河北赞皇杂岩官都群碎屑沉积岩锆石SHRIMPU-Pb定年及其地质意义

新太古代—古元古代表壳岩系在华北克拉通广泛发育,在赞皇地区也出露有较典型的中低级变质的火山-沉积岩系,即从原赞皇群解体出来的官都群,其形成时代和成因目前仍有争议。官都群的主要岩石组合为变基性火山岩(包括角闪片岩和斜长角闪岩)、大理岩、石英片岩,以及一系列长英质副片麻岩等。对其中的长英质副片麻岩进行碎屑锆石定年研究,并结合前人已报道的碎屑锆石数据可知,碎屑锆石年龄主要峰值约为2.5Ga,部分样品出现2.0～2.2Ga的峰值。变质锆石记录主要有2个范围,分别为2.48Ga左右和1.85～1.9Ga,可能代表了2期不同的构造热事件记录。结合该地区近年来的研究,可以得到如下认识:(1)样品中存在形态完好的长柱状锆石,表明是近源沉积;(2)约2.48Ga的变质记录与核部岩浆锆石的年龄(约2.5Ga)非常接近,可能代表了物源区中酸性岩体侵位后遭受的一次构造热事件,而不代表沉积岩形成后遭受变质的记录,即沉积过程晚于2.48Ga;(3)官都群至少有一部分岩石组合形成于古元古代;(4)官都群可能是不同时代、不同岩性单元拼贴而成,需要进一步解体。     

Interplay of S and As in Mekong Delta sediments during redox oscillations

The cumulative effects of periodic redox cycling on the mobility of As,Fe,and S from alluvial sediment to groundwater were investigated in bioreactor experiments.Two particular sediments from the alluvial floodplain of the Mekong Delta River were investigated:Matrix A(14 m deep)had a higher pyrite concentration than matrix B(7 m deep)sediments.Gypsum was present in matrix B but absent in matrix A.In the reactors,the sediment suspensions were supplemented with As(Ⅲ)and SO_4~(2-),and were subjected to three full-redox cycles entailing phases of nitrogen/CO_2,compressed air sparging,and cellobiose addition.Major differences in As concentration and speciation were observed upon redox cycling.Evidences support the fact that initial sediment composition is the main factor controlling arsenic release and its speciation during the redox cycles.Indeed,a high pyrite content associated with a low SO_4~(2-)content resulted in an increase in dissolved As concentrations,mainly in the form of As(Ⅲ),after anoxic half-cycles;whereas a decrease in As concentrations mainly in the form of As(Ⅴ),was instead observed after oxic half-cycles.In addition,oxic conditions were found to be responsible for pyrite and arsenian pyrite oxidation,increasing the As pool available for mobilization.The same processes seem to occur in sediment with the presence of gypsum,but,in this case,dissolved As were sequestered by biotic or abiotic redox reactions occurring in the Fe—S system,and by specific physico-chemical condition(e.g.pH).The contrasting results obtained for two sediments sampled from the same core show that many complexes and entangled factors are at work,and further refinement is needed to explain the spatial and temporal variability of As release to groundwater of the Mekong River Delta(Vietnam).     

基于CSA-PLS算法的养殖水体水质快速高光谱预测反演模型研究

养殖水体水质的优劣直接影响养殖对象的成长,准确、快速、全面地掌控养殖水环境的水质参数变化情况具有重要意义。传统的水质指标监测方法都通过人工采样的方式,不仅耗费时间长,且只能体现局部水体情况。针对这些问题,提出了一种乌鸦搜索算法(CSA)结合偏最小二乘回归(PLSR)的高光谱特征波段筛选方法,快速构建回归模型,实现光谱数据的精准预测反演。以连片的养殖小区为研究对象,采集养殖水体样本并拍摄同时期的高光谱影像数据。首先对提取的采样点光谱数据利用多种数据变换方法分别预处理;其次利用这些数据,对水质指标总氮(TN)、氨氮(NH₄⁺-N)、总磷(TP)和化学需氧量(COD)分别构建全波段的SVR和AdaBoost回归模型,同时与提出的CSA-PLS自动筛选波段方法和传统的连续投影算法(SPA)筛选波段后构建的模型进行比较分析;最后根据决定系数(R²)和均方根误差(REMS)选出适合各水质指标的最优模型。从实验结果可以看出,所提波段筛选方法的AdaBoost模型预测结果优于SVR和传统SPA方法提取特征波段后构建的模型,与全波段最优模...     

广利河口拦门沙发育动态和河口航道的选择

根据现场调查和历史资料,获取了广利河口拦门沙水动力特征、海底地形和底质特征,对拦门沙的动态发育和波浪作用下拦门沙运动状态进行了分析,探讨了广利河口的航道选择方案。分析结果认为,广利河槽外航道宜从东偏南向入海。     

