This paper describes a method of estimating emission fluxes of biogenic volatile organic compounds (BVOCs) based on the approach proposed by Guenther et al. (1995) and the high-resolution Corine land-cover 2000 database (1 × 1 km resolution). The computed emission fluxes for the Czech Republic (selected for analysis as being representative of a heavily cultivated, central European country) are compared with anthropogenic emissions, both for the entire country and for individual administrative regions. In some regions, BVOC emissions are as high as anthropogenic emissions; however, in most regions the BVOC emissions are approximately 50% of the anthropogenic emissions. The yearly course of BVOC emissions (represented by monoterpenes and isoprene) is presented, along with the spatial distribution of annual mean values. Differences in emission distributions during winter (January) and summer (June) are also considered. The amount of the biogenic VOCs emitted over the central Europe is comparable with the anthropogenic VOC emissions from this region.

Short- and long-term changes in the methanol-extractable UV-absorbing compounds and biomass of the pioneer moss Polytrichum juniperinum in response to natural and enhanced UV radiation were studied. Under natural conditions, the compounds were found to fluctuate seasonally. In summer these compounds correlated negatively with irradiation. The concentration was low in July after a period of simultaneous heat, drought and high irradiation. Transient positive correlation between daily concentration and UV was seen in June. The concentration increased towards autumn and was relatively high under snow. Two enhanced UV experiments were performed. Seasonality in the compounds was again observed, with negative correlations with irradiation. During the first weeks, a transient inhibition of compound production was observed after the daily UV-B treatment. After six years of modulated UV-treatment in situ, photosynthesising biomass decreased under UV-B and increased under UV-A. A larger variation in the UV-absorbing compounds was observed under UV-B treatment. Juniper polytrichum moss is affected by drought, overwintering conditions and UV.

Environmental pollution by mercury (Hg) is a considerable environmental problem world-wide. Due to the occurrence of Hg volatilization from their soils, floodplains can function as an important source of volatile Hg. Soil temperature and soil water content related to flood dynamics are considered as important factors affecting seasonal dynamics of total gaseous mercury (TGM) fluxes. We quantified seasonal variations of TGM fluxes and conducted a laboratory microcosm experiment to assess the effect of temperature and moisture on TGM fluxes in heavily polluted floodplain soils. Observed TGM emissions ranged from 10 to 850 ng m−2 h−1 and extremely exceeded the emissions of non-polluted sites. TGM emissions increased exponentially with raised air and soil temperatures in both field (R2: 0.49–0.70) and laboratory (R2: 0.99) experiments. Wet soil material showed higher TGM fluxes, whereas the role of soil water content was affected by sampling time during the microcosm experiments. Warmer environmental conditions result in higher Hg volatilization rates from floodplain soils.

Increases in reactive nitrogen deposition are a growing concern in the U.S. Rocky Mountain west. The Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study was designed to improve understanding of the species and pathways that contribute to nitrogen deposition in Rocky Mountain National Park (RMNP). During two 5-week field campaigns in spring and summer of 2006, the largest contributor to reactive nitrogen deposition in RMNP was found to be wet deposition of ammonium (34% spring and summer), followed by wet deposition of nitrate (24% spring, 28% summer). The third and fourth most important reactive nitrogen deposition pathways were found to be wet deposition of organic nitrogen (17%, 12%) and dry deposition of ammonia (14%, 16%), neither of which is routinely measured by air quality/deposition networks operating in the region. Total reactive nitrogen deposition during the spring campaign was determined to be 0.45 kg ha−1 and more than doubled to 0.95 kg ha−1 during the summer campaign. The reactive nitrogen deposition budget for Rocky Mountain National Park.

To delineate the character of contaminations in the Grand Canal, China, a three-year study (2004-2006) was conducted to investigate variations the water quality in the canal. Results showed that the variation of water quality within the Grand Canal was of there is remarkable spatial and seasonal heterogeneity regarding water quality within the Canal. Values of contaminants in dry-season were obviously higher than those in wet-season. Sites influenced strongly by industry and urbanization showed higher contents of nutrients and lower levels of dissolved oxygen in water body; moreover these sites were severely polluted by dissolved metals with the contents of cadmium, chromium and copper exceeding the Criteria Maximum Concentration (CMC), US EPA. Multivariate statistical analysis suggested nutrient and dissolved metals pollution was the dominant environmental problems within the Canal. Anthropogenic influences played a dominant role in the character of contaminations in the Grand Canal.

