Highest Average Abundance Research Articles

Dynamics of ectomycorrhizal mycobiota (Basidiomycota) communities on a former agricultural land (West Carpathians)

Ectomycorrhizal fungi (ECM) are very important in fundamental forest ecosystems. They play a very important role in the succession process, e.g., afforestation of former agricultural areas. Species richness and relative abundance of ECM macromycetes fruiting bodies were determined in spruce monocultures of different ages. Fifty-one ECM species were found; the most dominant were Ramaria formosa, Hygrophorus pustulatus, Lactarius aurantiacus, L. rufus, Paxillus involutus, and others. The highest average abundance was found in a 21-year-old forest stand; the highest number of species was found in a 51-year-old stand. Average monthly temperature (p < 0.001), precipitation (p < 0.01), and soil carbon content (p < 0.05) had the most significant impact on the dynamics of species richness and abundance. The highest values of abundance and species richness were noted in summer 2016 and autumn 2017 and 2018. The highest values of mycorrhizal percentage were recorded in 21-year-old forest stands (41.95%), and the lowest values were recorded in 51-year-old stands (35.86%). Shannon index values (H´) indicate a slightly lower species diversity of ECM fungi in young stands (1.65) compared with older stands (1.71). The values of species richness and fruiting bodies abundance were statistically strongly significant (p < 0.001) during seasonality (month) and through the interaction (month/year). Amanita muscaria, Chalciporus piperatus, Russula aeruginea, and Suillus grevillei were found as indication species in the youngest stands. Amanita rubescens, Imleria badia, Inocybe lacera, and Tricholoma equestre were found as indication species in the oldest stands.

Unraveling the Microbiota of Natural Black cv. Kalamata Fermented Olives through 16S and ITS Metataxonomic Analysis.

Kalamata natural black olives are one of the most economically important Greek varieties. The microbial ecology of table olives is highly influenced by the co-existence of bacteria and yeasts/fungi, as well as the physicochemical parameters throughout the fermentation. Therefore, the aim of this study was the identification of bacterial and yeast/fungal microbiota of both olives and brines obtained from 29 cv. Kalamata olive samples industrially fermented in the two main producing geographical regions of Greece, namely Aitoloakarnania and Messinia/Lakonia. The potential microbial biogeography association between certain taxa and geographical area was also assessed. The dominant bacterial family identified in olive and brine samples from both regions was Lactobacillaceae, presenting, however, higher average abundances in the samples from Aitoloakarnania compared to Messinia/Lakonia. At the genus level, Lactobacillus, Celerinatantimonas, Propionibacterium and Pseudomonas were the most abundant. In addition, the yeasts/fungal communities were less diverse compared to those of bacteria, with Pichiaceae being the dominant family and Pichia, Ogataea, and Saccharomyces being the most abundant genera. To the best of our knowledge, this is the first report on the microbiota of both olives and brines of cv. Kalamata black olives fermented on an industrial scale between two geographical regions of Greece using metagenomics analysis.

Comparison structural organization of phytoplankton communities on Ukrainian shelf and open water of Black Sea (spring 2016)

