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1.
We studied the responses of algae, corals, and small fish to elevated inorganic fertilizer, organic matter, and their combination over a 49-day summer period in cages that simulated the coral reef in the remote Glovers reef atoll, Belize. The addition of organic matter reduced while fertilization had no effect on the numbers of herbivorous damsel and parrotfishes. All measures of algal biomass were influenced by fertilization. The combined inorganic and organic enrichment produced the highest algal biomass, which is most likely due to the combined effect of higher nutrients and lower herbivory. The cover of turf and total algae were influenced by all treatments and their interactions and most strongly and positively influenced by fertilization followed by organic matter and the combination of organic matter and inorganic fertilizer. The inorganic and combined treatments were both dominated by two turf algae, Enteromorpha prolifera and Digenia simplex, while the nonfertilized treatments were dominated by brown frondose algae Lobophora variegata, Padina sanctae, and Dictyota cervicornis. The organic matter treatment had greater cover of P. sanctae and D. cervicornis than the untreated control, which was dominated by Lobophora variegata, also the dominant algae on the nearby patch reefs. Crustose corallines grew slowly ( approximately 2.5 mm/49 days) and were not influenced by the treatments when grown on vertical surfaces but decreased on horizontal coral plates in the combined organic matter and fertilization treatment. No mortality occurred for the two coral species that were added to the cages. Porites furcata darkened in the fertilized cages while there was a mix of paling and darkening for a small amount of the coral tissue of Diploria labyrinthiformes. Inorganic fertilization stimulates small filamentous turf algae and Symbiodinium living in coral but inhibits brown frondose algae. Organic matter inhibits small herbivorous fish, L. variegata, and encrusting coralline algae when growing on horizontal surfaces. 相似文献
2.
Algal growth and species composition under experimental control of herbivory,phosphorus and coral abundance in Glovers Reef,Belize 总被引：8，自引：0，他引：8
The proliferation of algae on disturbed coral reefs has often been attributed to (1) a loss of large-bodied herbivorous fishes, (2) increases in sea water nutrient concentrations, particularly phosphorus, and (3) a loss of hard coral cover or a combination of these and other factors. We performed replicated small-scale caging experiments in the offshore lagoon of Glovers Reef atoll, Belize where three treatments had closed-top (no large-bodied herbivores) and one treatment had open-top cages (grazing by large-bodied herbivores). Closed-top treatments simulated a reduced-herbivory situation, excluding large fishes but including small herbivorous fishes such as damselfishes and small parrotfishes. Treatments in the closed-top cages included the addition of high phosphorus fertilizer, live branches of Acropora cervicornis and a third unmanipulated control treatment. Colonization, algal biomass and species composition on dead A. palmata "plates" were studied weekly for 50 days in each of the four treatments. Fertilization doubled the concentration of phosphorus from 0.35 to 0.77 microM. Closed-top cages, particularly the fertilizer and A. cervicornis additions, attracted more small-bodied parrotfish and damselfish than the open-top cages such that there was moderate levels of herbivory in closed-top cages. The open-top cages did, however, have a higher abundance of the chemically and morphologically defended erect algal species including Caulerpa cupressoides, Laurencia obtusa, Dictyota menstrualis and Lobophora variegata. The most herbivore-resistant calcareous green algae (i.e. Halimeda) were, however, uncommon in all treatments. Algal biomass increased and fluctuated simultaneously in all treatments over time, but algal biomass, as measured by wet, dry and decalcified weight, did not differ greatly between the treatments with only marginally higher biomass (p < 0.06) in the fertilized compared to open-top cages. Algal species composition was influenced by all treatments with a maximum between-treatment Bray-Curtis similarity of only 29%. The fertilized cages showed rapid colonization by a mixed turf community largely composed of the filamentous brown (Hincksia mitchelliae) and green (Enteromorpha prolifera) species. Algal cover in the fertilized cages leveled at 80% after 20 days compared to less than 50% in the other treatments. There was no evidence that A. cervicornis suppressed algal colonization compared to the unmanipulated controls. Instead, the herbivore susceptible Padina sanctae-crucis was the most abundant algae followed by Jania capillacea in this treatment in contrast to the more chemically defended Dictyota menstrualis that dominated the unmanipulated controls. We conclude that A. cervicornis was not suppressing algae as a group and its loss cannot account for the observed changes in algal abundance in most reefs except for creating space. In contrast, A. cervicornis appears to attract aggressive damselfish that may reduce herbivory by larger herbivores. Phosphorus enrichment can lead to rapid colonization of space by filamentous turf communities but not high biomass and dominance of erect frondose algae within 50 days. Moderate levels of herbivory by large-bodied herbivores promoted moderately herbivore-resistant erect brown and green algae that are commonly reported on disturbed reefs. Consequently, all the studied factors influenced algal communities but seldom as commonly predicted. 相似文献
3.