We studied nutrient removal by Phragmites australis in the Albujón rambla, the main drainage system that discharges into the Mar Menor, a Mediterranean coastal lagoon of high conservation interest, but highly threatened by point and nonpoint pollution derived from tourism and agricultural activities. We measured aerial biomass and N and P concentrations in both aboveground and belowground tissues of common reed during an annual cycle that included two cutting events and two periods of reed growth (one at the end of summer after cutting and another at the beginning of spring, following their natural cycle). The temporal variation of N and P concentrations was related to the phenology of the plant and cutting events. The maximum nutrient concentrations were recorded in young stems in the initial stages of the autumn growing season (35.86 mg N g⁻¹ and 2.38 mg P g⁻¹). The phosphorus dynamics showed evidence of translocation processes related with growth activity, although no evidence of N translocation was found. In November and in summer, when aerial growth ceases because of the hard conditions, the P concentration in rhizomes was higher than in stems, while in spring and in September, the period of maximal growth, the reverse relation was found. The highest total amounts of the two elements in the aboveground biomass (0.54 Tm N ha⁻¹ and 0.25 Tm P ha⁻¹) were reached in July, coinciding with the highest biomass (3.72 kg DW m⁻²), which then decreased to approximately half in August. Nutrient content in the aboveground tissues was highly dependent on the ammonium and nitrate water concentrations. In addition, the N content was inversely related to the Corg/N of sediments, while the P content was influenced positively by the phosphorous concentration of the water. Common reed of the Albujón rambla corresponds to the assimilation type, adapted to nutrient-rich habitats, which is characterized by a pronounced external N cycle and P internal reserves. Based on the results obtained, we propose a management plan for common reed to help control eutrophication of the Mar Menor lagoon. This would bring forward reed cutting to the beginning of summer, instead of August, coinciding with the time of maximum aerial biomass, greater nutrient retention, and lower risk of strong precipitation.

Occurrence and distribution of three typical endocrine-disrupting chemicals (EDCs), nonylphenol mixture (NPs), bisphenol A (BPA), and 17α-ethynilestradiol (EE2), were investigated in the seawater, suspended solid, and sediment around the coastline of Shenzhen city. Field surveys were conducted in both dry season and rainy season to access the influence of rainfall and basic water quality parameters on the distribution of target EDCs. In the seawater, NPs, BPA, and EE2 ranged from 31 to 1,777 ng/l, from 11 to 777 ng/l, and from 10 to 269 ng/l, respectively. In the suspended solid, NPs, BPA, and EE2 were in the range from 3 to 289 ng/l, from 1 to 75 ng/l, and from 1 to 29 ng/l, respectively. In the sediment, NPs, BPA, and EE2 varied from 9 to 355 ng/g dry weight (dw), from 3 to 156 ng/g dw, and from 7 to 144 ng/g dw, respectively. With the increasing rainfall, the concentrations of target EDCs decreased in seawater and sediment and increased in suspended solid at all the sampling locations. Among the six measured basic water quality parameters, the volatile suspended solid value was positively related with the partition property of target EDCs between suspended solid and seawater. Based on the results of principal component analysis, dissolved organic carbon, total nitrogen, and total phosphorous had close relationships with the distribution of target EDCs in the seawater. Temperature and dissolved oxygen had little relationship with the distribution of target EDCs in the coastal area.

