A comparative study of nutrient transfer via surface runoff from two small agricultural catchments in north China   总被引：1，自引：0，他引：1  

Haiming Lu  Chengqing Yin  Weidong Wang  Baoqing Shan 《Environmental Geology》2007,52(8):1549-1558

A field study was conducted to determine the effect of landscape spatial pattern and micro-topography on nutrient transfer via runoff from two catchments into Yuqiao Reservoir in north China. The surface runoff discharge was measured during rainfall events and water samples were analyzed in 2004 and 2005. The mean annual total nitrogen (TN) and total phosphorus (TP) exports per unit area from Caogezhuang catchment (C catchment) were 1.048 and 0.561 kg ha⁻¹ year⁻¹, respectively, while the TN and TP exports from Taohuasi catchment (T catchment) were 0.158 and 0.027 kg ha⁻¹ year⁻¹. In both catchments, village and vineyard shared the highest nutrient export ability due to the accumulated animal waste and heavy application of fertilizer and manure. In T catchment, the distance of village and vineyard was about 1,500 m away from the receiving water and in between were woodland and cropland. In the hydrological pathway, there were sink landscape structures of small stone dams, roadside swale, vegetated filter strip and dry ponds, which could detain water and nutrients. In C catchment, the distance between the village and the receiving water was about 200 m, and the hydrological pathway was compacted roads and ditches with no sink structures. It is suggested that the distance between the pollution source area and the receiving water and the micro-topographical features were the main factors to control the great difference in nutrient export rates.  相似文献   

植物营养元素的含量和δ~(13)C值随海拔而变化的特征及营养元素相互作用对碳同位素分馏作用的影响   总被引：7，自引：0，他引：7  

朴河春  朱建明  朱书法  余登利  冉景丞 《地球科学进展》2004,(Z1)

为了研究植物营养元素的含量和δ~(13)C值随海拔而变化的相关关系,沿着海拔450 m的贵州茂兰至海拔1330 m的贵州安顺一线,采集和分析研究了C_3植物——小果蔷薇(R.cymosa Tratt)的叶片。分析结果表明,植物叶片中营养元素含量随着海拔的上升而产生的变化是:氮、磷和钾的含量会在增高,而钙和镁的含量却会降低。植物叶片的δ~(13)C值会增大,其变幅为 2.4‰/1000m。  相似文献   

Estuarine phytoplankton group-specific responses to sublethal concentrations of the agricultural herbicide,atrazine     

Pinckney JL  Ornólfsdóttir EB  Lumsden SE 《Marine pollution bulletin》2002,44(10):1109-1116

Atrazine is a common agricultural herbicide that is readily transported into estuaries through surface water runoff. In this study, we determined the short-term (24-48 h) sublethal effects of atrazine on estuarine phytoplankton biomass and community composition. Phytoplankton group-specific responses to atrazine exposure (25 microgh(-1)) were measured using natural water samples collected from two locations in Galveston Bay, Texas. Addition bioassays, coupled with HPLC pigment analysis, were used to quantify changes in the relative abundances of algal groups. For all algal groups except prasinophytes, the addition of atrazine in combination with nitrate was not significantly different from nitrate additions alone. These results suggest no significant negative effect of atrazine on phytoplankton under the specified environmental conditions for the bioassays. Although low concentrations of atrazine may have minimal impacts on phytoplankton, herbicide loadings need to be further characterized before generalizations can be applied to estuarine and coastal ecosystems.  相似文献   

Ecology and functional roles of biological soil crusts in semi-arid ecosystems of Spain   总被引：1，自引：0，他引：1  

F.T. Maestre  M.A. Bowker  Y. Cantón  A.P. Castillo-Monroy  J. Cortina  C. Escolar  A. Escudero  R. Lázaro  I. Martínez 《Journal of Arid Environments》2011,75(12):1282-1291

Biological soil crusts (BSCs), composed of lichens, cyanobacteria, mosses, liverworts and microorganisms, are key biotic components of arid and semi-arid ecosystems worldwide. Despite they are widespread in Spain, these organisms have been historically understudied in this country. This trend is beginning to change as a recent wave of research has been identifying BSCs as a model ecological system. Many studies and research projects carried out in Spain have explored the role of BSCs on water, carbon and nitrogen fluxes, the interactions between BSCs and vascular plants, their dynamics after disturbances, and their response to global change, among other topics. In this article we review the growing body of research on BSCs available from semi-arid areas of Spain, highlighting its importance for increasing our knowledge on this group of organisms. We also discuss how it is breaking new ground in emerging research areas on the ecology of BSCs, and how it can be use to guide management and restoration efforts. Finally, we provide directions for future research on the ecology of BSCs in Spain and abroad.  相似文献   

Variation of phytoplankton biomass and primary production in Daya Bay during spring and summer   总被引：11，自引：0，他引：11  

Song X  Huang L  Zhang J  Huang X  Zhang J  Yin J  Tan Y  Liu S 《Marine pollution bulletin》2004,49(11-12):1036-1044