Cages and fertilizers were used at Glover's Atoll, Belize to test the relative importance of nitrogen (N) and phosphorus (P) to microbial euendolithic communities (bacteria, algae and fungi) and their bioerosion rates of Strombus gigas shells after 56-days of exposure. By the end of the experiment, the abundance of green algae was higher than cyanobacteria and fungi in N and N+P treatments, although green algae did not increase proportionally with increasing N concentrations, suggesting that green algae were co-limited by P and N. In contrast, cyanobacteria abundance increased with increasing P concentration, suggesting that cyanobacteria were P-limited. Fungi were not significantly affected by the addition of nutrients. Microbioerosion rates in the N and N+P treatments were 2-times greater than rates in the P treatment and 15-times greater than the control treatment. Results demonstrate that increased nutrient concentrations on coral reefs may increase microbioerosion rates, and variations in nutrient ratios can modify microborers community composition. 相似文献
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5.
水生生态系统蓝藻固氮作用研究进展与展望 总被引：4，自引：2，他引：2
固氮蓝藻在水生生态系统中占优势是由多种因素所引起的,如营养盐浓度及形态、氮磷比、水温和微量元素等.一般认为,湖泊中正磷酸盐浓度≥0.01 mg/L、溶解性无机氮浓度≤0.1 mg/L时,固氮蓝藻出现,并且低的氮磷比是表征水体中固氮蓝藻出现的重要指标,但引起固氮与非固氮蓝藻分异的驱动机制还需要深入研究.此外,光照、无机氮浓度与形态、异形胞丰度和溶解性有机物对蓝藻固氮速率有重要影响,进而决定蓝藻氮释放通量及对水体中氮库的贡献作用.固氮蓝藻是贫营养盐海域和海洋生态系统中氮库的重要贡献者,但在富营养化湖泊中,其贡献作用还存在争议.因此就目前国内外对固氮蓝藻相关研究做综述,以期待业界同行能够对蓝藻固氮作用及其氮释放对水生生态系统中氮循环的贡献引起重视. 相似文献
6.
