Phosphorus Loadings Associated with a Park Tourist Attraction: Limnological Consequences of Feeding the Fish

The Linesville spillway of Pymatuning State Park is one of the most visited tourist attractions in Pennsylvania, USA, averaging more than 450,000 visitors · year⁻¹. Carp (Cyprinus carpio Linnaeus) and waterfowl congregate at the spillway where they are fed bread and other foods by park visitors. We hypothesized that the “breadthrowers” constitute a significant nutrient vector to the upper portion of Pymatuning Reservoir. In the summer of 2002, we estimated phosphorus loadings attributable to breadthrowers, and compared these values to background loadings from Linesville Creek, a major tributary to the upper reservoir. Items fed to fish included bread, donuts, bagels, canned corn, popcorn, corn chips, hot dogs, birthday cakes, and dog food. Phosphorus loading associated with park visitors feeding fish was estimated to be 3233 g day⁻¹, and estimated P export from the Linesville Creek watershed was 2235 g·day⁻¹. P loading attributable to breadthrowers exceeded that of the entire Linesville Creek watershed on 33 of the 35 days of study, with only a heavy rainfall event triggering watershed exports that exceeded spillway contributions. Averaged across 5 weeks, breadthrowers contributed 1.45-fold more P to Pymatuning Reservoir than the Linesville Creek watershed. If Linesville Creek P exports are extrapolated to the entire Sanctuary Lake watershed, spillway contributions of P added 48% to the non-point source watershed P entering the lake. Park visitors feeding fish at the Linesville Spillway are a significant source of nutrients entering Sanctuary Lake.     

Nutrient chemistry of the Densu River in Ghana

The impact of anthropogenic activities on the fluctuation of nutrients along the Densu River and its tributaries was studied. High concentrations of nutrients were observed in the study area but the river was found to be circumneutral and fresh with pH ranging between 6.54 and 7.84. The levels of NH₄ ⁺–N ranged between 0.21 and 2.1 mg L⁻¹ with mean concentration of 1.19 ± 0.02 mg L⁻¹ while that of nitrate is between 0.13 and 5.21 mg L⁻¹ with a mean concentration of 2.07 ± 0.01 mg L⁻¹. The levels of PO₄ ³⁻–P fluctuated within the range 0.54 and 1.04 mg L⁻¹ with a mean of 0.84 ± 0.01 mg L⁻¹. The Densu River Basin was also found to be with organic matter with depleted dissolved oxygen. The river recorded high BOD values ranging from 6.91 to 18.8 mg L⁻¹. Concentration of nutrients and organic pollutants increased as a consequence of anthropogenic inputs particularly from domestic, agricultural and municipal sources. The highly impaired sites were those located close to the urbanized, agricultural and high-density residential areas. The relatively high concentration of nitrate and phosphate in the river indicated that it was quite eutrophic.     

Changes in Soil Aggregate,Carbon, and Nitrogen Storages Following the Conversion of Cropland to Alfalfa Forage Land in the Marginal Oasis of Northwest China

