Interception loss, throughfall and stemflow in a maritime pine stand. II. An application of Gash's analytical model of interception

Science.gov (United States)

Loustau, D.; Berbigier, P.; Granier, A.

1992-10-01

Interception, throughfall and stemflow were determined in an 18-year-old maritime pine stand for a period of 30 months. This involved 71 rainfall events, each corresponding either to a single storm or to several storms. Gash's analytical model of interception was used to estimate the sensitivity of interception to canopy structure and climatic parameters. The seasonal cumulative interception loss corresponded to 12.6-21.0% of the amount of rainfall, whereas throughfall and stemflow accounted for 77-83% and 1-6%, respectively. On a seasonal basis, simulated data fitted the measured data satisfactorily ( r2 = 0.75). The rainfall partitioning between interception, throughfall and stemflow was shown to be sensitive to (1) the rainfall regime, i.e. the relative importance of light storms to total rainfall, (2) the climatic parameters, rainfall rate and average evaporation rate during storms, and (3) the canopy structure parameters of the model. The low interception rate of the canopy was attributed primarily to the low leaf area index of the stand.

Interception storage capacities of tropical rainforest canopy trees

Science.gov (United States)

Herwitz, Stanley R.

1985-04-01

The rainwater interception storage capacities of mature canopy trees in a tropical rainforest site in northeast Queensland, Australia, were approximated using a combination of field and laboratory measurements. The above-ground vegetative surfaces of five selected species (three flaky-barked; two smooth-barked) were saturated under laboratory conditions in order to establish their maximum interception storage capacities. Average leaf surface interception storages ranged from 112 to 161 ml m -2. The interception storages of bark ranged from 0.51 to 0.97 ml cm -3. These standardized interception storages were applied to estimates of leaf surface area and bark volume for 51 mature canopy trees representing the selected species in the field site. The average whole tree interception storage capacities of the five species ranged from 110 to 5281 per tree and 2.2 to 8.3 mm per unit projected crown area. The highly significant interspecific differences in interception storage capacity suggest that both floristic and demographic data are needed in order to accurately calculate a forest-wide interception storage capacity for species-rich tropical rainforest vegetation. Species with large woody surface areas and small projected crown areas are capable of storing the greatest depth equivalents of rainwater under heavy rainfall conditions. In the case of both the flaky-barked and the smooth-barked species, bark accounted for > 50% of the total interception storage capacity under still-air conditions, and > 80% under turbulent air conditions. The emphasis in past interception studies on the role of leaf surfaces in determining the interception storage capacity of a vegetative cover must be modified for tropical rainforests to include the storage capacity provided by the bark tissue on canopy trees.

Variability and Changes in Climate, Phenology, and Gross Primary Production of an Alpine Wetland Ecosystem

Directory of Open Access Journals (Sweden)

Xiaoming Kang

2016-05-01

Full Text Available Quantifying the variability and changes in phenology and gross primary production (GPP of alpine wetlands in the Qinghai–Tibetan Plateau under climate change is essential for assessing carbon (C balance dynamics at regional and global scales. In this study, in situ eddy covariance (EC flux tower observations and remote sensing data were integrated with a modified, satellite-based vegetation photosynthesis model (VPM to investigate the variability in climate change, phenology, and GPP of an alpine wetland ecosystem, located in Zoige, southwestern China. Two-year EC data and remote sensing vegetation indices showed that warmer temperatures corresponded to an earlier start date of the growing season, increased GPP, and ecosystem respiration, and hence increased the C sink strength of the alpine wetlands. Twelve-year long-term simulations (2000–2011 showed that: (1 there were significantly increasing trends for the mean annual enhanced vegetation index (EVI, land surface water index (LSWI, and growing season GPP (R2 ≥ 0.59, p < 0.01 at rates of 0.002, 0.11 year−1 and 16.32 g·C·m−2·year−1, respectively, which was in line with the observed warming trend (R2 = 0.54, p = 0.006; (2 the start and end of the vegetation growing season (SOS and EOS experienced a continuous advancing trend at a rate of 1.61 days·year−1 and a delaying trend at a rate of 1.57 days·year−1 from 2000 to 2011 (p ≤ 0.04, respectively; and (3 with increasing temperature, the advanced SOS and delayed EOS prolonged the wetland’s phenological and photosynthetically active period and, thereby, increased wetland productivity by about 3.7–4.2 g·C·m−2·year−1 per day. Furthermore, our results indicated that warming and the extension of the growing season had positive effects on carbon uptake in this alpine wetland ecosystem.

