Distributions of Picophytoplankton and Phytoplankton Pigments Along a Salinity Gradient in the Changjiang River Estuary,China     

WANG Baoli  ;LIU Congqiang  ;WANG Fushun  ;LI Siliang  ;Sivaji Patra 《青岛海洋大学学报(英文版)》2014,(4):621-627

We investigated the abundance of different picophytoplankton groups and the phytoplankton pigment ratio in relation to environmental factors such as nutrients and suspended solids along a salinity gradient in the Changjiang River Estuary.The average numbers of Synechococcus spp.（Syn） and picoeukaryotes （Euk） were （2.7 ±5.1）×l03 and （1.1±1.4）×l03 cells mL-1,respectively.Prochlorococcus spp.（Pro） was only found in the high-salinity brackish water with the concentration of 3.0× 10^3 cells mL-1.Syn and Euk numbers both tended to increase offshore and Syn showed a larger variation in cell abundance than Euk.The contribution of picophytoplankton to total phytoplankton biomass increased with increasing salinity and decreasing nutrient concentrations from the estuary to the open ocean.The response of different picophytoplankton groups to environmental variables was different.Water temperature was more important in its control over Euk than over Syn,while nutrients were more important in their influence over Syn than over Euk.Phytoplankton pigment ratios were different in the three different ecological zones along the salinity gradient （i.e.,freshwater zone with 0-5 range,fresh and saline water mixing zone with 5-20 range,and high-salinity brackish water zone with 20-32 range）,where three different phytoplankton communities were discovered,suggesting that phytoplankton pigment ratios can be considered as a complementary indicator of phytoplankton community structure in the Changjiang River Estuary.  相似文献   

Root structure,distribution and biomass in five multipurpose tree species of Western Himalayas   总被引：1，自引：0，他引：1  

Kartar Singh VERMA  Sandeep KOHLI  Rajesh KAUSHAL  Om Parkash CHATURVEDI 《山地科学学报》2014,11(2):519-525

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The tree root distribution pattern and biomass of seventeen year old trees of Grewia optiva, Morus alba, Celtis australis, Bauhinia variegata and Robinia pseudoacacia were studied by excavation method. B. variegata roots penetrated to a maximum depth of 4.78 m, whereas, M. alba roots were found down to 1.48 m depth. Lateral spread was minimum in B. variegata （1.10 m）and maximum inR. pseudoacacia （7.33 m）. Maximum root biomass of 6.30 kg was found in R. pseudoacacia and minimum （2.43 kg） was found in M. alba. For four species viz.,G. optiva, M. alba, C. australis andR. pseudoacacia, 68%-87% root biomass occurred within top 0-30 cm soil depth, but forB. variegata this was only45%. The soil binding factor was maximum in G. optiva and minimum in B. variegata. Soil physico-chemical properties also showed wide variation. The study suggests thatB. variegata with a deep root system is the most suitable species for plantation under agroforestry systems. R. pseudoacacia and G. optiva with deep root systems, more lateral spread and high soil binding factor are suitable for plantation on degraded lands for soil conservation.  相似文献   

千山 东北大地上的一颗明珠     

金生 《资源导刊(河南)》2014,(11):52-57

辽宁千山系长白山支脉,辽河与鸭绿江的分水岭,是辽东半岛的脊骨。据地质考察,大约4亿年前,千山一带是一片海洋,到古生代末期开始隆起露出水面形成陆地。经历海陆沧桑5次变迁,1．8亿年前,形成现在典型的粗粒花岗岩地貌……  相似文献   

2012年冬季菲律宾海浮游动物丰度和生物量的水平分布   总被引：1，自引：1，他引：0  

代鲁平  李超伦  孙晓霞  吉鹏  张武昌 《海洋与湖沼》2014,45(6):1225-1233

为了解西太平洋菲律宾海浮游动物丰度和生物量的水平分布特征,于2012年11月26日至2012年12月12日对菲律宾海上层海洋(0—200m)的浮游动物进行了调查。调查站位分别位于受赤道逆流(NECC)、棉兰老流(MC)、北赤道流(NEC)和黑潮(KC)影响的海域。通过比较浮游动物的丰度和生物量(分别用干重,灰分,无灰干重和含能量等指标表示),探讨不同海流中浮游动物的分布特征。结果表明:桡足类、毛颚类和水母类是菲律宾海浮游动物的三大主要类群。调查海域浮游动物丰度为11—116ind./m3,NECC区平均丰度最高((96±28)ind./m3),然后依次是MC区和KC区,NEC区最小((26±9)ind./m3)。在浮游动物生物量(干重)方面,同样NECC区最高((3.25±1.11)mg/m3),其次为MC区,但是平均丰度最小的NEC区生物量超过KC区。造成这一差异的主要原因,可能是由于KC区的浮游动物具有更高的含水量以及较小个体所占比例较高。不同水团之间浮游动物灰分、无灰干重和含能量的分布特征与干重相一致。结合环境因子分析显示,上升流、叶绿素a、初级生产力、海流和温度等因素对浮游动物的分布具有一定影响。  相似文献   

