Non-Point-Source Impacts on Stream Nutrient Concentrations Along a Forest to Urban Gradient

We conducted statistical analyses of a 10-year record of stream nutrient and sediment concentrations for 17 streams in the greater Seattle region to determine the impact of urban non-point-source pollutants on stream water quality. These catchments are dominated by either urban (22–87%) or forest (6–73%) land cover, with no major nutrient point sources. Stream water phosphorus concentrations were moderately strongly (r²=0.58) correlated with catchment land-cover type, whereas nitrogen concentrations were weakly (r²=0.19) and nonsignificantly (at < 0.05) correlated with land cover. The most urban streams had, on average, 95% higher total phosphorus (TP) and 122% higher soluble reactive phosphorus (SRP) and 71% higher turbidity than the most forested streams. Nitrate (NO₃), ammonium (NH₄), and total suspended solids (TSS) concentrations did not vary significantly with land cover. These results suggest that urbanization markedly increased stream phosphorus concentrations and modestly increased nitrogen concentrations. However, nutrient concentrations in Seattle region urban streams are significantly less than those previously reported for agricultural area streams.     

Eutrophication Status of Marine Environment of Mumbai and Jawaharlal Nehru Ports

The marine environment of Mumbai and Jawaharlal Nehru ports was monitored for some environmental and biological parameters during three different periods between 2001 and 2002. The results are compared with the records available since 1960s. With the passage of time the environmental status underwent changes, probably due to the increase in anthropogenic activities in the metropolis. The nutrient level especially the nitrate concentration has increased gradually over the years with a simultaneous decrease in dissolved oxygen, indicating increase in the biological activity. Characterization of this environment based on Assessment of Estuarine Trophic Status (ASSETS) model indicates that the current status is poor and may get worsen in future if no appropriate management policies are put into place.     

Combined and synergistic effects of climate change and urbanization on water quality in the Wolf Bay watershed, southern Alabama

This study investigated potential changes in flow, total suspended solid(TSS) and nutrient(nitrogen and phosphorous) loadings under future climate change, land use/cover(LULC)change and combined change scenarios in the Wolf Bay watershed, southern Alabama,USA. Four Global Circulation Models(GCMs) under three Special Report Emission Scenarios(SRES) of greenhouse gas were used to assess the future climate change(2016–2040). Three projected LULC maps(2030) were employed to reflect different extents of urbanization in future. The individual, combined and synergistic impacts of LULC and climate change on water quantity/quality were analyzed by the Soil and Water Assessment Tool(SWAT).Under the "climate change only" scenario, monthly distribution and projected variation of TSS are expected to follow a pattern similar to streamflow. Nutrients are influenced both by flow and management practices. The variation of Total Nitrogen(TN) and Total Phosphorous(TP) generally follow the flow trend as well. No evident difference in the N:P ratio was projected. Under the "LULC change only" scenario, TN was projected to decrease,mainly due to the shrinkage of croplands. TP will increase in fall and winter. The N:P ratio shows a strong decreasing potential. Under the "combined change" scenario, LULC and climate change effect were considered simultaneously. Results indicate that if future loadings are expected to increase/decrease under any individual scenario, then the combined change will intensify that trend. Conversely, if their effects are in opposite directions, an offsetting effect occurs. Science-based management practices are needed to reduce nutrient loadings to the Bay.     

Nutrient Abatement Potential and Abatement Costs of Waste Water Treatment Plants in the Baltic Sea Region

We assess the physical potential to reduce nutrient loads from waste water treatment plants in the Baltic Sea region and determine the costs of abating nutrients based on the estimated potential. We take a sample of waste water treatment plants of different size classes and generalize its properties to the whole population of waste water treatment plants. Based on a detailed investment and operational cost data on actual plants, we develop the total and marginal abatement cost functions for both nutrients. To our knowledge, our study is the first of its kind; there is no other study on this issue which would take advantage of detailed data on waste water treatment plants at this extent. We demonstrate that the reduction potential of nutrients is huge in waste water treatment plants. Increasing the abatement in waste water treatment plants can result in 70 % of the Baltic Sea Action Plan nitrogen reduction target and 80 % of the Baltic Sea Action Plan phosphorus reduction target. Another good finding is that the costs of reducing both nutrients are much lower than previously thought. The large reduction of nitrogen would cost 670 million euros and of phosphorus 150 million euros. We show that especially for phosphorus the abatement costs in agriculture would be much higher than in waste water treatment plants.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-013-0435-1) contains supplementary material, which is available to authorized users.     

Carcass Provisioning to Support Scavengers: Evaluating a Controversial Nature Conservation Practice

A number of scavenger species have suffered population declines across Europe. In attempts to reverse their decline, some land and wildlife managers have adopted the practice of leaving or placing out carcasses of wild or domestic herbivores to provide a source of carrion. However, this can be a controversial practice, with as yet unclear outcomes for many target species and the ecosystems they are part of. Here we bring out the key aspects of this increasingly common conservation practice illustrated using three contrasting cases studies. We show that the provision of carcasses is often motivated by a desire to benefit charismatic species or to facilitate nutrient cycling throughout an ecosystem. Evidence for the effectiveness of this practice in achieving these objectives, however, is mostly lacking, with ecologists studying “easier” species groups such as beetles and therefore not providing relevant insights. Moreover, conflicts between environmental policies that carcass provisioning is aimed at and other social and economic objectives do occur but these projects are often designed without taking into account this broader context. We conclude that expecting carcasses to simply be “good for biodiversity” may be too naïve a view. A greater knowledge of the impact of carcass provisioning and placement on ecosystems and society at large is required before it can become a more effective conservation tool at a wider scale.     

