin-Yong Jeong, Jae-Hoon Noh, Jongmin Jeong, Ahra Mo, Tae-Wook Kim
Summary: The surface carbonate chemistry in the Yellow Sea has been found to exhibit considerable seasonal variations, influenced by both biological processes and physical conditions, as well as tidal mixing. The intraseasonal variability in seawater pCO2 may introduce biases in estimated air-sea CO2 fluxes.
MARINE POLLUTION BULLETIN
(2022)
Article
Environmental Sciences
Shuping Zhang, Anna Rutgersson, Petra Philipson, Marcus B. Wallin
Summary: This study analyzed the variable importance for the sea surface pCO(2) estimation in the Baltic Sea and found that photosynthetically available radiation (PAR) was the most important variable for the pCO(2) estimation across the entire Baltic Sea. Additionally, the importance of variables for pCO(2) estimation varied between seasons and sub-basins.
Article
Geosciences, Multidisciplinary
Zebin Tu, Chengfeng Le, Yan Bai, Zongpei Jiang, Yingxu Wu, Zhangxian Ouyang, Wei-Jun Cai, Di Qi
Summary: The study constructed a 17-year time series of summer sea surface partial pressure of CO2 in the Chukchi Sea using machine learning, attributing the long-term increase in CO2 uptake capacity to enhanced biological uptake. The intraseasonal variability of surface CO2 in early summer also highlights the importance of sea ice melt and enhanced photosynthesis.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Wei Li, Chunli Liu, Weidong Zhai, Huizeng Liu, Wenjuan Ma
Summary: With global climate changing, the absorption of carbon dioxide (CO2) in marginal seas has increased. The current status of sea surface carbon dioxide partial pressure (pCO(2)) in the Yellow Sea is unclear due to limited availability of in-situ data. Therefore, a pCO(2) model based on a random forest algorithm was developed using cruise data from 2011 to 2019 and remote sensing satellite data. The model showed good performance and revealed seasonal and interannual variations of pCO(2) in the Yellow Sea.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Chun Hoe Chow, Yung-Yen Shih, Ya-Tang Chien, Jing Yi Chen, Ning Fan, Wei-Chang Wu, Chin-Chang Hung
Summary: This study found that not all eddies in the northern South China Sea were accompanied by eddy pumping, and the weakening of background thermocline was attributed to the strengthening of eddy pumping. The research also showed that small mesoscale eddies can efficiently provide nutrients to the subsurface and remove carbon from the euphotic zone, which is crucial for global warming and ocean stratification.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Xin Wang, Peng Zhou, Weifeng Yang, Min Chen, Hua Cheng, Guoxiang Chen, Yihua Cai
Summary: The vertical distributions of dissolved and particulate 210Po and 210Pb were examined in the water column of the northern South China Sea. The results showed a deficit of 210Po compared to 210Pb in the mixed layer, an increase in the 210Po/210Pb ratio at the base of the euphotic layer, and a depletion of 210Po in the mesopelagic layer. These findings indicated strong particle scavenging and subsequent removal of 210Po. The export flux of 210Po and total particulate matter in the mesopelagic layer was estimated to be higher than in the euphotic layer, suggesting additional particle supply from surrounding shelves.
Article
Environmental Sciences
Elizabeth H. Shadwick, Cathryn A. Wynn-Edwards, Richard J. Matear, Peter Jansen, Eric Schulz, Adrienne J. Sutton
Summary: The Subantarctic Zone in the Southern Ocean plays a crucial role in air-sea CO2 exchange and the storage of anthropogenic CO2. This study uses long-term observations to reveal that this region is a net sink for atmospheric CO2 and that the ocean pCO(2) may be increasing slightly faster than the atmosphere, indicating the contribution of both oceanic and anthropogenic forcings.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Biodiversity Conservation
Lin Deng, Wen Zhou, Jie Xu, Wenxi Cao, Jianzu Liao, Jun Zhao
Summary: This study estimated the size-fractionated phytoplankton primary production (PP) in the Northern South China Sea (NSCS) using hyperspectral absorption and irradiance data. The estimated results showed good agreement with in-situ measurements. The derived PP profiles exhibited different spatial distribution patterns in coastal and open ocean areas.
ECOLOGICAL INDICATORS
(2022)
Letter
Limnology
Thomas J. Browning, Xin Liu, Ruifeng Zhang, Zuozhu Wen, Jing Liu, Yaqian Zhou, Feipeng Xu, Yihua Cai, Kuanbo Zhou, Zhimian Cao, Yuanli Zhu, Dalin Shi, Eric P. Achterberg, Minhan Dai
Summary: Experimental results from the Philippine Sea indicate a gradient from nitrogen limitation in the north to nitrogen-iron co-limitation in the south, driving different phytoplankton growth responses. This large-scale phytoplankton response gradient is hypothesized to be climate sensitive and potentially important for regulating the distribution of predatory fish.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2022)
Article
Geochemistry & Geophysics
Zhongping Lee, Shaoling Shang, Yonghong Li, Kelly Luis, Minhan Dai, Yongchao Wang
Summary: The variation in light quality in the global ocean is quantified for the first time using the hue angle of downwelling irradiance, providing a new perspective on the three-dimensional changes in light quality. Global data highlights the distribution of light quality at different depths and its impact on the ratio of phytoplankton absorbed light. Emphasizing the importance of light quality on photosynthesis and oceanography.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Xiuli Yan, Jin-Yu Terence Yang, Min Nina Xu, Hongjie Wang, Minhan Dai, Shuh-Ji Kao
Summary: Information on the sources and transformations of particulate organic N (PN) and dissolved organic N (DON) at the coastal interface remains insufficient due to technological difficulties and complicated features of intensive physical mixing and rapid biological activities. The study investigated the spatial distribution of concentrations and isotopic compositions of PN and DON in the Changjiang plume during the summer flood period, revealing nonconservative DON behaviors and active transformations between the DON and PN pools.
SCIENCE OF THE TOTAL ENVIRONMENT
(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.
Article
Environmental Sciences
Congcong Guo, Shu Yang, Weidong Zhai, Yao Niu, Chunli Liu
Summary: This study investigated the potential vertical POC flux and transport in the South Yellow Sea using TSM, POC, and particulate nitrogen data. The estimates of resuspension fraction showed substantial uncertainty in summer but less uncertainty in other seasons. The study proposed a simple and effective method to address the influence of resuspension on the dynamics and budget of POM in the SYS.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Engineering, Environmental
Tianqi Xiong, Hongmei Li, Yufei Yue, Yubin Hu, Wei-dong Zhai, Liang Xue, Nianzhi Jiao, Yongyu Zhang
Summary: This study investigates the ability of macroalgae to sequester inorganic carbon in the ocean, using the largest green tide caused by Ulva prolifera as a case study. The research shows that massive macroalgae release organic carbon, which is transformed into dissolved inorganic carbon (DIC) by microorganisms. Field investigations reveal that DIC and total alkalinity (TAlk) increase significantly in areas covered by dense U. prolifera, and offshore mapping cruises confirm higher levels of DIC and TAlk during the bloom stage. Laboratory cultivation of U. prolifera further demonstrates the enhancement effect of DIC and TAlk in seawater. This research highlights the importance of macroalgae in regulating the carbon pool in the ocean.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
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.
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)
