Diurnal variation of nitric oxide emission flux from a mangrove wetland in Zhangjiang River Estuary,China

The diurnal variation of nitric oxide (NO) emission fluxes from a Kandelia obovata and Avicennia marina mangrove wetland were studied in the Zhangjiang River Estuary Mangrove National Nature Reserve using a dynamic chamber-based technique and a chemiluminescent analyzer. Results from field experiments show that NO emission from K. obovata and A. marina sampling sites reached maximal values of 1.07 ng N m⁻² s⁻¹ and 1.23 ng N m⁻² s⁻¹, respectively after the night tide. Meanwhile NO emission maintained at a steady lower level in daytime for both wetland sites. In laboratory experiments, NO emission from the mangrove wetland soil samples treated with simulated tides in the darkness exhibited higher values than those in the light, therefore it seems that tides and darkness could increase NO emission from mangrove wetlands, while intensive light, high temperature, and dryness in the daytime decreased NO emission. Compared with K. obovata soil samples, the diurnal average NO emission rate of the A. marina site was significantly higher, which was closely related to relatively higher diurnal average CO₂ emission rate, soil available nitrogen content and soil net nitrification rate of the A. marina site. Moreover, soil samples of the A. marina site were more responsive to simulated tides and the addition of nitrogen than those of the K. obovata site.     

长江口及邻近海区营养盐结构与限制

通过研究长江口及邻近海域溶解无机氮(DIN=NO₃-+NO₂-+NH₄+)、磷酸盐(PO₄3-)、硅酸盐(SiO₃2-)所表征的营养盐区域结构特征及影响因素,在分析营养盐绝对限制情况的基础上,划分了潜在相对营养限制区域。结果表明,123°E以西近岸表层区域DIN/P比值全年均高于16,而Si/DIN除秋季外基本小于1,显示出长江冲淡水影响下"过量氮"的特征。春夏季河口锋面区(31°~32.5°N,122.5°~124°E)硅藻的大量生长可使DIN/P异常升高和Si/DIN异常降低。秋季研究区域北部DIN/P西低东高且Si/DIN西高东低是由于在高DIN、低PO₄3-的长江冲淡水影响下,近岸受相对低DIN、高SiO₃2-的苏北沿岸流南下入侵影响而被分割而成。冬季长江口门东北部存在的高DIN/P和低Si/DIN区则主要由于寡营养盐的黑潮水深入陆架,向东北输送的部分长江冲淡水和增强的苏北沿岸流共同作用造成DIN升高所致。利用Redfield比值进行了不同站位表层潜在相对营养限制情况的区分。近岸123°E以西受高DIN、SiO₃2-长江冲淡水影响,四季多呈现PO₄3-潜在相对限制,而在春夏季由于浮游植物的大量吸收PO₄3-,造成局部PO₄3-绝对限制及潜在相对限制。春夏季氮限(DIN潜在相对限制)一般发生在外海部分站位,但较为零散。秋季除了东南外海大部分站位外,受苏北沿岸流影响在长江口北部近岸也存在氮限。随着低DIN/P的黑潮表层水(KSW)的入侵加强,冬季外海氮限站位增多。硅限(SiO₃2-潜在相对限制)在夏季发生在赤潮高发区,而冬季南部存在较多硅限站位表明KSW中SiO₃2-相对较为缺乏。     

