Bioconcentration of polycyclic aromatic hydrocarbons in roots of three mangrove species in Jiulong River Estuary

The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species(Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs(16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76±31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs(13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo[a]pyrene(five-ring), fluoranthene(four-ring) and pyrene(four-ring) dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene(two-ring) and phenathrene(three-ring) were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors(BCF SV s) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCF SV s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCF SV values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots, respectively.

The study on three-dimensional numerical model and fronts of the Jiulong Estuary and the Xiamen Bay

Applying the methods of on-site observation and dynamic model, the research on the fronts at the Jiulong Estuary has been carried out, during which spatial and temporal distribution, dynamic characteristics and formation mechanism of salinity fronts are analyzed and discussed. The research shows that the estuarine fronts mainly lie in the area from the Jiyu Islet to the Haimen Island, outside of Yuweizai to Hulishan cross-section, the near coast of Yuweizai and the south of the Songyu-Gulangyu Channel. The fronts in the former two regions are formed directly by plume, while the one near the coast of Yuweizai is a tidal intrusion front caused by flood current and the one at the south of the Songyu-Gulangyu Channel is the result of current shear transformation. Under normal circumstances, fresh water of the Jiulong River mainly influences the inside of the Xiamen Bay, and when it is in typhoon seasons, plume front can affect the Taiwan Strait and has an effect on the biogeochemical Drocesses in the strait.

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River

Four units and twenty-four zones of diatom have been discerned in the Borehole ZK5 in the estuarine plain of the Jiulong River, Fujian Province. Comprehensive analysis of these, together with microbiological assemblages and age determinations in some other boreholes, shows that during the Late Wurm Glacial, sea level of the study area rose and fell frequently, but had principally been in the environments of estuary-bay. This mainly resulted from the tectonic subouction. In this period 3 low sea levels occurred. at 18, 16 and 12 kaBP respectively. During Holocene, sea weter intruded massively and the sea level over the transgnaion maximum had been 5-10 m higher than that of the present.

Preliminary study on the distribution of nutrients, organic matter, trace metals in sea surface microlayer in Xiamen Bay and Jiulong Estuary

The enrichment of nutrients (Noa-, Noa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.

ENVIRONMENTAL CHANGES SINCE LATE PLEISTOCENE IN ESTUARINE PLAIN OF JIULONG RIVER, FUJIAN PROVINCE

Based on the evidences of lithostratigraphy, palynology, micropaleontolopy and geochronology, paleoenvironments since the Late Pleistocene in the study area have been reconstructed. One of the most important inferences is that two marine transgressions have occurred, one in Wurm Sub-interglacial and the other Postglacial. The former had caused the study area to be in an estuary-bay envirment over the transgression maximum, with a sea level of no less than 10 m below present; foe latter reached its maximum over the Atlantic stage, with sedimentary environments of estuary-bay, hay or shallow sea, and the sea level arrived at the highest elevation in about 6 - 5 ka B.P. Furthermore, it is notable that, during the Late Wurm Glacial, the study area area had principally been in an estuary-bay environment, although the climate, like many other areas, turned cold and dry, It reflects a general trend of crustal subduction in Jiulong Estudrine Plain over this pened.

Role of mangrove in mercury cycling and removal in the Jiulong Estuary

Baseline of mercury in mangrove swamp The mercury content in sediments in the Jiulong Estuary was determined in 1984 and 1985(Table 1). The highest content of mercury in sediments (300×10) was found in Ditou, contrast-ing strongly with the low content of 36×10in Port Dongzhai in the Hainan Island. Tab1e 1 showsthat the average content of mercury in sediments in the Jiulong Estuary is 140×10and the averageof four areas is 72×10. This value means that these areas have not been heavily contaminated by

Size-fractionated uranium isotopes in surface waters in the Jiulong Estuary in China

