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The Gross growth efficiency(GGE) is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for the ability of a consumer to convert the biomass of food into its population production. In this study, it was firstly applied to estimate the role of amphipods grazing in the biomass dynamics of macroalgae(Ulva lactuca) in Yundang Lagoon(a subtropical eutrophic coastal lagoon, Xiamen City, China). It was found that amphipods were the dominant group(82.2%–98.7%) in the benthic assemblage, in which five amphipod species(Corophium uenoi, Ampithoe valida, Grandidierella japonica, Grammaropsis laevipalmata and Caprella panantis) were observed in the lagoon. However, only A. valida significantly consumed U. lactuca among these amphipod species. A series of experiments were conducted to estimate the consumption of U. lactuca by A. valida. It was suggested that the monthly secondary production(P) of A. valida using size frequency method ranged from 2.39 to 13.68 g/m2. GGE of A. valida exponentially reduced with body size and was closely associated with water temperature. Therefore, GGE equation for different months using the temperature recorded during the field investigation was fitted. The monthly consumption of U. lactuca was figured out to be 86.7–1 549.0 g/m2 by the sum of consumption(P/GGE) by A. valida at different size, accounting for 2.0%–37.5% of U. lactuca production. It indicates that the grazing effect of A. valida did play a role in reducing the accumulation of U. lactuca biomass when A. valida was abundant, but it finally fails to limit the U. lactuca growth in Yundang Lagoon. Low abundance of A. valida and high nutrient loading may be two major reasons for the outbreak of U. lactuca bloom in the lagoon. 相似文献
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INTRODUCTIONPhosphorusisakeynutritiveelementforthegrowthofmarinephytoplankton .Recently ,be causeofenvironmentalpollution ,theeutrophicationproblemsincoastalandoceanicwatershavebe comemoreandmoreserious.Theenvironmentecologicalresponseinthelong termtothef… 相似文献
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筼筜湖绿潮期间颗粒有机物及沉积有机物的来源研究 总被引:4,自引:2,他引:2
以原子碳氮比Cat/Nat、TOC/Chl a、δ13C和δ15N等为指标,分析了筼筜湖绿潮爆发期间悬浮颗粒有机物(POM)和沉积有机物(SOM)的来源。结果显示,筼筜湖的POM主要以外源输入为主。在靠近海水入口的引水渠,POM主要来自厦门西海域的陆源有机碎屑;位于筼筜湖上游的干渠,生活污水及餐饮业废水的有机质是其POM的主要贡献者;内、外湖POM的Cat/Nat(6.94~7.08)与浮游植物接近,但它们并不以浮游植物为主,而主要来自引水渠和干渠有机质的输入。以内湖为例,它们对内湖POM的联合贡献高达54%~97%。筼筜湖SOM的潜在来源多样,但不同湖区差异显著:在大型海藻覆盖区,主要以大型海藻和POM为主,而在无海藻覆盖的区域,则主要来自POM的自然沉降或与底栖微藻的联合贡献。结果表明,在来源复杂的潟湖系统,有机物的化学组成并不能很好的指示有机物的来源和成因,它在有机质的示踪方面并不如稳定同位素来得有效可靠。不过,基于多种指标的分析结果可能更准确。 相似文献
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根据东北太平洋中国合同区东区和西区从1994年至2003年6个航次(DY85-4,DY95-7,DY95-8,DY95-10,DY105-11和DY105-12.14)初级生产力调查资料编写.结果表明:次表层高值分布为叶绿素a分布的一般特征,从表层至水深50 m,数值为0.1 mg/m3左右,在水深50~100 m上下,数值约在0.2~0.4 mg/m3之间,在水深大于100 m,特别是150 m以深数值逐渐减小为零;东区初级生产力(C)测值在76.8~191.9 mg/(m2·d),平均为116.1 mg/(m2·d);西区的在73.1~222.5 mg/(m2·d),平均为127.1 mg/(m2·d);在水深0~125 m,0.2~2μm颗粒的微微型浮游植物的叶绿素a比例占叶绿素a总量的70%以上,而在水深125 m以深,占50%以下;反之,2~20μm和大于20μm两种粒级所占比例的和在0~125 m深度范围占30%以下,在水深125m以深时为50%以上.调查显示东、西两区属于初级生产力比较低的海域. 相似文献