闽江河口短叶茳芏湿地及其围垦的养虾塘CH4排放通量的比较

以闽江河口鳝鱼滩的短叶茳芏湿地及由其围垦而成的养虾塘为研究对象,2016年5月—2017年3月,分别采用静态箱-气相色谱法和悬浮箱/静态箱-气相色谱法对短叶茳芏湿地和养虾塘白天CH_4排放通量进行观测,并同步测定短叶茳芏湿地和养虾塘水体/沉积物理化指标.观测期间短叶茳芏湿地和养虾塘均表现为大气中CH_4的排放源,释放量变化范围分别为1.09~38.38 mg·m~(-2)·h~(-1)和0.01~65.38 mg·m~(-2)·h~(-1),均值分别为(11.67±1.99)mg·m~(-2)·h~(-1)和(18.69±4.84)mg·m~(-2)·h~(-1),重复测量方差分析统计结果表明:虽然在整个观测时间尺度上,养虾塘CH_4排放通量与短叶茳芏湿地无显著性差异(p0.05),但是在养殖期养虾塘CH_4排放通量显著高于同期短叶茳芏湿地(p0.05),增加了68.0%.短叶茳芏湿地CH_4排放通量与沉积物温度、间隙水总磷含量呈显著正相关关系(p0.01),养虾塘水-气界面CH_4排放通量与养殖水水深呈显著负相关关系(p0.01).亚热带河口感潮沼泽湿地围垦成为陆基养虾塘后增加了CH_4排放通量.     

排水速率对潮汐流人工湿地中CANON作用的强化

为强化潮汐流人工湿地（TFCW）中基于亚硝化的全程自养脱氮（CANON）作用,探究了不同排水速率（v_d）下系统中氮素的迁移转化机制与微生物特征.结果表明,v_d可显著影响TFCW中脱氮功能微生物的数量与活性,进而影响其氮素转化速率.当v_d由1.00降至0.50L/min时,填料层中逐渐形成较为严格的限氧环境,有利于短程硝化的稳定和厌氧氨氧化菌的富集,进而有助于CANON反应体系在TFCW中形成.而当v_d小于0.50L/min时,填料层中溶解氧相对不足,好氧氨氧化菌活性受到抑制,数量随之减少,CANON作用的强化效果有限,系统脱氮性能受到影响.当v_d为0.50L/min时,TFCW中的CANON作用可得到最大限度的强化,系统脱氮性能达到最佳,其TN和NH₄⁺-N的去除负荷分别为（116.79±13.16）和（102.75±4.35） mg/（L·d）.对v_d的合理设置可实现TFCW中CANON作用的强化,有利于CANON型人工湿地的构建.     

氮、硫输入对河口湿地土壤有机碳矿化的实验研究

通过室内培养实验,研究了氮、硫输入对闽江河口湿地土壤有机碳矿化和土壤理化性质的影响.结果表明:NH_4Cl(N1)、NH_4NO_3(N3)、K_2SO_4(S)和NH_4Cl+K_2SO_4(NS1)处理显著促进了湿地土壤有机碳矿化速率(p0.05),较对照分别提高了76.57%、60.09%、83.20%和52.59%,并且不同处理下土壤有机碳矿化速率均表现为随培养时间的增加而递减.氮、硫输入在不同时间对湿地土壤有机碳矿化的影响不尽一致,在前6 d各处理的促进作用最明显.湿地土壤有机碳累积矿化量在不同处理下均表现为随培养时间逐渐增加,其增长速率在培养初始阶段较快,而后逐渐减慢;不同培养时间有机碳累积矿化量在N1、N3、S和NS1处理下与对照处理间均存在显著差异(p0.05).短期培养结束后,N3、NS1处理显著增加了湿地土壤DOC含量(p0.05);N1、N3、NS1和NH_4NO_3+K_2SO_4(NS3)处理均显著增加了土壤NH_4~+-N含量(p0.05);KNO_3(N2)、N3、NS2和NS3处理均显著增加了土壤NO_3~--N含量(p0.05);S、NS1、NS2和NS3处理均显著增加了土壤SO_4~(2-)含量(p0.05).不同处理下湿地土壤Cl-、pH、EC具有微弱的波动变化特征,但在不同处理组间均不存在显著差异(p0.05).多元回归分析显示,DOC、NH_4~+-N和SO_4~(2-)是氮、硫输入处理下影响闽江河口湿地土壤有机碳矿化速率的主要控制因素.     