Primary production and algae diversity vs. pollution in xochimilco wet-lands

Energy Technology Data Exchange (ETDEWEB)

Pedroza-Pichardo, R.; Hernandez-Delgadillo, R.; Boll-Arguello, G.

2009-07-01

Xochimilco is an ancient endorheic lake located in the Valley of Mexico. Due to its shallow water and the freshwater springs that lined the canals, they are surround raised agricultural fields called chinampas. Since the Valley of Mexico was originally wetlands, the chinampas were the most productive means of agricultural production. Xochimilco are considered one of the most important urban lungs in Mexico City. However, it is not clear how the huge urbanization around is to know if there is a correlation between primary production (PP), algae diversity, BOD{sub 5} and faecal coliforms. Sample collection was done every month over a year at six different canals named: Embarcadero Celada, Embarcadero Nuevo Nativitas, Canal Las Abejas, Canal Zacapa, Canal Santo Domingo y Canal Nacional. (Author)

Primary production and algae diversity vs. pollution in xochimilco wet-lands

International Nuclear Information System (INIS)

Pedroza-Pichardo, R.; Hernandez-Delgadillo, R.; Boll-Arguello, G.

2009-01-01

Xochimilco is an ancient endorheic lake located in the Valley of Mexico. Due to its shallow water and the freshwater springs that lined the canals, they are surround raised agricultural fields called chinampas. Since the Valley of Mexico was originally wetlands, the chinampas were the most productive means of agricultural production. Xochimilco are considered one of the most important urban lungs in Mexico City. However, it is not clear how the huge urbanization around is to know if there is a correlation between primary production (PP), algae diversity, BOD 5 and faecal coliforms. Sample collection was done every month over a year at six different canals named: Embarcadero Celada, Embarcadero Nuevo Nativitas, Canal Las Abejas, Canal Zacapa, Canal Santo Domingo y Canal Nacional. (Author)

A prospective, multicenter study of pharmacist activities resulting in medication error interception in the emergency department.

Science.gov (United States)

Patanwala, Asad E; Sanders, Arthur B; Thomas, Michael C; Acquisto, Nicole M; Weant, Kyle A; Baker, Stephanie N; Merritt, Erica M; Erstad, Brian L

2012-05-01

The primary objective of this study is to determine the activities of pharmacists that lead to medication error interception in the emergency department (ED). This was a prospective, multicenter cohort study conducted in 4 geographically diverse academic and community EDs in the United States. Each site had clinical pharmacy services. Pharmacists at each site recorded their medication error interceptions for 250 hours of cumulative time when present in the ED (1,000 hours total for all 4 sites). Items recorded included the activities of the pharmacist that led to medication error interception, type of orders, phase of medication use process, and type of error. Independent evaluators reviewed all medication errors. Descriptive analyses were performed for all variables. A total of 16,446 patients presented to the EDs during the study, resulting in 364 confirmed medication error interceptions by pharmacists. The pharmacists' activities that led to medication error interception were as follows: involvement in consultative activities (n=187; 51.4%), review of medication orders (n=127; 34.9%), and other (n=50; 13.7%). The types of orders resulting in medication error interceptions were written or computerized orders (n=198; 54.4%), verbal orders (n=119; 32.7%), and other (n=47; 12.9%). Most medication error interceptions occurred during the prescribing phase of the medication use process (n=300; 82.4%) and the most common type of error was wrong dose (n=161; 44.2%). Pharmacists' review of written or computerized medication orders accounts for only a third of medication error interceptions. Most medication error interceptions occur during consultative activities. Copyright © 2011. Published by Mosby, Inc.