白芍(Radix paeoniae alba)提取物对中华绒螯蟹(Eriocheir sinensis)造血组织发育及造血因子Astakine的影响

血淋巴细胞在甲壳动物免疫反应中起着非常重要的作用,其主要由造血组织(Hematopoietic tissue, HPT)生成并随着开管式循环分布到身体各处。到目前为止,还没有相关研究表明甲壳动物造血组织是否受草本植物的影响。本研究以中华绒螯蟹(Eriocheir sinensis)为对象,利用荧光定量PCR、免疫荧光和组织化学等技术,初步探索了白芍(Radix paeoniae alba)提取物对中华绒螯蟹造血组织和造血因子Astakine的影响。结果显示,在原代培养的造血组织细胞中添加终浓度为0.85mg/mL的白芍提取物后,造血因子Astakine mRNA的表达量显著上调(P0.05)。进一步制备含1%白芍提取物的中华绒螯蟹饲料并进行饲喂实验,结果显示饲喂含白芍提取物饲料的中华绒螯蟹造血组织的Astakine mRNA的表达量较饲喂前上调了10.5倍,要高于对照组。免疫荧光结果同样表明,饲喂含白芍提取物饲料后中华绒螯蟹造血组织的Astakine蛋白荧光信号也要强于对照组。通过造血组织的形态学观察和造血组织体重百分比的检测,我们发现白芍组中华绒螯蟹造血组织含有较多卵形小叶,且造血组织体重百分比较饲喂前增加了6.64%,而对照组仅增加1.6%。免疫保护率实验显示,在脂多糖急性刺激下,白芍添加组的中华绒螯蟹的存活率(77.5%)要高于对照组(57.5%)。综上所述,白芍提取物可以促进中华绒螯蟹造血因子的表达和造血组织的发育,从而提高中华绒螯蟹的免疫调节功能。     

Integrated Geological–Geophysical and Oceanographic Research in the South China Sea: Cruise 88 of the R/V “Akademik M.A. Lavrentyev”

Oceanology - Abstract—The paper gives brief results of comprehensive studies in the South China Sea obtained from a joint Russian–Vietnamese expedition in November 2019 (cruise 88 of...     

Mapping and Assessing Landfills Surface Temperature Using Landsat 8 Satellite Data. A Case Study in Vietnam

Izvestiya, Atmospheric and Oceanic Physics - In recent years, rapid urbanization and population growth have led to an overload of waste in big cities of Vietnam. Waste decomposition is always...     

Collision Analysis Between Spudcan and Seabed During the Process of Jack-up Platform Lowering Jack-up Legs

China Ocean Engineering - In the leg-lowering process, the offshore jack-up platform is in a floating state, and the spudcan may collide with the seabed due to the platform motion in waves, thereby...     

Holocene vegetation dynamics and hydrological variability in forested peatlands of the Clay Belt,eastern Canada,reconstructed using a palaeoecological approach

Forested peatlands are widespread in boreal regions of Canada, and these ecosystems, which are major terrestrial carbon sinks, are undergoing significant transformations linked to climate change, fires and human activities. This study targets millennial‐scale vegetation dynamics and related hydrological variability in forested peatlands of the Clay Belt south of James Bay, eastern Canada, using palaeoecological data. Changes in peatland vegetation communities were reconstructed using plant macrofossil analyses, and variations in water‐table depths were inferred using testate amoeba analyses. High‐resolution analyses of macroscopic charcoal >0.5 mm were used to reconstruct local fire history. Our data showed two successional pathways towards the development of present‐day forested peatlands influenced by autogenic processes such as vertical peat growth and related drying, and allogenic factors such as the occurrence of local fires. The oldest documented peatland initiated in a wet rich fen around 8000 cal. a BP shortly after land emergence and transformed into a drier forested bog rapidly after peat inception that persisted over millennia. In the second site, peat started to accumulate from ~5200 cal. a BP over a mesic coniferous forest that shifted into a wet forested peatland following a fire that partially consumed the organic layer ~4600 cal. a BP. The charcoal records show that fires rarely occurred in these peatlands, but they have favoured the process of forest paludification and influenced successional trajectories over millennia. The macrofossil data suggest that Picea mariana (black spruce) persisted on the peatlands throughout their development, although there were periods of more open canopy due to local fires in some cases. This study brings new understanding on the natural variability of boreal forested peatlands which may help predict their response to future changes in climate, fire regimes and anthropogenic disturbances.     

The information system of the French Peatland Observation Service: Service National d'Observation Tourbières – A valuable tool to assess the impact of global changes on the hydrology and biogeochemistry of temperate peatlands through long term monitoring

Mitigating and adapting to global changes requires a better understanding of the response of the Biosphere to these environmental variations. Human disturbances and their effects act in the long term (decades to centuries) and consequently, a similar time frame is needed to fully understand the hydrological and biogeochemical functioning of a natural system. To this end, the ‘Centre National de la Recherche Scientifique’ (CNRS) promotes and certifies long-term monitoring tools called national observation services or ‘Service National d'Observation’ (SNO) in a large range of hydrological and biogeochemical systems (e.g., cryosphere, catchments, aquifers). The SNO investigating peatlands, the SNO ‘Tourbières’, was certified in 2011 ( https://www.sno-tourbieres.cnrs.fr/ ). Peatlands are mostly found in the high latitudes of the northern hemisphere and French peatlands are located in the southern part of this area. Thus, they are located in environmental conditions that will occur in northern peatlands in coming decades or centuries and can be considered as sentinels. The SNO Tourbières is composed of four peatlands: La Guette (lowland central France), Landemarais (lowland oceanic western France), Frasne (upland continental eastern France) and Bernadouze (upland southern France). Thirty target variables are monitored to study the hydrological and biogeochemical functioning of the sites. They are grouped into four datasets: hydrology, fluvial export of organic matter, greenhouse gas fluxes and meteorology/soil physics. The data from all sites follow a common processing chain from the sensors to the public repository. The raw data are stored on an FTP server. After operator or automatic processing, data are stored in a database, from which a web application extracts the data to make them available ( https://data-snot.cnrs.fr/data-access/ ). Each year at least, an archive of each dataset is stored in Zenodo, with a digital object identifier (DOI) attribution ( https://zenodo.org/communities/sno_tourbieres_data/ ).