氮、磷等营养物质对低洼盐碱地鱼塘水质的影响 总被引：4，自引：0，他引：4
通过在实验围隔中添加不同浓度的氮、磷等营养物质,对黄淮海平原低洼盐碱地鱼塘中的水质变化情况进行了初步研究,结果表明：1）围隔水体中异养细菌数量的变动,与水体中氮、磷等营养物质的浓度及比例密切相关,尤其是水体中磷的浓度对异养细菌数量的影响更为显著。2）围隔水体中的氮、磷等营养浓度及比率,明显地影响着其中藻类的数量和生物量。在实验条件下,水体中磷对藻类生长的影响要大于氮对藻类生长的影响,水体中N：P比为10：1左右是比较适宜藻类生长的比例。3）围隔水体中氮、磷等营养盐的去除能力与其中藻类的生物量及水体中N：P的比率密切相关,当围隔水体中的N：P比为10：1左右时,围隔水体中的藻类生长最好,生物量增加最快,相应地其对TN、TP的去除率也是最高的。 相似文献
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水体氮、磷营养盐水平对蓝藻优势形成的影响 总被引：1，自引：1，他引：0
以江苏省南京市富营养化程度不同的清溪、护城河、玄武湖、月牙湖、琵琶湖和前湖为研究对象,调查各水体浮游植物的群落特征和优势种,并结合藻类生长潜力试验,探究不同氮、磷营养水平的自然水体对铜绿微囊藻（Microcystis aeruginosa）和斜生栅藻（Scenedesmus obliquus）生长与竞争的影响.野外调查发现不同营养水平水体浮游植物优势种不同,按水体富营养化程度从高到底依次以绿藻、蓝藻、硅藻和隐藻分别占优势.单一藻种培养时,铜绿微囊藻在清溪、护城河和玄武湖水体中生长均较好,而斜生栅藻仅在高氮、磷浓度的清溪和护城河水体中有较大生长量,说明斜生栅藻对氮、磷的需求高于铜绿微囊藻;两种藻共培养时,清溪水体中斜生栅藻占优势,护城河和玄武湖水体中铜绿微囊藻占优势,但其他水体中两种藻均不能生长,说明氮、磷浓度过高或过低都不利于蓝藻形成优势.对低营养水平的玄武湖、琵琶湖、月牙湖和前湖水体进行氮、磷加富后,两种藻均能较好地生长,且各组没有显著差异,说明藻类在这些水体中生长受到氮、磷的限制,氮、磷浓度升高会增加水华发生的风险.本研究将野外调查和藻类生长潜力实验相结合,深入探究了蓝藻优势形成与水体氮、磷营养水平的关系,揭示了蓝藻水华是湖泊富营养化发展到特定阶段的产物,水体氮、磷浓度过高或过低均不易产生蓝藻优势. 相似文献
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贵州红枫湖越冬藻类的空间分布与实验室复苏实验 总被引：1，自引：0，他引：1
本文选取贵州省红枫湖这一典型的亚深水型湖泊作为研究对象,在8个代表性湖区开展了为期一年的表层水体藻类浮游植物分布的月定量监测,并在4个采样点采集新鲜沉积物进行了越冬藻类赋存与复苏模拟实验研究.研究表明,红枫湖表层水体藻类种群密度蓝藻绿藻>硅藻>甲藻,蓝藻为优势门类,水体藻类种群密度秋季初期最高,其次是春季初期和夏季,具有明显的季节性演化特征.水体中越冬藻类以蓝藻为主,其次是硅藻和绿藻,水深对水体中藻类的种群密度及组成没有显著影响.沉积物中越冬藻类以硅藻为主,基本不含蓝藻.模拟实验表明,水体中的光照条件对藻类的复苏和生长有重要影响,温度和沉积物中藻类的种群密度与组成同样影响藻类的复苏. 相似文献
9.
《Limnologica》2019
An increase in the distribution and frequency of cyanobacterial blooms has been reported for many regions worldwide. Due to this fact, we studied the variables that influence the abundance of natural populations of planktonic cyanobacteria in temperate lakes of central and southern Chile. These lakes differed in trophic state and watershed use. Cyanobacteria dominated in meso- and eutrophic systems and their occurrence correlated to watershed use (tree plantations and urban). Ochrophyta and Bacillariophyta were dominant in oligotrophic lakes, where native forest dominated land usage. In these lakes, the maximum depth of the euphotic zone influenced the community structure and the genera of cyanobacteria. Dolichospermum was the most abundant, frequent, and widely distributed genus, found in oligotrophic and eutrophic lakes, forming blooms in eutrophic systems.The concentration of total phosphorus and total nitrogen positively influenced cyanobacterial abundance and bloom formation, mainly by Aphanizomenon, Aphanocapsa, Aphanothece, and Dolichospermum, and Microcystis.In contrast to many reports on their occurrence in the northern hemisphere, these genera occurred widely at less than 20 °C, forming dispersive blooms, at low temperatures in autumn and winter (10.8–15.6 °C). This shows that eutrophication is the main factor for bloom formation and these genera can form blooms independent of temperature. However, some genera, such as Microcystis, increased their abundance and presented more intense blooms (scums) at high temperatures. Our study provides baseline data to document long-term changes in lentic systems of the western south-central area of South America, including genera that could respond by increasing their abundance with eutrophication and projected climatic changes. 相似文献
10.
