Nutrient flux in the Rhode River: Tidal transport of microorganisms in brackish marshes     

P. A. Rublee  S. M. Merkel  M. A. Faust 《Estuarine, Coastal and Shelf Science》1983,17(6):669-680

Concentrations of bacteria, chlorophyll a, and several dissolved organic compounds were determined during 11 tidal cycles throughout the year in a high and a low elevation marsh of a brackish tidal estuary. Mean bacterial concentrations were slightly higher in flooding (7·1 × 10⁶ cells ml⁻¹) than in ebbing waters (6·5 × 10⁶ cells ml⁻¹), and there were no differences between marshes. Mean chlorophyll a concentrations were 36·7 μg l⁻¹ in the low marsh and 20·4 μg l⁻¹ in the high marsh. Flux calculations, based on tidal records and measured concentrations, suggested a small net import of bacterial and algal biomass into both marshes. Over the course of individual tidal cycles, concentrations of all parameters were variable and not related to tidal stage. Heterotrophic activity measured by the uptake of ³H-thymidine, was found predominantly in the smallest particle size fractions (< 1·0 μm). Thymidine uptake was correlated with temperature (r = 0·48, P < 0·01), and bacterial productivity was estimated to be 7 to 42 μg Cl⁻¹ day⁻¹.  相似文献   

中国河口地球化学研究的若干进展   总被引：15，自引：0，他引：15  

张经 《海洋与湖沼》1994,25(4):438-445

在过去１０年的河口地球化学研究的基础上，总结了中国一些大的河口体系中的化学要素的行为特点。与世界上的大河流相比，中国河流中具有较高的营养元素和较低的痕量元素浓度。流域盆地的风化作用指数由北向南逐渐增加，这与世界上其它地区十分相似。在河口淡－咸水混合过程中，颗粒态的化学要素多呈稳定态分布模式，这与高的泥沙量，较轻的污染程度和水文动力作用相对较弱有关，并县对生态系统有显著的影响。考虑到化学要素在中国河  相似文献   

光强和营养盐对伪矮海链藻昼夜节律变化的影响

Ⅰ.细胞分裂、叶绿素α及活体荧光特性   总被引：2，自引：0，他引：2       下载免费PDF全文

杨小龙  朱明远 《海洋与湖沼》1993,24(1):87-92

于1989年1月 - 1989年8月采用连续培养和半连续培养方法进行了伪矮海链藻细胞分裂、叶绿素a含量和活体荧光特性与光、营养盐关系的研究。结果表明,细胞分裂、活体荧光、叶绿素a均呈现光照期的增长速率明显高于黑暗期的增长速率的日变化规律,荧光增强比则在光照期开始后或黑暗期结束时出现最高值;光强和营养盐不仅影响各指标日变化的幅度,而且还可改变荧光增强比峰值出现时间。因此,在研究细胞分裂、叶绿素a和荧光特性的昼夜节律时,必须考虑光和营养盐这两个重要因素。  相似文献   

Variations of nutrient elements and its effect on ecological environment off the Changjiang estuarine waters     

Lin Yi''an  Tang Renyou  Pan Jianming  Jin Mingming 《海洋学报(英文版)》2001,20(2):197-207

I~IOXThe water off the Changjiang EstUary is one of the ~ areas Of land-sea interactionwith complex current series and convening water masses, such as the Changjiang River diluting water fm the west, the HUangha As "dxed water frn the north as well as the TaiwanWad Current wedging fm the ~theaSt (Mao et al., 1963). TheSe water masses havePtovided rich nutrients for the gtDwth and rep~tion of planktons, leading to the fonnationOf the fishing ~ Off the Changjiang Estuary with active bio…  相似文献   

Seasonal Cycle of Vertical Structure and Deep Water Renewal in the Clyde Sea     

R. P. Midgley  J. H. Simpson  P. Hyder  T. P. Rippeth 《Estuarine, Coastal and Shelf Science》2001,53(6):813

Two strings of moored current meters deployed between March 1993 and May 1994, together with monthly CTD surveys, provide the first comprehensive set of observations over the seasonal cycle in the Clyde Sea. In the summer, a strong thermal stratification maintained a partial isolation of the deep waters. In winter, the stratification was weaker, and a 1 °C temperature inversion was persistent from November to the end of March. Rapid inflow of dense water from the North Channel of the Irish Sea served to re-establish the strong stratification in the spring. The mean rate of exchange was estimated from the salinity (practical salinity scale) and mass budgets to be 1·1×10⁴ m³ s⁻¹, indicating an average flushing time for the Clyde Sea of 3–4 months.Episodic increases in deep water salinity indicated that bottom water renewal occurred throughout the winter. Intense renewal events were observed in March 1993 and February 1994, when the North Channel density was near its seasonal maximum, and were coincident with periods of high wind stress. In the month prior to these rapid spring inflows, the basin bottom salinity reached its seasonal minimum, indicating that the effects of mixing dominated over renewal at this time. A marked inflow in the summer was inferred from the salinity budget, and observed as a salinity increase at a depth of 90 m. A 2-layer flow was observed in the Arran Deep basin throughout the year, the surface flow forming part of a clockwise circulation about Arran, with an opposing bottom layer circulation. This surface circulation prevents freshwater from entering the Kilbrannan Sound, leaving this area relatively susceptible to deep water mixing by the wind.At a station in the north of the basin, the internal tidal current was observed to have an amplitude of 2–3 cm s⁻¹, which is half the amplitude of the barotropic tide. The energy available to mix the water column mixing associated with the internal tide at this position is estimated to be 0·01 mWm⁻², which is 2 orders of magnitude less than wind mixing. The kinetic energy density in the Clyde Sea was found to be predominantly in low frequency oscillations (<1·0 cycles per day), the seasonal variation exhibiting some correlation with the wind.  相似文献   