The results of researches of phytoplankton that was held in May-June 2016 within the framework of the EMBLAS project are presented. The results of the two cruis made it possible to compare the structure and distribution of phytoplankton in the shelf (NPMS-UA (Shelf-UA)) and open waters (JOSS-UA (OW-UA)) of Ukraine. The highest species diversity was found in the stations of Shelf-UA (224 species). In the open waters of the number of identified species decreases (138 species). Dinophyceae contribution in species diversity on the shelf was lower, and Bacillariophyceae contribution was higher than in open waters. The average biomass on the shelf (418.10 mg/m3) exceeded the similar value of open waters (274.23 mg/m3). Analysis of the vertical distribution showed the maximum values of abundance and biomass in the upper layer (to 20 m). The general trend of the spatial distribution of phytoplankton biomass was a decrease of the average values from the Ukrainian shelf to the open waters. High contribution of Bacillariophyceae in the average abundance at Shelf-UA stations (85%) decreased to 50% in OW-UA. The relative contribution of Prymnesiophyceae in the total abundance contrary increased from 4% (Shelf-UA) to 44% (OW-UA). Of the 10 mass species registered in the studied area, only Pseudo-nitzschia delicatissima reached the level of bloom (to 3.39∙106 cells/L for Shelf-UA and 2.39∙106 cells/L for OW-UA). In the study area was identified 14 potentially toxic species. The highest average abundance (302.46∙103 cells/L) and biomass (143.09 mg/m3) was formed by Pseudo-nitzschia delicatissima. Among the investigated sites, the most favorable environmental conditions were observed in the open Ukrainian shelf water (OW-UA). Worst category of ESC was noted in the Shelf-UA in the Danube Region (Poor).

Isolation and Molecular Identification of Hydrocarbon Degrading Bacteria from Contaminated Soil in Mechanic Village Dutse, Jigawa State

The spillage of oil and other petroleum products have been a major source of environmental pollution globally. Rampant use of chemical remediation methods were shown to be noxious with detrimental consequences. Exploration of microbiodata for probable candidate to be utilized for degradation of oil spillage or contamination is of great interest. In this study, soil samples from 10 different mechanic workshops in mechanic village Dutse were collected as well as control sample from unpolluted hydrocarbon free soil at same site, bacterial species were isolated, identified using biochemical and molecular 16S rRNA gene sequencing and post sequencing analyses. Species enumerated were Bacillus cereaus, Bacillus subtilis, Bacillus licheniformis and Paenibacillus alvei, The sequences were compared to closest relative species in the GenBank data base of National Centre for Biotechnology Information. However, the substrate used was engine oil and all the isolates were found to utilized the test substrate. Biodegradation studies have been carried out through Gas Chromatography Mass Spectrometry (GC-MS). Of all the isolates, Bacillus subtilis might be the most hydrocarbon degrading bacterial species due to high average relative abundance concentration of degraded hydrocarbon compound.

Degradation Analysis of FeF3 Positive Electrode Using Two-Compartment Type Cell

Iron trifluoride (FeF3) has been attracted as one of the promising candidates for the electrode material of lithium ion batteries due to their high theoretical capacity (712 mA g–1), high average potential and abundance of Fe. However, various problems such as low conductivity of FeF3, large overpotential and poor cyclability still remain with regard to overcoming for commercialization. Improvement of the cycling performance of FeF3-based lithium ion battery have been achieved by addition of anion receptor, nano-sizing of FeF3 and tuning of electrolyte composition so far [1-3], but the suppression of degradation and the elucidation of its mechanism have not accomplished completely. In the present study, we investigated charge and discharge behavior of FeF3 positive electrode using designed two-compartment type cell to analyze the degradation mechanism of FeF3 positive electrode. FeF3/C composite electrode and coin cell were prepared by following our previous literature. [4] The coin cell using 1.0 mol dm–3 LiPF6 in 1:1 ratio of ethylene carbonate (EC) and dimethyl carbonate (DMC) as an electrolyte showed over 600 mAh g–1 of discharge capacity at 2nd cycle. However, the discharge capacity decreased to 200 mAh g–1 at 30th cycle. Although several studies on the effects of additives to the electrolyte were conducted to improve the cycle performance, charge and discharge behavior did not changed drastically. Then, we designed the two-compartment cell which has lithium ion conducting ceramics as a separator to prevent the crossover of the electrolyte between the positive and negative electrode. In the case the electrolyte with a certain additive was used only for the positive electrode, the discharge capacity exhibited over 400 mAh g–1 at 30th cycle. This result indicates that crossover of the decomposed product of the electrolyte is one of the reasons for the degradation of the coin cell using additives. After cycling test, various analyses such as, electrochemical impedance, X-ray photoelectron spectroscopy and scanning electron microscopy, were also conducted for the electrode with and without additves in the electrolyte to examine the degradation mechanism of FeF3 positive electrode. The obtained results were considered useful for the improvement of the cycling performance of FeF3-based lithium ion batteries.