长江中下游湖泊沉积物氮磷形态与释放风险关系 总被引：14，自引：2，他引：12
运用聚类分析、主成分分析和相关矩阵的统计分析手段,对长江中下游湖群共18个湖泊的沉积物氮磷释放风险以及湖泊沉积物、间隙水和上覆水中氮磷形态以及其他相关地球化学参数进行分析。草型和藻型湖泊的环境差异是造成氮磷释放风险的主要原因。氮磷释放风险与铁磷、藻类可利用磷、总氮、总磷、上覆水氮磷含量、间隙水氮含量、孔隙度和有机质含量间的关系最为密切。决定磷酸盐释放风险的主要形态磷是藻类可利用磷和铁磷,其他形态磷或者含量较低或者不易被转化释放,对磷酸盐释放风险影响较小。有机磷含量对磷的释放风险没有直接决定作用,但它与有机质含量间呈显著正相关。 相似文献
11.
Effects of nitrogen and phosphorus on phytoplankton composition and biomass in 15 subtropical, urban shallow lakes in Wuhan, China 总被引：6，自引：0，他引：6
This study aims at investigating the composition and biomass of the phytoplankton community in 15 urban shallow eutrophic lakes as well as the effects of main environmental factors, including nutrient concentrations and the ratio of nitrogen to phosphorus, temperature, COD, BOD, water depth, etc. on the phytoplankton community structure. Lake water samples were taken and analyzed on a bimonthly basis during the period from March 2004 to March 2006. The redundancy analysis (RDA) and regression analysis (RA) were performed to identify the effects of nutrients on the phytoplankton community and biomass in these typical urban lakes. The results indicate that most of these urban lakes were hypertrophic due to high concentrations of total phosphorus (TP) and total nitrogen (TN), with mean levels of 490 and 5380 mg m−3, respectively. The phytoplankton community was dominated by Microcystis aeruginosa and Euglena caudate in summer and Cryptomonas ovata and Cyclotella meneghiniana in winter. The mean biomass of the phytoplankton reached 456.87 mg L−1 in summer months and the annual level was 189.24 mg L−1. Temperature and TP content were found to be the principal limiting factors for phytoplankton growth on an annual basis. On the other hand, the results of RDA and RA demonstrate that the dominant phytoplankton species were not nutrient-limited during summer months. Low TN:TP ratios (<10) were detected accompanied with fewer occurrences of N-fixing cyanobacteria and other filamentous algae in most lakes in summer, which implies that low N:P ratio does not always shifts the dominance of phytoplankton community to the N-fixing cyanobacteria. Moreover, TP always had higher correlation with chlorophyll a (Chl-a) than TN, even when the TN:TP ratios of most samples were lower than 10. Therefore, it is concluded that the TN:TP ratio is not always a suitable index to determine whether nitrogen or phosphorus limits the phytoplankton biomass in urban shallow eutrophic lakes. 相似文献
12.
