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Salinity fronts shape spatial patterns in zooplankton distribution in Hangzhou Bay

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Acta Oceanologica Sinica 2024年第6期43卷 96-106页

作者： Yepeng Xu Yiqi Wang Lin Zhan Yijun Ou Kangning Jia Ming Mao Xuyu Zhu Zhibing Jiang Yuanli Zhu Wei Huang Ping Du Jiangning Zeng Lu Shou Feng Zhou Key laboratory of Marine ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Key laboratory of Nearshore Engineering Environment and Ecological Security of Zhejiang Province Hangzhou 310012China State Key laboratory of Satellite Ocean Environment Dynamics Ministry of Natural ResourcesHangzhou 310012China Nantong Marine Environmental Monitoring Center Ministry of Natural ResourcesNantong 226002China Key laboratory of Ocean Space Resource management Technology Ministry of Natural ResourcesHangzhou 310012China Observation and Research Station of Marine ecosystem in the Yangtze River Delta Ministry of Natural ResourcesZhoushan 316021China

Ocean fronts play important roles in nutrient transport and in the shaping ecological *** zones in small bays are typically small in scale,have a complex structure,and they are spatially and temporally variable,but there are limited data on how biological communities respond to this *** Bay,a mediumsized estuary in China,is an ideal place in which to study the response of plankton to small-scale ocean fronts,because three water masses(Qiantang River Diluted Water,Changjiang River Diluted Water,and the East China Sea current) converge here and form dynamic salinity fronts throughout the *** investigate zooplankton communities,and temperature,salinity and chlorophyll a(Chl a) in Hangzhou Bay in June(wet perio d) and December(dry period) of 2022 and examine the dominant environmental factors that affect zooplankton community spatial *** then match the spatial distributions of zooplankton communities with those of salinity fronts.S alinity is the most important explanatory variable to affect zooplankton community spatial variability during both wet and dry periods,in that it contributes>60% of the variability in community ***,the spatial distributions of zooplankton match well with salinity *** December,with weaker Qiantang River Diluted Water and a stronger secondary Changjiang River Plume,zooplankton communities occur in moderate salinity(MS,salinity range 15.6±2.2) and high salinity(HS,22.4±1.7) regions,and their ecological boundaries closely match the Qiantang River Diluted Water *** June,different zooplankton communities occur in low salinity(LS,3.9±1.0),MS(11.7±3.6) and HS(21.3±1.9) *** the LS region occurs abnormally in the central bay rather than its apex because of the anomalous influence of rising and falling tides during the sampling perio d,the ecological boundaries still match salinity ***-salinity or brackish-water zooplankter taxa are relatively more abunda

关键词： zooplankton spatial distribution salinity fronts Hangzhou Bay

Off-farm employment,agriculture production activities,and household dietary diversity in environmentally and economically vulnerable areas of Asia

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Journal of Integrative Agriculture 2024年第2期23卷 359-373页

作者： Yunli Bai Xuanye Zeng Chao Fu Linxiu Zhang Key laboratory of ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China United Nations Environment Programme-International ecosystem management Partnership(UNEP-IEMP) Beijing 100101China University of Chinese Academy of Sciences Beijing 100101China

Access to off-farm employment has been expected to be a critical approach to ending hunger and all forms of malnutrition,two important targets of achieving Zero *** study aims to investigate the role of off-farm employment in improving dietary diversity through substitution effect and complementary effect with agricultural production activities and income *** study adopts Poisson/Tobit/Probit/OLS regressions and the instrument variable method based on the primary survey data collected among 1,282 households at 12 sites in environmentally and economically vulnerable areas of China,Nepal,Cambodia,Thailand,and Myanmar in *** results show that off-farm employment is positively associated with household dietary diversity and the consumption of flesh meat,fish and other aquatic animals,fruits,and milk and dairy products,which are rich in protein and *** results of mechanism analysis show that off-farm employment contributes to household dietary diversity by improving crop diversity,especially for poor households,boosting the probability of livestock raising for households with the middle one-third disposal income,and increasing household *** positive association between off-farm employment and household dietary diversity is much higher for households with the bottom one-third disposal income,low illiteracy,and from upper-middle income *** findings imply that off-farm employment does play a vital role in achieving multiple benefits of poverty alleviation,malnutrition reduction,and agrobiodiversity conservation in environmentally and economically vulnerable ***,it may enlarge the gaps in dietary diversity between households with low human capital and from low and lower-middle income countries and those with high human capital and from middle-high countries.

