华南亚热带山地土壤有机质更新特征定量研究

选择鼎湖山自然保护区森林植被带（SL）、灌丛一草甸过渡带土壤剖面（GC）进行薄层取样，根据土壤有机质^14C放射性水平，运用模型计算土壤有机质更新速率（m）。结果表明上部0－10cm土层有机质更新速率（m）最高；向下,m锐减；剖面下部m值极低，这说明土壤有机质由不同更新周期（T）组分构成。表层快循环组分占绝对优势，向下，慢循环组分为主，剖面下部为稳定组分。根据m、有机碳含量、有机碳含量、土壤容重、土层厚度计算有机质更新CO2产量，表层0－10cm层段CO2产量约为整个剖面的98％。SL剖面m值及有机质更新CO2产量均明显大于GC剖面相应值。分析表明在同一气候植被是制约土壤有机质更新及CO2产量的第一要素，这为通过绿化加强土壤碳汇功能提供重要依据。     

Getting by: The ethnomethods of everyday cycling navigation

Cycling is often carried out in public places, meaning that it is easy to both observe and video-record cycling in action. Within sociology, ethnomethodology focuses on practical activities, often by collecting and analysing video data. Geographers have also used video data in researching cycling, but the two perspectives have little crossover. This article showcases an ethnomethodological analysis of video data on everyday cycling navigation, presenting three empirical examples. We see that cycling, accomplished by real interacting people, needs analysing in fine detail. Further knowledge of the mundane aspects of cycling mobility can usefully build upon such a videographic approach.     

黔南晚石炭世旋回珊瑚礁群落演化研究

发育于黔南地区的扁坪—岩板寨晚石炭世旋回珊瑚礁由3个旋回组成,每个旋回都具有较高的生物含量和生物多样性。根据生物的丰度和功能可识别出叶状藻-"不明管状物"群落、Ivanovia cf.manchurica群落、Tubiphytes群落和Fomitchevella群落。旋回珊瑚礁的演化过程可划分为6个阶段。分析表明,礁体形成过程中曾一度出现了高能的环境,第二、三旋回经历了迅速的环境变化。     

Foraging across ecosystems: diet diversity and social foraging spanning aquatic and terrestrial ecosystems by an invertebrate

Ecosystems are fundamentally connected to one another, although empirical documentation of the links between them, especially the links between marine and terrestrial ecosystems, has been limited. This study examined the foraging behavior and ecology of an understudied invertebrate, the hermit crab Coenobita compressus, which is remarkably abundant at the nexus of marine, terrestrial, and freshwater ecosystems. Data collected between 2008 and 2011 in the Osa Peninsula of Costa Rica revealed that C. compressus plays a generalist scavenger role across ecosystems. Beach almond fruits (Terminalia catappa) were a staple of the crabs’ diet, but the crabs also commonly consumed a variety of other fruit species and various parts of plants (nuts, seeds, flowers, husk, stems, buds) as well as algae, fungus, animal feces, and the carcasses of insects, jellyfish, conspecifics, other crustacean species, freshwater and saltwater fish, sea turtles (eggs and adults), and mammals. The crabs fed on these resources in prominent social aggregations, also forming such aggregations as they exchanged the aquatically derived gastropod shells that they use as homes while roaming the land. The size of the crabs’ aggregations around plant versus animal resources and around terrestrial versus aquatic resources did not differ, underscoring the species’ generalist foraging behavior. Broadly, these results suggest that C. compressus has one of the most diverse diets of any crustacean and plays a critical role in recycling organic matter and nutrients. This species might also mediate the passage of resources across different ecosystems, although further research is needed to explore this possibility.     

海洋沉积物中氮的形态及其生态学意义

海洋沉积物作为生源要素氮的重要源与汇，在其生物地球化学循环中起着至关重要的作用。该项研究旨在查清海洋沉积物中氮的存在形态及其生态学意义。氮是生物生命活动必需的营养要素，海洋中的氮往往是海洋初级生产力的限制因子，氮的吸收与再生释放在估算海洋新生产力和生源要素的生物地球化学循环率上也有重要贡献。海洋沉积物中的氮作为海水中氮的重要供给源是海洋生物赖以生存的重要物质基础，对维持海洋生态平衡、修复失衡的海洋生态环境具有重要意义。但由于不同海区海洋沉积物的来源和环境不同，氮的形态和含量亦不相同，可被生物吸收和利用的数量就不相同，因此造成了不同海区生物种群和环境不同，进而影响生态环境。因此，研究海洋沉积物中氮的形态，了解各个形态与沉积物中生物种群及与环境的关系，确定其生物和化学活性，査清氮不同形态的生态学功能，对于深入探讨海洋生物资源可持续利用的方法和策略具有重要意义。本文主要阐述海洋沉积物中氮的存在形式与分布、氮的早期成岩和去营养化作用、硝化和反硝化作用以及氮与生物特定种群的关系等，探讨了影响海洋沉积物中的氮循环的主要因素，并分析了海洋沉积物中的氮与生态系的关系，以期对研究氮的海洋生物地球化学过程有所帮助。     