Analysis of continental shale gas accumulation conditions in a rifted basin: A case study of Lower Cretaceous shale in the southern Songliao Basin, northeastern China

Abstract The analysis of shale gas accumulation conditions is the basis of shale gas exploration. Previous research has mainly focused on the Upper Cretaceous shale in the Songliao Basin of northeastern China, and few studies have analyzed the Lower Cretaceous shale in this area. Based on an integrated analysis of the sedimentary facies, shale samples and seismic interpretation from the Lower Cretaceous Shahezi, Yingcheng and Denglouku Formations of the Fulongquan Depression in the Songliao Basin, the distribution of the shale and the generation, accumulation and preservation conditions of the shale gas are evaluated and discussed. Core observations and sedimentary facies analysis show that the sedimentary facies types in the Shahezi, Yingcheng and Denglouku Formations are mainly fan delta, braided river delta, sublacustrine fan and lacustrine facies. The semideep lake, shallow lake and delta front sedimentary subfacies are favorable for the deposition of shale. The study of the shale distribution indicates that the shale was mainly deposited near the maximum flooding surface of the third-order sequences, and the shales in the Shahezi and Yingcheng Formations are darker and thicker than those in the Denglouku Formation. In addition, the shale in this study area is laterally distributed in the depression belt and the steep slope belt near the boundary faults of the basin. According to the geochemistry tests, rock properties and mineral constituents, the shales in the Shahezi and Yingcheng Formations have favorable gas generation potential. Compared with the properties of the major gas-producing shales in China and the United States, the shales in the Shahezi and the Yingcheng Formations are thick and have a favorable organic matter type, high average organic matter abundance, high organic matter thermal maturity that reached a high maturation stage, high porosity and high gas contents; these properties meet the standards of industrial exploitation, and these shales can therefore be considered favorable targets for unconventional energy exploration.

Distribución de epífitas vasculares sobre cuatro especies arbóreas en un bosque xerofítico del Chaco Húmedo, Argentina

Fil: Alvarez Arnesi, Eugenio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentina

Composition and Density of Fouling Organism on the Wood Harbour at Karang-Karangan, Bua District, Luwu Regency

The Research on Composition and Abundance of Biofouling Biota at Woodenpier at Karang-Karangan Beach Bua Sub-district of Luwu Regency was conducted from December 2016-June 2017. The purpose of this research is to know the types of macrobiofouling, and the abundance of macrobiofouling on the wooden pier on the Beach Coral-Karangan, Bua Sub-district, Luwu Regency. Sampling method using a quadrant plot and performed two data retrieves on the poles of wooden pier which were either exposed or unexpressed by water with 12 point stations. The results showed there were 8 species of 6 families: Saccostrea sp (ostreidae), Saccostrea cucullata (Ostreidae), Littoraria scabra (Littorinidae), Thais rufotincta (Muricidae), Septifer sp (Mytilidea), Cladophora glomerata (Cladophoraceae), Balanus sp (Balanidae), and Haemocinus sp (Planopilumnidae). Saccostrea sp has the highest average abundance ofmacrobiofouling on exposed wooden pier (223 ind/m 2). The lowest abundance of Thais rufotincta and Haemocinus sp (1 ind/m2), respectively.

