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1.
Nile tilapia Oreochromis niloticus (L.) held in timed‐pulse feeding chambers, were provided with algal‐rich water dominated by either green algae (Scenedesmus, Ankistrodesmus, Chlorella and Tetraedron) or cyanobacteria (Microcystis) to determine the effect of temperature and phytoplankton concentration on filtration rates. Green algae and cyanobacteria filtration rates were measured as suspended particulate organic carbon (POC) kg?1 wet fish weight h?1. Ivlev's filter‐feeding model described the relationships between filtration rates and suspended POC concentration of green algae and cyanobacteria. Filtration rates of both green algae and cyanobacteria increased linearly as water temperature increased from 17 °C to 32 °C and were significantly higher in the warm‐water regime (26–32 °C) than in the cool‐water regime (17–23 °C). Filtration rates at 95% saturation POC (FR95) in green algal and cyanobacterial waters were 700 mg C kg?1 h?1 and 851 mg C kg?1 h?1 in the warm‐water regime and 369 mg C kg?1 h?1 and 439 mg C kg?1 h?1 in the cool‐water regime respectively. The FR95 in warm water were achieved at lower POC concentrations than in cool water. 相似文献
2.
The freshwater mussel Elliptio complanata was provided green algal‐dominated water from a Partitioned Aquaculture System (PAS) over a range of water temperatures (6.1–32.4 °C) and suspended particulate organic carbon (POC) concentrations (<1–32.2 mg C L?1) to determine filtration rates as mg POC kg?1 wet tissue weight h?1. The lowest filtration rates were observed at lowest temperatures and POC concentrations while the highest rates were at intermediate temperatures and the highest POC levels. The predicted filtration rate (PFR) in response to water temperature and POC concentrations was as follows: ln PFR=1.4352+0.1192 POC+0.1399 T?0.0001 T3. Within the experimental conditions, PFRs at any POC concentration increased with increased water temperature to a peak at 22 °C and then decreased. The maximum PFR occurred at 22 °C and 32 mg C L?1 and the minimum PFR at 7 °C and 1 mg C L?1. A model to describe the mussel filtration rate responses to PAS water conditions involves both water temperature and POC concentration. 相似文献
3.
Hakan Turker Arnold G. Eversole David E. Brune 《Aquaculture (Amsterdam, Netherlands)》2003,220(1-4):449-457
Nile tilapia (Oreochromis niloticus) and silver carp (Hypophthalmichthys molitrix) held in timed-pulse feeding chambers were provided water dominated either by green algae (Scenedesmus, Ankistrodesmus and Tetraedron) or by cyanobacteria (Microcystis) to compare filtration rates (FRs). FRs were expressed as suspended particulate organic carbon (POC)/kg wet fish weight/h and as phytoplankton units filtered based on counts. Nile tilapia and silver carp filtration significantly reduced phytoplankton number of both taxonomic groups with the larger phytoplankton being filtered proportionally more than the smaller phytoplankton. Nile tilapia FR of green algae was significantly higher than silver carp; however, silver carp FR of cyanobacteria was higher than Nile tilapia. Ivlev's 90% saturation FRs (FR90) in green-algal and cyanobacterial water sources were 702 and 812 mgC/kg/h for Nile tilapia and 414 and 1028 mgC/kg/h for silver carp, respectively. Silver carp were observed to reach these FR90 values at lower POC concentrations than Nile tilapia with both green algae and cyanobacteria. 相似文献
4.
Christopher R. Mueller Arnold G. Eversole Hakan Turker David E. Brune 《Journal of the World Aquaculture Society》2004,35(3):372-382
Growers produce over 2.8 million kg of catfish (over $350 million wholesale revenue) annually in the United States. The microbiology of the phytoplankton community in culture water affects the growth and flavor of the catfish and is a consideration for growers. Filter feeders, like silver carp and freshwater mussels, in controlled growth systems are used to adjust the phytoplankton species. Our goal was to successfully control the algal populations with filter feeders in catfish production. We used silver carp Hypophthalmichthys molitrix as a filter feeder in Partitioned Aquaculture System (PAS) water. Silver carp completely eliminated the cyanobacteria Microcystis by size and biovolume reduction. This created the desired effect of small green algae dominating the algal community. A significant but opposite change was observed when freshwater mussels Elliptio complanata filtered PAS water resulting in Microcystis biovolume and size dominance in the PAS; a less desirable algal community. This study also showed an immediate shift in the phytoplankton community when silver carp and mussels were interchanged between PAS waters. The size-selective filtration by the two filter-feeding taxa was important in determining the composition of the PAS phytoplankton community, and it was apparent that filtration with silver carp successfully depleted undesirable algae. 相似文献
5.