Maintenance of soil organic carbon (SOC) is important for sustainable use of soil resources due to the multiple effects of SOC on soil nutrient status and soil structural stability. The objective of this study was to identify the changes in soil aggregate distribution and stability, SOC, and nitrogen (N) concentrations after cropland was converted to perennial alfalfa (Medicago sativa L. Algonguin) grassland for 6 years in the marginal oasis of the middle of Hexi Corridor region, northwest China. Significant changes in the size distribution of dry-sieving aggregates and water-stable aggregates, SOC, and N concentrations occurred after the conversion from crop to alfalfa. SOC and N stocks increased by 20.2% and 18.5%, respectively, and the estimated C and N sequestration rates were 0.4 Mg C ha⁻¹ year⁻¹ and 0.04 Mg N ha⁻¹ year⁻¹ following the conversion. The large aggregate (>5 mm) was the most abundant dry aggregate size fraction in both crop and alfalfa soils, and significant difference in the distribution of dry aggregates between the two land use types occurred only in the >5 mm aggregate fraction. The percentage of water-stable macroaggregates (>2, 2–0.25 mm) and aggregate stability (mean weight diameter of water-stable aggregates, WMWD) were significantly higher in alfalfa soils than in crop soils. There was a significant linear relationship between total SOC concentration and aggregate parameters (mean weight diameter) for alfalfa soils, indicating that aggregate stability was closely associated with increased SOC concentration following the conversion of crops to alfalfa. The SOC and N concentrations and the C/N ratio were greatest in the >2 mm water-stable aggregates and the smallest in the 0.25–0.05 mm aggregates in crop and alfalfa soils. For the same aggregate, SOC and N concentrations in aggregate fractions increased with increasing total SOC and N concentrations. The result showed that the conversion of annual crops to alfalfa in the marginal land with coarse-texture soils can significantly increase SOC and N stocks, and improve soil structure.     

Field-Level Financial Assessment of Contour Prairie Strips for Enhancement of Environmental Quality

The impacts of strategically located contour prairie strips on sediment and nutrient runoff export from watersheds maintained under an annual row crop production system have been studied at a long-term research site in central Iowa. Data from 2007 to 2011 indicate that the contour prairie strips utilized within row crop-dominated landscapes have greater than proportionate and positive effects on the functioning of biophysical systems. Crop producers and land management agencies require comprehensive information about the Best Management Practices with regard to performance efficacy, operational/management parameters, and the full range of financial parameters. Here, a farm-level financial model assesses the establishment, management, and opportunity costs of contour prairie strips within cropped fields. Annualized, depending on variable opportunity costs the 15-year present value cost of utilizing contour prairie strips ranges from $590 to $865 ha^?1 year^?1 ($240–$350 ac^?1 year^?1). Expressed in the context of “treatment area” (e.g., in this study 1 ha of prairie treats 10 ha of crops), the costs of contour prairie strips can also be viewed as $59 to about $87 per treated hectare ($24–$35 ac^?1). If prairie strips were under a 15-year CRP contract, total per acre cost to farmers would be reduced by over 85 %. Based on sediment, phosphorus, and nitrogen export data from the related field studies and across low, medium, and high land rent scenarios, a megagram (Mg) of soil retained within the watershed costs between $7.79 and $11.46 mg^?1, phosphorus retained costs between $6.97 and $10.25 kg^?1, and nitrogen retained costs between $1.59 and $2.34 kg^?1. Based on overall project results, contour prairie strips may well become one of the key conservation practices used to sustain US Corn Belt agriculture in the decades to come.     

Enrichment of vermicomposts prepared from cow dung spiked solid textile mill sludge using nitrogen fixing and phosphate solubilizing bacteria

Textile mill waste can be vermicomposted if it is mixed in the range of 20–30% with cow dung. This article reports the effect of inoculation, of nitrogen fixing Azotobacter chroococcum strain; Azospirillum brasilense strain and phosphate solubilizing Pseudomonas maltophila, on nitrogen and phosphorus content of vermicomposts prepared from cow dung (CD) and cow dung spiked textile mill sludge (CD + STMS). The CD vermicompost was more supportive to the growth and multiplication of all the three bacteria than CD + STMS vermicompost. In Azotobacter chroococcum treated vermicomposts maximum nitrogen content was recorded between 45 and 60 days [CD␣vermicompost (25.9 ± 0.45 g kg⁻¹) and CD + STMS vermicompost (20.6 ± 0.62 g kg⁻¹)] followed by Azospirillum brasilense inoculation [CD vermicompost (19.4 ± 0.60 g kg⁻¹) and CD + STMS vermicompost (18.6 ± 0.17 g kg⁻¹)]. Phosphorus content in Pseudomonas maltophila inoculated CD vermicompost was 20.8 ± 0.20 g kg⁻¹ and CD + STMS vermicompost was 13.4 ± 0.45 g kg⁻¹ after 75th day of inoculation.     

