Modeling inverted biomass pyramids and refuges in ecosystems

Although the existence of robust inverted biomass pyramids (IBPs) seems paradoxical, they are well known to exist in planktonic communities, and have recently been discovered in pristine coral reefs and in a reef off the North Carolina coast. Understanding the underlying mechanisms which produce inverted biomass pyramids provides new ecological insights. Some ecologists hypothesize that “the high growth rate of prey and low death rate of predators” causes IBPs. However, we show this is not always the case (see Sections 3.1 and 4). We devise predator–prey models to describe three mechanisms that can lead to IBPs: (1) well-mixed populations with large prey turn-over rate, (2) well-mixed populations with prey immigration, and (3) non-mixed populations where the prey can hide in refuges. The three models are motivated by the three ecosystems where IBPs have been observed. We also devise three refuge mediated models, with explicit refuge size, which incorporate different prey responses in the refuge, and we discuss how these lead to IBPs.     

Evaluation of adsorption potential of adsorbents: a case of uptake of cationic dyes

Adsorption potential of a commercial activated carbon (FS300) has been evaluated for the uptake of cationic dyes namely methylene blue (MB) and rhodamine B (RB). Though, there are numerous studies in literature which report the sorption of MB (more than 40 studies) and RB (more than 10), however none of these use a common parameter to report the capacity of the sorbent. A protocol, based on the equilibrium dye concentration has been proposed to measure the sorption potential of a sorbent. The Langmuir model can very well describe the experimental equilibrium data for both dyes (coefficient of correlation > 0.999). MB (Qm = 312.5 mg g(-1)) is more adsorbable than the RB (Qm = 144.9 mg g(-1)). Molecular weight and chemical structure of dye molecules seem to affect the dye uptake. The effect of pH on dye uptake has also been evaluated by varyingpH from 3 to 11. Uptake of MB increases with pH, wherein RB removal decreases with pH. Dyes could not be desorbed either by distilled water (0.06 and 0.11% for MB and RB respectively), or by 0.1 NHCl (0.136 and 3.0% for MB and RB respectively) indicating, chemical adsorption type of adsorbent-adsorbate interactions.     

Impact of copper on haematological profile of freshwater fish, Channa punctatus

The present study was to evaluate heavy metal toxicity stress symptoms in fish blood during long-term exposure of sublethal concentration of copper sulphate (CuSO4). The effects of copper on various heamatological parameters were evaluated exposing Indian fresh water fish, Channa punctatus to a sub-lethal concentration of copper sulphate (0.36 mg l(-1)) for different periods. Exposure of fish to copper showed a significant decrease in the haemoglobin (Hb) content from 10.73 to 6.60%, red blood cells (RBC) from 2.86 to 1.84 x 10(6)/mm3 and packed cell volume (PCV) from 31.00 to 23.33% at the end of 45th day as compared to control. Whereas the white blood cells (WBC) increased from 60.00 to 92.48 x10(3)/mm3, clotting time (CT) from 27.66 to 43.00 second, erythrocyte sedimentation rate from 5.0 to 13.66 mm/hr and mean corpuscular volume from 108.11 to 126.85 cmu, significantly, with increase in exposure periods. Although mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular haemoglobin (MCH) values showed significant increase during 15 and 30 days exposures, both the values were found significantly increased at the end of the experimental period. The differential leucocytes count (DLC) showed a significant increase in the populations of lymphocytes and eosinophils, whereas neutrophils, monocytes and basophiles were found decreased after exposure to copper.     

Heavy metal pollution in Suva harbour sediments,Fiji

In Fiji, contamination of the coastal environment by heavy metals is proving to be a real concern. This work reports for the first time analyses carried out on an extensive basis, to ascertain the extent of anthropogenic contamination by heavy metals in the <0.063 mm surface sediments of Suva harbour. Sediment samples from 40 sites selected within the harbour were collected and analysed for five heavy metals. The levels of the metals range from 21.4 to 143.0 ± 0.1 mg/kg Cu, 1.40 to 4.87 ± 0.07 wt.% Fe, 22.1 to 93.5 ± 0.3 mg/kg Pb, 40.2 to 269.0 ± 0.3 mg/kg Zn and 1.1 to 2.6 ± 0.2 mg/kg Sn. With reference to the pristine area of the Great Astrolabe, in Kadavu, the acquired data from the harbour are indicative of heavy metal pollution. This could be attributed to the numerous industrial and commercial activities at Wailada and Walu Bay industrial areas, the municipal dump located at the Suva foreshore and the Suva wharf. The pollution is further compounded by the high population density in Suva city.     

