Recent biodiversity surveys in the lentic habitats of Singapore revealed that non-native cichlids (at least 14 species from different origins) were the most abundant species in the reservoirs of Singapore. To understand the diversity and distribution patterns in six reservoirs (two inland and four coastal), we investigated the species richness and abundances of these cichlids. We also investigated foodwebs to characterise the trophic relationships of cichlids relative to the aquatic community using stable isotope and gut content analyses in each reservoir. Based on various sampling methods (electrofishing, netting and trapping), a total of 5,675 individual cichlids representing 14 species and two hybrids were caught. The three most abundant species (contributing to 66.8% of all cichlids) included the green chromide, Etroplus suratensis, the eartheater cichlid, Geophagus altifrons, and the Orinoco peacock bass, Cichla orinocensis. Based on a canonical correspondence analysis, we found that the distribution and abundances of cichlids appeared to be related to abiotic parameters such as salinity and dissolved oxygen, and that species richness and abundances of cichlids differed between coastal and inland reservoirs. We also found that the trophic positions of different cichlid species varied within and across the reservoirs surveyed, where sympatry between highly specialised as well as generalist cichlid species was commonly observed. This was reflected in both the gut contents as well as the empirical foodwebs generated. While we are unable to determine source and timing of the introductions of these cichlids, we are at least confident that many of the cichlids have already established in these six reservoirs. We postulate that the establishment success and the co-existence of this nonnative group has come about through their ability to adapt to the conditions within each reservoir, and this is related to the life history strategies, feeding and behavioural patterns that these different cichlid species display.

In this study, biocontrol of harmful effect of cyanobacterial blooms and their toxins by “flocculation-biosorption” was achieved. Five fungal species were isolated from decayed cyanobacterial bloom which are: Aspergillus fumigatus, A. niger, Penicillium, Trichoderma ressei and Mucor rouxii. We chose the last species' pellets because they are the most stable and cocultured with Anabeana sp. (1:5 fungal: cyanobacteria ratio) of dry weight, Harvest Efficacy HE% by fungal pellets started after 12h of co-culturing about (4%) and almost complete harvesting after 48h with (98%), then we add 0.1g of Magnetite nano Fe₃o₄ to facilitate removing cyanobacterial blooms. Microcystin-LR extracted from Anabaena sp. were purified and collected by preparative high-performance liquid chromatography (HPLC) was 75.1 (µg ml^-1), M. rouxii pellet absorbed about 85% of Microcystin-LR after 72h of incubation at 25°C.

The present study envisages the importance of monitoring and management of freshwater springs of Kashmir Himalaya due to role they play in meeting ever-increasing drinking water demands and maintaining various ecosystem services. Therefore, some of the most pressing issues fundamental to the existence of springs is their monitoring and management because of their geological, ecological, scientific, cultural, religious and societal importance. Despite the key role that they play, springs are today continuously facing various types of threats. Springs have attained recently an extraordinary importance as they play role in providing drinking water, irrigation, sustaining habitats for fisheries, aquatic biodiversity, endemism, spiritual enrichment, recreation, aesthetics etc. especially in scenario of climate change threat predicted for Himalayas. In this backdrop a study directed to assess water quality status and potential of springs to offer the solution to ever-increasing water shortages was carried out. Identification of main threats to spring ecosystems and their subsequent monitoring and management in Kashmir Himalaya has been pleaded in this article. Major research highlights of the work revealed very well to excellent water quality class and Piper trilinear diagram of spring water depicted Ca–Mg–HCO₃ water type. ANOVA (Analysis of Variance) revealed significant variations whilst Principal Component Analysis (PCA) generated four principal components (PC1, PC2, PC3 and PC4) with higher Eigen values of 1.0 or more (1.4-9.5) accounting for 34.34, 30.03, 18.50 and 12.4% of the total variance respectively. Consequently, majority of the physico-chemical parameters (95.28%) loaded under PC1 and PC2 were having strong positive loading (>0.60) and are mainly responsible for regulating the hydrochemistry of spring waters. Cluster analysis revealed that springs like Kokernag, Achabal, Sherebagh, and Cheshmashahi and Dobinag fall in same cluster having 47-78% similarity while Verinag, Indraznag and Dobinag fall almost in same cluster showing similarity range of 61-80%.

A periphyton-based index for biological integrity was developed to assess the ecological status of lakes and reservoirs in Baiyangdian Watershed, China. Periphyton and environmental surveys were conducted at 20 sites during 2009-2010. A total of 22 surveyed metrics of periphyton, which were classified into 6 categories: biomass groups, community structure, pigment ratios, bacteria diversity, enzyme activities, and metabolism were evaluated in order to understand their responsiveness to environmental degradation. Out of these 22 metrics, six metrics were selected to constitute the periphyton-based index for biological integrity: chlorophyll b, chlorophyll c: chlorophyll a ratio, alkaline phosphatase activity, bacteria dominance, net daily metabolism, and autotrophic index by sensitivity and redundancy analysis. Then the periphyton-based index for biological integrity was verified by an independent validation-site data set. The test results indicated the index could not only discriminate disturbed sites from reference sites, but also be triggered by land use types. The scores of periphyton-based index for biological integrity were significantly correlated with the environmental parameters, especially ammonia nitrogen and total phosphorus. These results suggest that this index may be a potential tool for assessing the ecological status of lakes and reservoirs, polluted mainly by organic contaminants in Baiyangdian Watershed.