Ecosystem function in oil sands wetlands : rates of detrital decomposition, moss growth, and microbial respiration in oilsands wetlands

Energy Technology Data Exchange (ETDEWEB)

Wytrykush, C. [Windsor Univ., ON (Canada); Hornung, J. [Petro-Canada, Calgary, AB (Canada)

2007-07-01

A study was conducted in which leaf litter breakdown and biomass accrual in 31 reference and oilsands affected (OSPM) wetlands in Northeastern Alberta was examined. The purpose was to determine how the decomposition of dead plant matter controls the primary productivity in wetlands. The data collected from this study will provide information about carbon flow and dynamics in oilsands affected wetlands. The study involved the investigation of wetlands that contrasted in water origin (OSPM vs. reference), sediment origin (OSPM vs. natural), sediment organic content and age. Mesh bags containing 5 g of dried Typha (cattail) or 20 g of damp moss were placed into 31 wetlands in order to monitor the rate at which biomass was lost to decomposition, as measured by changes in dry mass. After 1 year, moss growth was found to be greatest in younger wetlands with natural sediments. Cattail decomposition was found to be slower in wetlands containing OSPM water than that in reference wetlands. Preliminary analysis of respiration rates of biota associated with decomposing cattail indicate that the amount of oxygen consumed is not affected by wetland water source, sediment source, level of initial sediment organic content, or age.

Fog interception by Ball moss (Tillandsia recurvata)

Science.gov (United States)

Guevara-Escobar, A.; Cervantes-Jiménez, M.; Suzán-Azpiri, H.; González-Sosa, E.; Hernández-Sandoval, L.; Malda-Barrera, G.; Martínez-Díaz, M.

2011-08-01

Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (Cmin) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted by rain. T. recurvata contributed 20 % to the rain interception capacity of their shrub hosts: Acacia farnesiana and Prosopis laevigata and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, p = 0.048). The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h-1 to reach saturation conditions when fog was applied.

Fog interception by Ball moss (Tillandsia recurvata

Directory of Open Access Journals (Sweden)

G. Malda-Barrera

2011-08-01

Full Text Available Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (Cmin was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted by rain. T. recurvata contributed 20 % to the rain interception capacity of their shrub hosts: Acacia farnesiana and Prosopis laevigata and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, p = 0.048. The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h−1 to reach saturation conditions

Boron in Pariette Wetland Sediments, Aquatic Vegetation & Benthic Organisms

Science.gov (United States)

Vasudeva, P.; Jones, C. P.; Powelson, D.; Jacobson, A. R.

2015-12-01

The Pariette Wetlands are comprised of 20 ponds located in Utah's Uintah Basin. Boron concentration in the Pariette Wetlands have been observed to exceed the total maximum daily limit of 750 µg L-1. Considering water flow in and out of the wetlands, boron is accumulating within the wetlands where it is sorbed to sediments and bioconcentrated by wetland plant and macro invertebrates. Since boron is an avian teratogen, an estimate of boron ingestion exposure is warranted. Samples from 3 of the 23 Pariette Wetland ponds with one pond near the inlet, one near the outlet, and one in the middle were collected. Five sampling points were designated along a 100 m transect of each pond. At each sampling point duplicate (or triplicate) samples of water, sediments, benthic organisms and wetland vegetation were collected. The sediments were collected with a KB-corer and divided at depths of 0-2 cm, 2-7 cm, and 7+ cm from the sediment surface. Sample splits were sent to the USU Bug lab for identification of invertebrate species. Whenever this transect was not intercepting vegetation, 2-3 additional sample sites were identified at the pond within stands of representative vegetation where bird nests are located. The plant parts used for boron analyses will include seeds, shoot and roots of vascular plants, as well as algae or duckweeds skimmed from the surface. Samples were processed within 2 days of collection. Water samples filtered through a 0.45 μ membrane filter were analyzed for DOC, pH and ECe. The dried and washed vegetation samples were ground and stored. The benthic organisms and macro invertebrates were netted at the water surface. The dried samples were weighed, ground and stored. Samples were weighed, oven dried and reweighed. For plant and macro-invertebrate samples, a nitric and hydrogen peroxide digestion procedure is used to dissolve environmentally available elements. The Hot Water extraction and DTPA-Sorbitol extraction were compared to estimate wetland plant

Computer-aided mathematical analysis of probability of intercept for ground-based communication intercept system

Science.gov (United States)

Park, Sang Chul

1989-09-01

We develop a mathematical analysis model to calculate the probability of intercept (POI) for the ground-based communication intercept (COMINT) system. The POI is a measure of the effectiveness of the intercept system. We define the POI as the product of the probability of detection and the probability of coincidence. The probability of detection is a measure of the receiver's capability to detect a signal in the presence of noise. The probability of coincidence is the probability that an intercept system is available, actively listening in the proper frequency band, in the right direction and at the same time that the signal is received. We investigate the behavior of the POI with respect to the observation time, the separation distance, antenna elevations, the frequency of the signal, and the receiver bandwidths. We observe that the coincidence characteristic between the receiver scanning parameters and the signal parameters is the key factor to determine the time to obtain a given POI. This model can be used to find the optimal parameter combination to maximize the POI in a given scenario. We expand this model to a multiple system. This analysis is conducted on a personal computer to provide the portability. The model is also flexible and can be easily implemented under different situations.

