辽河口邻近海域小型底栖生物的空间分布及季节变化

本文研究了辽河口邻近海域2013年8月、10月和2014年5月3个航次小型底栖生物的种类及其空间分布,分析了小型底栖生物丰度和生物量的季节变化。结果表明,3个航次（夏季、秋季和春季）小型底栖生物的平均丰度分别为（264±83） ind/（10 cm2）、（216±85） ind/（10 cm2）和（227±67） ind/（10 cm2）,平均生物量分别为（272±125）μg/（10 cm2）、（207±89）μg/（10 cm2）和（244±103）μg/（10 cm2）。与其他研究海域相比,辽河口小型底栖的丰度和生物量处于较低水平。共鉴定出了14个小型生物类群,按照丰度排序,线虫是最优势的类群,夏季、秋季和春季3个航次占总丰度的比例分别为94.0%、92.5%和90.8%;其他优势类群为多毛类、桡足类和双壳类。小型底栖生物量的优势类群则为多毛类（41.1%~44.0%）,高于线虫（33.8%~36.5%）,其次是双壳类（2.6%~6.7%）。水平分布的研究表明,调查海域近岸入海口小型底栖生物的丰度和生物量普遍低于近海海域,但是秋季时近岸分布与近海差距不大。垂直分布的研究表明,95.9%的小型底栖生物分布于0~5 cm的表层沉积物中。小型底栖生物的丰度和生物量在夏季时都达到高峰值。与环境因子的相关分析表明,小型底栖生物的数量分布与盐度和水深呈极显著正相关（P<0.01）,与叶绿素a呈显著正相关（P<0.05）。     

基于二次散射的水污染遥感模型及其在珠江口水域的应用

根据水中悬浮物、污染物和水分子等的散射和吸收物理机制建模是实现水污染定量遥感的有效途径.基于一次散射的水污染遥感模型简单易行,但在浑浊度较大时其精度不高.在基于一次散射模型的基础上分析了多次散射的能量组成特点,提出再考虑二次散射可使模型的精度显著提高且不至于使模型过于复杂;导出了二次散射的补偿因子,同时给出了考虑二次散射因子的简单计算方法.将该模型应用于珠江口水域的水污染遥感的结果表明,较之基于一次散射的模型,考虑二次散射的水污染遥感模型在精度上有明显改进.遥感提取结果显示,珠江口水域重污染区主要分布在伶仃洋东北部,香港维多利亚港和深圳湾.     

Assessment of spatial variation in carbon utilization by benthic and pelagic invertebrates in a temperate South African estuary using stable isotope signatures

Stable isotope analyses (δ¹³C and δ¹⁵N) were used to evaluate the spatial variations in carbon flow from primary producers to consumers at two sites in the temperate and permanently open Kariega Estuary on the southeastern coast of South Africa during October 2005 and February 2006. One site was located opposite a salt marsh while the second was upstream of the marsh. Except for significantly enriched δ¹³C values of Zostera capensis and surface sediments near the salt marsh, the δ¹³C and δ¹⁵N signatures of the producers were similar between sites. The invertebrates were clustered into groups roughly corresponding to the predominant feeding modes. The suspension feeders showed δ¹³C values closest to the seston, whereas the deposit feeders, detritivores and scavengers/predators had more enriched δ¹³C values reflecting primary carbon sources that were likely a combination of seston, Spartina maritima and Z. capensis at the upstream site, with an increased influence of benthic algae and Z. capensis at the salt marsh site. The δ¹⁵N signatures of the consumers showed a stepwise continuum rather than distinct levels of fractionation, indicating highly complex trophic linkages and significant dietary overlap among the species. Consumers exhibited significantly enriched δ¹³C values at the salt marsh site, an effect that was attributed to enriched Z. capensis detritus in this region in addition to increased phytoplankton biomass in their diets compared with invertebrates living upstream. The data reinforce the concept that between-site variations in the stable isotope ratios of consumers can result not only from dietary shifts, but also from alterations in the isotope ratios of primary producers.     

