Monitoring nitrogen deposition in typical forest ecosystems along a large transect in China

The nitrogen (N) deposition fluxes were investigated in eight typical forest ecosystems along the North–South Transect of Eastern China (NSTEC; based on the ChinaFLUX network) by ion-exchange resin (IER) columns from May 2008 to April 2009. Our results demonstrated that the method of IER columns was both labor cost saving and reliable for measuring dissolved inorganic nitrogen (DIN) deposition at the remote forest stations. The deposition of DIN in the throughfall ranged from 1.3 to 29.5 kg N ha^?1 a^?1, increasing from north to south along NSTEC. The relatively high average ratio of ammonium to nitrate in deposition (1.83) indicated that the N deposition along the NSTEC in China mostly originated in farming and animal husbandry rather than in industry and vehicle activities. For seasonal variability, the DIN deposition showed a single peak in the growing season in the northern part of NSTEC, while, in the southern part, it exhibited double-peaks in the early spring and the mid-summer, respectively. On the annual scale, the DIN deposition variations of the eight sites could be mainly explained by precipitation and the distances from forest stations to provincial capital cities.     

Atmospheric inorganic nitrogen deposition to a typical red soil forestland in southeastern China

A 2-year monitoring study was conducted to estimate nitrogen deposition to a typical red soil forestland in southeastern China. The dry deposition velocities (V(d)) were estimated using big leaf resistance analogy model. Atmospheric nitrogen dry deposition was estimated by combing V(d) and nitrogen compounds concentrations, and the wet deposition was calculated via rainfall and nitrogen concentrations in rainwater. The total inorganic nitrogen deposition was 83.7 kg ha(-1) a(-1) in 2004 and 81.3 kg ha(-1) a(-1) in 2005, respectively. The dry deposition contributed 78.6% to total nitrogen deposition, in which ammonia was the predominant contributor that accounted for 86.1%. Reduced nitrogen compounds were the predominant contributors, accounting for 78.3% of total nitrogen deposition. The results suggested that atmospheric inorganic nitrogen could be attributed to intensive agricultural practices such as excessive nitrogen fertilization and livestock production. Therefore, impacts of atmospheric nitrogen originated from agriculture practices on nearby forest ecosystems should be evaluated.     

Assessing uncertainty in annual nitrogen,phosphorus, and suspended sediment load estimates in three agricultural streams using a 21-year dataset

Accurate estimation of constituent loads is important for studies of ecosystem mass balance or total maximum daily loads. In response, there has been an effort to develop methods to increase both accuracy and precision of constituent load estimates. The relationship between constituent concentration and stream discharge is often complicated, potentially leading to high uncertainty in load estimates for certain constituents, especially at longer-term (annual) scales. We used the loadflex R package to compare uncertainty in annual load estimates from concentration vs. discharge relationships in constituents of interest in agricultural systems, including ammonium as nitrogen (NH₄-N), nitrate as nitrogen (NO₃-N), soluble reactive phosphorus (SRP), and suspended sediments (SS). We predicted that uncertainty would be greatest in NO₃-N and SS due to complex relationships between constituent concentration and discharge. We also predicted lower uncertainty with a composite method compared to regression or interpolation methods. Contrary to predictions, we observed the lowest uncertainty in annual NO₃-N load estimates (relative error 1.5–23%); however, uncertainty was greatest in SS load estimates, consistent with predictions (relative error 19–96%). For all constituents, we also generally observed reductions in uncertainty by up to 34% using the composite method compared to regression and interpolation approaches, as predicted. These results highlight differences in uncertainty among different constituents and will aid in model selection for future studies requiring accurate and precise estimates of constituent load.     

Wet deposition of nitrogen and sulfur in Guangzhou, a subtropical area in South China

Understanding the exchange mechanism between stratosphere and troposphere is one of the most important concerns of meteorologists and climatologists for decades. Different methods are being adopted to study those mechanisms. One of those methods is the study upon the tropospheric concentration of conserve or passive entities with stratospheric origin. One of those passive entities is ⁷Be that is produced upon the incident of cosmic rays on light atmospheric nuclei in the stratosphere. The availability of 5 years observations of ⁷Be concentration in surface air in Tehran (35°41^′ N, 51°18^′ E) encouraged us to investigate meteorological condition effect on the surface concentration of ⁷Be. Also, the intention was to see if there was any intrusion of stratospheric air into the troposphere at the time of high surface concentration of ⁷Be and scavenging mechanism when the concentration was low. During the course of this study, it has been found that ⁷Be concentration is high whenever there is a jet stream over Tehran. Since high-level jet streams normally form near tropopause folding, it could be interpreted as a sign of the intrusion of stratospheric air into the troposphere. It was also found that high concentration of ⁷Be in the Tehran surface air in summer is associated with an upper ridge on 500 hPa surface located east of the city, and low concentration in winter is associated with an upper trough. The latter normally is seen whenever there is precipitation that suggests wet scavenging could be the reason for that observed low concentration.     