联合星载光学和SAR影像的漳江口红树林与互花米草遥感监测

文章以福建省漳江口国家级红树林自然保护区为研究区, 提出了一种联合星载光学和合成孔径雷达(SAR)影像的红树林与互花米草分布的自动提取算法, 提取研究区内红树林和互花米草的空间分布。本研究选择2016年、2017年和2018年各一景低潮时的Sentinel-2 A光学影像数据, 获取植被和其他地物的光谱和纹理信息。算法首先基于归一化植被指数、增强型植被指数、地表水分指数以及数字高程模型的相关规则计算红树林和互花米草的潜在分布区; 通过随机森林分类算法区分红树林和互花米草, 2016年、2017年和2018年影像的分类总体精度和Kappa系数分别为98.53%和0.980、96.52%和0.952、98.71%和0.978, 分类效果良好; 使用当年所有Sentinel-1 A/B的SAR影像获得研究区的常年海水分布范围, 使用与海水交界的判据, 实现红树林、互花米草提取范围的优化。研究表明, 研究区2016年、2017年和2018年红树林总面积分别为56.85hm²、59.88hm²和58.61hm², 互花米草总面积分别为109.23hm²、124.00hm²和142.39hm², 与前人的研究成果在红树林和互花米草的空间分布和面积量级上有较好的一致性。     

Establishment of Avicennia marina mangroves on accreting coastline at Sungai Haji Dorani, Selangor, Malaysia

Avicennia marina saplings were established within a restoration area at Sg. Hj. Dorani, Malaysia between May and August 2010. Sapling establishment was achieved following the construction of segmented and hard breakwater as mitigating measure against coastal erosion. Geostructures known as brush faschines were installed within the restoration area as secondary sediment and seed traps. There was a steady increase in the sand content of the soil from 5% in November 2008 to 18% in May 2010. The dominant soil content was silt but it fluctuated and declined slightly over the same period, between 80% in November 2008 and 72% in May 2010. The accreting shoreline behind the breakwater had stabilised within 18 months. Subsequently, the first batch of A. marina wild seedlings or wildings was established on the mud surface in September 2009. Only about 10% of these wildings survived and showed high survival rate (90%) over the next eight months. Wildings that were naturally established near mother trees showed good growth performance. No wilding was established after the fruiting season in August 2010 as all seeds that were dispersed into the restoration area were washed away by September 2010. Tall, A. marina wild saplings (1 m) planted within the restoration area showed higher survival rate (80%) compared to planted saplings of Rhizophora apiculata (30%). Final planting of a thousand 1 m tall A. marina wild saplings was carried out from June 2010, in clumps of 20 and in 1 m × 1 m spacing. By the end of September 2010 clusters of regenerating A. marina mangroves about 1.5 m tall were successfully established on the accreting coastline.     

瓯江河口盐度层化数值研究

瓯江口是一个径流量变化剧烈的强潮河口。本文基于非结构网格FVCOM模型,建立瓯江口海域大范围三维数学模型,研究不同时间尺度（潮周期、大-小潮）的盐度变化,并利用势能异常动力方程对数值模拟结果分析了瓯江口层化过程的动力机制。同时,利用河口R_i数和层化参数△s/<s>研究了不同时间尺度的层化稳定性及其空间变化,得出决定层化状态的潮差和径流量的阈值。结果显示：瓯江北口上段、中段和口门在潮差分别超过3.8m、4.0m和4.6m时呈完全混合状态。当径流量小于280 m³/s或大于510 m³/s,北口上段持续完全混合;而在口门附近,完全混合和层化的临界径流量约为280 m³/s。研究认为瓯江河口北口存在周期性的层化,北口下段在落潮和涨潮初期呈部分混合状态,而其它时段为完全混合。上段只在落潮初期存在层化。层化增强主要是纵向对流与横向速度剪切导致,而湍混合和纵向潮应力是层化减弱的主要因素。     

长江口及邻近海域营养盐四季分布特征

利用2006年夏、冬季,2007年春、秋季四个航次营养盐调查数据,分析了硝酸盐(NO3)、亚硝酸盐(NO2-)、铵盐(NH4+)、活性磷酸盐(PO43-)和活性硅酸盐(SiO32-)四季大面及典型断面(M1、M4、O6断面)分布特征.结果表明:营养盐大面基本呈西高东低分布趋势,NO3-、PO43-和SiO32-,在长江...     