基于潮汐动态淹没过程的长江口潮滩地形信息反演研究

潮滩是陆地与海洋之间重要的生态过渡地带,具有复杂的生态过程和重要的服务功能。受陆海交互作用及人类活动的影响,潮滩处于高度动态变化过程中,而传统测绘技术受到潮滩可达性影响无法快速获取潮滩地形信息。为解决潮滩高程数据获取困难的问题,本文提出一种基于潮汐动态淹没过程和时序遥感影像的潮滩地形信息提取算法,利用K-means++聚类方法实现水域提取,并通过时序淹没特征计算潮滩淹没频率提取潮滩范围信息,最终综合区域潮汐特征反演潮滩地形。研究以崇明东滩为例,利用2016—2020年所有可用Sentinel-2和Landsat-8时序遥感影像,实现潮滩范围提取与高程反演,并通过实测高程数据进行精度验证。研究结果表明,潮滩范围提取总体精度为97.73%,F1_score为0.98;高程反演平均绝对误差为0.15 m,潮滩高程的反演精度与可用影像的数量呈正相关。研究利用该算法进一步反演长江口地区主要潮滩地形特征,结果表明区域内潮滩面积为346.93 km²,高程范围为1.00~3.84 m,且与现有潮滩范围数据集相比,本研究提取的长江口潮滩范围更为完整。该算法为潮滩地形的快速反演提供了可能,对潮滩资源动态监测和管理具有重要意义。     

Anoxic nitrification: Evidence from Humber Estuary sediments (UK)

Conventional understanding of the nitrogen cycle in marine sediments has changed in recent years with the discovery of an alternative pathway for ammonia oxidation via the reduction of manganese oxides (during anoxic nitrification). In anoxic sediments, the potential for manganese oxides to serve as oxidant for nitrification may be considerable yet previous work on manganese-rich sediments has suggested anoxic nitrification may not be significant. In this study, the potential for anoxic nitrification in a range of sediment types was investigated. Laboratory incubation of sediment from three sites on the Humber Estuary, a microbially diverse environment, showed anoxic accumulation of nitrate, nitrite and dinitrogen gas, with and without the addition of synthetic manganese oxides. Incubation experiments confirmed anoxic nitrification as microbially mediated, with heat-killed controls yielding negative results. The anoxic nitrification reaction significantly depleted ammonia concentrations, and occurred simultaneously with manganese-, iron- and sulphate reduction, and methanogenesis. Taken in conjunction with other studies, results suggest anoxic nitrification may not only be dependent on total manganese concentrations but on manganese dynamics. Anoxic nitrification may be explained as a non-steady state reaction, dependent on the recent stability of a sediment system. Physical perturbation of sediments may cause the redistribution and/or introduction of manganese oxides and promote anoxic nitrification. The significance and persistence of anoxic nitrification is likely to depend on the frequency and magnitude of sediment perturbation, which explains why the reaction varies so widely across studied sites, and why it may not occur in some manganese-rich sediment.     

A comparison of the early diagenetic environment in intertidal sands and muds of the Manukau Harbour,New Zealand

The early diagenetic environment of intertidal sandy sediments (sands) and muddy sediments (muds) is described and compared from two cores taken from an unpolluted part of the Manukau Harbour, New Zealand. Extraction techniques characterized the form of the trace elements (Fe, Mn, S, C, Pb, Zn, Cu) at different depths in the sediment. Dissolved forms of Fe, Mn, and S were measured in interstitial water. Nonresidual metal concentrations, humic acid, FeS, and FeS₂ are an order of magnitude higher in the muds than in the sands because of dilution by unreactive sand particles. Muds contain a larger proportion of metals in the mobile fractions; exchangeable (Mn), carbonate (Mn, Fe, Zn), and easily-reducible oxide (Fe, Mn, Zn, Pb). This is due to greater surface area (for Mn adsorption); the favorable conditions for MnCO₃, FeCO₃, and FeS precipitation; and higher concentrations of easily reducible iron oxide and humic acid. Therefore, compared to the sands, muds are more important as reservoirs for toxic metals, both in terms of quantity and availability. At either site there was very little difference between the forms of Zn, Pb or Cu identified by sequential extraction as sediments changed from oxic to anoxic conditions. One reason for this is that the amounts and proportions of some of the important components that bind metals, viz., amorphous iron hydrous oxides, humic acids, and FeS₂, do not change much. Other components that do change with redox conditions, for example, manganese phases and FeS, are only minor components of the sediment. Redox conditions, then, have relatively little effect on trace-metal partitioning in the sediment matrix of these unpolluted sediments.     

