海洋碎屑小生境形成演化过程中营养盐特殊迁移过程及脱氢酶活性的变化          下载免费PDF全文

王琰  曹文达 《海洋与湖沼》1993,24(4):360-366

研究了海洋碎屑小生境形成、演化过程中营养盐特殊迁移过程和脱氢酶活性的变化。结果表明,在充氧水体中同时存在硝化和反硝化过程,并有高浓度No(?)富集。脱氢酶活性在实验第4天达到最高值,在第96天和192天出现波动。碎屑聚集体表面不但有微生物群落的演替,而且存在物理化学微环境的连续变化;当碎屑表面O_2被消耗而出现氧化还原电位梯度时,电子最终受体出现更替,非平衡过程发生改变,为适应这种改变,微生物群落重新调节新陈代谢,在分叉点附近,脱氢酶活性增大。  相似文献   

Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp     

Stoner EW  Layman CA  Yeager LA  Hassett HM 《Marine pollution bulletin》2011,62(5):1109-1114

Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study.  相似文献   

Mussel farming as a nutrient reduction measure in the Baltic Sea: consideration of nutrient biogeochemical cycles   总被引：1，自引：0，他引：1  

Stadmark J  Conley DJ 《Marine pollution bulletin》2011,62(7):1385-1388

Nutrient loads from the land to the sea must be reduced to combat coastal eutrophication. It has been suggested that further mitigation efforts are needed in the brackish Baltic Sea to decrease nutrients, especially in eutrophic coastal areas. Mussel farming is a potential measure to remove nutrients directly from the sea. Mussels consume phytoplankton containing nitrogen (N) and phosphorus (P); when the mussels are harvested these nutrients are removed from the aquatic system. However, sedimentation of organic material in faeces and pseudo-faeces below a mussel farm consumes oxygen and can lead to hypoxic or even anoxic sediments causing an increased sediment release of ammonium and phosphate. Moreover, N losses from denitrification can be reduced due to low oxygen and reduced numbers of bioturbating organisms. To reveal if mussel farming is a cost-effective mitigation measure in the Baltic Sea the potential for enhanced sediment nutrient release must be assessed.  相似文献   

大亚湾网箱养殖区生物-化学特性与营养状况的周日变化     

黄洪辉  王寓平 《广东海洋大学学报》2001,21(2):35-43

根据1998年11月对大亚湾大鹏澳网箱养殖区进行的定点24h连续水质监测资料,分析并讨论了该养殖区海水生物-化学各要素的垂直分布和周日变化规律,并用单项指标评价法和改进的营养状态质量指数(NQI)法,参照营养指数(E)对该网箱养殖区海水的营养状况进行了评价和研究.结果表明,各项要素的平均值大都是表层＞中层＞底层;周日变化主要受潮汐运动和海水中生物的节律性生理活动的综合影响;表层海水的富营养化率明显高于中层海水,其各单项指标处于中度一富营养状态,而中层和底层海水则分别处于贫一中度和贫-富营养状态;PO4-P相对较贫乏,为养殖区富营养化的最关键限制因素.  相似文献   

How EU policies could reduce nutrient pollution in European inland and coastal waters     

《Global Environmental Change》2021

Intensive agriculture and densely populated areas represent major sources of nutrient pollution for European inland and coastal waters, altering the aquatic ecosystems and affecting their capacity to provide ecosystem services and support economic activities. Ambitious water policies are in place in the European Union (EU) for protecting and restoring aquatic ecosystems under the Water Framework Directive and the Marine Strategy Framework Directive. This research quantified the current pressures of point and diffuse nitrogen and phosphorus emissions to European fresh and coastal waters (2005–2012), and analysed the effects of three policy scenarios of nutrient reduction: 1) the application of measures currently planned in the Rural Development Programmes and under the Urban Waste Water Treatment Directive (UWWTD); 2) the full implementation of the UWWTD and the absence of derogations in the Nitrates Directive; 3) high reduction of nutrient, using best technologies in wastewaters treatment and optimal fertilisation in agriculture. The results of the study show that for the period 2005–2012, the nitrogen load to European seas was 3.3–4.1 TgN/y and the phosphorus load was 0.26–0.30 TgP/y. Policy measures supporting technological improvements (third scenario) could decrease the nutrient export to the seas up to 14% for nitrogen and 20% for phosphorus, improving the ecological status of rivers and lakes, but widening the nutrient imbalance in coastal ecosystems (i.e. increasing nitrogen availability with respect to phosphorus), affecting eutrophication. Further nutrient reductions could be possible by a combination of measures especially in the agricultural sector. However, without tackling current agricultural production and consumption system, the reduction might not be sufficient for achieving the goals of EU water policy in some regions. The study analysed the expected changes and the source contribution in different European regional seas, and highlights the advantages of addressing the land-sea dynamics, checking the coherence of measures taken under different policies.  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   

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   

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   

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