Predictors of specialist avifaunal decline in coastal marshes

Coastal marshes are one of the world's most productive ecosystems. Consequently, they have been heavily used by humans for centuries, resulting in ecosystem loss. Direct human modifications such as road crossings and ditches and climatic stressors such as sea‐level rise and extreme storm events have the potential to further degrade the quantity and quality of marsh along coastlines. We used an 18‐year marsh‐bird database to generate population trends for 5 avian species (Rallus crepitans, Tringa semipalmata semipalmata, Ammodramus nelsonii subvirgatus, Ammodramus caudacutus, and Ammodramus maritimus) that breed almost exclusively in tidal marshes, and are potentially vulnerable to marsh degradation and loss as a result of anthropogenic change. We generated community and species trends across 3 spatial scales and explored possible drivers of the changes we observed, including marsh ditching, tidal restriction through road crossings, local rates of sea‐level rise, and potential for extreme flooding events. The specialist community showed negative trends in tidally restricted marshes (?2.4% annually from 1998 to 2012) but was stable in unrestricted marshes across the same period. At the species level, we found negative population trends in 3 of the 5 specialist species, ranging from ?4.2% to 9.0% annually. We suggest that tidal restriction may accelerate degradation of tidal marsh resilience to sea‐level rise by limiting sediment supply necessary for marsh accretion, resulting in specialist habitat loss in tidally restricted marshes. Based on our findings, we predict a collapse of the global population of Saltmarsh Sparrows (A. caudacutus) within the next 50 years and suggest that immediate conservation action is needed to prevent extinction of this species. We also suggest mitigation actions to restore sediment supply to coastal marshes to help sustain this ecosystem into the future.     

温州沿海互花米草变迁及其与滩涂开发响应

利用TM数据比较了1993年、2000年和2003年温州沿海互花米草的面积变化,以灵昆岛为例,研究了互花米草引种、繁殖和扩散的特征,并且利用样地和样线对比互花米草与滩涂发育、围垦造陆、海水池塘养殖的相互响应关系.结果显示,温州滩涂互花米草1993～2003年间总面积增加231.99 hm2;互花米草在温州没有形成成熟种子,自然繁殖以根茎为主;在灵昆岛淤长型滩涂上,1993～2003期间互花米草与围垦海堤和海水养殖池塘呈现正响应关系,滩涂淤长速率远大于互花米草,为后者在潮间带中下部扩散提供条件.互花米草对滩涂潮上带的促淤作用明显,因而有利于海水池塘养殖规模扩大,也有利于围海造陆工程.     

A LOOK AT THE HUDSON RIVER ESTUARY1

This paper provides background information on the effect of tide waves upon the movement of water in the Hudson River estuary. Computations based on records from three continuous stage recorders and current-meter discharge measurements made throughout a tidal cycle show that peak discharge rates in the estuary at Poughkeep-sie may be as great as 500,000 cubic feet per second and that total daily tidal volumes as great as 20 billion cubic feet move in the estuary. Computation of water movement in the estuary requires precise field data and continued efforts are needed to perfect the data-collection system and the computation procedure in order to adequately define water movement in the Hudson estuary.     

用三性法对巴楚伽师6.8级地震的跨越式预测

介绍了用三性法对2003年2月24日新疆巴楚伽师6．8级地震的早期跨越式预测，并讨论了某些相关问题。所谓三性法就是大震时序上的周期性、倍周期性和黄金分割性的排列。     

MODIFICATION OF NEILL'S EQUATION FOR STORM‐TIDE DESIGN FLOW ANALYSIS1

ABSTRACT: Design of bridges spanning tidal estuaries or bays requires an estimate of peak tidal flow. One common approach to estimating these flows (Neill's method) uses a first‐order approximation of uniform water surface rise in the water body. For larger water bodies, the assumptions of this method are decreasingly valid. This study develops a simple modification that accounts for the spatial variability in the response of tidal waterways to storm surge flows. The peak tidal flow predicted by Neill's equation is compared to the peak flow determined by numerical simulation of estuaries with simple geometries, ranging from 1 to 25 km in length, using the U.S. Army Corps of Engineers one‐dimensional unsteady flow model, UNET. Results indicate that, under certain conditions, it may be appropriate to apply a correction factor to the peak discharge and peak velocity predicted by Neill's method. An algorithm, developed by nonlinear regression, is presented for computing correction factors based on estuary length, shape, mean depth, and storm‐tide characteristics. The results should permit the design of more reliable, cost‐effective structures by providing more realistic estimates of the potential for bridge scour in tidal waterways, especially when a full solution of the unsteady flow equations is impractical.     

潮滩沉积物重金属生物地球化学研究进展

潮滩是一个物理、化学以及生物条件复杂多变的场所,重金属在这个特殊的环境中有着独特的地球化学行为及其生物有效性.笔者意在对该领域的研究成果进行阐述,并指出该领域中研究比较薄弱的环节以及将来的发展方向,以期推动该领域的进一步研究.      

环境因子对长江口潮滩沉积物中NH+4的释放影响

以长江口潮滩沉积物湿样进行模拟实验,研究盐度、pH和温度等环境因子对沉积物中NH₄+释放的影响.结果表明,随着盐度和温度的上升,沉积物中NH₄+释放量都显著增加;由于潮滩沉积物缓冲性能较好,pH的影响不太明显.此外,NH₄+的释放与沉积物类型有关,沙性物质含量高的低潮滩沉积物NH₄+的释放量明显低于沙性物质低的高、中潮滩沉积物.