Impacts of industrial waste resources on maize (Zea mays L.) growth,yield, nutrients uptake and soil properties

Discharging untreated highly acidic (pH < 4.0), organic and nutrients rich monosodium glutamate wastewater (MW), and highly alkaline (pH > 10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5 ± 0.1) with PW and lime (treatments represented as MW + PW and MW + Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha^?1. Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear^?1 and 100-kernel weight were higher in MW + Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW + Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW + PW. The MW + PW and MW + Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.     

Reconstructing the Development of Baltic Sea Eutrophication 1850–2006

A comprehensive reconstruction of the Baltic Sea state from 1850 to 2006 is presented: driving forces are reconstructed and the evolution of the hydrography and biogeochemical cycles is simulated using the model BALTSEM. Driven by high resolution atmospheric forcing fields (HiResAFF), BALTSEM reproduces dynamics of salinity, temperature, and maximum ice extent. Nutrient loads have been increasing with a noteworthy acceleration from the 1950s until peak values around 1980 followed by a decrease continuing up to present. BALTSEM shows a delayed response to the massive load increase with most eutrophic conditions occurring only at the end of the simulation. This is accompanied by an intensification of the pelagic cycling driven by a shift from spring to summer primary production. The simulation indicates that no improvement in water quality of the Baltic Sea compared to its present state can be expected from the decrease in nutrient loads in recent decades.     

Responses of herbaceous mimosa (Mimosa strigillosa), a new reclamation species, to soil pH

Growth responses of herbaceous mimosa (Mimosa strigillosa Torr. and Gray), a potential new reclamation species in the SE USA and Mexico, to nine soil pH scales were studied under a controlled environment at Nacogdoches, TX, USA. Twenty seeds were planted in each of 40 (nine scales plus one control in four replicates) 20.3-cm pots filled with Tonkawa sandy soil. These pots were treated with H₂SO₄ or Ca(OH)₂ to adjust each pot to its designated pH level. After 15 days of seeding, the emergence rate was at best about 50–70% for pH 4.7–6.6. The plant can survive and grow at soil pH as low as 4.7, but the optimum growth seems to be on soils with pH ranging from 6.2 to 7.1. At this pH range, the plant exhibits higher values of green and dry biomass, longer shoot growth and lower root/shoot weight and length ratios. The survival rate was greater than 90% for all treatments, except for pH 4.1. There were no nutrient deficiencies in plant tissues on soil pH 4.7 or higher. The plant allocated more growth to the shoot under optimum conditions, but more growth to the roots under environmental stress. It is not suitable for herbaceous mimosa to grow on soils with pH 4.1 or less.     

Fauna-associated changes in soil biochemical properties beneath isolated trees in a desert pastureland of India and their importance in soil restoration

Biodiversity conservation and management of natural resources are the best options to restore and increase productivity of degrading pastureland in dry areas. Hence, arthropod abundance, organic matter, respiration, and dehydrogenase activity were measured in canopy zone soil of Prosopis cineraria (PC), Acacia nilotica (AN), Zizyphus nummularia (ZN), Capparis decidua (CD), and Acacia senegal (AS) associated with grasses with a view to establish interrelation for productivity enhancement of pastureland. Pure grass bock outside tree canopy was control plot. Acari, Myriapoda, Coleoptera, Isoptera, Collembola, and other soil arthropods were the major soil faunal groups. Integration of tree in pastureland enhanced population of soil arthropod by 9–65-fold in May 2001 and 8–13-fold in August/September as compared with control. The trends of changes in soil organic matter (SOM), soil respiration (SR), and dehydrogenase activity (DHA) were similar to the changes in soil arthropod population, indicating the role of soil fauna in facilitating biochemical processes and soil fertility. Two, eight, and nine times greater SOM, SR, and DHA, respectively, in silvipastoral system than the values in control suggest the beneficial effects of trees on improvement in biochemical processes and thus biodiversity in pastureland, as supported by negative values of relative tree effects (RTE). Microbial activities were highest in the ZN system, which had highest abundance of soil arthropods. In the other systems, CD and AS systems showed greater soil arthropod abundance and biological activities than with the PC and AN systems. Therefore, Z. nummularia-, C. decidua-, and A. senegal-based silvipastoral systems and related soil fauna may be promoted for enhancement of biological activity and productivity of pastureland in desert. The strategy may be adopted for developing a sustainable pedoecosystem in a region of the world where agriculture is notoriously difficult.     

Seasonal and interannual variability of hydrology and nutrients in the Northeastern Black Sea

The main objective of this work was to investigate the temporal variability of hydrochemical parameters in two coastal regions of the Northeastern Black Sea: the Gelendzhik bay, influenced by anthropogenic activities and the Golubaya bay an open coastal region. Dissolved oxygen, biochemical oxygen demand, pH, alkalinity, phosphate, organic phosphorus, silicates, nitrates, nitrites, ammonia, organic nitrogen, oil products and heavy metals were measured. Si/P and Si/N ratios showed that the Gelendzhik bay waters were significantly enriched in nitrogen and phosphorus compounds. Unlike the Golubaya bay, phosphates were always present in the Gelendzhik bay, and development of photo-synthesis was not limited by these. Features of seasonal variability of nutrients in the Gelendzhik bay (increased concentrations and pronounced summer-autumn maximum) appeared to be a result of human impact—outflow of nutrients with shore input and recreational activities during the summer holiday season. The data obtained indicate that pollution from local spots from the coast of the Black Sea, related primarily to eutrophication, could play a large role in the nutrient balance of the sea and could affect its ecological state.