This study aimed to understand the seasonal and spatial variations of N₂O emissions from newly created littoral marshes in the drawdown area of the Three Gorges Reservoir (TGR), China. We measured N₂O emissions at 10-day intervals during the growing season (early July to late September) in 2008. N₂O emissions were measured with static chambers in four typical vegetation stands. The results showed great spatial variations of N₂O emissions among the four stands. The greatest N₂O emissions (0.052 ± 0.063 mg N₂O m⁻² h⁻¹) were from Scirpus triqueter stand, while the lowest N₂O emissions (0.020 ± 0.020 mg N₂O m⁻² h⁻¹) were from Typha angustifolia stand. To such spatial variations in N₂O emissions, standing water depths and soil water content may be important explaining factors. Besides spatial variations, we also found significant temporal variations of N₂O emissions in this area. The temporal variation of N₂O emissions in the growing season was not found significantly related to any measured factor in the study. However, based on principal component analysis, we consider it partly caused by thermal conditions and the marked temporal variation of the standing water depth in the growing season, which to some degree influenced the process of denitrification and N₂O emissions. These results about TGR enable us to make a more reasonable estimate of N₂O emissions from large dam reservoirs, particularly those with a large drawdown area in the growing season in an agricultural landscape.

An outdoor pot experiments was conducted to investigate the effects of enhanced ultraviolet-B (UV-B) radiation on nitrous oxide (N₂O) emissions from soil-winter wheat systems. The enhanced UV-B radiation treatments were simulated by 20% increase in its intensity. N₂O fluxes were measured with a static opaque chamber-gas chromatograph method. The results showed that enhanced UV-B radiation did not change the seasonal patterns of N₂O emissions. Compared to the controls, the enhanced UV-B radiation reduced N₂O fluxes by 16.4% (p = 0.015) during the elongation-booting stage, while it had no significant effects on N₂O fluxes in the turning-green and heading-maturity phases. During the turning green-overall heading span, the accumulative N₂O was largely decreased by the enhanced UV-B radiation (p < 0.05). From the overall heading to maturity, however, the effects of enhanced UV-B on N₂O emissions were not pronounced (p > 0.10). At the elongation-booting stage, enhanced UV-B increased soluble proteins content in leaves, NO ₃ ⁻ -N and NO ₄ ⁺ -N content in rhizosphere soil, and soil microbial biomass C (C mic) and N (N mic; p < 0.05), as well as microbial biomass C:N ratio changing from 5.0 to 6.8. Our findings suggest that the effects of enhanced UV-B radiation on N₂O emissions differed with winter wheat developmental stages. To assess the overall effects of enhanced UV-B radiation on N₂O emissions from agroecosystems, nevertheless, more field measurements deserve to be carried out in various cropping systems.

The Nandong Underground River System (NURS) is located in Southeast Yunnan Province, China. Groundwater in NURS plays a critical role in socio-economical development of the region. However, with the rapid increase of population in recent years, groundwater quality has degraded greatly. In this study, the analysis of 36 groundwater samples collected from springs in both rain and dry seasons shows significant spatial disparities and slight seasonal variations of major element concentrations in the groundwater. In addition, results from factor analysis indicate that NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , Na⁺, K⁺, and EC in the groundwater are mainly from the sources related to human activities while Ca²⁺, Mg²⁺, HCO ₃ ⁻ , and pH are primarily controlled by water-rock interactions in karst system with Ca²⁺ and HCO ₃ ⁻ somewhat from anthropogenic inputs. With the increased anthropogenic contaminations, the groundwater chemistry changes widely from Ca-HCO₃ or Ca (Mg)-HCO₃ type to Ca-Cl (+NO₃) or Ca (Mg)-Cl (+NO₃), and Ca-Cl (+NO₃+SO₄) or Ca (Mg)-Cl (+NO₃+SO₄) type. Concentrations of NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , Na⁺, and K⁺ generally show an indistinct grouping with respect to land use types, with very high concentrations observed in the groundwater from residential and agricultural areas. This suggests that those ions are mainly derived from sewage effluents and fertilizers. No specific land use control on the Mg²⁺ ion distribution is observed, suggesting Mg²⁺ is originated from natural dissolution of carbonate rocks. The distribution of Ca²⁺ and HCO ₃ ⁻ does not show any distinct land use control either, except for the samples from residential zones, suggesting the Ca²⁺ and HCO ₃ ⁻ mainly come from both natural dissolution of carbonate rocks and sewage effluents.