High phylogenetic diversity and abundance pattern of Labyrinthulomycete protists in the coastal waters of the Bohai Sea

The unicellular Labyrinthulomycete protists have long been considered to play a significant role in ocean carbon cycling. However, their distribution and biogeochemical function remain poorly understood. We present a large-scale study of their spatiotemporal abundance and diversity in the coastal waters of Bohai Sea using flow cytometry and high-throughput sequencing. These protists display niche preferences and episodic higher biomass than that of bacterioplankton with much phylogenetic diversity (> 4000 OTUs) ever reported. They were ubiquitous with a typical abundance range of 100-1000 cells ml-1 and biomass range of 0.06-574.59 μg C L-1 . The observed spatiotemporal abundance variations support the current 'left-over scavengers' nutritional model and highlight these protists as a significant component of the marine microbial loop. The higher average abundance and phylogenetic diversity in the nearshore compared with those in the offshore reveal their predominant role in the terrigenous matter decomposition. Furthermore, the differential relationship of the protist genera to environmental conditions together with their co-occurrence network suggests their unique substrate preferences and niche partitioning. With few subnetworks and possible keystone species, their network topology indicates community resilience and high connectance level of few operational taxonomic units (OTUs). We demonstrate the significant contribution of these protists to the secondary production and nutrient cycling in the coastal waters. As secondary producers, their role will become more important with increasingly coastal eutrophication.

Influence of Temperature on the Bacterial Community in Substrate and Extracellular Enzyme Activity of Auricularia cornea

Temperature is an important environmental factor that can greatly influence the cultivation of Auricularia cornea. In this study, lignin peroxidase, laccase, manganese peroxidase, and cellulose in A. cornea fruiting bodies were tested under five different temperatures (20 °C, 25 °C, 30 °C, 35 °C, and 40 °C) in three different culture periods (10 days, 20 days and 30 days). In addition, the V4 region of bacterial 16S rRNA genes in the substrate of A. cornea cultivated for 30 days at different temperatures were sequenced using next-generation sequencing technology to explore the structure and diversity of bacterial communities in the substrate. Temperature and culture days had a significant effect on the activities of the four enzymes, and changes in activity were not synchronized with changes in temperature and culture days. Overall, we obtained 487,694 sequences from 15 samples and assigned them to 16 bacterial phyla. Bacterial community composition and structure in the substrate changed when the temperature was above 35 °C. The relative abundances of some bacteria were significantly affected by temperature. A total of 35 genera at five temperatures in the substrate were correlated, and 41 functional pathways were predicted in the study. Bacterial genes associated with the membrane transport pathway had the highest average abundance (16.16%), and this increased at 35 °C and 40 °C. Generally, different temperatures had impacts on the physiological activity of A. cornea and the bacterial community in the substrate; therefore, the data presented herein should facilitate cultivation of A. cornea.

Influence of physical chemical water parameters on abundance and presence of the arbovirus vector Aedes Albopictus (Dipteria: Culicidae) in Larval habitats of forest fragments

Introduction The species Aedes albopictus (Diptera: Culicidae) is a mosquito of great epidemiological importance because it carries several arboviruses that cause diseases in humans, including the dengue virus. In Brazil, this species was introduced in mid-1986 and nowadays is found in almost the whole country cities, developing in natural or artificial breeding sites in peri-urban and urban areas. For aquatic insects living in lentic environments, such as immature forms of mosquitoes, the physicochemical environment factors represent important constraints that can influence the development, survival and adaptation of the organism. Despite this, few studies have sought to investigate the influence of physicochemical factors on the incidence and abundance of vector mosquitoes. In this study we investigated the influence of pH, practical salinity unit (PSU), water temperature in degrees Celsius (°C) and oxygen dissolved in parts per million (DO ppm) on the incidence and abundance of Aedes albopictus collected in larval habitats found in four urban green spaces in the city of Sao Paulo. Methods Natural breeding sites (bromeliads, bamboos, trees holes, and puddles) and artificial ones were explored (water boxes, plant pots, tires, etc.) during 12 months of collection. The physicochemical parameters were measured using a multiparameter device Hanna-HI-9828. The predictive relationship between the measured physicochemical factors and the incidence and abundance of A. albopictus was evaluated by generalized additive models (GAM). Akaike Information Criterion corrected for small samples was used to select the model with the best fit and explanatory power. For a better understanding of the non-linearity of relationship between the variables, a tree regression analysis was made from the selected model. Results A total of 4212 specimens of A. albopictus were collected in 142 positive samples from both natural and artificial breeding sites. In relation to the positive samples the variation in the physicochemical parameters was: pH 2.3 to 9.8, PSU 4.8 and PSU > 0.175. The abundance was better explained by pH, salinity and temperature, with higher average abundance (151 individuals/mean) in PSU > 0.335, pH Conclusions The mosquito A. albopictus showed to be adapted to wide variations in physicochemical conditions of larval habitats, which in part explains its wide ecological valence and worldwide dispersion. The predictive models proposed in this study may be useful to help understand the relationship of A. albopictus and other vector mosquitoes with abiotic environment constraints.