Surface water was collected from the Jiulong Estuary for determination of activity concentrations of uranium isotopes in different size fractions, namely, greater than 53, 10 -53, 2 - 10, 0.4 -2 μm, 10 000 u -0.4 μm and less than 10 000 u fractions by microfihration and cross-flow uhrafiltration technologies. Results indicated that most of the dissolved uranium （ 〈 0.4 μm） exis- ted in the low molecular mass fraction （ 〈 10 000 u）, and the colloidal uranium-238 （10 000 u -0.4 μm） only contributed less than 1% of the dissolved uranium-238. The fractions of colloidal uranium in the dissolved phases decreased with the increasing sa- linity. A positive linear relationship between uranium-238 activities and salinities was observed for the dissolved, colloidal and low molecular mass fractions, indicating a conservative behavior of uranium in the Jiulong Estuary. In the particulate phases （ 〉 0.4 μm）, the partitioning of uranium isotopes among different size fractions was controlled by the partitioning of particle concentrations. In the regions with salinities below 20, the partitioning of uranium-238 among different size fractions was as follows： 10 - 53 μm 〉 2 - 10 μm 〉 0.4 - 2 μm greater than above 53 μm. However, the order at the offshore station with salinities above 30 changed as follows ： 0.4 - 2 μm 〉 10 - 53 μm 〉 2 - 10 μm greater than above 53 μm. The fraction of the 0.4 - 2 μm particles increased at the offshore station, suggesting the increased contribution of the authigenic uranium. The activity ratio of uranium-234 to uranium-238 in the dissolved phases, including the low molecular mass fraction and the colloidal fraction, was larger than unity, showing the occurrence of excess uranium-234. In contrast, the activity ratio of uranium-234 to uranium-238 in all size fractions of the particulate phase was close to the equilibrium value （1.0）. The observed different values of the activity ratio of uranium-234 to uranium-238 in the dissolved phase and the particulate phase were ascribed to the preferential leaching of uranium-234 and the small amount of the leaching particulate uranium. The mass ratio of thorium-232 to uranium-238 also showed different values between the dissolved phase and the particulate phase. Mass ratio of thorium-232 to uranium-238 in the dissolved, colloidal and low molecular mass fractions was less than unity, while those in the different size fractions of particulate phases were larger than unity, reflecting a different behavior between uranium and thorium during their transport into the ocean.

Qeochemical behaviour of iodine in Jiulong River Estuary

Dissolved iodine species and the relationship between its distribution and salinity in Jiulong River estuarine water have been determined. It has been found that the total iodine, iodate and iodide are positive linear with salinity. This indicates that dissolved iodine species (IO-3 and I- ) in estuarine water .how conservative behaviour. The river water contains 2. 40μg/1 as iodide and less than 1. 0μg/1 as iodate, and iodide is the predominant species. Whereas the sea water contains 39. 4μg/1 as iodate and 4. 00μg/1 as iodide, and iodate is the dominant form. The distribution of dissolved iodine in pore water, as a function of depth, has been studied. Iodine in pore water occurs as iodide. The apparent fluxes of soluble iodine from the sediment to the overlying water in the estuary have been determined. The values are 2. 4 (15℃) and 27μmol/(m2·d) (30℃) respectively.

Fast acclimation of phytoplankton assemblies to acute salinity stress in the Jiulong River Estuary

Mixing of freshwater and seawater creates the well-known salinity gradients along the estuaries. In order to investigate how phytoplankton respond to the acute salinity changes, we exposed natural phytoplankton assemblies from the Jiulong River Estuary to differential saline field water while continuously monitoring their photosynthetic performances under both indoor-and outdoor-growth conditions. When the natural cell assemblies from salinity 30 field water were exposed to series low saline field water(salinity 25, 17, 13 and 7.5), the effective Photosystem II quantum yield(ΔF/Fm′) decreased sharply, e.g., to one-fifth of its initials after 5 min exposure to salinity 7.5 field water, and then increased fast during the following 40 min and almost completely recovered after 320 min. During such an exposure process, non-photochemical quenching(NPQ) sharply increased from 0 to 0.85 within 5 min, and then decreased to nearly 0 within the following 70 min. When these cells re-acclimated to salinity 7.5 field water were exposed to series high saline field water(salinity 13, 17, 25 and 30), a similar response pattern was observed, with the decreased ΔF/Fm′ accompanied with increased NPQ, and followed by the recovery-induced increase in ΔF/Fm′ and decrease in NPQ. A similar response pattern as ΔF/Fm′to the acute osmotic stress was also observed in the photosynthetic carbon fixation capacity according to radiocarbon(14C) incorporation. Our results indicate that estuarine phytoplankton assemblies could rapidly recover from the acute osmotic stress, implying a potential cause for their frequent blooms in coastal-estuarine waters where despite drastically varying salinity, available nutrients are abundant due to the land-derived runoffs or mixing-caused relaxations from sediments.