Combinatorial effects of distillery and sugar factory effluents in crop plants

Under the reutilization and recycling strategy of industrial effluents, treated distillery and sugar factory mixed effluent was used in petridish culture experiments to investigate its effect on seed germination and seedling growth in wheat, garden pea, black gram and mustard. The seed germination and seedling growth were significantly reduced with increase in concentration of the effluent. The fresh matter was found significantly increased in barley (1.16 g per seedling in 25% dilution level of effluents in comparison to 0.93 in control), while other higher dilution levels reduce it. Wheat, garden pea, black gram, mustard invariably showed inhibition in fresh weight. Dry weight was found consistently reduced or unchanged in different treatments. Total chlorophyll contents in barley were significantly increased in different treatments (2.351 and 2.721 mg/g fresh weight of tissue at 25, 50% dilution levels in comparison to 1.781 of control) while in other crop it was reduced alloverthe treatments. Amylase activity in wheat, garden pea, black gram and mustard was reduced in all the treatments. Only in barley its level was enhanced from 0.76 to 0.85, 0.96, 0.81 in 25, 50, 75% dilution levels of the effluent mixture respectively Based on the data of different crops barley was found to be highly tolerant as the 25 and 50% dilution levels of combined effluents. It showed no change in germination %, while seedling growth was increased in lower dilution levels of combined effluent as compared to control Barley>garden pea>wheat>black gram>mustard gradually showed increased level of sensitivity respectively Most detrimental effects were seen in mustard. This toxicity might be due to excess of nutrients, beyond the limits of tolerance. Therefore, the higher concentration of mixed effluent was not advisable for irrigation purpose, however it could be used for irrigation purpose after proper treatment and dilution (one part treated effluent and five parts of available irrigation water), as this dilution level was found growth and yield promotory     

Tree plantations for restoration of degraded lands and greening of India: a case study of tree growers' cooperatives

India has over 100 m ha (million hectares) of village common lands. De jure, these lands are owned by the state but, de facto, they are used in common by villagers. Most of the village commons are degraded and denuded and are almost nonproductive. Several attempts have been made in the recent past to restore them through planting of trees by governmental and non-governmental organizations. Tree Growers' Co-operative Societies (TGCS), as an organisational innovation of relatively recent origin, have proved to be more cost-effective than other forms of organisations engaged in greening the village commons in India. This paper attempts to assess the financial viability of tree plantations carried out by three selected TGCS and to distil lessons of their experience useful for policy purposes. The study revealed that plantations founded by the sample TGCS were financially viable, and that the plantations had transformed the desolate village commons into 'green wealth'. The authors conclude that the TGCS have a high potential as an instrument for promoting the afforestation of India's degraded village common lands and thereby improving village economy and the quality of the environment.     

Illinois State Water Survey Bulletin 75: New Precipitation Frequency Study for Illinois

Storm frequency estimates and their temporal distributions are important in determining estimates of runoff or peak flow rates in many engineering and hydrological problems. Illinois State Water Survey Bulletin 70 has been serving as the design rainfall standard in Illinois since its publication in 1989. Although Bulletin 70 represented the best available data at the time of its publication, the standards needed to be reevaluated and updated after more than three decades and with the growing evidence of the nonstationary nature of heavy precipitation. The trends in heavy precipitation in Illinois prompted the creation of a new frequency study named Bulletin 75, providing precipitation frequencies for event durations ranging from 5 min to 10 days and for recurrence intervals ranging from 2 months to 500 years. The results are presented for the same 10 geographic sections in Illinois as in Bulletin 70 to maintain the continuity of hydrologic studies and compatibility with regulations. The primary goal of this paper is to outline some of the key methodological issues and challenges, to compare the results with the previous sources, and to highlight the effects of the changing precipitation standards on the development of amendments to existing ordinances. Lake County in Illinois, as one of the most affected urban areas with the highest change in heavy precipitation, was selected to illustrate issues related to the application of modified precipitation standards.     