The epiphytic lichen hypogymnia physodes as a biomonitor of atmospheric nitrogen and sulphur deposition in Norway

Hypogymnia physodes was sampled from 179 sites of Scots pine forests regularly distributed throughout Norway. The purpose was to map the nitrogen and sulphur contents of lichen thalli on a large-scale geographical basis, and to relate these values to differences in atmospheric deposition and climate.The lichen nitrogen and sulphur concentrations showed large differences; the highest concentration values being 4–5 times greater than the lowest. The highest nitrogen and sulphur values occurred along the coast of southern Norway and on some sites in the inland of southern Norway. There was a close correlation between the two elements. The lichen N/S ratio decreased with increasing latitude.The nitrogen and sulphur contents ofHypogymnia physodes were both significantly correlated to estimated atmospheric deposition of these two elements in Norway. The degree of explanation improved when climatic variables such as temperature sum, altitude, annual precipitation and temperature were included. Factors promoting growth, such as high bark pH, mild winters, hot summers, high precipitation, high ammonium deposition and high evapotranspiration, were all associated with lower lichen nitrogen and/or sulphur concentrations. Unfavourable growth conditions, such as at high altitude, was related to higher concentrations than expected from deposition models. This indicates that differences in element concentration between nearby localities might be related to local differences in climate and lichen growth conditions. This should be taken into consideration whenever using lichens for biomonitoring.     

Cross-border response of mosses to heavy metal atmospheric deposition in Southeastern Bulgaria and European Turkey

First cross-border atmospheric pollution of 11 heavy metals and toxic elements assessed by Hypnum cupressiforme was reported for a part of Southeastern Europe (Southeastern Bulgaria and European Turkey). Moss monitoring technique followed the main requirements of European Moss Survey. Moss samples were collected in April 2006 both in Bulgaria and Turkey. Concentration of Al, As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, V, and Zn were determined by ICP-AES. Interlaboratory parallel calibration (exchanged four moss samples from each country), standard reference moss materials (M2 and M3) results ensured the study. ANOVA showed no differences between measured results in both laboratories at the 99% confidence level. Principle Component Analyze proved two factors: F1 group of Al, As, Cd, Cr, Fe, Ni, and V and F2 of Cu, Pb, and Zn as main atmospheric pollutants. Results obtained showed approximately Cu and Pb high concentrations around Istanbul and Burgas and Zn pollution in Istanbul district. Arsenic cross-border atmospheric pollution in the study area of Southeastern Europe was found.     

Atmospheric NO2 and NH3 deposition into a typical agro-ecosystem in Southeast China

The dry deposition of atmospheric nitrogen (including NO(2) and NH(3)) into a typical agro-ecosystem in Southeast China during 2006-2007 was estimated. Results indicated that the dry deposition velocities of NO(2) and NH(3) ranged from 0.04-0.24 cm s(-1) and 0.09-0.47 cm s(-1), respectively. The higher values appeared in the non-crop growing period. Concentrations of atmospheric NO(2) and NH(3) ranged from 24.64-104.10 μgN m(-3) and 14.40-389.6 μgN m(-3), respectively. Variation of the NH(3) mixing ratio showed a clear double-peak. NO(2) and NH(3) deposition fluxes were 74.68-80.75 kgN ha(-1), which was equivalent to 162.4 and 175.5 kg ha(-1) of urea applied in 2006-2007. The N deposition fluxes were 13.91-40.38 and 5.33-22.73 kgN ha(-1) in peanut and rice growing periods, accounting for 8.18%-40.38% and 2.13%-23.06% of N fertilizer usages, respectively. NO(2) and NH(3) deposition were significant for the red soil farmland.     