Growth and fecundity of earthworms: <Emphasis Type="Italic">Perionyx excavatus</Emphasis> and <Emphasis Type="Italic">Perionyx sansibaricus</Emphasis> in cattle waste solids

Epigeic earthworms (Oligochaeta) have been appeared as key organisms to convert organic waste resources into value-added products, i.e., vermicompost and worm biomass. The assessment of reproduction potential of composting earthworm may be beneficial for large-scale earthworm production. Although, the waste minimizing potential of Perionyx excavatus and Perionyx sansibaricus is well proved, but little information is available about their fecundity rate. In this study, the efforts have been made to explore the growth and reproduction biology of P. excavatus and P. sansibaricus, using cattle waste solid as culture substrate, under laboratory conditions. Earthworms were weighed weekly and number of cocoons produced per week assessed. Biomass productions, fecundity, maturation, natality all were significantly different between P. excavatus and P. sansibaricus. The highest mean individual biomass was 767.7 ± 18.4 mg and 612.6 ± 20.6 mg, respectively in P. sansibaricus and P. excavatus. However, the highest cocoon numbers occurred in P. excavatus (492.3 ± 13.6), significantly higher than P. sansibaricus (269.6 ± 17.1). Fecundity was slightly different in both species: 1.38 ± 0.77 cocoons adult worm⁻¹ week⁻¹ (P. excavatus) and 1.58 ± 0.74 cocoons adult worm⁻¹ week⁻¹ (P. sansibaricus). The hatchling success rate (%) was highest in P. excavatus. Overall natality (juveniles adult⁻¹ week⁻¹) was highest in P. sansibaricus (1.52) than P. excavatus (1.26), which suggests that P. sansibaricus may be a better candidate for rapid propagation of earthworms in cattle waste solid.     

Arsenic uptake and phytotoxicity of T-aman rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) grown in the As-amended soil of Bangladesh

A pot-culture experiment was conducted in open-field conditions with highly cultivated locally transplanted (T) aman rice (Oryza sativa L.) named BR-22 in arsenic (As)-amended soil (0, 1.0, 5.0, 10.0, 20.0, 30.0, 40.0 and 50.0 mg kg⁻¹ As) of Bangladesh to see the effect of As on the growth, yield and metal uptake of rice. Arsenic was applied to soil in the form of sodium arsenate (Na₂HAsO₄). Arsenic affected the plant height, tiller and panicle numbers, grain and straw yield of T-aman rice significantly (P ≤ 0.05). The grain As uptake of T-aman rice was found to increase with increase of As in soil and a high grain As uptake was observed in the treatments of 30–50 mg kg⁻¹ As-containing soil. These levels exceed the food hygiene concentration limit of 1.0 mg kg⁻¹ As. However, the straw As uptake varied significantly (P ≤ 0.05) from a low concentration of As in soil (5 mg kg⁻¹) and the highest uptake was noticed in 20 mg kg⁻¹ As treatment.     

Multivariate approach for surface water quality mapping with special reference to nitrate enrichment in Sugadaira,Nagano Prefecture (Japan)

The hydrochemical study of the surface water along with land-use/land-cover study of its catchment area is useful for determining its suitability for support to aquatic ecosystem and agricultural purposes. The surface water quality around the wetland in Sugadaira region, Japan, is being affected both by complex hydrogeochemical processes and by anthropogenic activity, mainly intensive agricultural practices. Statistical analysis was carried out in this study using surface water chemistry data to enable hydrochemical evaluation of the water quality based on the ionic constituents, water types, and factors controlling water quality. Results show that the general trend of various ions was found to be Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃ ⁻ > NO₃ ⁻ > SO₄ ²⁻ > Cl⁻. Spatial distribution of water chemistry shows that enrichment of NO₃ ⁻ has taken place along one side of the wetland that is exposed directly to human settlement and agricultural practices. This study is vital considering that pollution in a wetland indicates that poor health of water resources in the region not only makes the situation alarming but also calls for immediate attention.     

