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Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary

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Acta Oceanologica Sinica 2007年第1期26卷 140-149页

作者： liU Qizhen li Jiufa DAI Zhijun li daoji State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China

For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . The effects of salinity and humus on the fine-grained sediments have been analyzed through the synthetic study of the aspects of flocculation/coagulation power （ F）, diameter （D） and zeta potential （Z）. And the microcosmic configuration of the flocs has been analyzed by using a scan electron microscope and Fourier Transform Infrared Spectrometry. The results show that：（ 1 ） with the increase of salinity, F and D become greater and Z becomes smaller, and with the increase of the concentration of humus, F becomes smaller, but D and Z become greater; （2） the microcosmic configuration of the flocculation shows that humus packs on the fine sediments in the form of salt, and the flocculation model of C - P - OM （C stands for clay; P cations; OM organic materials） can successfully demonstrate the mechanism of the formation of the finegrained sediments in the high-turbid area of the Changjiang Estuary.

关键词： Changjiang Estuary fine-grained sediment floceulation salinity

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Changes in nutrient uptake of phytoplankton under the interaction between sunlight and phosphate in the Changjiang (Yangtze) River Estuary

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Chinese Journal Of Geochemistry 2008年第2期27卷 161-170页

作者： FANG Tao li daoji YU lihua li Yun State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China

We conducted ship-board incubation experiments to investigate changes in nutrient uptake of phytoplankton under different phosphate concentrations and irradiances in the Changjiang River Estuary and its adjacent waters in China. Under 100% natural irradiance the uptake rates of phosphate, silicate, and nitrate were accelerated at high phosphate levels (1.84 μM), while under low irradiance (about 50% natural irradiance) their uptake rates were restrained at the high but stimulated greatly at the intermediate phosphate concentrations (1.26 μM), as the growth of phytoplankton, changes in nitrite and ammonium uptake didn't follow an obvious pattern. Our results also showed that there were linear relationships between nitrate, silicate and phosphate uptake at different phosphate concentrations under low and high irradiances, and the growth period of phytoplankton was prolonged both at the high phosphate concentrations under high irradiance and at the intermediate concentrations under low irradiance, suggesting that the limitation of phytoplankton growth mainly reflected changes in its growth period, and because no such environment (low irradiance and low phosphate concentrations) actually existed in a high turbidity zone, phytoplankton blooms hardly occurred there. In the absence of irradiance, denitrification occurred readily and phytoplankton was kept decreasing, which resulted in phosphate regeneration.

关键词：长江日光营养素浮游植物

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Estimation and prediction of plastic waste annual input into the sea from China

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Acta Oceanologica Sinica 2018年第11期37卷 26-39页

作者： BAI Mengyu ZHU lixin AN lihui PENG Guyu li daoji State Key Laboratory of Estuarine and Coastal Research East China Normal University State Environmental Protection Key Laboratory of Estuarine and Coastal Research Chinese Research Academy of Environmental Sciences

Marine plastic debris has been a pervasive issue since the last century, and research on its sources and fates plays a vital role in the establishment of mitigation measures. However, data on the quantity of plastic waste that enters the sea on a certain timescale remain largely unavailable in China. Here, we established a model using material flow analysis method based on life cycle assessment to follow plastic product from primary plastic to plastic waste with statistical data and monitoring data from accurate sources. This model can be used to estimate and forecast the annual input of plastic waste into the sea from China until 2020. In 2011, 0.547 3-0.751 5 million tons of plastic waste entered the seas in China, with a growth rate of 4.55% per year until 2017. And the amount will decrease to 0.257 1 to 0.353 1 million tons in 2020 under the influence of governmental management. The amount of plastic waste discharged from coastal areas calculated in this study was much larger than that from river, thus it is suggested to strengthen the governance and control of plastic waste in coastal fishery activities in China in order to reduce the amount of marine plastic waste input.

关键词： plastic waste prediction China marine material flow analysis

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Impacts of anthropogenic activities on the Changjiang(Yangtze)estuarine ecosystem(1998–2012)

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Acta Oceanologica Sinica 2015年第6期34卷 86-93页

作者： CHEN Dong DAI Zhijun XU Ren li daoji MEI Xuefei State Key Laboratory of Estuarine and Coastal Research East China Normal University East China Sea Environment Monitoring Center State Oceanic Administration

Estuarine ecosystem has greatly changed in the recent decades due to anthropogenic perturbations in the Changjiang Estuary. Change patterns and impact factors were analyzed based on the continuous data in relation to the Changjiang estuarine ecosystem from 1998 to 2012. The results showed significant decreases in plankton species and annual output of Coilia nasus, Coilia mystus. Furthermore, species and biomass of benthos showed abrupt change in 2003, downward before that and upward after that. It was noted that, Eriocheir sinensis, a high value commercial fish, had an annual production increase of 97%. Reduction of riverine nutrients, especially dissolved silicate （DSI） loads into the estuary could contribute to the decline in BaciUariophyta species. Dredging and dumping works of the North Passage led to the decreases in regional plankton species. However, the species reproduction and releasing projects could restore the estuarine ecosystem through increasing the output of E. sinensis, as well as species and biomass of benthos.

