Salt stress induced alteration in growth characteristics of a grass Pennisetum alopecuroides

Salinity is one of the major abiotic stresses that adversely affect crop productivity and quality. The present investigation was carried out to study the alterations in the growth characteristics of a grass species, Pennisetum alopecuroides under the influence of sodium chloride (NaCl) salinity. From the results it is clear that shoot length of Pennisetum alopecuroides was increased by 13.17% at 100 mM NaCl concentration while the root length was observed to be increased at 50 mM NaCI concentration by 26.93%.Maximum height of the plant was observed by 18.23% at 50 mM while shoot to root ratio was higher at 300 mM concentrations by 29.17% increase over the control. Moreover, the maximum percent increase in leaf area was recorded as 11.17% (100 mM). Fresh weight was increased by 50.92% at 100 mM while dry weight of the experimental grass was increased by 33.64% at the same concentration of salt to the rooting medium while moisture percentage was increased to a maximum by 24.61% at 50 mM. It appears that the grass species studied exhibit a moderate salinity tolerance as far as linear growth of plant is concerned.     

Knowledge gain and behavioral change in citizen-science programs

Citizen-science programs are often touted as useful for advancing conservation literacy, scientific knowledge, and increasing scientific-reasoning skills among the public. Guidelines for collaboration among scientists and the public are lacking and the extent to which these citizen-science initiatives change behavior is relatively unstudied. Over two years, we studied 82 participants in a three-day program that included education about non-native invasive plants and collection of data on the occurrence of those plants. Volunteers were given background knowledge about invasive plant ecology and trained on a specific protocol for collecting invasive plant data. They then collected data and later gathered as a group to analyze data and discuss responsible environmental behavior with respect to invasive plants. We tested whether participants without experience in plant identification and with little knowledge of invasive plants increased their knowledge of invasive species ecology, participation increased knowledge of scientific methods, and participation affected behavior. Knowledge of invasive plants increased on average 24%, but participation was insufficient to increase understanding of how scientific research is conducted. Participants reported increased ability to recognize invasive plants and increased awareness of effects of invasive plants on the environment, but this translated into little change in behavior regarding invasive plants. Potential conflicts between scientific goals, educational goals, and the motivation of participants must be considered during program design.     

Quantification of polyphenols during retting and characterization of bacteria from the Kadinamkulam Backwaters, Kerala

The retting environment which provides a competitive niche for specialized microbes is speculated to harbour a variety of microbes with high biodegradation potential. In this context, an effort has been made to isolate and identify bacterial species having high tolerance to phenol In vitro. Maximum polyphenol (1.897 mg l(-1)) as observed during the initial period of retting, which decreased as retting proceeded. Based on biochemical characterization, the isolated bacterial strains were identified as Micrococcus sp., Moraxella sp. strain MP1, Moraxella sp. strain MP2 and Moraxella sp. strain MP3, Pseudomonas sp. strain PP1 and Pseudomonas sp. strain PP2, Amphibacillus sp., Brucella sp. strain BP1 and Brucella sp. strain BP2, Aquaspirillum sp., Escherichia coli strain EP1 and Escherichia coli strain EP2, Campylobacter sp., Aeromonas sp., Neisseria sp., Vibrio sp., Erwinia sp. and Mesophilobacter sp. These strains were found to tolerate maximum concentration of phenol viz. 200 to 1000 mg l(-1). Plasmid analysis of phenol resistant bacterial isolates showed that almost all the cultures had at least one plasmid of size > 1Kb. Studies on the protein profile of isolated bacterial cultures showed the presence of proteins with molecular sizes ranging from 10 to 85 KDa with exception of Mesophilobacter and Neisseria having still high molecular weight protein (95 KDa). Bacterial strains isolated from coir-ret-liquor showed tolerance to high phenol concentration.     

Comparative larvicidal potential of different plant parts of Withania somnifera against vector mosquitoes in the semi-arid region of Rajasthan

