It is important to have reliable information on various natural and anthropogenic factors responsible for influencing and shaping stream water quality parameters as long as water resource conservation and management planning are concerned from the local to global scale. Daunting environmental pressures at multiple scales makes this necessity more pronounced owing to the special role of stream ecosystems in providing regional services. Understanding how coupled effect of natural and anthropogenic factors controls stream water quality parameters and how the relationships change over space and time will help policy makers and resource managers to target appropriate scales at watershed level for the quality management of stream waters. This paper sums up the information on various natural and anthropocentric factors as major determinants responsible for conditioning and shaping stream water quality parameters and their simultaneous influence on biota and its use.

The outbreak of the deadly virus (novel coronavirus or Severe Acute Respiratory Syndrome Coronavirus-2) that emerged in December 2019, remained a controversial subject of intense speculations regarding its origin, became a worldwide health problem resulting in serious coronavirus disease of 2019 (acronym COVID-19). The concern regarding this new viral strain “Severe Acute Respiratory Syndrome Coronavirus-2” (acronym SARS-CoV-2) and diseases it causes (COVID-19) is well deserved at all levels. The incidence of COVID-19 infection and infectious patients are increasing at a high rate. Coronaviruses (CoVs), enclosed positive-sense RNA viruses, are distinguished by club-like spikes extending from their surface, an exceptionally large genome of RNA, and a special mechanism for replication. Coronaviruses are associated with a broad variety of human and other animal diseases spanning from enteritis in cattle and pigs and upper chicken respiratory disease to extremely lethal human respiratory infections. With world health organization (WHO) declaring COVID-19 as pandemic, we deemed it necessary to provide a detailed review of coronaviruses discussing their 2019 Novel Coronavirus, history, current situation, coronavirus classification, pathogenesis, structure, mode of action, diagnosis and treatment, the effect of environmental factors, risk reduction and guidelines to understand the virus and develop ways to control it.

River health is sustained by time-based variation in their flows, and the maintenance of natural flow regime is essential for keeping the rivers healthy. However, the dynamism in natural flow regime now stands altered by changing climate, and the omnipresent regulation of river flows throughout the world has severely impacted the river health. It is well documented that harnessing and altering the flow of the rivers and streams comes at a huge cost. Numerous rivers in the world have stopped supporting socially and economically important native species or sustain vibrant ecosystems that offer valuable goods and services. The alteration of the natural flow regime has led to the collapse of many healthy and resilient river ecosystems throughout the world. Therefore, to ensure appropriate naturalized flow regimes for riverine organisms and a sustainable nexus between energy demand, water requirements and climate, more understanding is required to study the consequences of alteration in natural flow regime triggered by climate change and anthropogenic interventions. Moreover, conservation and management practices must be firmly based on scientific principles to restore the integrity of river ecosystems. The current approaches often fail to take into consideration a basic fundamental principle that the integrity of the river ecosystem is largely determined by the natural dynamic character of their flow regimes. In this synthesis, we try to explain how the maintenance of the natural flow regime is an essential requirement for maintaining river ecosystem health. K E Y W O R D S environmental flow, natural flow regime, river ecosystem, river health 1 | INTRODUCTION Rivers are important for the maintenance of ecological health, economic prosperity and human welfare, and the innate rhythm of the rivers is indispensable to human welfare even today (Palmer & Ruhi, 2019). For ages, rivers have provided food to the masses, water for domestic consumption, agricultural activities and transportation (Grill et al., 2019). The flow of rivers link people, places and various other life forms, inspire and support diverse cultural philosophies, ideas and ways of life (Anderson et al., 2019). The basic human need for freshwater (Poff et al., 1997) and development (Blythe & Schmidt, 2018) has led to the dramatic alteration of river ecosystems in the world. The rivers were subjected to anthropogenic pressures by means of fragmentation, leading to the loss of connectivity. This limits their potential to flow unimpeded and hamper their fundamental processes and functions (Dudgeon et al., 2006). These alterations result in rapid reduction of biodiversity and ecosystem services (Cardinale et al., 2012) and restrict various geomorphic processes (Sinnatamby et al., 2020). The practices such as regulation of different thermal regimes and water quality (Sabater et al., 2018), carbon input to aquatic food webs, supply of wood and physical space for habitat through the terrestrial-aquatic ecotone (Naiman & Decamps, 1997)

No abstract

No abstract