关键词： ecosystem anthropogenic activities Changjiang (Yangtze) Estuary

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Underestimated activity-based microplastic intake under scenariospecific exposures

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Environmental Science and Ecotechnology 2024年第2期18卷 124-136页

作者： Kai liu Qingqing li Anthony LAndrady Xiaohui Wang Yinan He daoji li State Key Laboratory of Estuarine and Coastal Research East China Normal University500 Dongchuan RoadShanghai200062China Department of Chemical and Biomolecular Engineering North Carolina State UniversityRaleighNC27695USA Plastic Marine Debris Research Center East China Normal University500 Dongchuan RoadShanghai200241China Regional Training and Research Center on Plastic Marine Debris and Microplastics IOC-UNESCO500 Dongchuan RoadShanghai200241China

Despite increasing alarms over the health impacts of microplastics(MPs)due to their detection in human organs and feces,precise exposure evaluations remain *** comprehend their risks,there is a distinct need to prioritize quantitive estimates in MP exposome,particularly at the environmentallyrealistic *** we used a method rooted in real-world MP measurements and activity patterns to determine the daily intake of MPs through inhalation and from ground dust/soil *** found that nearly 80%of this intake comes from residential sectors,with activity intensity and behavioral types significantly affecting the human MP *** data showed a peak in MP exposure for those aged *** compared to dietary MP intake sources like seafood,salt,and water,we identified a previously underestimated exposure from inhalation and dust/soil ingestion,emphasizing the need for more realistic evaluations that incorporate activity *** discovery raises questions about the accuracy of past studies and underscores MP's potential health ***,our time-based simulations revealed increased MP intake during the COVID-19 lockdown due to more surface dust ingestion,shedding light on how global health crises may inadvertently elevate MP exposure risks.

关键词： Microplastics Activity factors Inhalation and ingestion Simulation Exposure estimate

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Oxygen depletion off the Changjiang (Yangtze River)Estuary

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Science China Earth Sciences 2002年第12期45卷 1137-1146页

作者： li daoji ZHANG Jing HUANG Daji WU Ying liANG Jun State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai 200062China Second Institute of Oceanography State Oceanic AdministrationHangzhou 310012China

In a survey on the Yellow Sea and the East China Sea on August 20-30 of 1999,we found a hypoxic zone(<2 mg/L)of 13700 km2 with an average thickness of 20m at the bottom of the Changjiang(Yangtze River)Estuary,with an ... 详细信息

In a survey on the Yellow Sea and the East China Sea on August 20-30 of 1999,we found a hypoxic zone(lization(AOU)was 5.8 mg/L and the total oxygen depletion approximately 1.59×10^(6) *** strong halocline above the hypoxic zone,as a result of affluent water from the Changjiang,Taiwan Warm Current(TWC),and the high concentrations of particle organic carbon(POC)and nitrogen(PON)are the major factors causing the formation of the hypoxic *** POC:PON ratios and nutrient concentration distributions in the hypoxic zone suggest that the oxygen deficiency in the bottom water during the summer in the East China Sea off the Changjiang is the result of organic carbon production enhanced by nutrients from the Changjiang and fluvial organic matter input,followed by a shift in regeneration of nutrients in the East China Sea.

关键词： oxygen depletion dissolved oxygen hypoxia Changjiang Estuary

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Benthic nutrient fluxes in the intertidal flat within the Changjiang (Yangtze River) Estuary

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Chinese Journal Of Geochemistry 2008年第1期27卷 58-71页

作者： GAO Lei li daoji WANG Yanming YU lihua KONG Dingjiang li Mei li Yun FANG Tao State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China

In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang (Yangtze River) Estuary. Except for NH4+, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrifica- tion rates, that utilizing NO3- transported from overlying water (DW) in Dongtan sediments, were estimated to be from -16 to 193 μmol·h-1·m-2 with an average value of 63 μmol·h-1·m-2 (n=18). These estimated values are still un- derestimates of the in-situ rates owing to the lack of consideration of DN, i.e., denitrification supported by the local NO3- production via nitrification.