浮游动物牧食、水温及营养可利用性均可影响优势浮游植物功能群的转变,但这些驱动因素的交互作用尚不清楚。为了解云南高原湖泊——洱海浮游植物优势功能群的分布特征及其主要驱动因素,于2018年1月2020年12月进行月度采样,结合聚类分析、方差分析和冗余分析等,分析驱动浮游植物优势功能群转变的主要因素。结果表明,共鉴定浮游植物7门96属,划分为27个浮游植物功能群,其中优势功能群有15个。聚类分析结果表明,根据浮游植物功能群密度数据可将优势功能群转变过程分为3个由不同类型藻类主导的时期（S期、M期和P期）,其中S期（为期18个月）以功能群S1和H1（代表藻为假鱼腥藻、浮丝藻和长孢藻等丝状蓝藻）为主,M期（为期10个月）以功能群M（微囊藻群体）为主,P期（为期8个月）以功能群P和M（脆杆藻和单个微囊藻等）为主。RDA分析及变差分解分析结果表明,卡尔森营养状态指数（TSI）（主要是总磷）是影响以丝状藻类为主的浮游植物功能群的主要驱动因素,TSI和水温是影响以微囊藻为主的浮游植物功能群的重要驱动因素。因此,在富营养化初期湖泊中,降低湖泊营养负荷是首要任务。同时可以考虑增加浮游动物丰度的策略,以增强浮... 相似文献
13.
合肥塘西河异味物质及异味影响因子研究 总被引：2，自引：0，他引：2
以合肥市塘西河为研究对象,2014-2015年逐月对其水体水质和异味物质进行监测,同时结合塘西河浮游植物群落结构调查,综合分析塘西河异味物质变化规律及其影响因素.研究发现,塘西河异味暴发集中发生在夏季,夏季二甲基异莰醇浓度可达4909 ng/L,土腥素浓度可达197 ng/L.浮游植物群落结构调查表明,秋、冬季塘西河优势种类为蓝藻,春、夏季为硅藻、绿藻或隐藻.主成分分析得到5种主成分分别解释了光照、有机质、微生物活动、氮、磷等对水质的影响.相关性分析结果表明,氮是塘西河异味的限制因素,水体中氮浓度较高是异味产生的重要原因. 相似文献
14.
2010-2017年太湖总磷浓度变化趋势分析及成因探讨 总被引：4，自引：0，他引：4
近年来,太湖流域各省市政府加大治理力度,流域水体水质取得明显好转,氨氮浓度和总氮浓度呈大幅度下降趋势,然而太湖水体总磷浓度呈上升趋势.为探讨太湖总磷浓度升高的原因,采用太湖流域管理局2010年以来的水质水量实测数据、遥感监测数据等,分别从太湖入湖河流污染负荷量、水生植被和蓝藻与总磷浓度的关系3个方面进行相关性分析.结果表明,入湖河流总磷浓度高于太湖水体总磷浓度,且磷不易出湖,逐年总磷净入湖量持续累积与太湖总磷浓度有明显的正相关性,入湖污染负荷量大是太湖总磷浓度居高不下的根本原因;水生植被可吸收湖泊沉积物中的营养盐,并抑制底泥再悬浮从而降低内源性营养盐的释放,东太湖水生植被的大量减少,一方面减少了沉水植物对磷元素的吸收,另一方面增加了风浪对底泥的扰动再悬浮,造成磷元素释放,是造成湖水总磷浓度升高的重要因素;近年来太湖蓝藻密度呈上升趋势,受其影响,总磷浓度也有上升,蓝藻水华加快湖体磷循环,藻类密度增加也是太湖总磷浓度升高的影响因素之一. 相似文献
15.