The diatom Didymosphenia geminata can produce thick benthic mats along river bottoms, possibly in association with soluble reactive phosphorus mat-forming genetic variants, or gene expression associated with environmental variation. We isolated cells collected from mat-forming and non-mat-forming sites in British Columbia and Alberta, Canada and compared soluble reactive phosphorus, frequency of dividing cells and gene expression via RNA sequencing. Frequency of dividing cells and soluble reactive phosphorus were higher at the non-mat-forming site and there was no significant difference in frequency of dividing cells between Alberta and British Columbia sites, with one exception. Sixty-six gene products from reference diatom (Phaeodactylum tricornutum and Thalassiosira pseudonana) and bacterial (Caulobacter crescentus) genomes were expressed only in the mat-forming sample and many were related to phosphorus metabolism. One hundred seventy two genes were expressed only in the non-mat-forming sample and many were related to cell division and silica metabolism. Differential gene expression in the periphyton communities suggests that there might be different periphyton molecular phenotypes, including D. geminata, related to P acquisition and polysaccharide metabolism at the low P site and cell division and growth at the high P site.

This study investigates the relationship between macrobenthic functional group composition and hypoxia in the Changjiang River estuary and its adjacent sea areas. A total of 82 stations were divided into three areas, named non-hypoxic area, hypoxic area and the Changjiang River, respectively. A total of 256 macrobenthic species were collected, which were divided into five functional groups, including carnivorous, detritivorous, omnivorous, phytophagous, and the planktivorous functional group. A similarity analysis performed on the macrobenthic functional groups of the three zones indicates that the functional group distributions of non-hypoxic and hypoxic zones are not significantly different, whereas the functional group compositions of the Changjiang River estuary and the other two zones are rather different. The results of canonical correspondence analysis reveal that the distribution of macrobenthic functional groups is compounded by various environmental factors, of which dissolved inorganic nitrogen, salinity, and temperature exert a significant effect. Combining the results of previous studies, we speculate that macrobenthos are able to adapt to the occurrence of hypoxia by changing their body morphology, distribution location, and community structure. When the environmental conditions prevent the hypoxia from occurring, persisitent hypoxic zones can recover their marine microbenthic community.

The coral reef ecosystem plays an important role in scientific research and economy. An assessment research on status of the coral reefs was carried out at 6 sites of coastal water from Nghi Son (Thanh Hoa province) to Vung Ro (Khanh Hoa province), Viet Nam between October and December 2015. The research was done using the manta tow method for rapid reef assessment and reef area determination, using reef check for detailed assessment of reef substrate types, etc. 288 species of hard corals under 57 genera and 14 families were identified from the study sites. These species mainly belonged to 4 families, namely Acroporidae, Faviidae, Poritidae and Fungiidae. The research showed the bad condition of the reef at all study sites through such indicators as a low live hard coral cover (average cover of 19.8%), high dead coral cover, recently killed coral, fleshy seaweed, etc. Most of surveyed transects had poor level of hard coral cover, the number of transects having good coral cover was unsignificant. The total reef area of 6 surveyed sites was 809.5 hectares, mainly occupied in Son Tra and Vung Ro. This was the first time coral disease and bleaching widely ranged had been observed and described. However, the reason of this phenomenon has not been mentioned yet and there is a need for more detailed researches on these problems in the coming time to have a basis for protection and management of coral reef ecosystem in Vietnam's coastal water.

This study assessed the effects of different electric current densities on the calcification and photosynthetic physiology of a massive, colonial stony coral species. Coral survivorship, calcification rate, and photosynthetic parameters (zooxanthellae density and chlorophyll fluorescence) were measured to determine the physiological and photosynthetic performance of Galaxea fascicularis after exposure to different electric current densities. After 60 days of treatment, survival of G. fascicularis was higher at low electric current density (10mA m^–2) than in the control and at high electric current density (100mA m^–2). Electric current did not alter zooxanthellae densities, but did enhance the photosynthetic processes (e.g. maximum electron transport rates (rETR_m), and maximum quantum yield (F_v/ F_m)) within 45 days. Coral calcification rate increased in response to low electric current density up to 30 days, but the effects of the electric current were not significant after a longer period of treatment. Overall, our results indicated that mineral accretion technology with appropriate electric current density conditions was somewhat helpful in enhancing coral growth, and thus this technique may be used in the restoration and management of massive stony coral reefs.