Spatiotemporal modelling of crown‐of‐thorns starfish outbreaks on the Great Barrier Reef to inform control strategies

Summary Cyclical outbreaks of pests can impact the functioning of entire ecosystems. An eminent example is outbreaks of crown‐of‐thorns starfish (COTS; Acanthaster planci) that cause substantial coral mortality on the Great Barrier Reef (GBR). We analyse COTS abundance and outbreaks with a Bayesian spatiotemporal model applied to a long‐term survey of the GBR (1985–2014). We assess the relative increase in COTS abundance beyond that explained by a reef's location and explanatory covariates, and thereby incorporate local reef characteristics into the identification of outbreaks, while allowing for both randomness and predictable patterns in the development of outbreaks. The model results confirm that waves of COTS outbreaks originate near Lizard Island (14·67⁰S) and progress in a northwesterly or southeasterly direction, with the southward wave progressing about 60 km year−1. The model reveals several previously unidentified hotspots with high average COTS abundance. The abundance of COTS may also have decreased on reefs protected from fishing after an expansion of protected areas within the GBR Marine Park in 2004, which suggests that closing reefs to fishing may help control COTS. Synthesis and applications. In this study, we use 30 years of data from the Great Barrier Reef to show that the timing and geographic location of crown‐of‐thorns starfish (COTS) outbreaks can be modelled by incorporating covariates, spatial and spatiotemporal dependence within a single coherent framework. The model can be used to identify areas of high average COTS abundance, to assess the impact of fishery management actions such as no‐take areas and to identify areas where waves of outbreaks may originate. The identification of outbreaks from noisy long‐term spatially extensive data may help managers choose appropriate control strategies. This modelling approach is applicable to other ecosystems where outbreaks of damaging pests occur.

Variable coloration is associated with dampened population fluctuations in noctuid moths.

Theory and recent reviews state that greater genetic and phenotypic variation should be beneficial for population abundance and stability. Experimental evaluations of this prediction are rare, of short duration and conducted under controlled environmental settings. The question whether greater diversity in functionally important traits stabilizes populations under more complex ecological conditions in the wild has not been systematically evaluated. Moths are mainly nocturnal, with a large variation in colour patterns among species, and constitute an important food source for many types of organisms. Here, we report the results of a long-term (2003–2013) monitoring study of 115 100 noctuid moths from 246 species. Analysis of time-series data provide rare evidence that species with higher levels of inter-individual variation in colour pattern have higher average abundances and undergo smaller between-year fluctuations compared with species having less variable colour patterns. The signature of interspecific temporal synchronization of abundance fluctuations was weak, suggesting that the dynamics were driven by species-specific biotic interactions rather than by some common, density-independent factor(s). We conclude that individual variation in colour patterns dampens population abundance fluctuations, and suggest that this may partly reflect that colour pattern polymorphism provides protection from visually oriented predators and parasitoids.