Distribution and number change of the Littorinid (Gastropoda) on intertidal hard bed in the Jiulong Estuary, Fujian Province

-Among four species of Littorinid, Littorina scabra, L. brevicula, Nodiliitorina millegrana and N. pyramidalis pyramidalis, on the hard intertidal zone in the Jiulong Estuary, Fujian, L. scabra has the most extensive distribution both vertically and horizontally, and the highest anual average density. The uppermost limit of vertical distribution of N. pyramidalis pyramidalis is higher than the other three Littorinid. Desiccation is a main factor affecting the uppermost limit of vertical distribution of the Littorinid. The increasing wave action will raise the uppermost limit vertical distribution of Littorinid. With seasonal changes, the densities of the Littorinid also change in different tidal zonations. Difference in salinity is the main factor affecting the horizontal distribution of the Littorinid in the estuary.

Distribution and number change of the Littorinidae (Gastropoda) on intertidal hard bed in the Jiulong River Estuary

There are 4 species of Littorinidae on the intertidal hard bed in the Jiulong River Estu-ary. They are Littorina scabra, L. brevicula, Nodilittorina pyramidalis pyramidalis and N.millegrana. Of these species, L. scabra is a dominant species. According to the results of in-vestigation, we find distribution patterns of the Littorinidae on intertidal hard bed in theestuary as follows: (1)There is no Littorinid species at Haicheng Station. (2)There is only Lit-

Characteristics of nutrients in the Jiulong River and its impact on Xiamen Water, China

Water samples were collected at 20 sites on 4 occasions in 2009(twice in May,and once in both August and November) along the Jiulong River,South China to examine how nutrient inputs from the Jiulong River could affect the nutrient status of the Xiamen Water.Samples were analyzed for nitrite(NO2-N),nitrate(NO3-N),ammonium(NH4-N),phosphate(PO4-P),silicate(SiO3-Si),salinity,and temperature,to determine the nutrient and trophic status of the river.The results indicate that nutrients are derived mainly from river runoff.NO3-N was the main form of DIN in most parts of the river.In addition,NO3-N,DIN,and SiO3-Si behave conservatively.There is a surplus of DIN and SiO3-Si in the river,and PO4-P is a limitation on phytoplankton growth.The concentration of DIN is typically above 0.60 mg/dm3,and higher than 1.00 mg/dm3in most parts of the river.The concentration of PO4-P is typically above 0.02 mg/dm3,while the concentration of SiO3-Si is higher than 1.00 mg/dm3.Between 2003 and 2008,samples were collected 3 times per year(May,August and November) at 27 sites in the Xiamen Water and analyzed for NO2-N,NO3-N,NH4-N,PO4-P,salinity,and temperature.We discovered that the Jiulong River was the key source of DIN into the Xiamen Water,but not PO4-P,indicating the reason of the N/P molar ratio imbalance in the Xiamen Water.In the future,the effects of high DIN concentrations on the phytoplankton communities and marine ecosystems of the Xiamen Water shall be studied.

Dynamics of phytoplankton communities in the Jiangdong Reservoir of Jiulong River,Fujian,South China

Phytoplankton blooms occurring in the Jiangdong Reservoir of Jiulong River,Fujian Province,South China,are a potential source of contamination of the drinking water of Xiamen(Amoy)City.To understand the main factors governing phytoplankton composition and succession,we sampled phytoplankton and measured environmental parameters in the reservoir,weekly or biweekly from Jan.2010 to Feb.2012.We identifi ed 123 species of phytoplankton from 7 phyla and 74 genera.The major phyla were Chlorophyta,Bacillariophyta,Cryptophyta,Cyanophyta,and Dinophyta.The main trend in the succession of phytoplankton was from prevalence of Cryptophyta-Bacillariophyta communities to those of Chlorophyta-Cyanophyta.High cell concentrations of Cryptophyta,predominantly Komma caudate,Cryptomonas marssonii,and Cryptomonas erosa,were present in winter,associated with low river discharge and cold water.Bacillariophyta,primarily Cyclotella meneghiniana,Aulacoseira granulata,and Aulacoseira granulata var.angustissima,dominated in early spring,coinciding with high turbulence and low irradiance.During early summer and autumn,Chlorophyta,comprising Scenedesmus quadricauda,Dictyosphaerium ehrenbergianum,and Pandorina sp.were prevalent during conditions of warmer water temperatures and low turbulence.Cyanophyta,with dominance of Pseudanabaena mucicola,Merismopedia tenuissima and Raphidiopsis sp.increased throughout the summer,coinciding with higher water temperatures and lower nutrient concentrations.Dinophyta content was occasionally high during winter and summer.Peridiniopsis penardii(Dinophyta)bloomed during winter 2009,with a persistently high biomass recorded into early spring.Canonical correspondence analysis indicated that phytoplankton communities were infl uenced by river discharge,irradiance,water temperature,and nutrient concentrations.