本文以2种大型浮游动物和1种绿藻、2种铜绿微囊藻为研究对象,初步研究了浮游动物对藻类的摄食关系。实验结果表明当栅藻和无毒铜绿微囊藻CHAB109密度均为1.02×106cells/ml时,拟老年低额溞对二者的去除率分别为54.20%和6.45%,大型溞的则为49.77%和64.77%。同时,拟老年低额溞对栅藻和CHAB109混合藻液中的两种藻均有较好的去除效果,分别为60.65%和34.43%,高于对纯种藻的去除率。在遮光条件下浮游动物摄食量更大,对藻的去除效果更优。拟老年低额溞在锡箔遮光情况下,对初始藻细胞密度为3.023×105cells/ml的有毒微囊藻PCC7806去除率达到32.37%。7d日龄的浮游动物个体大,摄食量也大,有较好的去除效果,且随着添加浮游动物数量的增加,去除率也随着提高。高浓度的藻细胞对两种浮游动物存活率影响较低浓度大。浮游动物应用于藻类水华的控制,作用不容忽视,且若条件适宜,浮游动物也可较好的控制有毒蓝藻。当选用浮游动物控藻藻类水华时,需综合考量选用物种种类、大小、添加数量等因素。 相似文献
6.
滇池氮磷浓度变化对蓝、绿、硅藻年际变化的影响 总被引：3，自引：0，他引：3
为了探究滇池水体中藻类变化规律及营养盐对浮游藻类结构的影响,在滇池草海和外海共设10个采样点,于2013年5月至2015年4月,每月监测藻类变化及氮、磷含量。结果表明,草海在每年9月至来年2月,蓝藻、绿藻呈互为消长的变化趋势,硅藻生物量在8-10月和2-4月含量较高,变化范围5.81~44.80 mg/L;外海以蓝藻、绿藻为主,两种藻类在每年的11月至来年1月呈互为消长,而来年2种藻5-7月逐渐升高、10月开始又逐渐降低。草海和外海水体中的总磷均以在5-9月含量最高,变化范围分别为0.82~3.37 mg/L和0.20~0.51 mg/L;总氮全年变化剧烈,草海总氮为2.85~11.7 mg/L,外海总氮为1.05~4.89 mg/L。总体上看,草海的氮、磷含量高于外海,说明草海富营养化水平高于外海;而水体中绿藻生物量高于蓝藻成为绝对优势藻种,且绿藻生物量远远高于外海,表明高氮、磷水体中绿藻比蓝藻有更强的利用优势,致使在超富营养化水体中蓝藻不占优势。滇池水体中氮磷比较低的月份,水体中蓝藻和绿藻共存;在高氮磷比的时间段,绿藻生长占优势,说明滇池水体中绿藻比蓝藻更适合高氮磷比的环境。 相似文献
7.
为了研究海河下游天津段浮游生物的分布特征,在海河下游七个区域共设置28个调查站位,于2013年5月、7月、9月对各站位表层水体的浮游动植物丰度、生物量进行采样调查和分析。调查期间共发现浮游植物117种,浮游动物20种,浮游植物的平均丰度为8.145×104cells/L,主要优势种为蓝纤维藻(Dactylococcopsis)、颤藻(Oscillatoria)、四尾栅藻(Scenedesmus quadricauda(Turp.)de Bréb)、纤维藻(Ankistrodesmus),以蓝、绿藻为主;浮游动物的平均丰度为7.679×104 ind/L,主要优势种为近邻剑水蚤(Cyclops vicinus)、短尾秀体溞(Diaphanosoma brachyurum(Liévin,))、萼花臂尾轮虫(Brachionus calyciflorus)。 相似文献
8.