Environmental factors, phytoplankton biomass (Chl a) and primary production of two water areas in Daya Bay (Dapeng'ao Bay and Aotou Bay) were investigated during the transition period from spring to summer. Chl a ranged from 3.20 to 13.62 and 13.43 to 26.49 mg m(-3) in Dapeng'ao Bay and Aotou Bay respectively, if data obtained during red tides are excluded. Primary production varied between 239.7 and 1001.4 mg Cm(-2) d(-1) in Dapeng'ao Bay. The regional distribution of Chl a and primary production were mostly consistent from spring to summer in both bays. Seasonal transition characters have been found in Daya Bay from spring to summer, including high values of DO, nitrate and silicate. Size structures of phytoplankton and its primary production do not change very much from spring to summer, with micro-phytoplankton dominating and contributing about 50% of the whole. In Daya Bay, phytoplankton is limited by nitrogen in spring, and by phosphate in summer. Artificial impacts are evident from high temperature effluent from nuclear power stations, aquaculture and sewage. During the investigation, a red tide occurred in Aotou Bay, with a maximum Chl a of 103.23 mgm(-3) at surface and primary production of 2721.9 mg Cm(-2) d(-1) in the red tide center. Raised water temperature and nutrient supply from land-sources help to stimulate annual red tides.  相似文献   

Internal-wave-induced and double-diffusive nutrient fluxes to the nutrient-consuming surface layer in the oligotrophic subtropical North Atlantic     

Heiner?DietzeEmail author  Andreas?Oschlies  Paul?K?hler 《Ocean Dynamics》2004,54(1):1-7

In the literature, an inconsistency exists between estimates of biotically-effected carbon export inferred from large-scale geochemical studies (Jenkins 1982; 47 gC m^–2 a^–1) and local measurements of turbulent nutrient supply (Lewis et al. 1986; 4 gC m^–2 a^–1) in the eastern subtropical North Atlantic. Nutrient supply to the upper ocean by turbulent mixing is reexamined using local standard oceanographic measurements and high-resolution vertical profiles of nutrients averaged over a large region directly comparable to that investigated by Jenkins (1982).Responsible Editor: Franciscus Colijn  相似文献   

波纹巴非蛤肉的食品化学特性及其在鱼糜制品中的应用   总被引：5，自引：0，他引：5  

章超桦  洪鹏志  雷晓凌 《广东海洋大学学报》2000,20(1)

对波纹巴非蛤肉进行的食品化学特性研究表明 :其贝肉的粗蛋白含量为 70 .6 % (干基 ) ;蛋白质营养价高 ,氨基酸价为 85(第 1限制氨基酸为 Trp) ,并富含 Glu(10 0 g样品中 2 .2 g;以下单位同 )、Asp(1.4 7g)等呈味氨基酸及提取物成分 ,Ca、Fe等无机质含量丰富。波纹巴非蛤肉以 30 %的比例添加到蛇鲻鱼糜中 ,可制得具有贝类风味 ,色泽、弹性良好的“花甲螺丸”  相似文献   

红海湾水域营养水平的时空变化特点与评价     

蔡文贵  贾晓平  林钦  李纯厚 《广东海洋大学学报》2001,21(3):19-23

根据1997年8月～1998年11月的调查数据,本文分析和评价了红海湾4个不同水域营养水平的时空分布特点.红海湾水域E值的空间分布从北向南呈逐渐递减的趋势,即长沙湾滩涂养殖区＞长沙湾浅海养殖区＞自然水域、龟龄岛水域,其中长沙湾滩涂养殖区和长沙湾浅海养殖区有机污染十分明显,达高富营养化程度和富营养化程度,自然水域和龟龄岛水域则营养状况相似,基本上未受到明显的有机污染.E值的季节变化趋势为春季＞秋季＞夏季＞冬季,除冬季处于贫营养状况外,其余3个季节均达富营养化程度,其中以春季有机污染最为严重,达高富营养化程度.  相似文献   

长江口几种优势桡足类对微型浮游动物的摄食研究     

汤宏俊  孙松 《海洋与湖沼》2015,46(1):148-156

利用现场海水培养实验,结合浮游动物网样数据,研究长江口邻近海域几种优势桡足类(中华哲水蚤、背针胸刺水蚤、太平洋纺锤水蚤和精致真刺水蚤)对微型浮游动物的摄食影响。结果表明,精致真刺水蚤虽然属于肉食性种类,但几乎不摄食微型浮游动物;其余三种杂食性桡足类中华哲水蚤、背针胸刺水蚤和太平洋纺锤水蚤对微型浮游动物(纤毛虫+异养甲藻)的摄食率分别为0.66、0.09和0.59μg C/(ind·d),分别占其日总摄食量的29%、24%和37%。其中,异养甲藻在初始生物量和对桡足类饵料贡献上分别占整个微型浮游动物的30%和28%,是微型浮游动物中一个重要的组成类群。中华哲水蚤对微型浮游动物的摄食率与初始食物浓度有显著的正相关关系,并且对体长20μm纤毛虫的清滤率要明显高于对体长20μm的纤毛虫(P0.01)的清滤率,表明其偏好摄食较大个体的食物。通过Chesson选择性指数显示,尽管微型浮游动物在生物量上远小于浮游植物,但桡足类能优先选择摄食微型浮游动物;进一步结合网采浮游动物数据,获得各站三种优势桡足类丰度平均占桡足类总丰度的77%,但它们对微型浮游动物现存生物量的摄食压力仅为0.8%,表明桡足类对微型浮游动物群落的下行控制作用并不明显,仍有大部分微型浮游动物生物量未通过摄食途径进入到桡足类群落中。  相似文献   

南黄海营养盐的平面分布及横向输运   总被引：12，自引：3，他引：12  

王保栋  王桂云  郑昌洙  梁东范 《海洋学报》1999,21(6):124-129

黄海对我国是颇为重要的陆架海区,也是世界上最典型的半封闭性陆架浅海之一。它和所有陆架海区一样,是人类活动、经济开发最为集中的地带,也是陆地、海洋、大气各种过程相互作用较为激烈的地带。  相似文献