Stable isotope geochemical characteristics of dissolved inorganic carbon in the Jiulong River Estuary, Fujian Province, China

The isotopic composition of dissolved inorganic carbon(DIC) in estuarine environments has been studied for its significant role in determining the isotopic composition of inorganic/organic matter and its applications to the study of various natural processes. In this paper, based on the stable isotope geochemical characteristics of dissolved inorganic carbon in the Jiulong River Estuary, the following conclusions are drawn:(1) δ13CDIC values are mainly controlled by the mixing ratio of fresh water and sea water;(2) δ13Cphytoplankton values are linearly related to the δ13CDIC values;(3) δ13CPOM values for the Jiulong River Estuary are affected by anthropogenic pollution significantly; and(4) the comprehensive analysis of δ13Cphytoplankton, δ13CPOM and δ13CDIC shows that along with increasing salinity, the proportion of POM derived from the degradation of phytoplanktons gradually increases.

Characteristics of Heavy Minerals Composition and Distribution in Jiulong River Estuary Sediment

The bottom sediment samples were gathered during island investigation in 1994 and in the period of carrying out the natural science fund project of Fujian in 1999. The composition, distribution and assemblage characteristics of heavy minerals which granularity distributes from 0.063 to 0.125 mm in the sediment from Jiulong River estuary are studied in the paper. The results show that there are 49 kinds of heavy minerals and the average content of them is 9.38 %. The dominant and characteristic minerals are magnetite, hematite, epidote, ilmenite, limonite, hornblende, zircon, andalusite, biotite and so on. 4 mineral assemblage ⅠⅡzones (.The watercourse gateway of Jiulong River mineral zone, . The northern estuary ⅢⅣof Jiulong River mineral zone, . The southern estuary mineral zone, . The eastern estuary of Jiulong River mineral zone ), can be divided based on the heavy mineral contents and the distribution characteristics, which not only relates to the matter sources but also is controlled by hydrodynamic condition and the sedimentary environment in the Jiulong River estuary.

九龙江口表层沉积物碘含量分析

于2021年5—6月对九龙江红树林保护区与非红树林保护区进行布点采样,测定其表层沉积物碘含量和有机碳含量。结果表明:13个采样点中,碘含量范围为3.7~24.8 mg·kg^(-1),差值最高可达7倍,平均值为12.3 mg·kg^(-1);有机碳含量范围为16~45 g·kg^(-1),平均值为30 g·kg^(-1)。不同类型样品碘含量大小依次为:长林龄林下沉积物>河道清淤沉积物>非林下沉积物>短林龄林下沉积物,其中长林龄林下沉积物碘含量范围为15.7~24.8 mg·kg^(-1),平均值为19.2 mg·kg^(-1);短林龄林下沉积物含量为5.5~6.9 mg·kg^(-1),平均值为6.2 mg·kg^(-1);二者相差3倍以上。有机碳含量最高的为长林龄林下沉积物和河道清淤沉积物,平均值均为32 g·kg^(-1);最低值为短林龄沉积物,含量为22 g·kg^(-1)。不同类型沉积物有机碳含量与碘含量基本呈正相关关系,但相关性不显著;同等有机碳含量的样品,长林龄林下沉积物碘含量显著高于其它样品。

四川九龙古茶树种质资源农艺性状遗传多样性研究

为探究甘孜九龙古茶树种质资源的分布区域、形态特征和农艺性状的遗传多样性,通过基本统计分析、变异系数、多样性指数、主成分分析和聚类分析,对67份九龙古茶树种质资源的21个质量性状和12个数量性状进行了遗传多样性分析和评价。结果表明:九龙古茶树资源农艺性状变异丰富,除树型和树姿外,质量性状的遗传多样性指数范围为0.17~1.27,平均为0.82,其中以花瓣颜色多样性指数最小,果实形状的多样性指数最大;数量性状变异系数范围为1.38%~29.94%,平均为15.27%,以叶面积的变异系数最高,萼片数的变异系数最低。主成分分析显示,前11个主成分累计贡献率在76.49%,其中叶宽、叶长、叶色和花瓣颜色等性状是九龙古茶树种质资源农艺性状表现出差异的主要因素。21个质量性状聚类分析结果显示,在欧式距离为16.9时,可将67份九龙古茶树种质资源划分为4个类群,聚类结果与海拔高度及地理位置无明显相关性。本次调查的古茶树种质资源中有13份种质位于海拔2400 m以上,长势良好,展现出良好的抗寒性和抗旱性。此外,还有2份种质花瓣颜色特异,1份种质籽粒较大且结果率高。研究结果为九龙古茶树种质资源收集、保护和利用奠定一定基础。