Four different‐sized (390±3, 140±2, 40±2, 16±1 g) Nile tilapia, Oreochromis niloticus (L.), stocked at the same biomass in timed pulse feeding chambers were provided 27–29°C water dominated by Microcystis (82%) and Scenedesmus (18%) to determine the effect of fish size on filtration rates. The number of Microcystis and Scenedesmus units filtered from the water decreased significantly with increasing tilapia size. The shaping constants and maximum filtration rates for Ivlev's feeding model used to describe the relation between filtration rates and the suspended particulate organic carbon (POC) concentrations were significantly different among the four sizes. Filtration rates of 763, 671, 512 and 300 mg C kg?1 h?1, which correspond to 70%, 82%, 86% and 90% saturation levels, were achieved at POC levels of 30, 32, 32 and 33 mg C L?1 for 16, 40, 140 and 390 g Nile tilapia respectively. Smaller tilapia achieved these rates at lower POC concentrations than larger tilapia. 相似文献
9.
Daniel Jančula Přemysl Mikula Blahoslav Maršálek Pavel Rudolf František Pochylý 《Aquaculture International》2014,22(2):509-521
The aim of this study was to investigate the suitability of hydraulic jet cavitation as a method for cyanobacterial water-bloom management. Effects of cavitation were studied on laboratory culture of the cyanobacterium Microcystis aeruginosa, on a culture of a green alga Chlorella kessleri (as a non-target species) as well as on a real cyanobacterial biomass with Microcystis sp. as a dominant species. Our results suggested that the cavitation treatment of cyanobacteria is capable of causing the disintegration of their gas vesicles. Using this treatment, up to 99 % removal efficiency of cyanobacteria was achieved. Moreover, no effect on cyanobacterial membrane integrity or metabolic activity was detected by flow cytometry; thus, hydraulic cavitation seems to be harmless from the viewpoint of possible release of cyanotoxins into the water column. The green algae (here C. kessleri) were not affected negatively by the cavitation, and thus, they may still act as the natural nutrient competitors of cyanobacteria in lakes, ponds or reservoirs treated by cavitation. 相似文献
10.
Charles C. Mischke David J. Wise Paul V. Zimba 《Journal of the World Aquaculture Society》2009,40(1):122-128
Many fish culturists are interested in applying copper sulfate pentahydrate (CSP) to channel catfish, Ictalurus punctatus, nursery ponds as a prophylactic treatment for trematode infection and proliferative gill disease by killing snails and Dero sp., respectively, before stocking fry. However, copper is an algaecide and may adversely affect phytoplankton and zooplankton populations. We evaluated the effects of prophylactic use of copper sulfate in catfish nursery ponds on water quality and phytoplankton and zooplankton populations. In 2006, treatments of 0 mg/L CSP, 3 mg/L CSP (0.77 mg/L Cu), and 6 mg/L CSP (1.54 mg/L Cu) were randomly assigned to 0.04‐ha ponds. In 2007, only treatments of 0 and 3 mg/L CSP were randomly assigned to the 16 ponds. Ponds treated with CSP had significantly higher pH and significantly lower total ammonia concentrations. Treatment of both CSP rates increased total algal concentrations but reduced desirable zooplankton groups for catfish culture. CSP has been shown to be effective in reducing snail populations at the rate used in this study. CSP treatment also appears to be beneficial to the algal bloom, shifting the algal population to green algae and increasing total algal biomass within 1 wk after CSP treatment. Although zooplankton populations were adversely affected, populations of important zooplankton to catfish fry began rebounding 6–12 d after CSP treatment. Therefore, if CSP is used to treat catfish fry ponds of similar water composition used in this study, fry should not be stocked for about 2 wk after CSP application to allow time for the desirable zooplankton densities to begin increasing. 相似文献
11.