Periodical monitoring with lichen, <Emphasis Type="Italic">Phaeophyscia hispidula</Emphasis> (Ach.) Moberg in Dehradun city,Uttarakhand, India

Nine heavy metals were estimated in lichen, Phaeophyscia hispidula (Ach.) Moberg, collected from 12 different sites of Dehradun, capital city, to analyze the air quality of Uttarakhand. Total metal concentration was the highest at Mohkampur Railway Crossing, Hardwar Road (42,505 μg g⁻¹). Dela Ram Chowk, located in the center of the city, also had higher metal concentration, 34,317 μg g⁻¹, with maximum concentration of Pb at 12,433 μg g⁻¹, while Nalapani forest area had minimum total metal concentration (1,873 μg g⁻¹) as well as minimum Pb level at 66.6 μg g⁻¹, indicating anthropogenic activity, mainly vehicular activity, responsible for the increase in metal concentration in the ambient environment. In comparison with the earlier years 2004 and 2006, air pollution as indicated by similar lichen shows a considerable increase in the total metal concentration (especially Pb) in the ambient air of Dehradun city, which may be attributed to exponential rise in the traffic activity in the last 5 years.     

Bioremediation of aerobically treated distillery sludge mixed with cow dung by using an epigeic earthworm Eisenia fetida

The potential of the epigeic earthworm Eisenia fetida to stabilize sludge␣(generated from a distillation unit of the sugar industry) mixed with cow dung, in different proportions i.e. 20% (T₁), 40% (T₂), 60% (T₃) and 80% (T₄) has been studied under laboratory conditions for 90 days. The␣ready vermicompost was evaluated for its’ different physico-chemical parameters using standard methods. At the end of experiment, all vermibeds expressed a significant decrease in pH (7.8–19.2%) organic C (8.5–25.8%) content, and an increase in total N (130.4–170.7%), available P (22.2–120.8%), exchangeable K (104.9–159.5%), exchangeable Ca (49.1–118.1%), and exchangeable Mg (13.6–51.2%) content. Overall, earthworms could maximize decomposition and mineralization efficiency in bedding with lower proportions of distillery sludge. DTPA extractable metal reduction in substrate was recorded between the ranges of 12.5–38.8% for Zn, 5.9–30.4% for Fe, 4.7–38.2% for Mn and 4.5–42.1% for Cu. Maximum values for the mean individual live weight (809.69 ± 20.09 mg) and maximum individual growth rate (mg wt. worm⁻¹ day⁻¹) (5.81 ± 0.18) of earthworms was noted in T₁ treatment, whereas cocoon numbers (69.0 ± 7.94) and individual reproduction rate (cocoon worm⁻¹ day⁻¹) (0.046 ± 0.002) was highest in T₂ treatment. Earthworm mortality tended to increase with increasing proportion of distillery sludge, and maximum mortality in E. fetida was recorded for the T₄ (45.0 ± 5.0) treatment. Results indicate that vermicomposting might be useful for managing the energy and nutrient rich distillery sludge on a low-input basis. Products of this process can be used for sustainable land restoration practices. The feasibility of worms to mitigate the toxicity of metals also reduces the possibility of soil contamination, which has been reported in earlier studies during direct field application of industrial wastes.     

