21 resultados para LEVRERO, MARIO, 1940-2004
Resumo:
三江源区不仅是地处青藏高原的全球气候变化的敏感区,也是我国甚至亚洲最重要河流的上游关键源区。作为提供物质基础的植被净初级生产力(Netprimaryproduction,NPP),是评价生态系统状况的重要指标。该文应用已在碳通量观测塔验证,扩展到区域水平的遥感-过程耦合模型GLOPEM-CEVSA,以空间插值的气象数据和1km分辨率的AVHRR遥感反演的FPAR数据为模型主要输入,模拟并分析了1988~2004年该区NPP时空格局及其控制机制。结果表明,该区植被平均NPP为143.17gC·m–2·a–1,呈自东南向西北逐渐降低的空间格局,其中,以森林NPP最高(267.90gC·m–2·a–1),其次为农田(222.94gC·m–2·a–1)、草地(160.90gC·m–2·a–1)和湿地(161.36gC·m–2·a–1),荒漠最低(36.13gC·m–2·a–1)。其年际变化趋势在空间上呈现出明显的差异,西部地区NPP表现为增加趋势,每10a增加7.8~28.8gC·m–2;而中、东部表现为降低趋势,每10a降低13.1~42.8gC·m–2。根据显著性检验,NPP呈增加趋势(趋势斜率b>0),显著性水平高于99%和95%的区域占研究区总面积的13.43%和20.34%,主要分布在西部地区;NPP呈降低趋势(趋势斜率b<0),显著性水平高于99%和95%的区域占研究区面积的0.75%和3.77%,主要分布在中、东部地区,尤以该区长江和黄河等沿线区分布更为集中,变化显著性也更高。三江源NPP的年际变化趋势的气候驱动力分析表明,整个区域水平上该地区植被生产力受气候变化的主导,西部地区暖湿化趋势,造成了该地区生产力较为明显的、大范围的增加趋势;但东、中部地区则主要受人类活动的影响,特别是长江、黄河等河流沿线,是人类居住活动密集的地区,造成这些地区放牧压力较大、草地退化严重,而该地区暖干化趋势加剧了这一过程。
Resumo:
Data collected from 12 marine monitoring stations in Daya Bay from 1982 to 2004 reveal a substantial change in the ecological environment of this region. The average N/P ratio increased from 1.377 in 1985 to 49.09 in 2004. Algal species changed from 159 species of 46 genera in 1982 to 126 species of 44 genera in 2004. Major zooplankton species went from 46 species in 1983 to 36 species in 2004. The annual mean biomass of benthic animals was recorded at 123.10 gm(2) in 1982 and 126.68 g m(2) in 2004. Mean biomass and species of benthic animals near nuclear power plants ranged froth 317.9 g m(2) in 1991 to 45.24 g m(2) in 2004 and from 250 species in 1991 to 177 species in 2004. A total of 12-19 species of hermatypic corals and 13 species of mangrove plants were observed in Daya Bay from 1984 to 2002. 2008 Elsevier Ltd. All rights reserved.
Resumo:
The source and significance. of two mitrients, nitrogen. and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton, maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d(-1) outside the bay, 0.42 and 0.32 d(-1) inside the bay and 0.98 and 0.62 d(-1) in the harbor respectively. Outside the bay, the remineralized nitrogen (K-r = 24.49) had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus(K-r = 3.49) strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus (K-r = 3.73) was in larger demand by phytoplankton growth. The results demonstrated that the different nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that, nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed.
Resumo:
Eleven species of the caridean family Crangonidae are reported from the material collected by the Philippine PANGLAO 2004 and PANGLAO 2005 expeditions. Although they have been reported from the Philippines before, all the species have their colouration described and illustrated here for the first time.
Resumo:
对青海钩虾的营养价值进行了初步的研究。首先分析三种不同品级的青海钩虾,一般营养成分及氨基酸含量,并同两种鱼粉比较;第二,养鸡试验的结果表明,钩虾组在平均增量和总增重量等方面都优于鱼粉;第三,真鲷Pagrosomusmajor(Temminck&Schlegel)的实验是按照逐次降低钩虾的含量的方法,分为4组。Ⅰ.钩虾:鱼粉=6:4,Ⅱ.钧虾:鱼粉=4:6,Ⅲ.钩虾:鱼粉=2:8,Ⅳ.钩虾:鱼粉=0:10。实验结果显示在其鲷的成活率、体长平均增长率、增重率和饲料系数等方面,含钩虾组较无钩虾(Ⅳ)为佳,而Ⅱ组具有最好的促增重效果和最经济的特点。最后,根据上述分析和实验结果,作者认为青海钩虾是一种可以代替鱼粉的新蛋白源,值得开发利用和推广。
Resumo:
Thus far, grassland ecosystem research has mainly been focused on low-lying grassland areas, whereas research on high-altitude grassland areas, especially on the carbon budget of remote areas like the Qinghai-Tibetan plateau is insufficient. To address this issue, flux of CO2 were measured over an alpine shrubland ecosystem (37 degrees 36'N, 101 degrees 18'E; 325 above sea level [a. s. l.]) on the Qinghai-Tibetan Plateau, China, for 2 years (2003 and 2004) with the eddy covariance method. The vegetation is dominated by formation Potentilla fruticosa L. The soil is Mol-Cryic Cambisols. To interpret the biotic and abiotic factors that modulate CO2 flux over the course of a year we decomposed net ecosystem CO2 exchange (NEE) into its constituent components, and ecosystem respiration (R-eco). Results showed that seasonal trends of annual total biomass and NEE followed closely the change in leaf area index. Integrated NEE were -58.5 and -75.5 g C m(-2), respectively, for the 2003 and 2004 years. Carbon uptake was mainly attributed from June, July, August, and September of the growing season. In July, NEE reached seasonal peaks of similar magnitude (4-5 g C m(-2) day(-1)) each of the 2 years. Also, the integrated night-time NEE reached comparable peak values (1.5-2 g C m(-2) day(-1)) in the 2 years of study. Despite the large difference in time between carbon uptake and release (carbon uptake time < release time), the alpine shrubland was carbon sink. This is probably because the ecosystem respiration at our site was confined significantly by low temperature and small biomass and large day/night temperature difference and usually soil moisture was not limiting factor for carbon uptake. In general, R-eco was an exponential function of soil temperature, but with season-dependent values of Q(10). The temperature-dependent respiration model failed immediately after rain events, when large pulses of R-eco were observed. Thus, for this alpine shrubland in Qinghai-Tibetan plateau, the timing of rain events had more impact than the total amount of precipitation on ecosystem R-eco and NEE.