Institute of Hydrobiology, Chinese Academy Of Sciences
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生态悬床技术对白洋淀水环境修复效果的研究
No full text为解决白洋淀深水区沉水植被恢复的问题,开发了一种由水生植物、绳索及支撑杆构建的生态悬床。生态悬床可根据水位变化调整在水体中的上下位置,2019年7月-2019年11月连续测定悬床周围水体中水质状况,研究了悬床种植沉水植物对湖泊深水区氮磷营养盐的净化效果。结果显示:狐尾藻在悬床上生长良好,并能有效地降低水体中的氮磷营养盐;试验开始一个月后,悬床周围水体总氮、总磷、亚硝酸盐氮去除率分别为40.54%、53.45%、99%;试验结束时,悬床周围水体总氮、亚硝酸盐氮和化学需氧量(COD)质量浓度分别比试验开始时下降了12.43%、33.93%、17.09%。研究表明:悬床种植沉水植物可有效解决沉水植物生长光照不足的问题,是北方藻型湖泊恢复沉水植被的有效措施之一。</p
不同营养盐及浓度对黄丝藻Tribonema sp.FACHB-1786生长及脂质积累的影响
No full text丝状微藻黄丝藻Tribonema sp.具有抗浮游动物捕食、易收获、油脂含量高等优点,且其脂肪酸组分中含有丰富的棕榈油酸(Palmitoleic acid,PA)和二十碳五烯酸(Eicosapentaenoic acid,EPA),被认为是生产生物柴油和高附加值产品的重要原料。为了提高黄丝藻脂质生产效率,文中研究了不同浓度的氮(NaNO_3:255–3060 mg/L)、磷(K_2HPO_4:4–240 mg/L)、铁((NH_4)_3FeC_(12)H_(10)O_(14):0.6–12 mg/L)、镁(MgSO_4:7.5–450 mg/L)元素对黄丝藻FACHB-1786生长、油脂积累和脂肪酸组分的影响。结果表明,培养基中磷、铁、镁三种元素的浓度对黄丝藻生长具有显著影响,其中增加MgSO_4浓度可显著提高黄丝藻的生物量,当MgSO_4浓度增加至450 mg/L时,获得最大生物量为8.09 g/L,显著高于目前报道的有关黄丝藻自养条件下获得的生物量;氮元素浓度对黄丝藻的生长没有显著影响(P>0.05),但高浓度氮元素有利于黄丝藻脂质的积累;黄丝藻FACHB-1786在765 mg/L NaNO_3、80 mg/L K_2HPO_4、6 mg/L (NH_4)_3FeC_(12)H_(10)O_(14)、75 mg/L MgSO_4的营养盐条件下可获得最大总脂单位体积产率、棕榈油酸和EPA产率,分别为319.6 mg/(L·d)、135.7 mg/(L·d)和24.2 mg/(L·d)。研究结果为后期黄丝藻的生产应用提供一定的理论依据和参考。</p
Aerobic denitrification affects gaseous nitrogen loss in biofloc-based recirculating aquaculture system
No full textBiofloc-based recirculating aquaculture system (BRAS) is beneficial for nitrogen recovery and culturing turbidity-intolerant fish. BRAS and traditional flow-through system were established to evaluate nitrogen mass balance for 90 days. In comparison with the flow-through system, BRAS increased the nitrogen recovery in the forms of fish and biofloc biomass by 3.2% and 11.9%, respectively. However, BRAS showed a significantly high level of gaseous nitrogen loss (64.4%). Aerobic denitrifiers such as bacteria belonging to the genera Hydrogenophaga, Flavobacterium, Rhodobacter, Pseudomonas, Zoogloea, and Dechloromonas were observed in both systems through Illumina Miseq sequencing. Hydrogenophaga, an autotrophic denitrifier, was predominant in the flow-through system (17% +/- 7%). In BRAS, the relative abundance of napA, which is a functional marker for aerobic denitrification, together with nirK and nosZ, significantly increased. These findings indicate that increased aerobic denitrification may be a key factor for the increased gaseous nitrogen loss in BRAS
Dynamic Change of Sedimental Microbial Community During Black Bloom-an In Situ Enclosure Simulation Study
No full textBlack bloom is a worldwide environmental problem. Sediment microbes play important roles in the process of black bloom. The dynamic change of sedimental microbial community and their potential link between taste and odor compounds during black bloom was investigated in an in situ black bloom enclosure simulation experiment. Through high-throughput sequencing and analysis, pronounced shifts of sedimental microbial community were observed on the 3rd and 7th day in the black bloom group. Microbes in Cyanobacteria, Verrucomicrobia, Planctomycetes, and Actinobacteria were obviously increased, while microbes from the phyla OP8, Chloroflexi, and Acidobacteria were decreased significantly. RDA analysis revealed that the concentrations of chlorophyll a (Chla), total phosphorus (TP), and turbidity (NTU) in the water and the TP, TN concentrations in the sediment were the main environmental factors that affect the microbial community in the sediment. Correlation analysis revealed that microbesDechloromonassp.(OTU003567 and OTU000093),Desulfococcussp. (OTU000911),Chromatiaceae(OTU001222), andMethanosaetasp. (OTU004809) were positively correlated with the taste and odor substances in the sediment, such as dimethyl sulfide (DMS), beta-ionone, beta-cyclocitral and geosmin. The sedimental microbial community gradually recovered in the late phase of black bloom, indicating the stability and self-recovery ability of the sedimental microbial community during black bloom. Noteworthily, we observed many possible pathogens increased significantly during the black bloom, which alerts us to keep away from contaminated sediment when black bloom occurred
Dynamic Change of Sedimental Microbial Community During Black Bloom-an In Situ Enclosure Simulation Study