Elemental contaminants in groundwater: A study of trace metals from residential area in the vicinity of an industrial area in Lagos, Nigeria

Groundwater (well water) from a residential area within the vicinity of an industrial estate in Lagos, Nigeria were sampled and analysed by Flame Atomic Absorption Spectroscopy for their heavy metals content. This was with a view of assessing the quality of the water, which was being used for domestic activities, especially, drinking usually without treatment. Total trace metal determination by mineral acid digestion of water samples was applied. This method proved to be better than an extractive concentration technique in the quality assurance protocols with the recovery range being 90.7 ± 0.006–97.6 ± 0.003%. Mean concentration of trace metals in water samples ranged from Fe: 0.05–0.47 mg l⁻¹; Al: 0.1–1.54 mg l⁻¹; Cu: 0.14–1.39 mg l⁻¹; Zn: 0.04–0.43 mg l⁻¹; Cd: trace–0.02 mg l⁻¹; Pb: trace–0.03 mg l⁻¹, Mn: 0.01–0.18 mg l⁻¹ and Ni: 0.02–0.11 mg l⁻¹. Physical parameters of water samples examined were within the drinking water safety limits except for conductivity. Results generally indicate the presence of heavy metal constituents in groundwater samples. Detection of metals such as cadmium and lead which have serious health implications above WHO and USEPA limits in drinking water gives cause for concern.     

Response of Soil Inorganic Nitrogen to Land Use and Topographic Position in the Cofre de Perote Volcano (Mexico)

This study addressed the effects of land use and slope position on soil inorganic nitrogen and was conducted in small watersheds. The study covered three land use types: tropical cloud forest, grassland, and coffee crop. To conduct this research, typical slope small watersheds were chosen in each land use type. Slopes were divided into three positions: shoulder, backslope, and footslope. At the center of each slope position, soil sampling was carried out. Soil inorganic nitrogen was measured monthly during a period of 14 months (July 2005–August 2006) with 11 observations. Significant differences in soil NH₄ ⁺–N and NO₃ ⁻–N content were detected for both land use and sampling date effects, as well as for interactions. A significant slope position-by-sampling date interaction was found only in coffee crop for NO₃ ⁻–N content. In tropical cloud forest and grassland, high soil NH₄ ⁺–N and low NO₃ ⁻–N content were recorded, while soil NO₃ ⁻–N content was high in coffee crop. Low NO₃ ⁻–N contents could mean a substantial microbial assimilation of NO₃ ⁻–N, constituting an important mechanism for nitrogen retention. Across the entire land use set, the relationship between soil temperature and soil inorganic N concentration was described by an exponential decay function (N = 33 + 2459exp^−0.23T, R ² = 0.44, P < 0.0001). This study also showed that together, soil temperature and gravimetric soil water content explained more variation in soil inorganic N concentration than gravimetric soil water content alone.     

Germinable Soil Seed Banks and the Restoration Potential of Abandoned Cropland on the Chinese Hilly-Gullied Loess Plateau

Poor vegetation cover is generally considered to be a major factor causing soil erosion on the Loess Plateau in China. It has been argued that tree planting restoration is ineffective, and natural re-vegetation is an alternative ecological solution for restoring abandoned cropland and controlling soil erosion. The aims of this study were to investigate the characteristics of soil seed banks and to assess the natural restoration potential of abandoned cropland in the hilly-gullied Loess Plateau. The soil seed bank was identified by the germination method with the soil samples, which were collected at four sampling times (April, August, and October 2005 and August 2006) from 12 plots abandoned 3–30 years prior to sampling. The seed bank densities of all of the samples in the 0–10 cm soil layer varied from 1,067 ± 225 to 14,967 ± 1,606 seeds m⁻². Fifty-one species (24 annual and 27 perennial species) belonging to 18 families were identified, and 39% of these species belonged to the families Compositae and Gramineae. The pioneer species Artemisia scoparia dominated the seed bank, with an average seed density of 3,722 seeds m⁻², and accounted for 74.4% of the seeds in the bank. The local dominant species (such as Lespedeza davurica, Artemisia gmelinii, Bothriochloa ischaemun and Stipa bungeana) of the later succession stages also existed at densities varying from 17 to 1, 383 seeds m⁻². The combination of soil seed bank characteristics, reproductive traits of the species, the specific landscape conditions indicates that the potential to restoring the abandoned croplands in the hilly-gullied Loess Plateau via natural re-vegetation could be substantial.     