A methodology to estimate carbon storage and flux in forestland using existing forest and soils databases

Sequestration of carbon through expansion and management offorestland can assist in reducing greenhouse gas concentrationsin the atmosphere. Quantification of the amount of carbonpresents an ongoing challenge that calls for new approaches.These new approaches must seek to simplify the science-basedaccounting of carbon storage and flux, while adhering to generalprinciples of greenhous gas accounting. Quantifying change incarbon storage and carbon flux consists of two steps: developinga baseline of carbon storage, and measuring resulting storageand flux following a change of conditions. A methodology isproposed that accomplishes both steps, applicable to anaggregate-level analysis using the state of Iowa (U.S.A.) as a case study. The method combines existing databasesfrom the U.S. Forest Service (USFS) and U.S. Department ofAgriculture (USDA), and merges these with the methods of Birdsey(USDA, 1992, 1995; IPCC, 1997; EIIP, 1999) for partitioningcarbon stocks into storage pools. Forested ecosystems in the study area contain approximately 137.3 metric tons organiccarbon per hectare, or 114 million metric tons of carbon inaggregate. Of this total, 44.7 million tons are stored inbiomass tissue, and 69.2 million tons of carbon are contained insoils. Carbon flux due to forests in the state of Iowa isestimated to be a net annual sequestration (removal from theatmosphere) of 4.3 million metric tons of CO₂-equivalent,approximately 5% of the net annual CO₂-equivalentemissions from the state (Ney et al., 1996).     

Cloud water and throughfall deposition of mercury and trace elements in a high elevation spruce-fir forest at Mt. Mansfield,Vermont

As part of the Lake Champlain Basin watershed study of mercury (Hg) and pollutant deposition, cloud water and cloud throughfall collections were conducted at the south summit (1204 m) of Mt. Mansfield, Vermont between August 1 and October 31, 1998, for multi-element chemical analysis. A passive Teflon string collector was deployed during non-precipitating events to sample cloud/fog water at timberline, while three sets of paired funnels collected cloud throughfall under the red spruce-balsam fir canopy. Samples were analyzed for concentrations of Hg, major ions, and 10 trace elements. Ultra-clean sampling and analysis techniques were utilized throughout the study. Six events were sampled for cloud water alone and four events were sampled for both cloud water and cloud throughfall. Cloud throughfall chemistry showed substantial modification from incident cloud water. Much higher concentrations of Hg (2.3 x), base cations (Ca2+, K-, Mg2+; 3-18 x) and certain trace elements (Ni, Cu, Mn, Rb, Sr; 2-34 x) were observed in throughfall than in cloud water. These results confirm that cloud water can leach a wide variety of elements from tree foliage and wash off dry deposited elements. Cloud water deposited an average of 0.42 +/- 0.12 mm of water per hour. Estimated cloud water deposition of Hg was 7.4 microg m(-2) for the period August 1-October 31, approximately twice that deposited by rain during this period at a nearby low elevation Hg monitoring site. Our results indicate that cloud water and Hg deposition at Mt. Mansfield are likely to have considerable ecological effects.     

Immune response of earthworms (Lumbricus terrestris, Eisenia andrei and Aporrectodea tuberculata) following in situ soil exposure to atmospheric deposition from a cement factory

In order to reduce their energy costs, many cement plants use fuel product substitutes (old tyres and used oil). The combustion of these products generates a metal increase (e.g. Cu, Cd, Pb and Zn) in the atmospheric emissions. After their release, these elements are deposited into the environment and could eventually accumulate up to concentrations of concern. At the Saint-Laurent cement factory (Joliette, QC, Canada), maximum deposition of these elements occurs in the direction of prevailing winds (North-East). We evaluated the potential impact of these depositions upon the immune system of three earthworm species (Lumbricus terrestris, Eisenia andrei and Aporrectodea tuberculata) exposed in a natural environment. The exposure sites were 0.5, 1.0, and 2.0 km downwind from the cement factory, along with an upwind reference site. The immune parameters studied were the cell viability and phagocytic potential of the immune cells (coelomocytes). For both L. terrestris and E. andrei, after 7 d exposure, none of the measured parameters showed significant differences among the sites. On the other hand, for the indigenous worm A. tuberculata, in the most exposed zone (at 0.5 km), we observed an increase in cell viability and phagocytic potential. This increase could possibly be attributed to physicochemical effects such as the alkaline pH of the soil, or alternatively, it could result from beneficial effects induced by an increased calcium supply.     

Habitat evaluation using suitability index and habitat type diversity: a case study involving a shallow forest stream in central Taiwan

In recent years, the Taiwanese government has strongly promoted the concept of ecological engineering in the hope that doing so will encourage the maintenance of the ecosystem and its integrity. As a result, the riprap spur dike is one of the most commonly used measures for protecting stream banks. Traditionally, a spur dike is used at concave banks to prevent their scouring and/or to increase their stabilization. An additional benefit of deflector structures, like spur dikes, may be to increase the weighted usable area (WUA) for aquatic life survival during periods of increased flow (examples include typhoon, flood, etc.). A two-dimensional river habitat simulation program (River2D) coupled with a developed shallow water habitat type diversity module was used for the case study at a headwater stream in central Taiwan. The habitat suitability index for this study was established using substrate, depth, and velocity from field surveys for the fish family Cyprinidae by prepositioned area electrofisher. The ungauged flood conditions were calculated using digital elevation models within a watershed delineation and hydrological modeling system in accordance with local regulations. Simulated results indicate that the spur dikes currently in use on the stream in this study need be improved from a WUA point of view more effectively handle a flood event.     