十到百年尺度动力形态模型在珠江磨刀门河口的应用

在人类活动的参与下磨刀门河口演变已不再是纯粹的自然过程,而是自然和人类活动共同塑造的过程。建立了一个以过程模拟为主的10~100 a尺度的长周期动力形态模型(PRD-LTMM-10)用于模拟磨刀门河口在人类活动作用下的演变过程。 该模型建立在水体运动方程和沉积物输运方程的基础上,应用约简技术对模型输入和计算进行处理,并包含了用于评价和量化人类活动的抛石促淤模块和航道疏浚模块。应用该模型较真实地模拟了磨刀门河口在1977-1988 年的动力地形演变过程,并且通过模拟结果和情景分析,合理地分离了人类各种工程活动的长期影响和自然因素在河口演变中的作用。研究表明,治理工程对河口自然发展趋势造成了较大的改造,淤积强度表现为西侧大于东侧。抛石和围垦工程使横洲水道主槽逐年冲刷,深槽外移,而龙屎窟深槽上端则表现为严重淤积,深槽不断缩窄。     

水动力条件差异导致潮坪分形特征变化实例研究

研究区位于1964～1976年黄河由刁口流路入海时形成的三角洲潮坪.为进行石油开采在潮坪上构筑的交通设施对波浪形成了良好的屏障,水动力条件具有显著差异的屏障两侧潮坪是研究潮坪特征对水动力条件响应的天然实验场所.在屏障两侧各选择一典型区,实测地貌形态,取样品进行粒度成分分析,根据实测资料分析确定潮坪分形特征.发现水动力环境的强弱决定着潮坪的形貌、沉积物粒度分维值的变化规律.水动力环境强的一侧潮坪滩面分维值高,且随着初始计算网格宽度增大迅速降维;表层沉积物粒度分维值小,且离散性大.相反,在另一侧潮坪滩面分维值低,且随着初始计算网格宽度增大分维值无显著变化;表层沉积物粒度分维值高,且具有较好的一致性.当初始计算网格宽度增大到某个值时,两侧潮坪形貌分维值渐趋一致.在屏障两侧各沿一条与屏障大角度相交的测线取样,并各选择一点采取不同深度的样品做分析计算,发现在水动力条件弱的一侧,样品的粒度分维值表现为远离屏障逐步降维、随深度增加分维值增大的规律;相反一侧粒度分维值变化的规律性很不明显.讨论了水动力环境对潮坪分形特征影响机理.     

Distribution of ammonia-oxidizing Betaproteobacteria community in surface sediment off the Changjiang River Estuary in summer

The spatial distribution of ammonia-oxidizing Betaproteobacteria ( β AOB) was investigated by FISH (fluorescence in situ hybridization) and DGGE (denaturing gradient gel electrophoresis) techniques in the sediment off the Changjiang River Estuary.Sediment samples were collected from eight stations in June before the formation of hypoxia zone in 2006.The abundance of β AOB ranged from 1.87 × 10 5 to 3.53 × 10 5 cells/g of sediment.β AOB abundance did not present a negative correlation with salinity,whereas salinity was implicated as the primary factor affecting nitrification rates.The DGGE profiles of PCR-amplified amo A gene fragments revealed that the β AOB community structure of sample S2 separated from other samples at the level of 40% similarity.The variations in composition of β AOB were significantly correlated with the salinity,temperature,absorption ability of sediments and TOC. The statistical analysis indicates that the β AOB abundance was a main factor to influence nitrification rates with an influence ratio of 87.7% at the level of 40% biodiversity similarity.Considering the good correlation between β AOB abundance and nitrification estimates,the abundance and diversity of β AOB community could be expected as an indirect index of nitrification activity at the study sea area in summer.     

基于生态化人工海岸建设的理论研究与应用 ——以天津永定新河口综合整治修复工程为例

分析生态文明背景下围填海区域人工海岸建设存在的问题,结合淤泥质人工海岸空间特点,总结提出了生态岸线整治修复技术、仿自然化处理设计、景观构建适宜性、人工海岸生态系统等生态化建设基础理论,并以天津永定新河口综合整治修复工程为例,重点阐述了人工海岸生态化建设过程中生态系统和景观构建的方法要点和具体思路.结果表明:在人工海岸生...