Spatial Heterogeneity of Water Quality in a Highly Degraded Tropical Freshwater Ecosystem

Awareness of environmental heterogeneity in ecosystems is critical for management and conservation. We used the Xochimilco freshwater system to describe the relationship between heterogeneity and human activities. This tropical aquatic ecosystem south of Mexico City is comprised of a network of interconnected canals and lakes that are influenced by agricultural and urban activities. Environmental heterogeneity was characterized by spatially extensive surveys within four regions of Xochimilco during rainy and dry seasons over 2 years. These surveys revealed a heterogeneous system that was shallow (1.1 m, SD = 0.4 ), warm (17°C, SD = 2.9), well oxygenated (5.0 mg l⁻¹, SD = 3), turbid (45.7 NTU SD = 26.96), and extremely nutrient-rich (NO₃–N = 15.9 mg l⁻¹, SD=13.7; NH₄–N = 2.88 mg l⁻¹, SD = 4.24; and PO₄–P =  8.3 mg l⁻¹, SD = 2.4). Most of the variables were not significantly different between years, but did differ between seasons, suggesting a dynamic system within a span of a year but with a high resilience over longer periods of time. Maps were produced using interpolations to describe distributions of all variables. There was no correlation between individual variables and land use. Consequently, we searched for relationships using all variables together by generating a combined water quality index. Significant differences in the index were apparent among the four regions. Index values also differed within individual region and individual water bodies (e.g., within canals), indicating that Xochimilco has high local heterogeneity. Using this index on a map helped to relate water quality to human activities and provides a simple and clear tool for managers and policymakers.     

Production of vermifertilizer from guar gum industrial wastes by using composting earthworm <Emphasis Type="Italic">Perionyx sansibaricus</Emphasis> (Perrier)

Efforts have been made to convert the guar gum industrial waste into a value-added product, by employing a new earthworm species for vermicomposting e.g. Perionyx sansibaricus (Perrier) (Megascolecidae), under laboratory conditions. Industrial lignocellulosic waste was amended with other organic supplements (saw dust and cow dung); and three types of vermibeds were prepared: guar gum industrial waste + cow dung + saw dust in 40: 30: 30 ratio (T₁), guar gum industrial waste + cow dung + saw dust in 60: 20: 20 ratio (T_2,), and guar gum industrial waste + cow dung + saw dust in 75: 15: 10 ratio (T₃). As compared to initial concentrations, vermicomposts exhibited a decrease in organic C content (5.0–11.3%) and C:N ratio (11.1–24.4%) and an increase in total N (18.4–22.8%), available P (39.7–92.4%), and exchangeable K (9.4–19.7%) contents, after 150 days of vermicomposting. A vermicomposting coefficient (VC) was used to compare of vermicomposting with the experimental control (composting). P. sansibaricus exhibited maximum value of mean individual live weight (742.8 ± 21.1 mg), biomass gain (442.94 ± 21.8 mg), growth rate (2.95 ± 0.15 mg day⁻¹), cocoon numbers (96.0 ± 5.1) and reproduction rate (cocoons worm⁻¹ day⁻¹) (0.034 ± 0.001) in T₂ treatment. In T₃ maximum mortality (30.0 ± 4.01 %) in earthworm population was observed. Overall, T₂ vermibed appeared as an ideal substrate to manage guar gum industrial waste effectively. Vermicomposting can be proposed as a low-input basis technology to convert industrial waste into value-added biofertilizer.     