本文通过选取水华鱼腥藻(Anabaena flos-aquae)、铜绿微囊藻(Microcystis aeruginosa)、空球藻(Eudorina sp.)和湖北小环藻(Cyclotella hubeiana)为三峡库区流域中典型的优势藻,在澎溪河进行原位培养试验,跟踪监测了三峡水库不同运行时期4种典型优势藻细胞氮(Cell-N)、磷(Cell-P)浓度以及环境水体中的总氮(TN)、总磷(TP)浓度,并且结合团队之前的研究成果,根据临界(供应)N/P摩尔比、细胞N/P摩尔比和Guildford的TN/TP摩尔比评价标准对库区水体的营养限制状态进行了评价,为进一步揭示三峡水库运行下支流水域富营养化过程与生理特征的限制性评价提供研究基础.原位试验结果表明:3个评价标准下水体的营养(氮或磷)限制状态基本相同,低水位时期水体无机磷营养盐比较贫乏,在试验初期没有显著的营养盐限制而在末期受到了磷的相对限制;高水位试验初期和末期均未呈现显著的营养盐限制;泄水期营养盐变动频繁,试验初期表现为氮限制而末期表现为磷限制.虽然各藻种在不同时期会表现出不同的营养盐限制性,但总的来看,临界N/P比和细胞N/P比的阈值范围具有一定指示作用,能够从藻类细胞生理的角度对水体的营养状况作出初步评价. 相似文献
16.
比较了毛竹、石栎和山胡椒叶片的理化属性,采用粗网叶袋法研究了三种落叶在太湖流域上游西苕溪中的分解过程,探讨了毛竹叶成为溪流优势外来能源后对溪流生态过程和底栖动物群落结构的影响.三种落叶的氮、磷含量及叶片厚度都存在显著差异,毛竹叶的氮含量(30.23 g/kg)远高于石栎(20.98 g/kg)和山胡椒(9.69 g/kg),其中毛竹叶的分解速率最快(k=0.00592 d-1),山胡椒(0.00297 d-1)和石栎叶(0.00212 d-1)较慢.三种落叶叶袋间的大型底栖无脊椎动物包括各取食功能团的多度和生物量无显著差异,而4次采样间的差异很显著.大型底栖动物的取食功能团中,撕食者的数量比例最高(40.3%),生物量比例为41.6%,是落叶分解的重要功能类群.撕食者中,利用阔叶筑巢的鳞石蛾Lepi-dostoma数量最多,占全部底栖动物的14%,是该溪流中主要的撕食者类群.因此,由于毛竹叶具有氮、磷含量较高、叶形较窄,以及两年进行一次换叶的特点,当毛竹叶替代其他阔叶秋季落叶的树种成为源头溪流优势外来能源后,可能会改变源头溪流中的氮磷含量、溪流外来能源的量和滞留时间以及底栖动物群落结构. 相似文献
17.
一种淡水水华硅藻——链状弯壳藻(Achnanthidium catenatum) 总被引：1，自引：0，他引：1
作为区域重要饮用水源的浙江绍兴汤浦水库于2010年5月期间暴发以硅藻和蓝藻为主的藻类水华.对库尾、库中和坝前3处浮游植物样品进行采集和分析,结果表明,汤浦水库浮游植物密度在1.13×108～1.56×108cells/L之间,水华优势种之一为我国大陆地区首次报道的羽纹纲硅藻———链状弯壳藻(Achnanthidium catenatum),另一种为丝状蓝藻———湖泊假鱼腥藻(Pseudanabaena limnetica),两者的平均相对丰度分别为65.6%和28.2%;链状弯壳藻是弯壳藻属中唯一适应浮游生长的种类,具有独特的带面观,能以壳面相连形成2～3个细胞的短链状群体;对国内外3次链状弯壳藻为优势种的水华案例进行分析,发现该藻为广温性种类,适应低光强和低磷浓度生长;水华生消机理则需进一步研究. 相似文献
18.