Fecundity of the pine processionary moth Thaumetopoea pityocampa (Lepidoptera: Notodontidae) at the southern edge of its distribution range

AbstractAnalysis of annual and plot variations of egg batches number of Thaumetopoea pityocampa at the southern limit of its distribution area and in Pinus halepensis afforestations situated in the Algerian sub-Saharan region showed that its fecundity depends on the density of its population, plots, years and interaction of plots-years. It appears that the high average abundance of egg batches/trees during the outbreak period of this pest insect exceeds 24. The real fecundity is the lowest in the Mediterranean Basin and suggests that local adaptation can occur. The low fecundity is not an obstacle to caterpillar survival under different selection pressures. It is compensated by merging of colonies during the larval cycle. Moreover, in this study we noted a significant correlation between the number of eggs and the size of egg batches deposited on needles or around small pine branches. Size of egg batches is also intimately linked to the length of adult female forewings, fresh weight of females and weight of their pupae. Females with a biennial cycle have a low potential fecundity compared to those with an annual one.

Population dynamics of Aurelia sp.1 ephyrae and medusae in Jiaozhou Bay, China

The scyphozoan Aurelia aurita (Linnaeus) s. l., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. We hypothesized that ephyrae of Aurelia sp.1 are released from the inner part of the Jiaozhou Bay, China when water temperature is below 15°C in late autumn and winter. The seasonal occurrence, growth, and variation of the scyphomedusa Aurelia sp.1 were investigated in Jiaozhou Bay from January 2011 to December 2011. Ephyrae occurred from May through June with a peak abundance of 2.38 ± 0.56 ind/m3 in May, while the temperature during this period ranged from 12 to 18°C. The distribution of ephyrae was mainly restricted to the coastal area of the bay, and the abundance was higher in the dock of the bay than at the other inner bay stations. Young medusae derived from ephyrae with a median diameter of 9.74 ± 1.7 mm were present from May 22. Growth was rapid from May 22 to July 2 with a maximum daily growth rate of 39%. Median diameter of the medusae was 161.80 ± 18.39 mm at the beginning of July. In August, a high proportion of deteriorated specimens was observed and the median diameter decreased. The highest average abundance is 0.62 ± 1.06 ind/km2 in Jiaozhou Bay in August. The abundance of Aurelia sp.1 medusae was low from September and then decreased to zero. It is concluded that water temperature is the main driver regulating the life cycle of Aurelia sp.1 in Jiaozhou Bay.

Amount and distribution of neustonic micro-plastic off the western Sardinian coast (Central-Western Mediterranean Sea)

A plethora of different sampling methodologies has been used to document the presence of micro-plastic fragments in sea water. European Marine Strategy suggests to improve standard techniques to make future data comparable. We use Manta Trawl sampling technique to quantify abundance and distribution of micro-plastic fragments in Sardinian Sea (Western Mediterranean), and their relation with phthalates and organoclorine in the neustonic habitat. Our results highlight a quite high average plastic abundance value (0.15 items/m3), comparable to the levels detected in other areas of the Mediterranean. “Site” is the only factor that significantly explains the differences observed in micro-plastic densities. Contaminant levels show high spatial and temporal variation. In every station, HCB is the contaminant with the lowest concentration while PCBs shows the highest levels. This work, in line with Marine Strategy directives, represents a preliminary study for the analysis of plastic impact on marine environment of Sardinia.

