Photosynthetic production and its regulating factors in the Baltic Sea

Measurements of primary production in the Baltic Sea over a period of 2 years (1969/1971) by the ¹⁴C method are reported. The rate of total annual production for the Baltic Sea proper and the Gulf of Finland including coastal areas appears to lie between 35 and 40 gC·m², a rate which can be assumed as characteristic for oligotrophic waters with a low production rate. An apparent increase in productivity between the 2 years could be noted. Calculations for the water mass below the halocline show that between 0.7 and 0.8 ml/l oxygen is used up during a period of 3 months required for the development of anoxic conditions. The major portion of the organic matter in the Baltic Sea undergoes decomposition in the sub-photic zone above the halocline. The ratio of organic material in deep water to the total available oxidizable matter appears to remain constant with time; therefore, the apparent increase in productivity in the photic layer does not affect apprecibly the development of anoxic conditions in deep water. Of the different areas investigated, the Gulf of Finland seems to be the most productive. In the southern Baltic Sea, the rate of production over 5 years between 1966 and 1971 has not changed appreciably. In fact, it shows a trend toward a slight decrease, whereas, in other areas of the Baltic Sea, the rate of production indicates an apparent increase. Comparison with oceanic coastal areas of the west coast of Sweden shows that the rate of production there is higher than in the Baltic Sea. Of the micronutrients controlling productivity in the photic layer of the Baltic Sea, nitrate has a stronger limiting effect on plant growth than phosphate, a fact which is in agreement with existing conceptions on the subject. Dissolved iron does not seem to exert any appreciable influence on the productivity.     

Concept of optimum basin thickness in heat exchanger–assisted solar stills

Environmental Science and Pollution Research - It is suggested by many works on solar stills that water thickness should be kept as low as possible to reduce its thermal inertia and obtain best...     

Analysis of stability of silica nano-particle-laden microbubble dispersion

Microbubbles are small gas-filled bubbles which have wide application in various industries. The stability of microbubble is of primary concern for the application of microbubble. In this research, the stability of microbubble dispersion generated using CTAB surfactant is analyzed by drainage mechanism. The stability of microbubble dispersion is studied on the basis of the half-life of microbubble dispersion. Microbubble dispersion gas fraction and apparent rise velocity of interface of microbubble dispersion are also calculated. The size of microbubble is estimated from the apparent rise velocity of interface of microbubble dispersion. Further, silica nano-particles are added to the surfactants to study their effect on the stability of microbubble dispersion. The observed results clearly indicate that the stability of microbubble dispersion is significantly affected by the surfactant concentration and the weight of silica nano-particle in the liquid. Similar results were observed for the apparent rise velocity of interface and bubble size of dispersion. The present work may be beneficial for the application of microbubble in various chemical and biochemical industries and scientific community.

     

Post tsunami mangrove evaluation in coastal vicinity of Andaman Islands,India

The present study was carried out to determine the mangrove area water quality, mangrove diversity and density at Minnie Bay, Lalaji Bay and Aerial Bay (Andaman Islands, India). The physicochemical parameters such as salinity, nitrate, inorganic phosphate and total phosphorus varied significantly. Mangrove diversity was high at Minnie Bay while density at Aerial Bay. Rhizophora mucronata dominated at all three sites during the study period. Shannon-Wiener diversity index (H′?=?2.261) and Pielou’s evenness (J′?=?0.8348) were high at Minnie Bay. The higher species density cover (5.679 Nos./m²) was recorded at Aerial Bay. Bray-Curtis cluster analysis showed 63.35 % similarity and formed two clusters. Though uplift and subsidence of coastal land due to the Mw 9.3 Sumatra earthquake in 2004 has affected the mangrove vegetation, its rejuvenation was observed in the newly formed inter-tidal areas due to changes in coastal geomorphology. The comparative study on physicochemical parameters, mangrove coverage and conservation are discussed in detail.     