Larvicidal potential of the extracts from different parts viz. green and red fruits, seeds, fruit without seeds, leaves and roots of Withania somnifera in different solvents was evaluated against larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, the important disease vectors prevalent in the semi-arid region. Experiments were carried out on late 3rd or early 4th instar larvae of these mosquitoes using standard WHO technique. 24 and 48 hr LC50 values along with their 95% confidence limits, regression equation, chi-square (chi2)/heterogeneity of the response have been determined by log probit regression analysis. The 24 hr LC50 values as observed for whole green fruits in water, methanol and petroleum ether were 350.9, 372.4, 576.9; 115.0, 197.1, 554.6; 154.9, 312.0, 1085.0 while corresponding values for red fruits were 473.5, 406.4,445.2; 94.7, 94.5, 1013.0; 241.8, 535.0, 893.3 mg l(-1) for An. stephensi, Ae. aegypti and Cx. quinquefasciatus respectively showing that methanol extracts were more effective against anophelines as compared to culicines when whole fruits were taken. The 24 hr LC50 values as observed for seeds in acetone, methanol and petroleum ether were 188.1, 777.5, 822.5; 245.5, 769.0, 1169.0; 140.3, 822.9, 778.4 and for fruit without seeds were 80.2, 97.6, 146.6; 88.4, 404.4, 1030.0; 30.0, 44.5, 54.2 mg l(-1) for the above mosquito species respectively showing that extract of fruit without seeds were most effective in petroleum ether followed by acetone and methanol extracts. However, experiments conducted with methanol extracts of leaves and roots of this plant species did not show any appreciable larvicidal activity and a 20-40% mortality was observed up to 500 mg l(-1) of the extracts. Overall larvae of anophelines were found more susceptible as compared to culicines to all the extracts tested. Petroleum ether extract of fruit without seeds was found most effective against all the mosquito species showing that active ingredient might be present in this part of the plant species. The study would be of great importance while planning vector control strategy based on alternative plant derived insecticides.     

Pollution of River Mahaweli and farmlands under irrigation by cadmium from agricultural inputs leading to a chronic renal failure epidemic among farmers in NCP, Sri Lanka

Chronic renal failure (CRF) associated with elevated dietary cadmium (Cd) among farming communities in the irrigated agricultural area under the River Mahaweli diversion scheme has reached a significantly higher level of 9,000 patients. Cadmium, derived from contaminated phosphate fertilizer, in irrigation water finds its way into reservoirs, and finally to food, causing chronic renal failure among consumers. Water samples of River Mahaweli and its tributaries in the upper catchment were analyzed to assess the total cadmium contamination of river water and the possible source of cadmium. Except a single tributary (Ulapane Stream, 3.9?μg?Cd/l), all other tested tributaries carried more than 5?μg?Cd/l, the maximum concentration level accepted to be safe in drinking water. Seven medium-sized streams carrying surface runoff from tea estates had 5.1-10?μg?Cd/l. Twenty larger tributaries (Oya), where the catchment is under vegetable and home garden cultivation, carried 10.1-15?μg?Cd/l. Nine other major tributaries had extremely high levels of Cd, reaching 20?μg?Cd/l. Using geographic information system (GIS), the area in the catchment of each tributary was studied. The specific cropping system in each watershed was determined. The total cadmium loading from each crop area was estimated using the rates and types of phosphate fertilizer used by the respective farmers and the amount of cadmium contained in each type of fertilizer used. Eppawala rock phosphate (ERP), which is mostly used in tea estates, caused least pollution. The amount of cadmium in tributaries had a significant positive correlation with the cadmium loading of the cropping system. Dimbula Tea Estate Stream had the lowest Cd loading (495.9?g/ha/year), compared with vegetable-growing areas in Uma Oya catchment with 50,852.5?g?Cd/ha/year. Kendall's τ rank correlation value of total Cd loading from the catchment by phosphate fertilizer used in all crops in the catchment to the Cd content in the tributaries was +0.48. This indicated a major contribution by the cropping system in the upper catchment area of River Mahaweli to the eventual Cd pollution of river water. Low soil pH (4.5-5.2), higher organic matter content (2-3%), and 18-20?cmol/kg cation exchange capacity (CEC) in upcountry soil have a cumulative effect in the easy release of Cd from soil with the heavy surface runoff in the upcountry wet zone. In view of the existing water conveyance system from upcountry to reservoirs in North Central Province (NCP) through diversion of River Mahaweli, in addition to their own nonpoint pollution by triple superphosphate fertilizer (TSP), this demands a change in overall upper catchment management to minimize Cd pollution through agriculture inputs to prevent CRF due to elevated dietary cadmium among NCP farmers.     

Effects of Road Networks on Bird Populations

Abstract: One potential contributor to the worldwide decline of bird populations is the increasing prevalence of roads, which have several negative effects on birds and other vertebrates. We synthesized the results of studies and reviews that explore the effects of roads on birds with an emphasis on paved roads. The well‐known direct effects of roads on birds include habitat loss and fragmentation, vehicle‐caused mortality, pollution, and poisoning. Nevertheless, indirect effects may exert a greater influence on bird populations. These effects include noise, artificial light, barriers to movement, and edges associated with roads. Moreover, indirect and direct effects may act synergistically to cause decreases in population density and species richness. Of the many effects of roads, it appears that road mortality and traffic noise may have the most substantial effects on birds relative to other effects and taxonomic groups. Potential measures for mitigating the detrimental effects of roads include noise‐reduction strategies and changes to roadway lighting and vegetation and traffic flow. Road networks and traffic volumes are projected to increase in many countries around the world. Increasing habitat loss and fragmentation and predicted species distribution shifts due to climate change are likely to compound the overall effects of roads on birds.     