浮游植物群落对海南小水电建设的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 浮游植物群落对海南小水电建设的响应 DOI: 10.5846/stxb201205300790 作者: 作者单位: 海南省环境科学研究院,海南省环境科学研究院,暨南大学水生生物研究中心,海南省环境科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 2009年海南省重点科技项目(KJXM20090002) Responses of phytoplankton community to the construction of small hydropower stations in Hainan Province Author: Affiliation: Hainan Research Academy of Environmental Sciences,Hainan Research Academy of Environmental Sciences,Institute of the Hydrobiology,Jinan University,Hainan Research Academy of Environmental Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨浮游植物群落对海南省小水电建设的响应,分别在海南省主要河流的上游支流已建小水电的蓄水水域与河道、规划(未建)小水电河段采集浮游植物样品进行比较分析。共鉴定出浮游植物种类62个属178种,曲壳藻(Achnanthaceae)、异极藻(Gomphonema)、菱形藻(Nitzschia)、颗粒直链藻(Melosira granulat)、席藻(Phormidium)、颤藻(Oscillatoria)、小球藻(Chlorella vulgaris)、平裂藻(Merismopedia)、舟形藻(Navicula)为主要的优势藻类,浮游植物丰度在5.1-163.6×104 个/L之间,浮游植物Shannon-Wiener多样性指数在2.73-4.53之间。研究结果表明,小水电建设对浮游植物的种类组成、优势种、丰度及多样性均有较大的影响。就浮游植物优势种而言,规划小水电河道以蓝藻及部分硅藻为主要优势种,已建小水电河道曲壳藻、异极藻、菱形藻等大型硅藻为主要优势种。在浮游植物组成及生物多样性上,未建小水电河道浮游植物Shannon-Wiener多样性指数略高,且种属分布更加均衡,而已建设水电站均趋向某一类藻占主导优势种。就浮游植物丰度而言,规划小水电河道浮游植物丰度均保持在20-30×104 个/L内,已建小水电河段浮游植物保持在5-160×104 个/L内且浮游植物丰度差异性较规划小水电大,小水电建设促进了浮游植物丰度的提升,但降低了浮游植物群落结构的稳定性、均衡性。虽然存在水电站阻隔,同一河流水系浮游植物种属来源仍可表现一定的趋同性,梯级水电特别是相邻水电间浮游植物群落组成存在较大的相似性。 Abstract:Small hydropower stations (SHS) not only play an important role in electricity generation and water resource regulation in mountain areas, but also at the same time, impose ecological and environmental impacts. To study the responses of phytoplankton community in rivers with construction of SHS, samples of phytoplankton from 7 rivers in Hainan Province where SHS had been or will be built were taken and analyzed. According the results, a total of 178 phytoplankton species belonging to 62 genera were identified, and the dominant species includes Achnanthaceae, Gomphonema, Nitzschia, Melosira granulat, Phormidium, Oscillatoria, Chlorella vulgaris, Merismopedia, and Navicula. Phytoplankton abundance in rivers was from 5.1×104cells/L to 63.6×104cells/L, the diversity index was from 2.73 to 4.53, and Desmids had been found in most SHS. SHS had a great influence on phytoplankton biomass, species composition and dominant species in the rivers. Comparing with thfe rivers with SHS, the rivers without SHS had higher Shannon-Wiener diversity index and the composition of phytoplankton species were more balanced, Cyanobacterias and some Diatoms always dominated the phytoplankton community in the rivers, such as in NDJ-JJ-9 (Cyanophyta 25.7%,Chlorophyta36.9%, Bacillariophyta 36.1%), ZBJ-MMD-11 (Cyanophyta 41.8%, Chlorophyta 33.2%,Bacillariophyta 23.1%), and WLH-SX-13(Cyanophyta 29.1%, Chlorophyta 25.2%, Bacillariophyta 38.8%). In the rivers with SHS, large diatom Achnanthacea,Gomphonema and Nitzschia becoming predominated were common, such as in CHJ-YJ-1 (Bacillariophyta 91.3%), CHJ-YJ-2 (Bacillariophyta 65.9%), and NDJ-GL-6 (Bacillariophyta 56.5%).To phytoplankton abundance, most rivers without SHS were 20-30×104cells/L, while the rivers with SHS were widely different 5-160×104cells/L. The rivers with SHS had higher average abundance and abundance difference index than the ones without SHS. The construction of SHS had changed the hydrodynamic of the rivers, and the changed hydrodynamic might had played an important role in the phytoplankton community. In mountain areas of Hainan province, most rivers were Shallow with less water flow. Stable water environment was suitable for Cyanobacterias and some Diatoms in the river without any SHS. Once SHS had been built, agitation of water body increased and lager Diatoms such as Achnanthaceae Gomphonema and Nitzschia might be dominated. The construction of SHS would also promoted the biomass of the river, but weaken the stability and proportionality of phytoplankton community by increasing fluctuation and agitation. Among cascade SHS, the barrier of the stations, the phytoplankton community could still be some similar especially between adjacent SHS. The correlation coefficient of phytoplankton community between adjacent SHS were all over 0.9 with highly significant correlation(P<0.01). 参考文献 相似文献 引证文献