A simple and robust method for determination of neem (Azadirachta indica A. Juss) oil in neem oil coated urea

The production of neem oil coated urea (NOCU), a technology developed by the Indian Agricultural Research Institute, has been grown to over 2.0 million tons per year. The estimation of neem oil content in NOCU is important due to its significance in ensuring agronomic efficiency. Therefore, this study was taken up to develop a simple method for the determination of neem oil in NOCU. The procedure involves extraction of neem oil from NOCU; saponification of extracted oil; oxidation of released glycerol to formaldehyde, and subsequent conversion of formaldehyde to a dihydrolutidine derivative. Its concentration was determined spectrophotometrically. The recoveries of neem oil from NOCU with oil load of 500 and 1000?ppm were 87.6?±?3.0% and 90.0?±?4.8% respectively with direct method; and improved to 92.6?±?4.0% and 96.7?±?3.8% after including the in situ purification. A simple method based on the Hantzsch reaction was developed for the determination of neem oil in NOCU. This method is superior to earlier methods in terms of sensitivity, simplicity, and time required.     

Immunotoxic manifestations in rats following inhalative exposure to furfural vapors

Furfural is an industrial compound used as a process intermediate and as a solvent; it poses a potential inhalation hazard in occupational settings. This study was carried out to find furfural-induced immunotoxicity in Wistar rat following inhalative exposure. The weights of thymus and lymph node were found decreased, while the weights of the liver and the adrenal gland were significantly increased following furfural exposure. Delayed-type hypersensitivity response was found decreased in furfural vapors-exposed animals when compared to that of control animals. The phagocytic index of peritoneal and alveolar exudates showed significant decrease and was most prominent (90%) in 30 days-exposed groups. The number of anti-rat anti-sheep red blood cell immunoglobulin M plaque forming cells of spleen got decreased in furfural-exposed groups in comparison to control. Taken together, this study indicates that inhalation of furfural induces immunotoxic manifestations that could lead to severe immunological disorders.     

Effects of the level of dietary protein on the toxicity of hexachlorocyclohexane in rats

Male albino rats were fed for 28 days from weaning on diets containing 5% (group 1), 10% (group 2) and 21% (group 3, normal protein) protein as casein. At the end of dietary period, HCH was administered daily for 30 days to investigate the interaction between protein deficiency and pesticide toxicity. The results indicated that rats fed a lower protein diet and HCH had a higher mortality, lower rate of growth, increased liver weight and deposition of the pesticide in blood and tissues in larger amounts. Blood pressure (systolic and diastolic) was significantly increased and the heart rate showed tachycardia in low protein exposed animals. A significant increase of total lipids, cholesterol, triglycirides, free fatty acids in serum and tissues of animals exposed to low protein was observed. A close correlation existed between lipid accumulation and storage of HCH in tissues and dietary protein seemed to play an important role in detoxification.     

Measurement of the leaching behaviour of granular solid wastes

Leaching of granular solids can be described in terms of specific mass transfer functions of a simple mathematical form.

The parameters can be determined by column leaching experiments under well known flow conditions.

Initially available concentrations are obtained from batch experiments at high dilution. Total concentrations in the solids are determined independently to calculate the available fractions.

The determination of the flow pattern is done by radiotracer measurements. Leachates are analyzed by various analytical methods including AAS and INAA. Total concentrations in the solids are determined by INAA preferably.     

Photodegradation of the organophosphorus herbicide “anilophos”

Photodecomposition of the organophosphorus herbicide anilophos [S‐(N‐(4‐chlorophenyl) N‐isopropyl carbaniloyl methyl] 0,0‐dimethyl phosphorodithioate has been studied in methanol. It underwent oxidation, hydrolysis and dimerisation on irradiation with U.V. light and produced a number of photoproducts which were characterised by ¹H‐NMR and Mass spectroscopy.     

Community structure of zooplankton across environmental variables in a high-altitude lake of central Himalayas,India

We determined seasonal and spatial variation of zooplankton and their correlation with environment variables in a subtropical lake of the Himalayas. Thirty-eight species of zooplankton were identified, of which, 38.0% belonged to rotifera, 26.3% to cladocera, and 15.7% to copepoda. Nitrogen nutrients, total organic matter (TOM), and clay particles significantly influenced on the distribution pattern of zooplankton. Non-metric multidimensional scaling analysis showed homogeneous assemblages of dominant zooplankton species except Chydorus gibbus which has wider range of niche partitioning. Turbidity formed by suspended materials facilitated better avoidance of larger zooplankton like Daphnia similis from predators. Sedimentary silt particles influenced on the assemblages of sensitive species such as Tropocyclops prasinus, Asplanchna priodonta and Colurella obtuse. Changes within the land-use pattern in the catchment of the central Himalayan lakes either directly or indirectly impact on the distribution of zooplankton community.