胶州湾大沽河口小型底栖动物分布的季节变动

Sediment samples were collected in the intertidal zone of the Dagu River Estuary, Jiaozhou Bay, China in April,July and October 2010 and February 2011 for examining seasonal dynamics of meiofaunal distribution and their relationship with environmental variables. A total of ten meiofaunal taxa were identified, including free-living marine nematodes, benthic copepods, polychaetes, oligochaetes, bivalves, ostracods, cnidarians, turbellarians,tardigrades and other animals. Free-living marine nematodes were the most dominant group in both abundance and biomass. The abundances of marine nematodes were higher in winter and spring than those in summer and autumn. Most of the meiofauna distributed in the 0–2 cm sediment layer. The abundance of meiofauna in hightidal zone was lower than those in low-tidal and mid-tidal zones. Results of correlation analysis showed that Chlorophyll a was the most important factor to influence the seasonal dynamics of the abundance, biomass of meiofauna and abundances of nematodes and copepods. CLUSTER analysis divided the meiofaunal assemblages into three groups and BIOENV results indicated that salinity, concentration of organic matter, sediment sorting coefficient and sediment median diameter were the main environmental factors influencing the meiofaunal assemblages.     

福建漳江口红树林保护区浮游植物群落的季节变化研究

于2001年1月～2003年1月对福建省漳江口红树林区水体浮游植物群落的季节变化进行了研究。结果表明,漳江口红树林区浮游植物以硅藻门种类为主,优势种为长菱形藻(Nitzschia longissima)和菱形藻(Nitzschia sp.1)等,同时出现多种裸藻、绿藻和甲藻。本次调查共鉴定到浮游植物31属87种(包括变种),其中硅藻门23属75种(包括变种),蓝藻门3属3种,绿藻门1属4种,金藻门1属1种,甲藻门2属2种,裸藻门1属2种。浮游植物密度变化范围为2.78×104～1.14×106个/L,平均为3.51×105个/L,季节变化为双峰型。出现大量的底栖硅藻和淡水性藻类是该水域浮游植物的一个特点。浮游植物的组成和结构表明该水域水质较好。     

Spatial and temporal distributions of nitrogen, phosphorus and heavy metals in the intertidal sediment of the Chang jiang River Estuary in China

Spatial and temporal distributions of nutrients (N and P) and heavy metals (Cu, Zn, Pb and Cd) in the intertidal sediments at Dongtan wetland of the Changjiang River (Yangtze River) Estuary were examined by laying one transect running seaward to landward during January, April, June, August and October of 2005. Total nitrogen (TN) and heavy metal concentrations in the intertidal sediment showed an increasing trend from open bare °at to the high marsh, with the maximum concentrations in the high marsh and the minimum values in open bare °at. In contrast, sediment total phosphorus (TP) concentrations changed little among sampling sites. One-way ANOVA found that there were signiˉcantly temporal variations of nutrients and heavy metals concentrations in the intertidal sediment (P <0.05). The concentrations of heavy metals generally showed an increasing trend from January to October. As compared with other large estuaries, heavy metal contamination in the intertidal sediment of the Changjiang River Estuary was relatively low.     

我国瓯江口和珠江口凤鲚洄游模式和生境利用研究

Habitat use of the tapertail anchovy(Coilia mystus Linnaeus, 1758) from the Oujiang River Estuary and the Zhujiang(Pearl) River Estuary was studied by examining the environmental signatures of Sr and Ca in otoliths using electron probe microanalysis. Individuals from the Oujiang River had higher and varied Sr:Ca ratios(expressed as(Sr:Ca)×1 000, 3.83–13.0 average) in the otolith core regions, suggesting that they were born in brackish or sea waters, and that a freshwater habitat might not be necessary for egg hatching and larval growth.While, individuals from the Zhujiang River had lower Sr:Ca ratios(0.39–2.51 average) in the core regions,suggesting a freshwater origin. After hatching, anchovies from the Zhujiang River migrate downstream to the river estuary close to brackish water. Our results demonstrated varied habitat use for spawning during stages of early life history between the two populations, and suggested that such variations are promoting diversity of life history strategies of this species.     