Step-up multiple regression model to compute Chlorophyll a in the coastal waters off Cochin, southwest coast of India

The interaction effects of abiotic processes in the production of phytoplankton in a coastal marine region off Cochin are evaluated using multiple regression models. The study shows that chlorophyll production is not limited by nutrients, but their physiological regulations (responses to nutrients, pH, temperature and salinity) are mainly responsible for the increased biological production. The model explaining 77% of variability for chlorophyll a production is indicative of preconditioning of the coastal waters. The phytoplankton production is found to be sensitive to the environment, which varies seasonally. Further, the study suggests that supply of organic matter and grazing of zooplankton (not included) would improve the model efficiency. Despite this, the good agreement in the computed and measured chlorophyll a values shows that step-up multiple regression model is a useful tool to understand the influence of environmental variables on the production of phytoplankton in these coastal waters.     

Application of GIS in the study of mass transport of pollutants by Adyar and Cooum Rivers in Chennai, Tamilnadu

Residential, industrial, commercial, institutional and recreational activities discharge degradable and non-degradable wastes that reach the coastal water through rivers and cause coastal pollution. In the present study, mass transport of pollutants by Adyar and Cooum Rivers to the coastal water as a result of land-based discharges was estimated during low tide. The lowest and the highest flow recorded in Adyar varied from 514.59 to 2,585.08×10⁶ litres/day. Similarly, the flow in Cooum River fluctuated between 266.45 and 709.34×10⁶ litres/day. The present study revealed that the Adyar River transported 53.89–454.11 t/d of suspended solids, 0.06–19.64 t/d of ammonia, 15.95–123.24 t/d of nitrate and 0.4–17.86 t/d of phosphate, 0.004–0.09 kg/d of cadmium, 0.15–1.29 kg/d of lead and 3.03–17.58 kg/d of zinc to the coastal water owing to its high discharge. Similarly, the Cooum River transported 11.87–120.06 t/d of suspended solids, 0.08–58.7 t/d of ammonia, 6.11–29.25 t/d of nitrate and 0.66–10.73 t/d of phosphate, 0.003–0.021 kg/d of cadmium, 0.02–0.44 kg/d of lead and 1.36–3.87 kg/d of zinc. A higher concentration of suspended solids was noticed in post monsoon and summer months. An increase in the mass transport of ammonia, nitrate, phosphate in summer months (April and May) and an increase in the mass transport of cadmium, lead and zinc were observed in monsoon months (October–December) in both the rivers. Thus mass transport of pollutants study reveal that Cooum and Adyar Rivers in Chennai contribute to coastal pollution by transporting inorganic and trace metals significantly through land drainage.     

Inputs of chemicals from recreational activities into the Norwegian coastal zone

Wastewater treatment works effluent is often considered to be one of the most important point sources of a wide range of anthropogenic contaminants to aquatic systems, however, this paper discusses other potential sources. With the aim of establishing the important sources of UV filters, insect repellent and biocides to the aquatic environment, samples were collected from sites with direct (bathing areas and marinas) and indirect (sites receiving wastewater effluent) human influences. Sunscreens containing UV filters are used in large volumes during the summer months and often applied shortly before a person enters the water for swimming activities. The results presented here demonstrate that washing directly from the skin is an important point source of 4 UV filters to the Oslofjord. The insect repellent, diethyl toluamide, was also measured and it was concluded that washing from the skin was not such an important point source into the fjord. Concentrations of the biocide Irgarol 1051 were also measured and were elevated in the small boat marina and surrounding enclosed area. This work demonstrates that man recreational water-based activities are a diffuse source of some contaminants into coastal and fjord environments and this study provides an initial assessment of the levels being released.     

The characteristics of size distribution of suspended particulates in the air for sulphates and selected metals in different areas and seasons

The characteristics of the distribution of particles by size were investigated for sulphates and selected metals (Pb, Fe, Mn, and Cu) in the air in two urban and an industrial area during the winter and summer periods using an Andersen cascade impactor.In the case of metals, but not sulphates, the character of the area affected the value of mass median diameter. Lowest values were obtained in a sparsely populated urban area, whereas in a densely populated urban area and in the industrial area the values were higher.In the industrial area a high correlation coefficient was found between sulphate and manganese, and between sulphate and lead, as well as a high value of the equivalent Mn²⁺/SO _inf4 ^sup2- ratio for the total sample. It may therefore be assumed that in the industrial area manganese produces a catalytic effect on SO₂ conversion to sulphate. Among the investigated metals lead stands out as a dominant cation which binds to the sulphate ion in the industrial and densely populated areas.