Environmental influence on phytoplankton production during summer on the KwaZulu-Natal shelf of the Agulhas ecosystem     

T Lamont  RG Barlow 《African Journal of Marine Science》2015,37(4):485-501

During February 2010, studies of primary production (PP) and physiology were conducted at five selected sites in the KwaZulu-Natal (KZN) Bight of the Agulhas ecosystem as part of a programme to elucidate the influence of major physical driving forces and nutrient inputs on the structure and functioning of biological communities. These sites were located in the vicinity of the Durban lee eddy, in the midshelf region of the central part of the bight, off the Thukela Mouth, and to the north and south of Richards Bay. At four of the sites, chlorophyll a ranged from 0.10 to 1.44?mg m–3 and integrated PP ranged between 0.35 and 2.58?g C m–² d–1. The highest biomass and PP, which were comparable to those observed in a wind-driven upwelling system, were associated with a diatom community observed at the midshelf site, and varied between 0.26 and 4.27?mg m–³ and 7.22 and 9.89?g C m–² d–1, respectively. Environmental conditions at each of the sites differed substantially and appeared to be influential in initiating and controlling the development and distribution of phytoplankton biomass and production. Phytoplankton adaptation to variable environmental conditions was characterised by a decreased light-limited slope (αB) and increased rate of photosynthesis (P_m ) and light saturation (Ek) with elevated temperatures. The converse (increased α^B and decreased P_m and Ek) was observed as irradiance levels declined. Generalised additive models indicated that irradiance, temperature and biomass were important variables influencing photosynthetic parameters and photosynthetic rates.  相似文献   

硅铝络合两性离子聚合物强抑制防塌钻井液体系在查干花地区的研究及应用          下载免费PDF全文

潘振杰 《探矿工程》2010,37(1):24-26,39

针对查干花地区不同地层存在缩径、掉块和垮塌等井壁稳定问题,研制了一种硅铝络合两性离子聚合物强抑制防塌钻井液体系。结合室内水敏性、配伍性、滚动回收率实验,对该体系中的AOS-1（硅铝络合抑制防塌剂）的作用进行室内实验研究,并在查干花地区6口井进行了现场的应用。试验结果表明,新型强抑制性钻井液体系与其他处理剂配伍性好,抑制性强,能有效防止井壁失稳。  相似文献   

新型水基钻井液成膜处理剂的研制与应用          下载免费PDF全文

李浩  陈礼仪  陈尔志  吴林 《探矿工程》2010,37(4):20-22,26

从深孔金刚石绳索取心钻探工艺对钻井液性能的要求出发,运用成膜理论和技术,开发了一种新型水基钻井液成膜处理剂。现场实践证明了这种水基钻井液成膜处理剂对强水敏性地层具有较强的抑制能力和良好的护壁效果。介绍了水基钻井液的成膜作用机理,以及X-1水基成膜剂的研制和工程应用情况。  相似文献   

长度计量仪器测距指标处理系统的开发运用     

汤清伟 《测绘科学》2002,27(2):46-48

测绘行业近几年发生了巨大的变化 ,传统的测量方法大多被数字化手段所代替 ,然而部分测绘仪检部门在处理测距仪器检定数据时有的采用自行编制的功能不甚完备的程序进行计算。针对这种情况 ,作者开发了长度计量仪器测距指标处理系统 (KRA) ,该系统能较为全面地满足光电测量仪器检测数据的后期处理。本文就该系统的开发和运用作了详细阐述。  相似文献   

含水率和添加剂对膨润土导热性能影响的研究     

朱国平  刘晓东  罗太安 《华东地质学院学报》2007,30(1):60-63

膨润土的热学性能是评价膨润土作为高放废物深地质处置库缓冲/回填材料的重要参数。高庙子膨润土矿床初步确定为我国缓冲/回填材料的供应基地,本研究以石英砂作为添加剂,通过实验获得了高庙子膨润土在不同含水率和不同砂含量时所对应的导热系数。结果表明,在相同压实条件下,导热系数随着含水率、石英砂含量的增加而增加。  相似文献   

测距仪周期误差及加常数的同时测定     

师郡 《测绘与空间地理信息》2000,23(2):38-39

文章提出的方法近似于平台法,但又有不同,不需要设置专用平台、检测可在室内进行,因此一般的测绘单位都可自己定期对测距仪进行检定,并且由于消除了外界因素的影响,使得检定结果更为可靠。  相似文献   