Classification and mapping forest sites using geographic information system (GIS): a case study in Artvin Province

The productivity of forest sites has been indirectly determined with solo wood production objective in forest management. Forest site productivity should, however, be determined directly in order to implement ecosystem based multipurpose forest management philosophy. This article tackles the problem in distinguishing and mapping forest sites using both direct method and indirect method in Genya Mountain located in central of Artvin State Forest Enterprise. About 112 sample plots were designed and distributed over the area. In each sample plot, soil samples were collected and the classical timber inventory measurements were taken. According to direct method, Soil Moisture Regime (SMR) method is preferred due to a water deficiency in the study area. Water holding capacity was used as an essential criterion for the classification of the forest site. Forest site classifications were assigned regarding the physiographic factors such as landform, aspect, and slope. Five different forest sites classes; dry, moderate fresh, fresh, humid and hygric were determined. According to direct method, the guiding curve was used to generate anamorphic site index (SI) equations and three site index classes; good (SI=I–II), medium (SI=III) and low (SI=IV–V) were determined. Some important differences between the methods were realized. The forest sites determined with site index estimation method indicate that site index I and II is 505.99 ha, III 1095.79 ha and IV and V 992.95 ha, whereas forest sites determined with direct method related to dry site of 937.58 ha, moderate fresh site of 931.90 ha, fresh site of 1,797.71 ha, humid site of 80.48 ha and hygric site of 356.55 ha. The forest site maps of both methods were created using GIS functions. The forest sites of open and degraded areas should be determined according to direct method.     

Impact of long-term exposure to mosquito coils: residual deposition and dissipation of D-trans-allethrin in a room

A D-trans-allethrin-based mosquito repellent coil formulation was used continuously in a room for 30 d. Two different experiments were conducted and the deposition of residues on different surfaces of the room was determined. Studies were conducted continuously for a period of 30 d in a fully closed room and in another room kept open for 14 h per day. The residues deposited on different surfaces, ceiling, side walls and floor, were measured. The results showed the accumulation of high concentrations of allethrin on all the surfaces of the room when the room was in a fully closed condition. Samples collected from the ceiling showed residues of D-trans-allethrin of 6.34-148.63 microg m(-2) during the 30 d study, the side walls 4.68-170.72 microg m(-2) and the floor 20.00-184.52 microg m(-2) Maximum residues were observed in 30 d samples collected from the ceiling and floor. The residual concentrations were nearly 10 times higher in samples collected from the closed room. Discontinuation of the use of the mosquito repellent after 30 d led to a gradual decrease in the concentrations of residues on all the surfaces. The influence of environmental parameters on the dissipation of residues was also studied.     

Testing the validity of a critical sulfur and nitrogen load model in southern Ontario, Canada, using soil chemistry data from MARYP

The validity of a steady-state massbalance model (Arp et al., 1996; referred to asARP) was tested using physicochemical soil data fromthe Monitoring Acid Rain Youth Program (MARYP). FourARP sites were matched with ten MARYP sites accordingto proximity, bedrock type and subsoil pH to test thevalidity of the ARP model for critical loadexceedances. Soil solution pH, base concentration andAl concentration from MARYP sites, which were wellmatched to ARP sites, validated the modelled criticalload exceedances. Higher exceedance areas wereassociated with more acidic pH and lower base andhigher Al concentrations from matched MARYP sites andvice versa. One ARP site was inappropriately matchedwith MARYP sites and could not be validated using baseand Al concentrations. This study also confirmed thesouthern limit of the zero critical load exceedanceisopleth from the model. However, variability of theother exceedance isopleths was noted due to thelimited number of sites used in the model. Thevalidation of these sites in the ARP model and thezero critical load exceedance isopleth nonethelessallows greater confidence in using this model as amanagement tool for acidic deposition.     

Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India

Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.     