The Effect of Organic Carbon-Iron Oxide Association on the Preservation of Sedimentary Organic Carbon in Marine Environments

Understanding the mechanisms responsible for long-term storage of organic carbon (OC) in marine environment is important for studying the marine carbon cycling and predicting how the global carbon cycle will respond to climate change. It is estimated that more than 20% of the OC in marine sediments is associated with iron oxides and thus these complexes are one of the most important factors in the long-term storage of OC. The OC-iron oxide (OC-Fe) association can be formed through either adsorption or co-precipitation, but the dominant mechanism of OC-Fe association in marine environments is co-precipitation. The combination of OC from different sources with iron oxides is selective. Iron oxides preferentially combine with marine OC in most marine environments, but in estuarine delta regions they prefer terrestrial OC. Due to large inputs of terrestrial materials, high primary production and frequent re-suspension, estuarine and marginal seas are suitable sites for OC-Fe association studies, which should be emphasized in the future.     

桂林潮田河水溶解无机碳昼夜变化与通量

小型山区河流系统具有流域面积小、响应时间短、人类活动的水化学影响易识别等特点,是研究生物地球化学过程的理想场所.本文以桂林潮田河为例,通过高分辨率监测与高频取样,研究水化学昼夜动态变化,无机碳移除及其生物地球化学控制机理.受水生光合作用与钙沉积作用的控制,河水pH、DO、SpC、HCO–3和Ca2+离子产生显著的昼夜动态变化,这些水化学指标昼夜变幅大小又与河床基质和水生植物类型有关.砾石类河床藻类发育的鸟岭桥河段Ca2+和HCO3-含量白天下降幅度平均值分别为12%和11%,泥质类河床沉水植物发育的两河沟河段为10.6%和8.9%.DO浓度与pH值主要受局地河流内部过程控制,即水生植物或藻类光合作用控制,而电导率受上游传输影响较大,滞后时间与两点之间信号平流传输时间相关.监测河段水体因光合作用产生的钙沉降与溶解无机碳移除量分别为302 kg/d和997 kg/d,即188.75 g/m/d和623.13 g/m/d,是西南亚热带典型地下河出口河流的4~5倍,小型岩溶河流沿流程发生的无机碳向有机碳转化,对水体碳通量而言,是真正意义上的自然碳汇过程.     

土壤圈在全球变化中的意义与研究内容

土壤圈是地圈系统的重要组成部分，它处于地圈系统，即气圈、水圈、生物圈与岩石圈的交界面，是最活跃、最富生命力的圈层。土壤圈的物质循环是全球变化中物质循环的重要内容，因此，研究土壤圈及其物质循环的结构与功能，对全球变化，特别对全球土壤变化有密切关系。土壤圈在全球土壤变化中的研究内容包括：土壤圈与地圈各圈层的物质循环；水土资源的时空变化；土壤肥力变化与农业持续发展，区域治理与环境建设等，这些都是全球土壤变化，特别是中国全球变化的主题，应引起高度重视。     

俯冲带中水流体的化学性质研究进展

俯冲带中的水在壳幔演化和物质交换中起重要作用。本文就俯冲带中水的物理化学性质、溶液中的离子缔合、混溶、主量元素与微量元素组成等方面进行了阐述。重点剖析:1)超临界态下温度压力条件的改变导致水微观结构与性质的变化,扩散系数、粘度等性质随之改变,进而对水岩反应产生影响;2)富水流体中离子缔合影响着金属配合物数量,很大程度制约流体中矿物的溶解行为;3)低Cl流体中微量元素配分模式与岛弧玄武岩类似,意味着富水贫氯碱性硅酸盐成分的流体在地幔楔元素运移中起关键作用。并展望了俯冲带中流体化学性质研究的新手段。     

氧同位素在海洋磷酸盐研究中的应用

海洋中磷酸盐的氧同位素组成不但记录现代海水磷循环的信息(磷酸盐的来源和生物地球化学作用),还记录古环境的信息。因此,利用氧同位素研究海洋磷酸盐正日益受到国内外研究人员的重视。本文综述了利用磷酸盐氧同位素研究方法及其在现代海洋环境与古海洋的应用进展,展示了中国海洋磷酸盐氧同位素研究现状,提出了今后的研究方向。