中性柠檬酸菌对几种常见藻类生长的他感作用 总被引：11，自引：0，他引：11
在４５００～４８００ｌｕｘ光照,２６～２８℃的培养条件下,从绿裸藻（Ｅｕｇｌｅｎａｖｉｒｉｄｉｓ）水华中分离的优势菌种之一中性柠檬酸菌（Ｃｉｔｒｏｂａｃｔｅｒｉｎｔｅｒｍｅｄｉｕｓ）的分泌物对斜生栅藻（Ｓｃｅｎｅｄｅｓｍｕｓｏｂｌｉｑｕｕｓ）、粉核小球藻（Ｃｈｌｏｒｅｌａｐｙｒｅｎｏｉｄｏｓａ）、羊角月牙藻（Ｓｅｌｅｎａｓｔｒｕｍｃａｐｒｉ ｃｏｒｍｕｔｕｍ）、水华鱼腥藻（Ａｎａｂａｅｎａｆｌｏｓ－ａｑｕａｅ）和易变鱼腥藻（Ａｎａｂａｅｎａｖｑｒｉａｂｉｌｉｓ）的生长有促进作用;对银灰平裂藻（Ｍｅｒｉｓｍｏｐｅｄｉａｇｌａｕｃａ）、莱茵衣藻（Ｃｈｌａｍｙｄｏｎｏｎａｓｒｅｉｎｈａｒｄｉ）和铜绿微囊藻（Ｍｉｃｒｏｃｙｓｔｉｓａｅｒｕｇｉｕｏｓａ）的生长具有抑制作用。中性柠檬酸菌胞外分泌物能促进粉核小球藻细胞个体的长大,对其他藻类主要是影响细胞的大小。中性柠檬酸菌对不同藻类影响的差异对水华过程可能具有重要意义。 相似文献
12.
作为淡水生态系统浮游植物的重要组成部分，绿藻是很多动物的开口饵料，其群体形成是应对外界环境压力的一种诱导型防御策略，当环境压力不存在时，会恢复单细胞形态。总结了影响绿藻单细胞-群体形态转变的外源因子及种间作用机制，包括非生物因子（营养、光照、温度）、生物因子（植食性浮游动物摄食、藻-藻竞争、沉水植物-藻竞争）以及人类活动对水生态系统的潜在压力，外源因子（低温、种间信息物质）诱导的多糖积累及胞外多糖分泌增加，可能是诱导绿藻群体聚集的重要原因；而人类活动造成的气候变暖、UVB辐射增强、微污染物增加（重金属、除草剂等），可能会打破绿藻由单细胞向群体形态的转换，提高绿藻被小型食草性动物摄食的概率，影响水生态系统的信息流，从而引发食物网级联效应，进而影响生态系统功能。基于已有的相关研究，总结了绿藻群体形成对于水生态系统结构、藻类毒理学以及微藻收获的重要意义与研究价值。 相似文献
13.
流式细胞摄像系统(FlowCAM)用于藻类形态特征识别与快速定量检测是目前先进和可行的方法之一。通过FlowCAM对3种培养藻类(斜生栅藻Scenedesmus obliquus、蛋白核小球藻Chlorella pyrenoidosa和莱茵衣藻Chlamydomonas reinhardtii)细胞密度和粒径大小进行检测,并与显微镜人工观察结果进行差异性统计对比。结果表明,FlowCAM为藻类分类鉴定提供了良好的图像及数据,可进行种类鉴定的藻类直径不应小于5μm。定量检测藻类样品的密度不应小于3×105个/L,即FlowCAM适合于藻类密度较高水体、特别是有水华发生水体的藻类鉴定和定量检测。 相似文献
14.