九龙江流域丰枯水期表层水体氮污染特征及其来源解析

为探明九龙江流域表层水体氮污染分布特征及其污染来源,于2020年7月(丰水期)和2021年1月(枯水期)开展九龙江全流域表层水体多点多断面原位观测,利用正定矩阵因子分析模型(positive matrix factorization,PMF)对不同水期全流域表层水体氮污染来源及贡献率进行解析,耦合相关性统计分析方法研究不同水期流域表层水体氮污染的关键驱动因子。结果表明,九龙江流域表层水体氮污染存在明显的水期分异特征,ρ(TN)为0.72~13.14 mg·L^(-1),丰水期ρ(TN)为1.39~10.95 mg·L^(-1),枯水期为0.72~13.14 mg·L^(-1)。硝态氮(NO_(3)^(-)-N)、氨氮(NH_(4)^(+)-N)、亚硝态氮(NO_(2)^(-)-N)和溶解性有机氮(DON)浓度均表现为丰水期大于枯水期,但颗粒态氮(PN)浓度则表现为枯水期大于丰水期。丰水期氮污染以NO_(3)^(-)-N、NH_(4)^(+)-N和DON形态为主,枯水期则以NO_(3)^(-)-N、DON和PN形态为主。应用PMF模型对流域表层水体氮污染来源进行解析,结果表明,丰水期流域农业化肥施用引起的农业面源污染、生活污水及河流内动植物残体、微生物、矿物颗粒是流域水体氮污染的主要来源,而枯水期流域农业化肥污染、城市工业污水排放及河流中动植物残体等悬浮颗粒则是流域水体氮污染的主要来源。该结果强化了丰枯水期九龙江流域表层水体氮污染受流域农业生产活动和径流变化共同影响的认识,建议将流域农业、工业生产氮污染源头控制和氮污染的水期分异有效纳入流域水体氮污染综合管理。

基于时序InSAR的九龙江河口地区地面沉降时空演变规律及成因分析

为探明九龙江河口地区地面沉降情况,本研究采用小基线集合成孔径雷达干涉测量(small baseline subset interferometric synthetic aperture radar, SBAS-InSAR)和永久散射体合成孔径雷达干涉测量(persistent scatterer interferometric synthetic aperture rader, PS-InSAR)技术获取了2017年1月至2022年3月地面沉降的时空分布信息和演变规律,并结合实地调查数据和水文地质调查监测资料对地面沉降成因进行了系统分析。研究结果表明:SBAS-InSAR和PS-InSAR两种方法均发现在研究期间九龙河口地区地面整体呈现出沉降趋势,SBAS-InSAR监测结果发现研究区沉降速率为6.2 mm/a;研究期间该区域的沉降中心持续扩大且沉降量呈增加趋势,最大累积沉降量达到250 mm以上,主要分布在浮宫镇中南部地区、海澄镇、东园镇中南部地区、角美镇和榜山镇东南部地区;该区域由于大量抽取地下水用于养殖,地下水位下降,引起淤泥层发生固结排水、压密,从而导致地面沉降。

水体微塑料的垂向分布及采样方法比较研究——以九龙江河口为例

由于受到潮汐过程的影响,河口区微塑料的调查和研究存在着方法不统一、数据误差较大的问题.2019年夏季使用泵采法在九龙江河口开展原位全水层微塑料采样,对不同水层、不同站位间的微塑料丰度及其赋存特征进行分析,并与其他在该河口的相关调查研究结果进行对比.结果表明:九龙江河口表、中、底层水体中的微塑料赋存量存在明显差异,河流入海口及靠近污染源处表层水中微塑料丰度明显高于中、底层中,在潮汐作用剧烈的河口区,中、底层中微塑料丰度高于表层水中,存在明显分层现象;使用不同采样方法获取的微塑料数量浓度值存在较大差异,泵采法相比拖网法能更有效地截留塑料纤维;使用泵采法过滤水样体积、滤经筛网孔径大小都对收集到的微塑料丰度、尺寸有显著影响.采样方法的不同将导致微塑料丰度结果的显著差异,在潮汐河口进行微塑料监测有必要将潮汐作用考虑在内.因此,建议建立潮汐河口的微塑料业务化监测和通量观测,并采用洪、枯季,大、小潮的全潮时段的观测采样方法.