In this study, a protective seed core method for planting seeds of the common eelgrass Zostera marina was developed and evaluated through laboratory and field experiments. We studied the suitable desiccation period of the protective seed cores, and their effect on seed germination and seedling establishment in a laboratory experiment. New patches established by seeds planted with the protective seed cores were evaluated through an 11-month-seed-sowing field experiment. Observations of the stability of the protective seed cores and the change in viability of Z. marina seeds placed in the protective seed cores demonstrated that the optimum desiccation period was 2 days. Seed germination and seedling establishment of Z. marina were promoted by the protective seed cores during the 90-day laboratory experiment. The field experiment showed that the seedling establishment of Z. marina seeds was significantly enhanced by the protective cores, ranging from 12% to 64%, with an average of 30%, 6 months after seeding. New patches were successfully established by protective seed cores with a maximum shoot density of 367 shoots m^–211 months after planting. The average planting cost per Z. marina seed was $0.03; thus, $14,820 would be incurred for planting 1ha of Z. marina beds using this method. These results indicate that the protective seed core method is an efficient and cost-effective restoration technique with a potential in facilitating large-scale restoration projects.

Rehabilitation efforts for Lake Trout Salvelinus namaycush in Lake Huron have resulted in increased capture of young wild Lake Trout in annual bottom trawl surveys conducted by the U.S. Geological Survey. To better understand the ecology of juvenile (<400mm) Lake Trout, we summarized the spatial distribution of their capture in bottom trawls at six ports in Lake Huron during October/November 2008–2017 and analyzed diets of wild (n = 306 of 337 total) and hatchery-origin (n = 18 of 30 total) fish captured. Lake Trout ranged in size from 27 to 399mm, representing at least three age-classes, and 92% were wild origin. Most wild juvenile Lake Trout (83%) were captured at 46–64 m depths at the two northernmost ports, typically below the thermocline. Mysis diluviana was the most prevalent prey type, found in 75% of wild fish with non-empty stomachs, followed by two non-native species: Spiny Water Flea Bythotrephes longimanus (31%) and Round Goby Neogobius melanostomus (12%). Small Lake Trout (<185mm) consumed invertebrates but transitioned to mostly fish-based diets by >185mm (∼age 2). The variety of taxa consumed by young Lake Trout increased with length. Further declines in Mysis populations due to increased predation pressure after the loss of Diporeia from the system may hinder the recovery of wild Lake Trout, and although they have been able to utilize invasive species as prey, impacts to Lake Trout growth remain unknown. Additional research on the habitat use and diets of wild juvenile Lake Trout may provide insight into the reasons behind the recent successful natural reproduction and recruitment of Lake Trout in Lake Huron.

Escalating pesticide deposition in the aquatic environment is becoming a potential threat to aquatic organisms. Present study was designed to investigate acute toxicity in O. niloticus. the fish were exposed to five different concentrations of malathion, chlorpyrifos and lambda-cyhalothrin (synthetic pyrethroid) pesticides in the laboratory using separate aquaria for each chemical. Mortality ranged from 100 to 0%. The 24h LC₅₀ (median lethal concentration) for O. niloticus was 5.70, 0.5 and 0.015ppm for malathion, chlorpyrifos and Lambda-cyhalothrin, respectively. LC₅₀ values obtained after 24h of exposure indicated that the fish were sensitive to all the three tested pesticides. The mortality rate was directly proportional to the pesticides concentration. The results showed that the lambda- cyhalothrin was found more toxic followed by chlorpyrifos and malathion. The study results suggested that the runoff of organophosphates and synthetic pyrethorid pesticides from nearby agricultural fields to aquatic environment posed health hazards on fish.

Studying interactions of coupled human-natural system components provides better understanding of their influences on ecosystem health and improves effectiveness of managing such systems. To understand how human-nature interactions determine the sustainability of tourist destinations, using Jiuzhaigou Nature Reserve as an example, we analyzed how human-nature interactions influenced the reserve's ecological services extraction, environmental conditions, and corresponding management actions through a historical lens. We first developed a model that represented the components and their interactions under coupled human and natural systems framework. We then summarized such interactions and their resulted environmental conditions in a time sequence. Human activities have changed Jiuzhaigou system from largely human-nature balanced to partially degraded, and then to recovered and intensively managed system during the past six decades. Such changes resulted from human-nature interactions predominantly driven by overuse of natural resources, responded to by natural components in loss of ecosystem functions, and then responded by management actions to restore the functions. The increased nutrient and sediment, modified benthic communities, and decreased travertine (crystal substrate formed by the precipitation of carbonate minerals) indicate that tourism pressure in Jiuzhaigou under the current intensive management strategy has exceeded its carrying capacity. Much more aggressive environmental friendly tourism policies are needed to sustain this valuable tourist destination. Our findings based on coupled human-natural system framework analysis have important implications for sustaining natural resources and ecological services, and the governance of both for the management of nature reserves.