Filtration rates of hatchery-reared king scallop (Pecten maximus L.) juveniles, fed a single species alga diet (Pavlova lutheri (Droop) Green), were measured at a range of temperatures (6–21 °C). Weight specific filtration rate (ml min−1 g−1 (live weight)) of juveniles of a selected size range of 17–19 mm shell height (0.26–0.36 g live weight) increased with temperature above 16 °C and decreased below 11 °C, but was not significantly different between these two temperatures. Measurements at 16 °C using juveniles with a wider size range of 10–25 mm shell height (0.05–0.8 g live weight) gave the allometric equation: filtration rate (ml min−1)=12.19×weight (g)0.887. Filtration rate decreased significantly when the cell concentration was greater than 200 cells μl−1 (4.25 mg (organic weight) l−1). With six other algae food species, filtration rates similar to those with P. lutheri were only achieved with Chaetoceros calcitrans (Paulsen) Takano. All other algae species tested were cleared from suspension at significantly lower rates. Experiments with diet mixtures of P. lutheri and these other algae suggested that this was usually a reflection of lowered filtration activity, rather than pre-ingestive rejection of cells. In experimental outdoor nursery rearing systems, the filtration rate was inversely proportional to the concentration of cells in the inflow, in the range 5–210 cells μl−1. It was not affected by flow rate (2–130 l h−1, equivalent to 0.12–28.38 l h−1 g−1 (live weight)) with scallop juveniles stocked from 2 to 62 g l−1. The results are discussed in relation to on-growing scallops at field sites. 相似文献
15.
Alfalfa meal as a source of organic fertilizer was used in a series of pond, enclosure and laboratory experiments to determine its effect on bacteria, algae and water quality. Bacteria and flagellate algae were increased, whereas nonflagellate algae were not significantly affected by organic loadings. Bacterial and algal turnover rates we re 1.9-2.7 times daily and 0.18-0.22 times daily at 20-25oC, respectively. Oxygen consumption rates were enhanced by increasing organic input or temperature. Dissolved oxygen in ponds with organic fertilizer was significantly lower than that in ponds without organic input. Because of low N and P content and high oxygen consumption, organic fertilizer alone is unlikely to provide adequate nutrients for algae and sufficient oxygen for fish. To stimulate the growth of food organisms for fish in aquaculture ponds, a combined use of inorganic and organic fertilizer is recommended, but the amount of organic fertilizer should be determined with care to avoid water quality deterioration. The amount of 10mg alfalfa 1?1 wk?1 is considered the upper safety limit for organic fertilization. The nitrogen and phosphorus ratio should be kept weekly at 20:1 by weight to promote the development of food organisms in ponds. 相似文献
16.
- During this study, the effects of epiphytic filamentous algae on the survival of demersal spawned fish eggs were investigated in one of the most important spawning grounds of herring in the western Baltic Sea, which is subject to intense and ongoing eutrophication.
- In coastal marine ecosystems all over the world, eutrophication is a primary water quality issue, often resulting in mass developments of bloom‐forming algae. Macro‐algal blooms have immense ecological effects, as they alter the structure and the function of an ecosystem. Numerous fish species are affected, as they depend on those coastal areas for spawning and as juvenile habitats.
- A comparison of the survival of herring eggs on two natural spawning beds re‐vealed an immense impact of a filamentous algal bloom. The mortality rate reached nearly 100% in the area with massive occurrence of filamentous brown algae.
- Hypothesizing that the presence of filamentous algae facilitates herring egg mortality, field and laboratory experiments were conducted and revealed particular effects of distinct algal species. The survival rate of artificially spawned eggs on algal substrates and control substrates was compared. Whereas filamentous forms of the green alga Ulva intestinalis induced no immediate effect, significantly higher egg mortality was documented in experiments with the filamentous brown alga Pylaiella littoralis.
- Considering the ecological and economical importance of herring and other coastal spawners on the one hand and the persisting and increasing effects of eutrophication and climate change on the other hand, the results of our study clearly underpin the necessity to increase global efforts to reduce nutrient loads in coastal waters.
17.
The effects of phosphorus and nitrogen on phytoplankton dominance in tropical fish ponds 总被引：2，自引：1，他引：1
Nine ponds were used to determine the effects of phosphorus (P) and nitrogen (N) loading on the phytoplankton dominance in tropical fish ponds. Three ponds received triple superphosphate (TSP), three received triple superphosphate plus urea (TSP-Urea) and the rest served as the control. Addition of both phosphorus and nitrogen (TSP-Urea treatment) resulted in higher total phytoplankton than the TSP treatment and the control (P < 0.05). In general, blue-green algae formed the dominant group in TSP-Urea treatment ponds, followed by dinoflagellates, green algae, euglenoids and diatoms. In TSP-Urea treatment ponds, green algae was the most abundant group followed by blue-green, dinoflagellates, euglenoids and diatoms. Addition of combined nitrogen and phosphorus to the ponds not only significantly increased (P < 0.05) total phytoplankton densities, but also caused a shift from blue-green algal dominance to green algae. TSP treatment ponds showed significantly higher blue-green algae than TSP-Urea treatment in the early culture cycle. However, as the ponds became more productive with time, blue-green algae also appeared to be common in TSP-Urea treatment in spite of high N : P ratios. The blue-green algae increased linearly with the increase of total phytoplankton in all treatments (r2= 0.58, P < 0.01). 相似文献
18.