Age dependency of high-affinity ouabain receptors and their magnetosensitivity

Age dependency of [³H]-ouabain binding, ⁴⁵Ca²⁺ eflux and its magnetosensitivity in rats’ brain cortex and heart muscle tissues were studied. Curves of dose-dependent [³H]-ouabain binding consisted of three components with different affinities (10⁻⁷–10⁻⁴ M (α₁); 10⁻⁹–10⁻⁷ M (α₂); and 10⁻¹¹–10⁻⁹ M (α₃)). These curves were also characterized by different dose-dependent kinetics. [³H]-ouabain binding with α₃ receptors in brain cortex and heart muscle tissues of young and adult animals had a dose-dependent character, while that in old ones had a dose-independent character. A 0.2 T static magnetic field (SMF) exposure had modulation effect on ouabain binding with α₁, α₂ and α₃ receptors in young rats, while in adult ones, only α₃ receptors were magnetosensitive. In old animals, SMF exposure had no significant effect on ouabain binding with α₃ receptors in brain cortex, while in heart muscle, it had inhibitory effect on it. Age-dependent effect of ouabain impact on ⁴⁵Ca²⁺ efflux showed that all concentrations of ouabain lead to inhibitory effect in young animals’ brain cortex and heart muscle (with the exception of 10⁻¹⁰ and 10⁻⁶ M), while in old ones, it had activation effect as compared with data received without ouabain. SMF exposure in young animals had activation effect on ⁴⁵Ca²⁺ efflux from brain cortex and heart muscle in data without ouabain, and in old rats, ⁴⁵Ca²⁺ efflux from brain cortex was magnetic insensitive. In old animals, SMF increased ⁴⁵Ca²⁺ efflux even after extra low concentration of ouabain. It is suggested that α₃ receptors having a crucial role in the regulation of Na⁺/Ca²⁺ exchange serve as age-dependent magnetosensors of excitable cells.     

Soil-erosion and runoff prevention by plant covers in a mountainous area (se spain): Implications for sustainable agriculture

In the Mediterranean region the intensities and amounts of soil loss and runoff on sloping land are governed by rainfall pattern and vegetation cover. Over a two-year period (1998–1999), six wild species of aromatic and mellipherous plants (Thymus serpylloides subsp. Gadorensis, Thymus baeticus Boiss, Salvia lavandulifolia Vahl., Santolina rosmarinifolia L., Lavandula stoechas L. and Genista umbellata Poiret) were selected for erosion plots to determine their effectiveness in reducing water erosion on hillslopes of the Sierra Nevada Mountain (SE Spain). The erosion plots (including a bare-soil plot as control), located at 1,345 m in altitude, were 2 m² (2 m × 1 m) in area and had 13% incline. The lowest runoff and soil erosion rates, ranging from 9 to 26 mm yr⁻¹ and from 0.01 to 0.31 Mg ha⁻¹ yr⁻¹, respectively, over the entire study period, were measured under the Thymus serpylloides. Lavandula stoechas L. registered the highest rates among the plant covers tested, runoff ranging from 77 to 127 mm yr⁻¹ and erosion from 1.67 to 3.50 Mg ha⁻¹ yr⁻¹. In the bare-soil plot, runoff ranged from 154 to 210 mm yr⁻¹ and erosion from 4.45 to 7.82 Mg ha⁻¹ yr⁻¹. According to the results, the lowest-growing plant covers (Thymus serpylloides and Salvia lavandulifolia Vahl.) discouraged the soil erosion and runoff more effectively than did the taller and open medium-sized shrubs (Santolina rosmarinifolia L., Genista umbellata Poiret, Thymus baeticus Boiss and Lavandula stoechas L.). Monitoring allowed more direct linkage to be made between plant covers and the prevention of erosion, with implications for sustainable mountain agriculture and environmental protection.     

Metal contamination of surface water,sediment and <Emphasis Type="Italic">Tympanotonus fuscatus</Emphasis> var. <Emphasis Type="Italic">radula</Emphasis> of Iko River and environmental impact due to Utapete gas flare station,Nigeria