Should tobacco products’ waste be considered as hazardous in India?

Tobacco and its associated products are known to be harmful for health. Moreover, the waste emanating out of the production, processing, packaging, and consumption of these products is equally harmful for humans as well as other biotic/abiotic agencies. Taking into account the toxic nature of these waste products, it is necessary to have a well-defined approach to deal with this waste. Consideration of tobacco products’ waste as municipal solid waste has serious implications in the long-term as it results in dumping of these wastes mixed-up with domestic waste in landfills. With time, toxic components become part of the leachate which contaminates water and soil, further leading to the contamination in food chain. Therefore, many countries are now considering this waste under the hazardous category and evolving various measures to safely dispose it off. In the light of recent researches and policies, it is time to re-consider this important public health issue.     

Controlled sintering for cadmium stabilization by beneficially using the dredged river sediment

● Dredged river sediment was proved as a ceramic precursor rather than a solid waste. ● Cd was stabilized in Cd-Al-Si-O phases at low temperatures via sediment addition. ● < 5% of Cd was leached out from sintered products even after a prolonged time. ● A strategy was proposed to simultaneously reuse wastes and stabilize heavy metals. Cd-bearing solid wastes are considered to be a serious threat to the environment, and effective strategies for their treatment are urgently needed. Ceramic sintering has been considered as a promising method for efficiently incorporating heavy metal-containing solid wastes into various ceramic products. Mineral-rich dredged river sediment, especially Al and Si-containing oxides, can be treated as alternative ceramic precursors rather than being disposed of as solid wastes. To examine the feasibility of using waste sediment for Cd stabilization and the phase transition mechanisms, this study conducted a sintering scheme for the mixtures of CdO and dredged river sediment with different (Al+Si):Cd mole ratios. Detailed investigations have been performed on phases transformation, Cd incorporation mechanisms, elemental distribution, and leaching behaviors of the sintered products. Results showed that Cd incorporation and transformation in the sintered products were influenced by the mole ratio of (Al+Si):Cd. Among the high-Cd series ((Al+Si):Cd = 6:1), CdSiO₃, Cd₂SiO₄, CdAl₂(SiO₄)₂ and Cd₂Al₂Si₂O₉ were predominant Cd-containing product phases, while Cd₂Al₂Si₂O₉ was replaced by CdAl₄O₇ when the mole ratio of (Al+Si):Cd was 12:1 (low-Cd series). Cd was efficiently stabilized in both reaction series after being sintered at ≥ 900 °C, with < 5% leached ratio even after a prolonged leaching time, indicating excellent long-term Cd stabilization. This study demonstrated that both Cd-containing phases and the amorphous Al-/Si-containing matrices all played critical roles in Cd stabilization. A promising strategy can be proposed to simultaneously reuse the solid waste as ceramic precursors and stabilize heavy metals in the ceramic products.     

Biochemical and Ultrastructural Changes in Plant Foliage Exposed to Auto-Pollution

Auto-pollution is the by-product of our mechanized mobility, which adversely affects both plant and human life. However, plants growing in the urban locations provide a great respite to us from the brunt of auto-pollution by absorbing the pollutants at their foliar surface. Foliar surface configuration and biochemical changes in two selected plant species, namely Ficus religiosa L. and Thevetia nerifolia L., growing at IT crossing (highly polluted sites), Picup bhawan crossing (moderately polluted site) and Kukrail Forest Picnic Spot (Low polluted site) were investigated. It was observed that auto-exhaust pollution showed marked alterations in photosynthetic pigments, protein and cysteine contents and also in leaf area and foliar surface architecture of plants growing at HP site as compared to LP site. The changes in the foliar configuration reveal that these plants can be used as biomarkers of auto-pollution.