Growth,settlement and survival of Dicathais orbita (Neogastropoda,Mollusca) larvae in response to temperature,diet and settlement cues 
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下载免费PDF全文 The southern Australian whelk, Dicathais orbita, is a potential candidate for aquaculture, as both seafood and for bioactive compound production. Larval rearing experiments to determine the effects of temperature and diet on the growth and survival of D. orbita larvae under laboratory conditions comprised five different unicellular algal diets of two brown algal species; Isochysis galbana and Chaetoceros muelleri, two green algae; Tetraselmis seucica and Nannochloropsis oculata, and a mixture of all four strains for larvae maintained at 16 and 22°C. Absolute growth, specific growth rate (SGR) and survival were determined regularly. Larvae reared at 22°C on a mixed diet, or brown algae, performed significantly better than those reared on green algal diets alone. Preliminary trials with settlement cues were undertaken on different aged larvae to determine when larvae become competent. An array of natural cues (carrion, Xenostrobus pulex, adult mucus and Ulvella lens), as well as concentrations of KCl was tested. KCl(concentration of 20 mM) induced the greatest settlement, however, no larvae metamorphosed under the conditions provided. This study confirms long‐lived planktotrophic larval development for Dicathais orbita with higher development rates at the higher water temperatures. Further studies will optimize culture conditions and cues for settlement and metamorphosis. 相似文献
19.
汉江流域是多个引调水工程水源地,在国家水资源配置战略中具有重要地位,其水质安全问题一直备受关注。汉江中下游自1992年首次爆发水华以来,水华事件已累计发生10余次,给沿岸居民生产生活带来严重影响。本文系统调研了汉江水华相关研究进展,归纳分析了汉江中下游水华优势藻种及其生物学特性,统计分析了汉江中下游历次水华的发生特征,从营养盐、水文水动力、气象等条件方面归纳了现有研究成果中对于汉江中下游水华爆发成因的解释,总结了汉江中下游水华预测相关模型及水华可调控环境因子的阈值。当前汉江中下游水华防控面临新的挑战,未来仍需在环境因子对硅藻水华生消的影响机理、水华预测模型与方法、水华预警和抑制水华生态调度技术等方面继续开展深入研究。 相似文献
20.
氮磷浓度对惠氏微囊藻和斜生栅藻生长的影响 总被引：1，自引：0，他引：1
以惠氏微囊藻(Microcystis wesenbergii)和斜生栅藻(Scenedesmus obliquus)为研究对象,对比研究了氮(N)或磷(P)营养盐的相对限制对种群增长的影响。结果表明,培养11 d后,氮限制对惠氏微囊藻比生长速率、生物量、叶绿素浓度的最大抑制效应分别为2.25%、2.75%和40.01%;而对斜生栅藻的抑制效应分别为38.56%、58.64%和72.51%。磷限制对惠氏微囊藻比生长速率、生物量、叶绿素浓度的最大抑制效应分别为11.79%、10.94%和51.94%;对斜生栅藻的抑制效应分别为22.69%、49.62%和26.87%。氮磷营养盐起始浓度与2种微藻比生长速率、生物量之间多呈线性或指数型正相关关系。氮或磷单一营养盐处于富营养状态时,磷或氮营养盐浓度降低,惠氏微囊藻的生长仍能够维持在较高的水平,而斜生栅藻的生长则表现出显著的抑制效应。惠氏微囊藻对氮、磷限制的低敏感性是其获得种间竞争优势的生理学基础。 相似文献