No full textBlack bloom is a worldwide environmental problem. Sediment microbes play important roles in the process of black bloom. The dynamic change of sedimental microbial community and their potential link between taste and odor compounds during black bloom was investigated in an in situ black bloom enclosure simulation experiment. Through high-throughput sequencing and analysis, pronounced shifts of sedimental microbial community were observed on the 3rd and 7th day in the black bloom group. Microbes in Cyanobacteria, Verrucomicrobia, Planctomycetes, and Actinobacteria were obviously increased, while microbes from the phyla OP8, Chloroflexi, and Acidobacteria were decreased significantly. RDA analysis revealed that the concentrations of chlorophyll a (Chla), total phosphorus (TP), and turbidity (NTU) in the water and the TP, TN concentrations in the sediment were the main environmental factors that affect the microbial community in the sediment. Correlation analysis revealed that microbesDechloromonassp.(OTU003567 and OTU000093),Desulfococcussp. (OTU000911),Chromatiaceae(OTU001222), andMethanosaetasp. (OTU004809) were positively correlated with the taste and odor substances in the sediment, such as dimethyl sulfide (DMS), beta-ionone, beta-cyclocitral and geosmin. The sedimental microbial community gradually recovered in the late phase of black bloom, indicating the stability and self-recovery ability of the sedimental microbial community during black bloom. Noteworthily, we observed many possible pathogens increased significantly during the black bloom, which alerts us to keep away from contaminated sediment when black bloom occurred
Temporal and Spatial Variations of Chlorophyll a Concentration and Eutrophication Assessment (1987-2018) of Donghu Lake in Wuhan Using Landsat Images
No full textChlorophyll a (Chl-a) concentration, which reflects the biomass and primary productivity of phytoplankton in water, is an important water quality parameter to assess the eutrophication status of water. The band combinations shown in the images of Donghu Lake (Wuhan City, China) captured by Landsat satellites from 1987 to 2018 were analyzed. The (B4 - B3)/(B4 + B3) [(Green-Red)/(Green+Red)] band combination was employed to construct linear, power, exponential, logarithmic and cubic polynomial models based on Chl-a values in Donghu Lake in April 2016. The correlation coefficient (R-2), the relative error (RE) and the root mean square error (RMSE) of the cubic model were 0.859, 9.175% and 11.194 mu g/L, respectively and those of the validation model were 0.831, 6.509% and 19.846 mu g/L, respectively. Remote sensing images from 1987 to 2018 were applied to the model and the spatial distribution of Chl-a concentrations in spring and autumn of these years was obtained. At the same time, the eutrophication status of Donghu Lake was monitored and evaluated based on the comprehensive trophic level index (TLI). The results showed that theTLI( n-ary sumation ) of Donghu Lake in April 2016 was 63.49 and the historical data on Chl-a concentration showed that Donghu Lake had been eutrophic. The distribution of Chl-a concentration in Donghu Lake was affected by factors such as construction of bridges and dams, commercial activities and enclosure culture in the lake. The overall distribution of Chl-a concentration in each sub-lake was higher than that in the main lake region and Chl-a concentration was highest in summer, followed by spring, autumn and winter. Based on the data of three long-term (2005-2018) monitoring points in Donghu Lake, the matching patterns between meteorological data and Chl-a concentration were analyzed. It revealed that the Chl-a concentration was relatively high in warmer years or rainy years. The long-term measured data also verified the accuracy of the cubic model for Chl-a concentration. The R-2, RE and RMSE of the validation model were 0.641, 2.518% and 22.606 mu g/L, respectively, which indicated that it was feasible to use Landsat images to retrieve long-term Chl-a concentrations. Based on longitudinal remote sensing data from 1987 to 2018, long-term and large-scale dynamic monitoring of Chl-a concentrations in Donghu Lake was carried out in this study, providing reference and guidance for lake water quality management in the future
Revealing Cryptic Changes of Cyanobacterial Community Structure in Two Eutrophic Lakes Using eDNA Sequencing