关键词： off-farm employment dietary diversity income effect substitution effect complementary effect

Temporal changes in mixing effects on litter decay and nitrogen release in a boreal riparian forest in northeastern China

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Journal of Forestry Research 2024年第2期35卷 33-41页

作者： Simin Wang Bo Liu Rui Li Xiaoxin Sun Rong Mao Key laboratory of National Forestry and Grassland Administration on Forest ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricultural UniversityNanchang 330045People’s Republic of China Key laboratory of Wetland ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102People’s Republic of China Key laboratory of Sustainable Forest ecosystem management of Ministry of Education School of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China Heilongjiang Sanjiang Plain Wetland ecosystem Research Station Fuyuan 156500People’s Republic of China

In riparian forests,litter decay provides essential energy and nutrients for both terrestrial and fluvial *** mixing effects(LMEs)are crucial in regulating litter decay and nutrient dynamics,yet how LMEs change over time is unclear in riparian *** this study,leaf litter of three common species(Alnus sibirica *** Turcz,Betula platyphylla Sukaczev,and Betula fruticosa Pall.)were mixed in an equal mass ratio and LMEs were measured for mass and nitrogen(N)remaining in whole litter mixtures over a 3-year period in a boreal riparian forest,northeastern *** were also assessed for component litter mass and N remaining by separating litter mixtures by *** the decay of litter mixtures,antagonistic effects on mass and N remaining were dominant after one and two years of decay,whereas only additive effects were observed after three *** correlated negatively with functional diversity after the first and two years of decay but disappeared after three *** sorting litter mixtures by species,non-additive LMEs on mass and N remaining decreased over incubation ***,non-additive LMEs were more frequent for litter of both *** and *** with lower N concentration than for *** litter with higher N *** results indicate that incubation time is a key determinant of litter mixing effects during decay and highlight that late-stage litter mixture decay may be predicted from single litter decay dynamics in boreal riparian forests.

关键词： Biodiversity Litter quality Litter mixtures Synergistic effects Functional diversity

Effects of nutrient limitations on the sinking velocity of Thalassiosira weissflogii

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Acta Oceanologica Sinica 2024年第6期43卷 163-172页

作者： Jie Zhu Qiang Hao Wei Zhang Yingying Ma Jiangning Zeng Ocean College Zhejiang UniversityZhoushan 316000China Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China Key laboratory of Marine ecosystem Dynamics Ministry of Natural ResourcesHangzhou 310012China Zhejiang Key laboratory of Nearshore Engineering Environment and Ecological Security Hangzhou 310012China Tianjin Key Lab of Aqua-ecology and Aquaculture College of FisheriesTianjin Agricultural UniversityTianjin 300384China

The sinking of diatoms is critic al to the formation of oceanic biological pumps and coastal hypoxic ***,little is known about the effects of different nutrient restrictions on diatom *** this study,we measured the sinking velocity(SV) of Thalassiosira weissflogii using a new phytoplankton video observation instrument and analyzed major biochemical components under varying nutrient *** results showed that the SV of *** under different nutrient limitation conditions varied *** highest SV of(1.77±0.02) m/d was obtained under nitrate limitation,signific antly surpassing that under phosphate limitation at(0.98±0.13) m/*** the nutrient limitation was released,the SV steadily decreased to(0.32±0.03) m/d and(0.15±0.05) m/d,***;under conditions with limited nitrate and phosphate concentrations,the SV values of *** significantly positively correlated with the lipid content(P <0.001),with R^(2) values of 0.86 and 0.69,*** change of the phytoplankton SV was primarily related to the intracellular compo sition,which is controlled by nutrient conditions but did not significantly correlate with transparent extracellular polymer and biosilica *** results of this study help to understand the regulation of the vertical sinking process of diatoms by nutrient restriction and provide new insights into phytoplankton dynamics and their relationship with the marine nutrient structure.

关键词： nutrient limitation Thalassiosira weissflogii sinking velocity biochemical component lipid content

Long-term changes in radial growth of seven tree species in the mixed broadleaf-Korean pine forest in Northeast China:Are deciduous trees favored by climate change?