长江口营养盐结构特征及其对浮游植物的限制

根据2013年5月、11月两个航次的调查资料,分析了长江口营养盐浓度及其结构的分布变化,并探讨了营养盐对浮游植物的限制情况。长江口营养盐分布存在季节差异:口门外NO3-N、NO2-N浓度均为春季高秋季低,PO34-P、3SiO2-Si、NH4-N浓度则秋季高春季低,口门内除NO2-N外,NO3-N、PO34-P、SiO23-Si、NH4-N浓度均为秋季高于春季。NO3-N、PO34-P、SiO23-Si浓度从近岸向外海逐渐降低,NO2-N、NH4-N浓度分布规律不明显。NO3-N是DIN的主要存在形态,其占DIN的比例为春季95%、秋季83%。春季、秋季DIN/P均高于16,表现出长江口过量的DIN输入,春季Si/DIN基本小于1,秋季Si/DIN大于1。春季由于硅藻的局部生长使DIN/P异常升高、Si/DIN异常降低,秋季西北部海区受苏北沿岸流影响,呈低DIN/P值和高Si/DIN值分布。受含过量DIN、SiO23-Si的长江冲淡水的影响,春、秋季均表现为PO34-P潜在相对限制。春季由于浮游植物的大量吸收,局部出现PO34-P、SiO23-Si的绝对限制。当同时考虑绝对限制和潜在相对限制时,春季15.38%的站位受PO34-P限制,限制情况较上世纪90年代更为突出。     

珠江口滨海湿地退化现状、原因及保护对策

2007年和2008年秋季对珠江口滨海湿地进行了环境现状综合调查,结果表明,珠江口滨海湿地退化主要表现在4个方面:天然湿地面积减少、湿地生产力不断下降、湿地环境状况持续恶化和湿地景观破碎化。珠江口滨海湿地退化的原因主要为滩涂开发与围填海、污染物排放、养殖污染、海平面上升、过度捕捞、海砂开采和港口码头建设以及水土资源开发等因素。滨海湿地保护与利用对策主要有:制定有关滨海湿地保护的法律法规和湿地保护与利用规划;加强人才队伍建设和滨海湿地有关技术研究;建立滨海湿地动态监测体系;加大滨海湿地保护区建设的力度;加强宣传和教育。     

长江口及邻近水域氮、磷的形态特征及分布研究

根据近几年大面调查的监测资料,对长江口及邻近水域氮、磷营养盐的形态组成、时空分布及氮磷比的变动规律及其影响因素进行了分析研究。结果表明,长江口及邻近水域中硝酸盐是水体无机氮存在的主要形态,其约占总无机氮的90%,无机氮含量河口高,向东南方向愈来愈低;从该水域总磷的形态组成来看,磷营养盐主要以溶解态和颗粒态共存的形式存在,TDP略高于TPP,无机磷的平面分布与无机氮十分相似,春季无机磷含量高于夏季;N/P值变动范围大和平均值较高是该水域的主要特征,N/P值与长江径流量的大小有关系,夏季N/P值比春季高,综合分析来看,磷营养盐和光照都有可能成为该水域浮游植物生长的重要限制因子。     

珠江河口的能量传播和能量耗散

建立了包括河网区、河口湾区和近海水域的ECOMSED-3D数学模型,计算了珠江河口的能量传播和能量耗散特征。研究表明:1)珠江河口能量来源受潮汐和径流共同作用,季节性变化明显;2)珠江河口存在若干高能耗区,其单位面积能耗率比上下游河段平均能耗率高1—2个量级,它们和一定的动力结构与地貌单元相联系。根据地貌特征和消能特点,可以划分为以下3种类型:门的高能耗区、曲折河段高能耗区和分汊汇流高能耗区。     

日本大叶藻（Zostera japonica）根状茎和不同发育阶段叶片的热值动态

对广西沿岸海草优势种日本大叶藻（Zostera japonica）根状茎、幼叶、成熟叶和老叶的灰分含量、干质量热值和去灰分热值进行了初步研究。结果表明, （1） 日本大叶藻叶片从幼叶到成熟叶再到老叶的生长发育过程中, 灰分含量升高, 而干质量热值和去灰分热值下降; （2） 日本大叶藻根状茎的灰分含量和去灰分热值大于叶片...     