Development of a zooplankton community including Heterocope saliens Lillijeborg in an experiment with hydrophytes

The influence of the submerged plants Ceratophyllum demersum L. and Elodea canadensis Michx. and the floating plant Hydrocharis morsus-ranae L. on the species composition and quantitative parameters of a zooplankton community was studied experimentally. Among submerged vegetation, the development of the predaceous calanid Heterocope saliens Lilljeborg was suppressed. An increase in the number of zooplankter species was observed in all experimental ecosystems with hydrophytes. The species similarity of zooplankton was higher between communities with plants of the same ecological group than with plants of different groups. The highest average zooplankton biomass, as determined by the abundance of Daphnia longispina O.F. Muller and Simocephalus vetulus (O.F. Muller), was observed in experiments with Elodea. The highest average abundance over the experimental period was recorded among Ceratophyllum, where the abundance of Rotifera, chydorids, and copepods common in hydrophyte beds was higher than in other versions of the experiment.

Community structure and fish assemblage at Marsa Abu Dabab, Red Sea, Egypt.

he fish assemblages of different habitats at Marsa Abu Dabab (north Marsa Alam, Red Sea) were examined by visual census techniques. Fish communities were estimated for each of the investigated habitats; seagrasses and coral reefs which have divided into three sectors; sector A (at north) and C (at south) represent coral reef habitats, whereas sector B (in the middle) represents seagrass habitat. A total of 172 fish species representing 94 genera were recorded at Marsa Abu Dabab. The coral reef habitat had the highest number of species (162 species), while the seagrass habitat had the lowest (90 species). The highest average abundance was recorded at sector C in the reef wall habitat (1119 fish/1000 m 3 ), with the lowest value at sector B in the seagrass habitat (240 fish/1000 m 3 ). Some fish species were restricted to seagrass or coral reefs, while others were widespread along the gradient. Regarding to fish distribution patterns, five families showed increasing in coral reef habitat (Pomacentridae, Labridae, Acanthuridae, Chaetodontidae and Serranidae), while other three families were abundant in seagrass beds (Siganidae, Sparidae and Mullidae). The five families in coral reef habitats showed in high abundance on reef wall (RW) more than reef flat (RF), except Acanthuridae.

Genetic variability of Anisakis simplex s.s. parasitizing European hake (Merluccius merluccius) in the Little Sole Bank area in the Northeast Atlantic

In this study, we researched the presence of anisakids in specimens of Merluccius merluccius caught in the area of Little Sole Bank, in the Northeast Atlantic, and found that 100% of the European hake examined were infected and showed high average values of abundance (976.88) and intensity (976.88). The larvae were identified in morphological terms as morphotype type I and in molecular terms as Anisakis simplex s.s via polymerase chain reaction (PCR) restriction fragment length polymorphism of the rDNA. The genetic variability of the A. simplex s.s population in the North Atlantic is notable, with at least two ribosomal and three mitochondrial haplotypes which are different from the specimen used as control, reflecting the diversity of this species, an aspect which has scarcely been studied to date. The cox-2 gene appears to be an interesting candidate for generating new genetic markers which can be applied to differentiate between A. simplex s.s and Anisakis pegreffii. We detected 11 fixed differences in this gene, and it also offers the advantage of being easily amplified by PCR. The high prevalence of infection by A. simplex s.s and the extremely high average intensity and abundance values can have significant repercussions on public health, especially among populations which regularly eat insufficiently cooked or raw fish and have a certain genetic predisposition; the genetic variability of the parasite could be another factor to take into account.