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Journal of Forestry Research 2024年第5期35卷 63-77页

作者： Xiufang Gong Danyang Yuan Liangjun Zhu Zongshan Li Xiaochun Wang National Engineering laboratory for Applied Technology of Forestry and ecology in South China College of Life Science and TechnologyCentral South University of Forestry and TechnologyChangsha 410004People’s Republic of China Center for Ecological Research and Key laboratory of Sustainable Forest ecosystem management-Ministry of Education School of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China State Key laboratory of Urban and Regional ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085People’s Republic of China

The role of the temperate mixed broadleaf-Korean pine forest(BKF)in global biogeochemical cycles will depend on how the tree species community responds to climate;however,species-specific responses and vulner-abilities of common trees in BKF to extreme climates are poorly *** we used dendrochronological meth-ods to assess radial growth of seven main tree species(Pinus koraiensis,Picea jezoensis,Abies nephrolepis,Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Ulmus davidiana)in an old-growth BKF in response to climate changes in the Xiaoxing’an Mountains and to improve predictions of changes in the tree species *** in most months and winter precipita-tion significantly negatively affected growth of *** and ***,but positively impacted growth of *** and the broadleaf species,especially ***-rica and *** and relative humidity in June significantly positively impacted the growth of most tree *** positive effect of the temperature during the previous non-growing season(PNG)on growth of *** and *** strengthened significantly with rapid warming around 1981,while the impact of PNG temperature on the growth of *** and *** changed from significantly negative to weakly negative or positive at this *** negative response of radial growth of *** and *** to precipitation during the growing season gradually weakened,and the negative response to PNG precipitation was *** the studied species,*** was the most resistant to drought,and *** recovered the best after extreme *** davidiana,*** and *** were more resistant to extreme cold than the other *** warming generally exacerbated the opposite growth patterns of conifer(decline)and broadleaf(increase)*** broadleaf tree species in the old-growth BKF probably will gradually become dominan

关键词： Tree rings Extreme climate Resistance and recovery Broad-leaved and Korean pine mixed forest

Aging Mongolian pine plantations face high risks of drought-induced growth decline:evidence from both individual tree and forest stand measurements

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Journal of Forestry Research 2024年第2期35卷 109-120页

作者： Mingyong Li Leilei Yang Yu Cao Dedong Wu Guangyou Hao CAS Key laboratory of Forest ecology and management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016People’s Republic of China Key laboratory of Terrestrial ecosystem Carbon Neutrality Liaoning ProvinceShenyang 110016People’s Republic of China Daqinggou Ecological Research Station Institute of Applied EcologyChinese Academy of SciencesShenyang 110016People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China Research Institute of Sand Control and Utilization Liaoning ProvinceFuxin 123000People’s Republic of China

Discerning vulnerability differences among different aged trees to drought-driven growth decline or to mortality is critical to implement age-specific countermeasures for forest management in water-limited *** important species for afforestation in dry environments of northern China,Mongolian pine(Pinus sylvestris *** Litv.)has recently exhibited growth decline and dieback on many sites,particularly pronounced in old-growth ***,changes in response to drought stress by this species with age as well as the underlying mechanisms are poorly *** this study,tree-ring data and remotely sensed vegetation data were combined to investigate variations in growth at individual tree and stand scales for young(9-13 years)and aging(35-52 years)plantations of Mongolian pine in a water-limited area of northern China.A recent decline in tree-ring width in the older plantation also had lower values in satellited-derived normalized difference vegetation indices and normalized difference water indices relative to the younger *** addition,all measured growth-related metrics were strongly correlated with the self-calibrating Palmer drought severity index during the growing season in the older *** of growth to drought of the older plantation might be attributed to more severe hydraulic limitations,as reflected by their lower sapwood-and leaf-specific hydraulic *** study presents a comprehensive view on changes of growth with age by integrating multiple methods and provides an explanation from the perspective of plant hydraulics for growth decline with *** results indicate that old-growth Mongolian pine plantations in water-limited environments may face increased growth declines under the context of climate warming and drying.

关键词： Tree age Drought stress Mongolian pine plantation Tree rings Remote sensing Plant hydraulics

Nitrogen availability mediates the effects of roots and mycorrhizal fungi on soil organic carbon decomposition:A meta-analysis

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Pedosphere 2024年第2期34卷 289-296页

作者： Tongshuo BAI Yunpeng QIU Shuijin HU ecosystem ecology laboratory College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China Department of Entomology&Plant Pathology North Carolina State UniversityRaleigh NC 27695USA

Plant roots and their associated mycorrhizal fungi critically mediate the decomposition of soil organic carbon(C),but the general patterns of their impacts over a broad geographical range and the primary mediating factors remain *** on a synthesis of 596 paired observations from both field and greenhouse experiments,we found that living roots and/or mycorrhizal fungi increased organic C decomposition by 30.9%,but low soil nitrogen(N)availability(i.e.,high soil C:N ratio)critically mitigated this promotion *** addition,the positive effects of living roots and/or mycorrhizal fungi on organic C decomposition were higher under herbaceous and leguminous plants than under woody and non-leguminous plants,***,there was no significant difference between arbuscular mycorrhizal fungi and ectomycorrhizal fungi in their effects on organic C ***,roots and/or mycorrhizal fungi significantly enhanced the decomposition of leaf litter but not root *** findings advance our understanding of how roots and their symbiotic fungi modulate soil C dynamics in the rhizosphere or mycorrhizosphere and may help improve predictions of soil global C balance under a changing climate.