The chemical inputs by rainfall, throughfall and stemflow were studied in a pine plantation located in Pierces Creek Forest, Canberra, Australia. Three treatments were included in the study: a control (C) and two fertilizer treatments. The first fertilizer treatment (F) involved two applications of mixed fertilizers at high rates, the second (IL) involved application of a complete liquid fertilizer with irrigation, so as to remove nutrient and water restrictions to growth. The application rates of nutrients were higher for IL than F. Net inputs of elements in throughfall and stemflow, obtained by subtracting the amounts in the rainfall, were compared for different treatments. For cations (the sum of Ca, Mg, Na and K), the treatment effect on leaching by throughfall and stemflow was IL > F > C; but the F to C differences were greater for throughfall than stemflow. The effects were almost entirely due to increases in concentration, rather than the amount of rainfall becoming throughfall or stemflow. The concentration of nitrogen (as NH4 or NO3) in throughfall or stemflow could be lower or higher than in rainfall, indicating net removal or leaching, respectively. Net removal occurred for most rainfall events for the control treatment, for a substantial number of events for treatment F, but for few events for treatment IL. The ammonium ion was preferentially removed from throughfall, and nitrate from stemflow. Transfers of potassium and total nitrogen by litterfall, throughfall and stemflow were also studied. The proportions of potassium and nitrogen being transferred by these processes showed little difference between treatments; the overall values for potassium being 60% by throughfall, 4% by stemflow and 36% by litterfall. In contrast the transfer of nitrogen was dominated by litterfall (81%), with 18% by throughfall and 1% by stemflow. © 1997 John Wiley & Sons, Ltd. 相似文献
19.
三峡小江回水区段2007年春季水华与营养盐特征 总被引：19，自引：5，他引：14
2007年5月中下旬,三峡水库小江回水区发生水华,主要分布在高阳平湖、黄石代李子和双江大桥三处,对水华期间浮游植物群落特点和水环境特征的分析发现蓝藻占主导,约为浮游植物生物量的81.43%,优势藻种为水华鱼腥藻(Anabaena flos-aquae),结合水华期间总氮含量较非水华期间明显偏高且有机氮为氮素主要成份和许多蓝藻门藻种均带有异形胞的分析结果,认为此次水华是同氮型蓝藻水华,水华暴发前初春的强降雨过程导致小江回水区TP水平的普遍增加促使了TN/TP发生显著的变化,4月份较低的TN/TP水平诱使同氮型蓝藻在小江回水区迅速生长,并在5月份形成水华,水华期间生物量的增加造成水中磷酸盐浓度的降低,使得小江回水区表现出显著的磷限制特征,调查认为:高阳平湖段可能是小江回水区蓝藻水华的发源地,蓝藻生物体随流漂移至下游黄石代李子处并逐渐聚集,形成自岸边缓流带向河道中心逐渐延伸的肉眼可见的蓝藻生物聚集体,从而使得黄石代李子处具有最高的生物量和叶绿素值,而双江大桥处,则主要是由于河道过水断面的放大导致流速的降低,同时沿岸云阳县县城的排污使得这一河段的营养负荷相对提高,从而为上游随流漂移下来的蓝藻提供了较佳的生长环境. 相似文献
20.
《Acta Geochimica》2016,(1)
This study aims to investigate the effects of region and three regional dominated mangrove species(Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus. Measurement of the inorganic nitrogen and phosphorus and enzymatic activities was carried out in soils covered by three mangrove species in the Quanzhou Bay estuarine wetlands, a typical coastal wetland in China.Species with a higher biomass in upstream and midstream absorb more nitrogen from soils, and the retention of the available phosphorus in the soils of different regions causes the regional variation of phosphorus. In areas dominated by A. marina, nitrate nitrogen is lower while available phosphorus is higher. Meanwhile, nitrate nitrogen and available phosphorus are higher in the soils covered by K. candel.Moreover, all three species affect the elemental and enzymic stoichiometry. The mangrove species influences the diversity of the elemental and enzymic stoichiometric relationship through differential microenvironments, which induce the biodiversity of wetland ecosystems. Thus, this study may facilitate a better understanding of the transformation ability of mangroves to nitrogen and phosphorus and will therefore be beneficial for providing a basis for the ecological restoration of estuarine wetlands. 相似文献