A GIS-based decision support system for determining the shortest and safest route to forest fires: a case study in Mediterranean Region of Turkey

The ability of firefighting vehicles and staff to reach a fire area as quickly as possible is critical in fighting against forest fires. In this study, a Geographical Information System-based decision support system was developed to assist fire managers in determining the fastest and the safest or more reliable access routes from firefighting headquarters to fire areas. The decision support system was tested in the Kahramanmaras Forestry Regional Directoratein the Mediterranean region of Turkey. The study area consisted of forested lands which had been classified according to fire sensitivity. The fire response routing simulations considered firefighting teams located in 20 firefighting headquarter locations. The road network, the locations of the firefighting headquarters, and possible fire locations were mapped for simulation analysis. In alternative application simulations, inaccessible roads which might be closed due to fire or other reasons were indicated in the network analysis so that the optimum route was not only the fastest but also the safest and most reliable path. The selection of which firefighting headquarters to use was evaluated by considering critical response time to potential fire areas based on fire sensitivity levels. Results indicated that new firefighting headquarters should be established in the region in order to provide sufficient firefighting response to all forested lands. In addition, building new fire access roads and increasing the design speed on current roads could also increase firefighting response capabilities within the study area.     

Separate estimation of N export into baseline N leakage without disturbance and N loss due to insect defoliation in a pine forest watershed in central Japan

Pine wilt disease (PWD) is caused by a non-native pest that has spread extensively throughout Japan. Previous research has indicated that most infected trees have died and the litter deposited has resulted in changes to stream-water chemistry, particularly increased nitrate (NO ₃ ^? ) concentrations. In this study, we divided stream nitrogen (N) export into N loss due to PWD and baseline N leakage without disturbance based on long-term monitoring. The annual N export was 110.0 mol N ha^?1 year^?1 in 1990 and 749.8 mol N ha^?1 year^?1 in 1997, and had decreased to 37.0 mol N ha^?1 year^?1 in 2005. N export under PWD influence was estimated to be 3697 mol N ha^?1, and N loss due to PWD was 2810 mol N ha^?1. N loss due to PWD was three times larger than baseline N leakage for the disturbed period. These changes in plant–herbivore relationships could affect N status in a forest ecosystem. So-called “semi-natural” disturbances related to non-native species invasion and increases of atmospheric N deposition caused by human activity will increase. Long-term monitoring studies of various aspects are necessary to offer insight into this ecosystem.     

Continuous flow methods for evaluating the response of a copper ion selective electrode to total and free copper in seawater

This work describes the development of an instrument for measuring free and total copper in seawater by continuous flow analysis (CFA) with an Orion copper (II) ion selective electrode (CuISE). Sample analysis times are reduced considerably by using an extrapolation technique based on the fitting of an empirical mathematical expression to the electrode time-response curve enabling a prediction of the final equilibrium potential. CuISE measurements in seawater samples containing nanomolar levels of total copper can be very time consuming, and this predictive approach significantly reduces sample analysis time, and improves sample throughput. The time taken to measure pCu in seawater to a precision of +/- 0.1, using conventional potentiometry, varies considerably depending on the condition of the electrode membrane but can be reduced by a factor of 3-6 (typically from 60 to 10 min) by using the extrapolation technique in conjunction with CFA. Details are given of the protocols used for preconditioning the CuISE. The system can be used as a portable instrument for field measurements or for shipboard measurements of free copper in seawater. Extrapolated equilibrium potentials are within +/- 0.5 mV of true steady state values.     

Biological response to physical processes in the Indian Ocean sector of the Southern Ocean: a case study in the coastal and oceanic waters

The spatial variation of chlorophyll a (Chl a) and factors influencing the high Chl a were studied during austral summer based on the physical and biogeochemical parameters collected near the coastal waters of Antarctica in 2010 and a zonal section along 60°S in 2011. In the coastal waters, high Chl a (>3 mg m^?3) was observed near the upper layers (～15 m) between 53°30′E and 54°30′E. A comparatively higher mesozooplankton biomass (53.33 ml 100 m^?3) was also observed concordant with the elevated Chl a. Low saline water formed by melting of glacial ice and snow, as well as deep mixed-layer depth (60 m) due to strong wind (>11 ms^?1) could be the dominant factors for this biological response. In the open ocean, moderately high surface Chl a was observed (>0.6 mg m^?3) between 47°E and 50°E along with a Deep Chlorophyll Maximum of ～1 mg m^?3 present at 30–40 m depth. Melt water advected from the Antarctic continent could be the prime reason for this high Chl a. The mesozooplankton biomass (22.76 ml 100 m^?3) observed in the open ocean was comparatively lower than that in the coastal waters. Physical factors such as melting, advection of melt water from Antarctic continent, water masses and wind-induced vertical mixing may be the possible reasons that led to the increase in phytoplankton biomass (Chl a).