No full textHarmful cyanobacterial blooms pose a risk to human health worldwide. To enhance understanding on the bloom-forming mechanism, the spatiotemporal changes in cyanobacterial diversity and composition in two eutrophic lakes (Erhai Lake and Lushui Reservoir) of China were investigated from 2010 to 2011 by high-throughput sequencing of environmental DNA. For each sample, 118 to 260cpcBA-IGS operational taxonomic units (OTUs) were obtained. Fifty-two abundant OTUs were identified, which made up 95.2% of the total sequences and were clustered into nine cyanobacterial groups. Although the cyanobacterial communities of both lakes were mainly dominated byMicrocystis, Erhai Lake had a higher cyanobacterial diversity. The abundance of mixed Nostocales species was lower than that ofMicrocystis, whereasPhormidiumandSynechococcuswere opportunistically dominant. The correlation between the occurrence frequency and relative abundance of OTUs was poorly fitted by the Sloan neutral model. Deterministic processes such as phosphorus availability were shown to have significant effects on the cyanobacterial community structure in Erhai Lake. In summary, theMicrocystis-dominated cyanobacterial community was mainly affected by the deterministic process. Opportunistically dominant species have the potential to replaceMicrocystisand form blooms in eutrophic lakes, indicating the necessity to monitor these species for drinking water safety
'Henicorhynchus' thaitui, a new species of cavefish from Central Vietnam (Teleostei, Cyprinidae)
No full text'Henicorhynchus' thaitui sp. nov. is described from a subterranean stream in a karst cave in Phong Nha Ke Bang National Park, Quang Binh Province, Central Vietnam. It differs from all congeners in having a pale pink body in life, smaller eyes with diameter less than the maxillary barbel length, and two pairs of barbels, the maxillary barbel being much longer than the rostral barbel
Functional characterization of a group II interferon, IFNc in the perciform fish, Nile tilapia (Oreochromis niloticus)
No full textInterferons are a family of class II alpha-helical cytokines playing vital roles in antiviral immune response, and little information is available to date regarding the interferon system of tilapia. In this study, a type I IFN gene, named On-IFNc, was identified in Nile tilapia, Oreochromis niloticus. The predicted protein of On-IFNc contains several structural features known in type I IFNs, and On-IFNc was clustered together with the known IFNc in fish into a separated Glade in the phylogenetic tree. On-IFNc gene was constitutively expressed in all tissues examined, with the highest expression level observed in liver, and was rapidly induced in all organs/tissues tested following the stimulation of poly(I:C). In addition, recombinant On-IFNc has been proven to markedly induce the expression of the antiviral effectors, Mx and viperin, the signalling components, STAT1, STAT2, and IRF9, and the transcription factors, IRF3 and IRF7, as well as the tyrosine phosphorylation of STAT1 and STAT2 in fish cells. Furthermore, recombinant On-IFNc has been proven to possess antiviral activity against ISKNV. The present study thus contributes to a better understanding of the functional properties of the type I IFN system in tilapia
Binary exposure to hypoxia and perfluorobutane sulfonate disturbs sensory perception and chromatin topography in marine medaka embryos
No full textPerfluorobutane sulfonate (PFBS), an environmental pollutant of emerging concern, is previously shown to dynamically interact with hypoxia on aquatic developmental toxicities. However, the molecular mechanisms underlying the interaction remain unknown. In this follow-up study, marine medaka embryos were exposed to 0 and 3.3 mg/L of PFBS under normoxia (6.9 mg/L) or hypoxia (1.7 mg/L) condition till 15 days post-fertilization. High-throughput transcriptomic sequencing was employed to filter differentially expressed genes and provide mechanistic insight into interactive action between hypoxia and PFBS. The results showed that hypoxia alone and the coexposure paradigm were similarly potent to modify transcriptional profiles, with the majority of genes significantly down-regulated. In contrast, transcriptional toxicity of PFBS was relatively milder. Functional annotation analyses found that hypoxia and coexposure groups mainly impacted phototransduction signaling by decreasing the transcriptions of cyclic nucleotide-gated (CNG) cation channels and retinol transport genes. However, this study demonstrated the first toxicological evidence that toxic effects of PFBS targeted the perception of chemical stimulus through olfactory and gustatory receptors. The addition of PFBS moderately exacerbated the toxic actions of hypoxia, which largely shaped the transcriptional pattern of coexposure group. In addition, gene interactive networks were constructed for hypoxia and coexposure groups, underlining the increased chromatin deacetylation and methylation to epigenetically repress genome-wide transcriptional initiation. Overall, PFBS and hypoxia interact to interrupt the embryonic development of sensory systems, which may compromise the individual fitness and survival, especially during early life stages when precocious perception of food and escape from predators are essential. (C) 2020 Elsevier Ltd. All rights reserved