快速加固吹填泥浆的试验研究与分析   总被引：3，自引：0，他引：3  

刘娉慧  王清  石丙飞  蒋剑 《岩土力学》2005,26(12):2023-2026

为了研究利用外掺剂加快吹填泥浆的沉积落淤问题,找到能够使吹填土尽快地从泥浆状态转变为具有一定承载力的地基方法,将吹填泥浆中分别加入水泥、生石灰、水泥和生石灰混合剂,通过沉降柱试验模拟了外掺剂作用下吹填泥浆的落淤、自重固结、预压下强度增长等过程,并从粒度成分、矿物成分、和微观结构方面进行了加固机理的分析,从而在吹填的同时对吹填泥浆进行加固。结合处理前后相关试验结果的对比分析发现,外掺剂能够加速吹填泥浆的落淤、固结及强度增长。  相似文献   

利用累加指数对老湾金矿带地表及深部含矿性评价   总被引：2，自引：0，他引：2  

何孝良 《华南地质与矿产》2005,(1):13-19

老湾金矿带是桐柏-大别山(北坡)金银成矿带的重要组成部分,位于金银成矿带的南亚带。在对该成矿带成矿地质背景和原生地球化学异常分析研究的基础上,采用矿体前缘元素As,Sb和尾部元素Mo,Pb(Ni)的累加比值: (As+Sb) /(Mo×10+Pb)和(As+Sb) /(Mo×10+Ni),确立了该矿带的累加指数评价指标。利用累加指数结合原生地球化学异常元素组合,对该矿带地表及深部的含矿性进行预测评价,扩大了原矿体规模且发现了新矿体。  相似文献   

Effects of spatio-temporal and environmental factors on distribution and abundance of wintering anchovy Engraulis japonicus in central and southern Yellow Sea     

牛明香  金显仕  李显森  王俊 《中国海洋湖沼学报》2014,32(3):565-575

We investigated the spatio-temporal and environmental factors that affect the distribution and abundance of wintering anchovy and quantifi es the infl uences of these factors. Generalized additive models(GAMs) were developed to examine the variation in species distribution and abundance with a set of spatiotemporal and oceanographic factors, using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea during 2000–2011. The fi nal model accounted for 28.21% and 41.03% of the variance in anchovy distribution and abundance, respectively. The results of a two-step GAM showed that hour, longitude, latitude, temperature gradient(TGR), and chlorophyll a(Chl- a) concentration best explained the anchovy distribution(presence/absence) and that a model including year, longitude, latitude, depth, sea surface temperature(SST), and TGR best described anchovy abundance(given presence). Longitude and latitude were the most important factors affecting both distribution and abundance, but the area of high abundance tended to be east and south of the area where anchovy were most likely to be present. Hour had a signifi cant effect on distribution, but year was more important for anchovy abundance, indicating that the anchovy catch ratio varied across the day but abundance had an apparent interannual variation. With respect to environmental factors, TGR and Chl- a concentration had effects on distribution, while depth, SST, and TGR affected abundance. Changes in SST between two successive years or between any year and the 2000–2011 mean were not associated with changes in anchovy distribution or abundance. This fi nding indicated that short- and long-term water temperature changes during 2000–2011 were not of suffi cient magnitude to give rise to variation in wintering anchovy distribution or abundance in the study area. The results of this study have important implications for fi sheries management.  相似文献   

如何消除雾霾天气对全站仪野外检定的影响     

李彩霞  赵海燕 《测绘与空间地理信息》2014,(12)

在全站仪野外检定过程中通常采用光照准模式,该模式对较远距离点测量时需要较好的气象条件的配合.近年来,我国秋冬季节普发的雾霾天气使得仪器野外测量时无法精确照准目标,使检定工作不能顺利完成.本文主要探讨了应用智能全站仪的ATR照准模式进行全站仪野外检定的可行性,通过选用不同型号的全站仪用光照准模式及ATR照准模式进行野外检定,并对实验数据进行统计分析,得出了采用ATR照准模式进行野外检定可消除雾霾天气的不利影响,得到准确可靠地检定数据的实验结论.  相似文献