塔里木河下游间歇性输水对土壤水化学的影响

根据塔里木河下游2000-2006 年11 次间歇性输水影响下沿输水河道两侧地下水埋深、地下水化学组分变化的资料, 结合有关输水的基本资料和土壤盐分含量变化的适时监测数据, 分析了地下水化学特征的变化及影响其变化的各相关因子,结果表明：地下水化学特征的变化呈现明显的阶段性规律, 地下水化学组分的变化与距离输水河道的远近、地下水埋深、河道径流量以及土壤盐分含量之间具有较高的相关性; 地下水埋深在5 m 及5 m 以下时, 地下水化学组分含量较低, 水质较好。而埋深在5 m 时的水位条件能够满足该区域建群种植物的生存, 为输水条件下的理想水位;地下水化学特征变化的阶段性特点和土壤剖面盐分含量的分布规律及其相互关系说明,在当前输水模式下配合面上输水将能更好地促进生态恢复。     

Discrepancies in Simulated Ocean Net Surface Heat Fluxes over the North Atlantic

The change in ocean net surface heat flux plays an important role in the climate system. It is closely related to the ocean heat content change and ocean heat transport, particularly over the North Atlantic, where the ocean loses heat to the atmosphere, affecting the AMOC(Atlantic Meridional Overturning Circulation) variability and hence the global climate.However, the difference between simulated surface heat fluxes is still large due to poorly represented dynamical processes involving multisca...     

古田水口库区ML4.8地震成因探讨

介绍水口库区地震地质构造特征与地震活动特点,重点分析2008年3月6日古田4.8级地震序列以及震时福建地区应力场特征。分析认为：1) 2008年3月水口库区处于明显的应力积累区域;2）古田4.8级地震为构造型水库地震, NE向湾口断裂（F2）是可能的发震构造之一;3）水口水库前两次4级地震发震时间相隔近12年,表明水库水位的升降与发震之间的相关性并不明显,区域构造应力的变化是导致水口库区地震的决定因素。     

三江平原萝北县湿地农田化过程与驱动机制分析

通过获取三江平原萝北县自1954年以来的六期土地利用数据,定量分析了过去50余年湿地农田化过程,并从自然因素和人为因素两方面探讨了湿地农田化过程的驱动机制。结果表明,1954-2005年,三江平原萝北县耕地面积净增21.85×10⁴hm²,湿地是新增耕地的主要来源。在空间上,湿地斑块越来越分散,景观破碎化程度明显加剧,而耕地斑块则趋于集中分布;目前,耕地已成为三江平原萝北县的基质景观,地势低平、坡度较小、土壤条件、地貌条件良好的平原区是湿地农田化的首选区域。随着可开垦湿地资源的减少,人类的开垦对象开始转向地势、土壤、地貌等条件相对较差的湿地景观单元。气候变暖加速了湿地农田化进程,而人口数量的增加和政策的引导作用,对湿地农田化过程具有重要的影响。     

The biomarker changes of a heavy fuel oil after different weathering times

This paper presents the experimental results of composition changes of heavy fuel oil by simulating weathering in static seawater under natural environmental conditions. The results indicate: n-C10 to n-C15 were lost gradually in 24 weeks and the relative abundance of alkanes with long chains (n-C19) increased markedly. The aromatic compounds with less than two rings (except C4N) were completely lost in 24 weeks and CnP and CnD became the main aromatics in the heavy fuel oil after 24 weeks. The ratios of n-C17/Pristane (Pr) and n-C18/Phytane (Ph) were suitable for identifying lightly weathered (3 weeks) heavy fuel oil. The ratios of n-C17/n-C18 and Pr/Ph were suitable for identifying moderately weathered heavy fuel oil (12 weeks); the ratios of C2D/C2P and C3D/C3P did not change significantly in 24 weeks and were more suitable for identifying moderately weathered heavy fuel oil (24 weeks).     

~(10)Be exposure ages of Quaternary Glaciers in Antarctica

In situ terrestrial cosmogenic nuclides(TCN) have been widely applied to date the ages of Quaternary glacial deposits in Antarctica and plays an important role in reconstructing the glacial evolution and climate change. It helps to understand the Antarctic ice sheet's evolution process in Quaternary and shed light on the application of Cosmogenic Nuclide exposure dating technique in glacial geomorphology. In this paper, we retrieved 49510 Be age samples in Antarctica from literature published between 2004 and 2020 and recalculated the TCN ages using version 3.0 online calculator of Cosmic-Ray Produced Nuclide Systematics on Earth(CRONUS-Earth). Several conclusions can be drawn from the results:(1) 75% of the exposure ages are younger than 400 ka, and 91% younger than 1, 100 ka. Northern Antarctic Peninsula exposure result is visibly younger than the main glaciers area in East Antarctica due to climate change and geological evaluation since the LGM(Last Glacial Maximum).(2) TCN ages are relevant to the samples' relative positions in the Antarctic continent, but a relationship between their ages and elevations is yet to be determined based on the collected data.     

