Effective monitoring of freshwater fish

Freshwater ecosystems constitute only a small fraction of the planet’s water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians, or reptiles. Fresh waters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, nutrient enrichment, and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish assemblages. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g. early detection of alien species), tracking changes in the abundance of threatened species, or documenting long-term temporal changes in entire communities. Irrespective of their motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes, and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasise that investigators must address issues around sampling design, statistical power, species’ detectability, taxonomy, and ethics in their monitoring programmes. Additionally, programmes must ensure that high-quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review aims to help programmes improve understanding of the processes that shape the Earth's freshwater ecosystems, and help protect these systems in face of rapid environmental change

Capacity of Vitiver grass in treatment of a mixture of labaratory and domestic wastewaters

 In this study, laboratory wastewater containing organic matters, heavy metals and aromatic compounds, was treated by vetiver grass (Vetiveria zizanioides) as a phytoremediation method to remove the above three groups of pollutants. Sewage effluent, as a source of nutrient supply for plant growth, was firstly fed to two wetland systems: mini horizontal subsurface flow (HSSF) and floating raft (FR) wetlands. Next, laboratory wastewater was added gradually to mix with sewage. Nominal hydraulic retention time in both wetlands are 12 hours. Pollutants removal efficiencies were monitored. Microbial community change corresponding with each stages of sewage only and mixture with laboratory wastewater was also examined. The examined microbial community includes Nitrogen-fixing (N-fixing) bacteria, Phosphate-solubilizing (P-solubilizing) microorganism, Pseudomonas sp., and Zoogloea sp.  In HSSF wetland, base materials (gravel and sand), algae, and vetiver root were in turn investigated for pollutant removal efficiencies. The results reveal that even with the presences of heavy metals and aromatic compounds, vetiver presented reasonable removal efficiencies of about 62%, 68.6%, and 58.3% for BOD, TN, and TP removal, respectively. Base materials showed almost no effect on pollutant removal. Algae was slightly responsible for approximate 6.3%, 16.6%, and 19.7% of BOD, TN, and TP removals, respectively. On the other hand vetiver roots, in term of heavy metals, had an impressive removal efficiencies of 99.2, 95.8, 96.2, and 96.7% of Cr+6 (in K2Cr2O7), Mn (MnSO4), Fe (FeSO4), and Cu (CuSO4), respectively. For aromatic compounds, the wetland is responsible for 96.8 and almost 100% of correspondingly phenol and benzene removal efficiencies. For microbial aspect, N-fixing microorganisms (e.g. Azospirillum sp., Azotobacter sp.) and Phosphate-solubilizing bacteria (Bacillus sp.) increased gradually in population during domestic wastewater feeding stage. When laboratory wastewater was added, N-fixing and P-solubilizing bacteria were quantitatively decreased slightly while population of Pseudomonas sp. increased. Besides, Zoogloea sp. was also found increasing through out the experiment and keeping a stable growth even during laboratory wastewater adding.  In FR wetland, both algae and vetiver root were also investigated for BOD and aromatic compounds and heavy metals. The outcomes show similar tendencies in treatment and microbial behaviours as in HSSF wetland. Vetiver grass, mainly responsible for organic matters and nutrients removal, presented slightly lower removal efficiencies than those in HSSF wetland. The average values of removal efficiencies are 59%, 63.5%, and 53.0% for BOD, TN, and TP removal, respectively. Algae, also, took minor responsibility for approximate 3.3%, 9.1%, and 8.9% of BOD, TN, and TP removals, respectively. Heavy metals of Cr+6 (in K2Cr2O7), Mn (MnSO4), Fe (FeSO4), and Cu (CuSO4) were found removing less than in HSSF wetland with average removal efficiencies values of 92.4, 85.1, 91.8, and 91.5%, respectively, by  vetiver root. Algae show almost no effect on heavy metals and aromatic removals. The vetiver root likewise plays important role in phenol and benzene removals with values of 91.5 and 96% in efficiency, respectively. N-fixing and P-solubilizing microorganisms, Pseudomonas sp., and Zoogloea sp. presented similar responses tendencies to different living condition when domestic and laboratory wastewaters, in turn, were fed

Author Correction: Effects of sampling effort on biodiversity patterns estimated from environmental DNA metabarcoding surveys (Scientific Reports, (2018), 8, 1, (8843), 10.1038/s41598-018-27048-2)

10.1038/s41598-019-43804-4Scientific Reports911589