Inter-seasonal studies on the trace metal load of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River were conducted between 2003 and 2004. The impact of anthropogenic activities especially industrial effluent, petroleum related wastes, gas flare and episodic oil spills on the ecosystem are remarkable. Trace metals analyzed included cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), vanadium (V) and zinc (Zn). Sediment particle size analysis revealed that they were characteristically psammitic and were predominantly of medium to fine grained sand (>73%), less of silt (<15%) and clay (<10%). These results correlated with low levels of trace elements such as Pb (0.03 ± 0.02 mg kg⁻¹), Cr (0.22 ± 0.12 mg kg⁻¹), Cd (0.05 ± 0.03 mg kg⁻¹), Cu (0.04 ± 0.02 mg kg⁻¹) and Mn (0.23 ± 0.22 mg kg⁻¹) in the sediment samples. This observation is consistent with the scarcity of clayey materials known to be good scavengers for metallic and organic contaminants. Sediments indicated enhanced concentration of Fe, Ni and V, while other metal levels were relatively low. The concentrations of all the metals except Pb in surface water were within the permissible levels, suggesting that the petroleum contaminants had minimal effect on the state of pollution by trace metals in Iko River. Notably, the pollutant concentrations in the sediments were markedly higher than the corresponding concentrations in surface water and T. fuscatus tissues, and decreased with distance from point sources of pollution.     

Balancing Conservation and Economic Sustainability: The Future of the Amazon Timber Industry

Logging has been a much maligned feature of frontier development in the Amazon. Most discussions ignore the fact that logging can be part of a renewable, environmentally benign, and broadly equitable economic activity in these remote places. We estimate there to be some 4.5 ± 1.35 billion m³ of commercial timber volume in the Brazilian Amazon today, of which 1.2 billion m³ is currently profitable to harvest, with a total potential stumpage value of $15.4 billion. A successful forest sector in the Brazilian Amazon will integrate timber harvesting on private lands and on unprotected and unsettled government lands with timber concessions on public lands. If a legal, productive, timber industry can be established outside of protected areas, it will deliver environmental benefits in synergy with those provided by the region’s network of protected areas, the latter of which we estimate to have an opportunity cost from lost timber revenues of $2.3 billion over 30 years. Indeed, on all land accessible to harvesting, the timber industry could produce an average of more than 16 million m³ per year over a 30-year harvest cycle—entirely outside of current protected areas—providing $4.8 billion in returns to landowners and generating $1.8 billion in sawnwood sales tax revenue. This level of harvest could be profitably complemented with an additional 10% from logging concessions on National Forests. This advance, however, should be realized only through widespread adoption of reduced impact logging techniques.     

Net Carbon Sequestration Potential and Emissions in Home Lawn Turfgrasses of the United States

Soil analyses were conducted on home lawns across diverse ecoregions of the U.S. to determine the soil organic carbon (SOC) sink capacity of turfgrass soils. Establishment of lawns sequestered SOC over time. Due to variations in ecoregions, sequestration rates varied among sites from 0.9 Mg carbon (C) ha^?1 year^?1 to 5.4 Mg C ha^?1 year^?1. Potential SOC sink capacity also varied among sites ranging from 20.8 ± 1.0–96.3 ± 6.0 Mg C ha^?1. Average sequestration rate and sink capacity for all sites sampled were 2.8 ± 0.3 Mg C ha^?1 year^?1 and 45.8 ± 3.5 Mg C ha^?1, respectively. Additionally, the hidden carbon costs (HCC) due to lawn mowing (189.7 kg Ce (carbon equivalent) ha^?1 year^?1) and fertilizer use (63.6 kg Ce ha^?1 year^?1) for all sites totaled 254.3 kg Ce ha^?1 year^?1. Considering home lawn SOC sink capacity and HCC, mean home lawn sequestration was completely negated 184 years post establishment. The potential SOC sink capacity of home lawns in the U.S. was estimated at 496.3 Tg C, with HCC of between 2,504.1 Gg Ce year^?1 under low management regimes and 7551.4 Gg Ce year^?1 under high management. This leads to a carbon-positive system for between 66 and 199 years in U.S. home lawns. More efficient and reduction of C-intensive maintenance practices could increase the overall sequestration longevity of home lawns and improve their climate change mitigation potential.