旧镇湾海水中营养盐的分布     

林峰  许清辉 《台湾海峡》1991,10(2):170-175

本文利用1988至1989年春、夏、秋、冬4个航次的调查资料,研究了福建省旧镇湾海水中营养盐的含量和分布,讨论了该湾中营养盐的丰度及其与浮游植物盛衰的关系。该湾春、夏季活性磷酸盐含量偏低,并可能成为浮游植物生长的限制因素。  相似文献   

不同种群泥蚶肉营养成分的比较研究   总被引：24，自引：1，他引：24  

张永普  贾守菊  应雪萍 《海洋湖沼通报》2002,(2):33-38

本文对广西北海、浙江乐清湾和山东乳山湾的3个野生种群和2个养殖种群泥蚶肉的营养成分进行了比较研究，结果表明：同一地区野生种群干物质中中的可溶性糖、脂肪和灰分含量高于养殖种群，蛋白质、不饱和脂肪酸。不同野生种群水分含量和干物质中的蛋白质、脂肪、灰分、不饱和脂肪、高度不饱和脂肪酸、氨基酸总量及必需氨基酸的含量以广西野生种群最高，可溶性糖含量以乐清野生种群最高。  相似文献   

胶州湾浮游植物对营养盐添加的响应关系   总被引：12，自引：0，他引：12  

王勇  焦念志 《海洋科学》2002,26(4):8-13

于1998年8月、11月、1999年2月 ,在胶州湾采用现场实验的方法初步研究了浮游植物对营养盐添加的时间响应效果。分级叶绿素a的结果显示 ,网采浮游植物(netphytoplankton ,简称net ,20～200μm)对同时添加氮(N)与磷(P)营养盐有最明显的响应 ;1998年8月微型浮游植物(nanophytoplankton ,简称nano ,2～20μm)对铁(Fe)或N +P的添加有比较明显的响应 ,在1998年11月与1999年2月则几乎无营养盐限制nano 的生长 ;1998年8月与1999年2月超微型浮游植物(picophytoplankton ,简称 pico ,<2μm)对N +P或N的添加有较明显的响应。  相似文献   

Variations in the distributions of Centropages chierchiae and Temora stylifera (Copepoda: Calanoida) in the north-eastern Atlantic Ocean and western European shelf waters     

Lindley  J.A.; Daykin  S. 《ICES Journal of Marine Science》2005,62(5):869-877

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Contrasting trace element geochemistry in two American and French salt marshes     

B. Velde  T. Church  A. Bauer 《Marine Chemistry》2003,83(3-4):131

Trace metals were analyzed in the bulk fine phase of two contrasting salt marsh cores on the North Atlantic east (Baie de l'Aiguillon, LaRochelle, France) and west (Lewes, DE, USA) coasts. The purpose is to gauge how the different clay mineral sources and surface sedimentary diagenetic conditions affect the respective trace element geochemistries. It has been established that there is considerably more clay mineral diagenesis at the zone of redox transition in the Delaware core than in the l'Aiguillon core. The Delaware core shows unweathered glacial sedimentary material directly deposited from the continental shelf whereas the l'Aiguillon core is formed from soil clays deposited after river and estuarine transport. Although there is strong Mn redox depletion in the Delaware salt marsh core, and enrichment in the French one at l'Aiguillon, transition elements seem to follow iron content in both cores. The trace pollutant elements Pb, Sn and Zn show pronounced depth profiles in both North Atlantic cores. The Pb, Sn and Zn appear to be carried by clay sources into the French marshes, while appearing to be largely deposited by atmospheric processes as well into the Delaware marsh.Upon deposition, the Zn appears to become decoupled from lead, which is probably more strongly fixed on clays. The Sn seems to be both air transported, and carried as well on non-clay phases contaminated by industrial organo-tins, including antifouling bottom paints. Copper while uniformly enriched in France, probably from use in regional vineyards, appears enriched only near the top at Delaware, suggesting diagenetic recycling in the more abundant peat in the surface. The Cs and Li appear to be tracers for specific soil-derived clay sources in the French core source materials. These observations suggest that clay is a very important carrier in fixing trace elements for historical records as salt marsh sediments.  相似文献