H2S paper strip method - A bacteriological test for faecal coliforms in drinking water at various temperatures

Epidemics arising from waterborne diseases are a global health problem. Faecal contamination of drinking water is the main cause of these outbreaks. According to WHO (1996) for drinking water to be safe, a 100 ml sample should not contain any coliform bacteria. The standard methods currently used for routine testing have many limitations especially when applied in remote areas. The H2S method has been developed as an on-site, inexpensive and easy to use method to test drinking water for remote and rural areas. The present work analyses the reliability of the H2S method for detecting faecal contamination in drinking water. The minimum level of faecal coliforms that could be detected and the incubation period required at various levels of contamination were studied. The range of temperatures at which the method was effective and the incubation period required at various temperatures were also determined. The H2S method was found to be able to detect contamination down to a level of 1 CFU/100 ml of coliform bacteria. Although the H2S method could be used at a temperature range of 20 to 44oC, temperatures between 28 to 37oC gave faster results. An incubation period of only 24 hours was required at 37oC, which was found to be the most suitable incubation temperature. The incubation period increased with a decrease or increase in temperature

സമുദ്രത്തിലെ ജന്തുപ്ളവകങ്ങള്‍ (Zooplankton in the sea)

Food is one of the important requirements for the existence of any living organism. In the oceans the food production takes place at two levels - primary level and secondary level. Among these, the food is synthesised only at the primary level in the form of carbohydrates. The micro and macrophytes in the seas are responsible for primary production. The zooplankters carry out the important function of converting plant matter into animal substances which forms the food for fi~ha nd other higher animals

Studies on Euphausiacea (Crustacea) of the Indian Ocean with special reference to the EEZ of India

The Euphausiac(?a an order of Ihe sub-class Malacostraca (Class : Crustacea) is an abundantly occurring zooplankton group in the EEZ of India. Understanding the importance of this group in the marine economy, studies on their various aspects have been carried out in the Indian Ocean since 1886 and in the Indian waters since 1966. While there is substantial amount of knowledge on the distribution, ecology and biology oj various species of euphausiids oJ the southwest coast and Lakshadweep seas there is dearth of information on euphausiids from the other parts of the EEZ. The present paper reviews the information available on euphausiids of the Indian ocean in general and the Indian EEZ in particular with special reference to the contributions of CM.F.R.I

Organic wealth and fish production in the sea - Zooplankton production

Food is one of the important requirements for the existence of any living organism. In the oceans the food production takes place at two levels - primary level and secondary level. Among these, the food is synthesised only at the primary level in the form of carbohydrates. The micro and macrophytes in the seas are responsible for primary production. The zooplankters carry out the important function of converting plant matter into animal substances which forms the food for fi~ha nd other higher animals

Dr. E.G. Silas (90) the doyen of Indian marine fisheries and mariculture research expired on 27-04-2018.

Dr. E.G. Silas (90) the doyen of Indian marine fisheries and mariculture research expired on 27-04-2018. He was my research guide and mentor under whom I worked for 20 years in Cochin from 1965 to 1985. I was his first Ph.D. student. As a Tribute to him I reproduce below an extract from the article under the title “Golden Moments in My Research Career” written by me and published by the Central Marine Fisheries Research Institute (CMFRI), Kochi in one of its publications entitled “Down Memory Lane” published in 2007 during the Diamond Jubilee Year of the Institute

Collection of material

Plankton sampling, by nets started a little more, than 150 years ago and it is therefore v6ry much in its infancy compared to fishing operations. In 1828, a surgeon, Dr. J,. Vaughan Thompson made a small net to sample crab and barnacle larvae., Darwin used a small net on the Beagle and in 1844 Muller us6d a small meshed conical net to catch a host of minute -creature

Studies on Chaetognatha of the Indian EEZ

The Phylum Chaetognatha, the members of which are popularly known as 'arrow worms'is a holoplanklonic group found in all the oceans in the epi. mesa and bathypelagic zones. The animals play a vital role in the marine food web forming food for a variety of animals and themselves feeding on a host of zooplankters. Recognising the importance of chaetognaths in the marine ecosystem, the CMFRI had taken up irwestigations on different aspects of these organisms to understand their role as predator and prey in the food chain. The facilities offered by several ocean going research vessels enabled us to get a comprehensive picture of the chaeiognaths of our EEZ. The present paper is a digest of the work done at the CMFRI on the distribution, ecology, biology and taxonomy of the Chaetognatha of the Indian EEZ

Temporal extension of stable glow discharges in fluorine-based excimer laser gas mixtures by the addition of xenon

The effect of addition of xenon on the long term homogeneity of discharges in F2and ArF excimer laser gas mixtures was investigated in a small-volume discharge chamber. The gas mixture in the discharge chamber was preionized by X-rays. A special electrical excitation circuit containing a pulse forming line provided a long, square-shaped current pumping pulse of a predetermined duration to the discharge electrodes. The initiation and the development of the discharge was monitored via its fluorescence signal with an intensified CCD camera. We found that adding Xe up to partial pressures of 0.53 mbar extended the homogeneous phase of the discharge from 80 ns to approximately 200 ns in He/F2as well as in He/Ar/F2and Ne/Ar/F2excimer laser gas mixtures. Monitoring of the ArF and XeF spontaneous emission signals showed that the formation of ArF excimers remained unaffected by the addition of xenon (up to 1.3 mbar) to the laser gas mixture

Spatial Distribution of Krill (Euphausia Superba) and Other Zooplankton off Queen Maud Land, Antarctica

The Euphausia superba Dana, popularly known as the krill is the richest single species resource of the Antarctic waters and they form the chiefforage for whales, seals, birds, fishes and squids of this ecosystem. Several estimates regarding the magnitude of krill resource which has a circumpolar distribution within the Antarctic Convergence have been made. However, paucity of substantial data added with the behavioural characteristics of these animals such as forming into patches, shoals, schools and swarms have made it difficult to assess the real stock of these protein rich organism