Growth marks in eyestalks of Portunus trituberculatus:A development of technique and evidence of molting

The analysis of growth bands in the eyestalk has been increasingly used for estimating crustacean ageing and molting. In this study, we developed an effective method to process and observe the eyestalk microstructure of the swimming crab(Portunus trituberculatus). We found that dark pigmentation as a result of boiling has an influence on the observation of the eyestalk microstructure. Choosing an unboiled eyestalk, this study compared the cross section and longitudinal section, and concluded that the cross section is suitable for the observation of growth increments with 6.1% CV(coefficient of variation), and growth bands are suitable for the observation of the longitudinal section with 5.4% CV. The width of growth increments near the edge of the endocuticle is small, and the width of growth increments of the middle part of the endocuticle is large. Relationship of number of growth bands to molting time was fitted to a linear function with the slope not significantly different from 1, indicating that growth bands are formed associated with molting. Periodicity of growth increment formation was calculated as 3.7 d, however was not verified. Our results provide a new improved technique for identification of crustacean molting and growth.     

粤港澳大湾区海洋生态环境协同共治策略探讨

粤港澳三地为共同应对跨境污染等环境问题开始携手,经过多年的交流深化,已形成总体规划引领,合作框架协议约束,联席会议与粤港、粤澳环保合作小组及其下设的专题小组相结合的海洋环境协同共治平台。目前,粤港澳大湾区仍面临海域水质不断恶化、湿地生态功能退化、海洋生物资源衰退等严峻的生态问题。通过系统梳理,借鉴国际三大湾区先进经验,提出健全大湾区海洋生态环境协同治理法制体系、完善协同共治平台、统筹规划海洋生态环境保护、健全公众参与制度等策略,完善大湾区海洋生态环境协同共治机制。     

Land use/cover changes and environmental consequences in Songnen Plain, Northeast China

The Songnen Plain in Northeast China, one of the key national bases of agricultural production, went through remarkable land use/cover changes in recent years. This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment. The Landsat-based analysis showed that, during 1986–2000, cropland, built-up land and barren land had increased, among which cropland had the largest increase of 9,198km² with an increase rate of 7.5%. Woodland, grassland, water body and swampland had decreased correspondingly, among which grassland had the most dramatic decrease of 6,127km² with a decrease rate of 25.6%. The transition matrix results revealed that grassland, woodland and swampland were the three main land use types converted to cropland. Climate warming created the potential environment for the conversion of grassland and swampland into cropland. Land resources policy made by central and provincial governments of China affected the pattern and intensity of land use. Land use/cover changes accompanied by climatic variation brought out a series of environmental consequences, such as sand desertification of land, land salinization and alkalinization, grassland degradation, and more frequent floods. Under this circumstance, optimized land use structure and restoration measures are needed.     

Hybrids between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus： karyotype, allozyme and RAPD analyses

The hybrid between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus was produced by artificial insemination of olive flounder eggs with stone flounder sperm. Sinistral and dextral are two types of hybrid progeny after metamorphosis. Karyotypes of both hybrid flounders are the same as those of the two parental species. Of the 22 loci examined from 12 allozymes, 12 confirmed hybridization of the paternal and maternal loci in hybrids and no difference was found in allozyme patterns of sinistral and dextral hybrid fishes. RAPD patterns of these specimens were also studied with 38 primers selected from 104 tested. Among them, the PCR products of 30 primers showed hybridization of the paternal and maternal bands. Genetic variation between hybrids and their parental stocks was analyzed by RAPD using 10 of the above 38 primers. The average heterozygosity and genetic distance were calculated. The results suggested that the filial generation could inherit a little more genetic materials from paternal fish than that from maternal fish. Supported by National Natural Science Foundation of China (No. 30571445), National High-Technology Research and Development Program (863 Program, No. 2006AA10A404), and Project from the Ministry of Science and Technology of China (No. 2006DKA30470-017)