关键词： arbuscular mycorrhizal fungi ectomycorrhizal fungi leaf litter leguminous plant mycorhizosphere rhizosphere root litter soil C:N ratio

A New Method to Identify the Maximum Time Interval between Individual Events in Compound Rainstorm and Heatwave Events

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International Journal of Disaster Risk Science 2024年第3期15卷 453-466页

作者： Junlin Zhang Wei Xu Yu Qiao Xinli Liao Chenna Meng Qinmei Han Key laboratory of Environmental Change and natural Disaster of Ministry of Education Faculty of Geographical Science Beijing Normal University Academy of Disaster Reduction and Emergency management Ministry of Emergency Management and Ministry of Education Beijing Normal University State Key laboratory of Earth Surface Processes and Resource ecology Beijing Normal University National Climate Center China Meteorological Administration

Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space. Therefore, many studies have examined the impacts of compound hazard events on the social-ecological system at various scales. The definition of compound events is fundamental for such research. However, there are no existing studies that support the determination of time interval between individual events of a compound rainstorm and heatwave(CRH) event, which consists of two or more potentially qualifying component heatwave and rainstorm events. To address the deficiency in defining what individual events can constitute a CRH event, this study proposed a novel method to determine the maximum time interval for CRH events through the change in CRH event frequency with increasing time interval between individual events, using southern China as a case study. The results show that the threshold identified by the proposed method is reasonable. For more than 90% of the meteorological stations, the frequency of CRH events has reached a maximum when the time interval is less than or equal to the threshold. This study can aid in time interval selection, which is an important step for subsequent study of CRH events.

关键词： Compound extreme weather event Rainstorm and heatwave Southern China Threshold Time interval

Spatial patterns of zooplankton abundance,biovolume,and size structure in response to environmental variables:a case study in the Yellow Sea and East China Sea

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Journal of Oceanology and Limnology 2024年第1期42卷 113-127页

作者： Song SUN Haochen XIAN Xiaoxia SUN Mingliang ZHU Mengtan LIU Key laboratory of Marine ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Jiaozhou Bay National Marine ecosystem Research Station Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China laboratory for Marine ecology and Environmental Science Laoshan LaboratoryQingdao 266237China

The Yellow Sea(YS)and East China Sea(ECS)are highly dynamic marginal seas of the northwestern Pacific *** gain an in-depth understanding of zooplankton community structure,zooplankton abundance,biovolume,and size structure in summer 2017 in the YS and ECS were assessed using ZooScan imaging *** abundance and biovolume ranged 2.94–1187.14 inds./m^(3)and 3.13–3438.51 mm^(3)/m^(3),*** on the biovolume data of the categorized size classes of 26 identified taxonomic groups,the zooplankton community was classified into five groups,and each group was coupled with distinctive oceanographic *** the influence of the Yellow Sea Cold Water Mass,the Yellow Sea offshore group featured the lowest bottom temperature(10.84±3.42℃)and the most abundant Calanoids(mainly in the 2–3 mm size class).In the Yellow Sea inshore group,Hydrozoans showed the largest biovolume and dominated in the 3–4-mm and>5-mm size *** East China Sea offshore group,which was affected by the Kuroshio Branch Current,featured high temperature and salinity,and the lowest bottom dissolved oxygen(2.58±0.5 mg/L).The lowest values of zooplankton abundance and biovolume in the East China Sea offshore group might be attributed to the bottom dissolved oxygen *** East China Sea inshore group,which was mainly influenced by the Zhejiang-Fujian Coastal Current and Changjiang Diluted Water,was characterized by high chlorophyll a and the largest biovolume of carnivorous Siphonophores(280.82±303.37 mm^(3)/m^(3)).The Changjiang River estuary offshore group showed the most abundant Cyclopoids,which might be associated with the less turbid water mass in this *** temperature was considered the most important factor in shaping the size compositions of Calanoids in different groups.

关键词： zooplankton size structure ZooScan Yellow Sea East China Sea