山东荣成天鹅湖大叶藻形态和生长的季节性变化研究     

李勇  李文涛  聂猛  张秀梅 《海洋科学》2014,38(9):39-46

2012年8月至2013年7月,作者逐月对天鹅湖大叶藻(Zostera marina L.)的形态特征、植株密度、生物量和生产力进行了监测。结果表明,大叶藻周年株高最高值和最低值分别出现在7月和1月;叶鞘高度、叶鞘宽度和叶宽的最高值均出现在7月,叶鞘高度最低值出现在1月,叶鞘宽度和叶宽最低值均出现在2月;大叶藻顶枝、侧枝和花枝的周年密度最大值分别出现在6月、4月和5月,最小值分别出现在1月、8月和7月;单株生物量和地上部分生物量最大值均出现在7月,地下部分出现在10月,而单株生物量和地上部分生物量最小值均出现在1月,地下部分生物量最小值出现在3月;单株地上和地下生产力最大值均出现在6月,最小值则分别出现在1月和2月。分析显示,大叶藻在冬季由于水温较低导致生长缓慢,且植株较小,在春季随水温上升,生长开始加快。水温在夏初达到大叶藻的最适生长水温,大叶藻的生物量和初级生产力达到最高值,而夏末和初秋由于水温过高导致大叶藻个体生物量、密度和初级生产力开始降低。这种季节性变化与水温的季节性变化密切相关。  相似文献   

Zooplankton community structure in relation to environmental factors and ecological assessment of water quality in the Harbin Section of the Songhua River     

李晓钰  于洪贤  马成学 《中国海洋湖沼学报》2014,32(6):1344-1351

To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River, investigations were carried out in June, August, and October 2011. Canonical correspondence analysis （CCA） and saprobic indices were used to process and analyze the data. Seasonal variability was identified as a significant source of variation, which explains the fluctuation in zooplankton density. In autumn, the dry season, water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters. Zooplankton abundance increased when food conditions improved. Therefore, the total zooplankton abundance in autumn is much higher than that in spring and summer. According to the saprobic indices, all the sample sites had mesosaprobic water and water quality was worse in autumn. CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community. Moreover, pH, dissolved oxygen saturation, and turbidity were important factors affecting zooplankton community distribution.  相似文献   

Effects of Nitrogen Addition on Plant Functional Traits in Freshwater Wetland of Sanjiang Plain,Northeast China   总被引：1，自引：0，他引：1  

MAO Rong  ZHANG Xinhou  SONG Changchun 《中国地理科学(英文版)》2014,(6):674-681

To clarify the responses of plant functional traits to nitrogen（N） enrichment, we investigated the whole-plant traits（plant height and aboveground biomass）, leaf morphological（specific leaf area（SLA） and leaf dry mass content（LDMC）） and chemical traits（leaf N concentration（LNC） and leaf phosphorus（P） concentration（LPC）） of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates（0 g N/（m^2·yr）, 6 g N/（m^2·yr）, 12 g N/（m^2·yr） and 24 g N/（m^2·yr）） in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands.  相似文献   

从新中国邮票看中国地貌     

毕世哲 《国土资源》2014,(5):63-64

正我国幅员辽阔,有着雄伟的河山和绚丽多彩的景色。本文将通过新中国邮票介绍国土资源的基础知识,展现我国地貌的概况。一、河谷河谷是一种线状延伸的倾斜凹地,是流水的侵蚀和堆积作用形成的。分为河床、河滩地、谷坡地。在山区,河床由基岩和粗大的冲击物组成。山区的河谷一般狭窄,两岸不规则,坡度较大,多成阶梯状。由于岩性的软硬和地质构造的不同,有些河谷还会受到差别侵蚀,形成瀑布。在平原地区河床宽,坡度小,水流缓,所以泥沙容易沉积而形成"地上河",例如:黄河。河流洪水期淹没的河床以外谷底部分叫做河滩地。这是由于河床受到流水的侧向侵蚀,凹岸后退,凸岸堆积逐步形成的。  相似文献   

安阳：“诚、实、节、快”服务重点项目     

《南方国土资源》2014,(5):63-63

2014年,河南省安阳市文峰区国土资源局把保障重点项目用地作为保发展的重中之重,针对本年度辖区13个重点项目,创新思路,采取4项举措,做好项目用地保障工作。一是主动对接做到“诚”。组织人员先后到恒宇电器设备公司、利浦简仓公司、龙宇公司等13个重点建设企业进行走访座谈,摸清用地需求,提供用地咨询服务,超前做好项目定性、用地定位、选址踏勘等前期准备工作。二是全程参与体现“实”。针对13个重点项目不同情况,制定不同的服务方案,跟踪问效到底,从拟征地范围内的土地权属认定、地上附着物清点评估、勘测定界到施工建设,全程提供高效服务,确保重点项目用地的每个环节通畅无阻。  相似文献   

宁波：鄞州南部商务区地下地上空间统一开发     

《浙江国土资源》2014,(5):14-14

一、基本情况 作为宁波市鄞州区新一轮城市发展五年规划中的龙头工程,南部商务区以总部经济、国际贸易、科技创意、服务外包为发展方向,集中了杉杉、奥克斯、罗蒙、中基等宁波众多的龙头企业和500强企业,是鄞州区工业企业总部经济的节地典型,是迄今浙江省建筑密度最高、规模最大的商务集聚区。  相似文献