关键词：潮水长江深海生物元素化合物

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海洋微塑料污染状况及其应对措施建议

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环境科学研究 2019年第2期32卷 197-202页

作者：李道季华东师范大学河口海岸学国家重点实验室上海200062 华东师范大学海洋塑料研究中心上海200062

海洋塑料垃圾污染是人类面临的最为急迫的全球海洋环境问题之一,已引起各国政府、公众、科学界、媒体及非政府组织等的广泛关注,并成为当前海洋生态与环境研究的热点问题之一,亟待应对和解决.从水体、沉积物及生物体内海洋塑料垃圾及微... 详细信息

海洋塑料垃圾污染是人类面临的最为急迫的全球海洋环境问题之一,已引起各国政府、公众、科学界、媒体及非政府组织等的广泛关注,并成为当前海洋生态与环境研究的热点问题之一,亟待应对和解决.从水体、沉积物及生物体内海洋塑料垃圾及微塑料污染特征、来源及归趋角度,阐述了海洋微塑料垃圾的分布特征、潜在生态风险和应对措施,以及国内外应对海洋塑料及微塑料污染所采取的管控措施,介绍了各国政府和非政府组织所提出的法律法规和公约倡议.鉴于当前鲜见典型区域塑料污染管控和生态风险评估体系研究,从科学研究和管理控制两个方面,进一步指出现阶段在海洋塑料垃圾及微塑料研究和管控方面存在的诸多问题,如方法学(采集、预处理和分析)的差异性,来源、输运与归趋尚不明确,生态风险评估体系未建立及相关管控的法律法规待健全等.在此基础上对我国海洋塑料和微塑料研究提出建议:(1)深入研究与国际接轨的标准化塑料及微塑料研究方法学(样本采集、预处理和分析)问题、准确估算入海通量、环境归趋及环境浓度下潜在的生态风险等;(2)支持开展海洋塑料垃圾和微塑料研究专题的大洋航次(太平洋和印度洋等),系统地开展河流系统-深海海盆-极地等的海洋微塑料综合研究;(3)研发水环境中塑料和微塑料垃圾的拦截和处理技术,制定和强化塑料及微塑料管控的法律法规和政策措施;(4)建立完善的海洋塑料垃圾污染公共环境意识教育体系,以唤起公众对海洋污染的关注.

关键词：海洋污染海洋塑料垃圾微塑料管控建议

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海洋微塑料研究焦点及存在的科学认知误区

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科技导报 2020年第14期38卷 46-53页

作者：李道季华东师范大学河口海岸学国家重点实验室海洋塑料研究中心上海200062

评述了当前海洋微塑料研究的有关前沿热点问题,指出了海洋微塑料研究在样品采集和分析方法存在的缺陷及人们对海洋微塑料认知产生偏差的原因,分析了这些错误认知导致在微塑料毒理学、塑料入海通量、环境风险评估等热点研究方面存在的不... 详细信息

评述了当前海洋微塑料研究的有关前沿热点问题,指出了海洋微塑料研究在样品采集和分析方法存在的缺陷及人们对海洋微塑料认知产生偏差的原因,分析了这些错误认知导致在微塑料毒理学、塑料入海通量、环境风险评估等热点研究方面存在的不足和错误,并介绍了一些新的研究观点和进展。提出了海洋微塑料研究有待解决的重要科学问题及未来研究发展的建议。

关键词：海洋微塑料塑料垃圾环境风险

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长江口邻近海域浮游细菌分布与环境因子的关系

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海洋通报 2007年第6期26卷 9-18页

作者：李云李道季华东师范大学河口海岸学国家重点实验室上海200062

利用2003年9-10月"东海陆架水交换"调查航次期间获得的浮游异养细菌、寡营养细菌和光合细菌的分布资料和实测水环境数据,探讨了这三类细菌的分布特征及其与相关环境因子的关系。结果表明:在长江口邻近海域,以30等盐线为界,三类细菌的空... 详细信息

利用2003年9-10月"东海陆架水交换"调查航次期间获得的浮游异养细菌、寡营养细菌和光合细菌的分布资料和实测水环境数据,探讨了这三类细菌的分布特征及其与相关环境因子的关系。结果表明:在长江口邻近海域,以30等盐线为界,三类细菌的空间分布具有显著差异;调节制约这三类细菌类群生长和分布的环境因子不同;表层硝酸盐浓度1μmol/L可作为一个特征浓度,高于1μmol/L的海域,陆源输入的硝酸盐对于这三类细菌的生长和分布具有重要影响,低于1μmol/L的海域,硝酸盐的影响较小或无影响。同时,采用法国梅里埃API STAPH系统,结合电镜观察,对两株已获得纯培养的有色菌株进行了属种的鉴定,分别是变异微球菌(Micrococcus varians)和玫瑰微球菌(Micrococcus roseus),目前尚未发现这两种细菌在长江口及其邻近海域分布的报道。

关键词：异养细菌寡营养细菌光合细菌长江口环境因子

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