地形作用下的珠江河口能量平衡

The Zhujiang River(Pearl River) Estuary(ZRE) is a very complicated and large-scale estuarine system in China. It consists of two parts: the river networks and the estuarine bays. Not only is the network system one of the most complicated in the world, but also each estuarine bay has a very special morphodynamic feature due to the geological settings. Morphological boundary conditions have direct effects on the energy dissipation and balance. On the basis of a three-dimensional(3-D) barotropic model whose domain includes the river networks and the estuarine bays, the energy budget is discussed under the influence of topography in the ZRE. The elevation and discharge of this model are validated by the observations collected in July 1999 and February 2001. The results show that(1) the source of energy in the ZRE is mainly generated by tides and river runoffs, which have an obvious seasonal change, and(2) there are some typical hotspots where the energy dissipation is 1–2 orders higher than those in the immediate upstream and downstream sections in the ZRE. These hotspots are linked with the small-scale dynamic structures(SSDS) and morphological units. On the basis of the characteristics of the morphology and the energy dissipation, the hotspots can be categorized into three types: the outlet of the ZRE, the meandering river, the branch and junction.     

长江口不同沉积环境沉积物中碳的分布和来源

利用2004年5月在长江口门区获得的R3、N3、S3和S1四个沉积物柱状样品,对其各种形态碳的含量和垂直分布、TOC/N值以及同位素δ13Corg值进行了分析,并结合该区域的水文悬沙特征,探讨了影响沉积物中碳埋藏的因素及其物质来源,结果表明:长江的径流量和沉积速率是影响长江口碳埋藏的两大重要因素,对各种形态碳在沉积柱中...     

Nitrous oxide concentration and nitrification and denitrification in Zhujiang River Estuary, China

1 Introduction Estuaries have been subject to intense anthro- pogenic influences over recent decades by inputs of ni- trogen as a consequence of fertilizer usage and sewage/waste input (Howarth et al., 1996). Thus, the capacity of an estuary to buffer or alleviate additional nutrients is of importance in modifying the load of ni- trogen in the marine ecosystem. The role of microor- ganisms in regulating fluxes of nitrogen from land to sea through estuaries has received increased attention (Ni…     

2006年秋季长江口及其邻近水域浮游植物群集

根据2006年11月在长江口及其邻近水域(30°30′N～32°30′N,121°E～123°30′E)39个测站采集的浮游植物水样研究了该水域浮游植物群集特征。调查区浮游植物以硅藻和甲藻为主,此外还有少量的金藻、蓝藻和绿藻。浮游植物细胞丰度介于0.13～59.69个/mL之间,平均为4.39个/mL,主要优势物种为圆海链藻Thalassiosira rotula和骨条藻Skeletonema spp.,调查区两个细胞丰度密集区分别出现在靠近口门以及外海水域。浮游植物细胞在20m层出现最大值。调查区两个典型断面的浮游植物分布特征分别由骨条藻和圆海链藻所刻画。固氮蓝藻铁氏束毛藻Trichodesmium thiebautii主要出现在调查区东部水域表层。根据浮游植物物种和细胞丰度进行聚类分析后,发现存在调查区东部与近岸2个浮游植物分区。     

珠江口分粒级叶绿素a和初级生产力研究

珠江是我国第三大江,年径流量仅次于长江,珠江口是我国南方重要的运输通道和沿岸渔场.近20 a来,由于珠江三角洲地区经济的迅速发展,河口区的富营养化和赤潮时有发生[1,2].因此,关于该水域生态系统结构和功能的研究日益受到重视.河口区是陆海相互作用的耦合带和生产力较高的区域,开展对该水域叶绿素a和初级生产力的研究,对于阐明该生态系统的结构和功能及其诸如富营养化和赤潮等环境问题具有重要意义,对于生物资源的开发亦具实际价值.