The Dark Side of Microbial Processes: Accumulation of Nitrate During Storage of Surface Water in the Dark and the Underlying Mechanism

Microbial communities play an essential role in maintaining a healthy aquatic ecosystem. For example, in surface water reservoirs, microorganisms produce oxygen, break down toxic contaminants, and remove excess nitrogen.

Purification of Copper-Containing Wastewater in Inner-Cooling Oil Channel of Piston with Magnesium Hydroxide

The treating fluid in the piston of inner-cooling oil channel is acid wastewater containing copper ion, it would adversely affect the aquatic ecosystem when emission directly. This paper use magnesium hydroxide as a wastewater treatment agent, to study the effect of magnesium hydroxide dose, stirring time, temerature on the results of treating fluid treatment, and get the best treatment conditions. The results indicate that magnesium hydroxide has an excellent performance including easy operation, super removing rate, supernatant can meet emission standards: c(Cu2+)≤2mg/L.

Evaluation and Re-estimation of Instream Flow Considering the Water Quality and Aquatic Ecosystem of the Seomjingang River Watershed

In this study, the appropriateness of the current publicly announced and managed instream flow in the Seomjingang River watershed was evaluated based on the water quantity, water quality, and state of the aquatic ecosystem. The stream flow was evaluated based on the observed water flow rate at the Gurye-gun (Songjeong-ri) station that is the main point of the Seomjingang River flow management and located at the lowest downstream of the main stream of the Seomjingang River. Another important reason for choosing this station was that observational data from before the construction of the major dam to the present day were available. The water quality and aquatic ecosystem conditions were reviewed based on the data measured over the past 20 years, and the achievement ratio of instream flow was compared with that of stations in the other major river systems. Based on the evaluation result, the instream flow was re-estimated for the 11 important stations of the Seomjingang River and its two branches. Based on the currently permitted water use of the Seomjingang River, the amount of water required to supply for the instream flow deficit during dry seasons was predicted and presented as a reference for water management work.

Zooplankton composition and abundance from Nideban Reservoir, Udgir Dist. Latur

Zooplanktons are the microscope free swimming organisms of aquatic system. There are represented by a wide array of taxonomic groups of which the members belonging to protozoa, Rotifera, Cladocera and Copepoda are most common and often dominate the entire communities. They have many remarkable features which hamper their predation by higher organisms. The members of Zooplankton community are important for their role in trophic dynamics, energy transfer in the aquatic ecosystem. They provide food for fishes in the water bodies and play a major role in the fish production. The zooplankton community was studied by monthly samples taken from Oct. 2018 to Feb. 2019. The reservoir water is used for agriculture and fishery activities.

Water Quality of Marshyangdi River, Nepal: An Assessment Using Water Quaity Index (WQI)

Water quality index (WQI) is a valuable arithmetic tool that depicts the overall status of water quality in a single number to prioritize for management interventions. This study aims to assess water quality based on the WQI to provide insights into the status of the aquatic ecosystems in the Marshyangdi River basin, a tributary of the Narayani River, originating from the Himalaya. Water samples were collected from twenty-one sampling locations in the Marshyangdi River covering four districts from upstream (Kangsar) to the downstream region (Mugling) during pre-monsoon season (May) 2019. Eight selected physico-chemical parameters (TDS, pH, EC, DO, Cl-, NH3, PO43-, NO3-) were analyzed and aggregated in the form of WQI. Results showed that WQI ranges from 32.5 to 46.9, indicating the excellent water quality suitable for the sustenance of the aquatic ecosystem at all the sampling locations. These study results are expected to provide the baseline information on the present status of water quality along the longitudinal section of the Marshyangdi River, which could be helpful for the concerned authorities to manage water quality for the sustenance of the aquatic ecosystem.

Zooplankton Diversity Indices for the Assessment of Perennial Freshwater Body in Bishnupur, Bankura, West Bengal

The status of health of any aquatic ecosystem is largely dependent on the diversity and density of zooplankton inhabiting the water body. Zooplankton are considered to be the most vital primary consumer in any aquatic ecosystem. At the same time, they also influence to a greater extent in determining the total productivity of an aquatic body. The present study is an attempt to estimate the diversity of zooplankton and to find out the richness, evenness, of the freshwater perennial aquatic body, Lalbundh of Bishnupur, Bankura.The study was carried out during December 2018 to November 2019. The whole period of study was divided into four major seasons viz winter (December2018 to February2018), Summer (March2019to May 2019), Monsoon (June 2019 to August 2019) and post monsoon (September 2019 to November 2019). Collection of the zooplankton samples and their quantitative analysis was done following the standard procedures. During the whole period of study 18 different species of zooplankton have been identified from the study area. Out of them 7 species belong to the Rotifera group, 6 species belong to Cladocera group, 3 species of Copepoda group and 2 species of Ostracoda group. Rotifera group comprise the dominant of all the groups constituting 39% of the total zooplankton species, followed by Cladocera (33%), Copepoda(18%) and Ostracoda (11%). The range of Shannon diversity index value of zooplankton varies from 2.76 to 2.88. The species richness value varies from 2.45 (winter) to 2.56 (monsoon). Evenness value varies from 0.95 in summer to0.98in monsoon. Zooplankton diversity indices values of Lalbundh give a clear indication of light condition of pollution level of the water body. The main reason behind the pollution of this perennial water body may be the floating dead and decomposed macrophytes in it. They should be removed as far as possible at regular intervals so that the pollution level can be reduced and the water body can be more efficiently used for pisciculture practices.

Indigenous Fishing Methods of the Moyon Tribe of Manipur (India) and Myanmar

Fishing is one of the main economic activities of the Moyon tribe living in Manipur (India), and Myanmar. For many centuries, Moyons used indigenous methods for fishing. However, in recent years, indiscriminate fishing using modern technologies has led to an ecological crisis which not only affected the ichthyofauna diversity but also affected the livelihood of individuals depending on fishing as well as the sustainability of the indigenous fishing methods. The paper explores the indigenous fishing techniques and practices of the Moyon tribe. The study adopted a qualitative-exploratory research method with ethnography as the primary component. Data were collected from on-site observations of fishing and discussions with the local Moyon population. The study revealed that indigenous fishing methods have become unsustainable due to misuse by the fishers. Another significant observation was the shift in fishing methods from traditional to modern (market) gears. The recently used fishing gears are a threat to the fish population, aquatic ecosystem, and indigenous knowledge of fishing crafts. The study concludes that unsustainable fishing by the Moyon tribe is connected with poverty and the lack of development and education.

Optimizing efforts to restore aquatic ecosystem connectivity requires thinking beyond large dams

Infrastructure-induced fragmentation of riverine ecosystems has prompted the need for more effective aquatic restoration efforts globally. Fragmentation assessments have been extensively undertaken to inform connectivity restoration efforts for fish and other aquatic biota, but they have potentially underestimated the extent of fragmentation by fixating on large dams and overlooking the contribution of other barriers like road crossings and small irrigation structures. The current study addresses this limitation in Mekong region countries (MReCs) of Southeast Asia, by assessing the fragmentation impacts of road crossings and small irrigation structures together with large dams. Our analysis indicates that the basin-scale fragmentation impact of road crossings is similar to that of large dams in MReCs, while small irrigation structures have a far greater impact. These findings raise concerns about the real global extent of aquatic fragmentation, and highlight the need for decision-makers to think beyond dams when attempting to restore connectivity for aquatic biota.