Tidal Wetlands and Coastal Ocean Carbon Dynamics

Science.gov (United States)

Hopkinson, C.; Wang, S. R.; Forbrich, I.; Giblin, A. E.; Cai, W. J.

2017-12-01

Recent overviews of coastal ocean C dynamics have tidal wetlands in a prominent position: a local sink for atmospheric CO2, a local store of OC, and a source of DIC and OC for the adjacent estuary and nearshore ocean. Over the past decade there have been great strides made in quantifying and understanding these flows and linkages. GPP and R of the wetlands are not nearly as imbalanced as thought 30 yrs ago. Heterotrophy of adjacent estuarine waters is not solely due to the respiration of OC exported from the marsh, rather we see the marsh directly respiring into the water during tidal inundation and accumulated marsh DIC draining into tidal creeks. Organic carbon burial on the marsh is still a relatively minor flux, but it is large relative to marsh NEE. Using literature and unpublished data on marsh DIC export, we used examples from Sapelo Island GA USA and Plum Island MA USA to constrain estimates of NEP and potential OC export. P. There remain large uncertainties in quantifying C dynamics of coupled wetland - estuary systems. Gas exchange from the water to atmosphere is one of the largest uncertainties. Work at Sapelo suggests that upwards of 40% of all daily exchange occurs from water flooding the marsh, which is but a few hours a day. This estimate is based on the intercept value for gas exchange vs wind velocity. Another major uncertainty comes from converting between O2 based estimates of metabolism to C. At Sapelo we find PQ and RQ values diverging greatly from Redfield. Finally, C dynamics of the coastal ocean, especially the role of tidal wetlands is likely to change substantially in the future. Studies at Plum Island show a reversal of the 4000 yr process of marsh progradation with marshes eroding away at their edges because of inadequate sediment supply and rising sea level. The fate of eroded OC is questionable. Landward transgression with SLR is the only likely counter to continued wetland loss - but that's a complex social issue requiring new

Tropical Wetlands as Carbon Sinks

Science.gov (United States)

Jones, M. B.; Saunders, M.

2007-12-01

This presentation focuses on the tropical wetlands of sub-Saharan Africa. These are an understudied ecosystem in which large emergent grasses and sedges normally dominate and which have the potential to sequester significant amounts of carbon. Measurements of Net Primary Production of these wetlands show that they are some of the highest values recorded for any ecosystem. We have used eddy covariance to measure Net Ecosystem Exchange of pristine and disturbed wetlands and show that pristine systems can have sink strengths as strong as tropical forests while disturbed systems that have been reclaimed for agricultural purposes have a very much reduced carbon sink activity and may be net carbon sources. The management issues surrounding the use of these wetlands illustrate a direct conflict between the production of food crops for the local population and the maintenance of carbon sequestration as an ecosystem service.

Quarterly sampling of the wetlands along the old F-Area effluent ditch: March 1994

International Nuclear Information System (INIS)

Dixon, K.L.; Cummins, C.L.; Rogers, V.A.

1994-05-01

In March 1994, well point water and near surface water (bucket) samples were collected to further characterize tritium and volatile organic compounds (VOC) in the wetlands along the old F-Area effluent ditch south of 643-E (old burial ground). Groundwater flow paths suggest that compounds detected in water table wells around 643-E would migrate towards the old F-Area effluent ditch and Fourmile Branch. Recent analytical results from near surface water sampling in the wetlands that comprise the old F-Area effluent ditch have shown that tritium and small quantities of VOCs are outcropping in the area. Results of the March 1994 sampling event further support findings that tritium and volatile organic compounds originating from 643-E are outcropping in the wetlands near the old F-Area effluent ditch. Six different analytes were detected in the well points at least once at concentrations greater than the method detection limit: d 1,2-dichloroethylene, acetone, methyl ethyl ketone, tetrachloroethylene, trichloroethylene, and tritium. 1,2-dichloroethylene, tetrachloroethylene, trichloroethylene, and tritium were detected at levels above Primary Drinking Water Standards or Maximum Contaminant Levels list. Four analytes, 1,2-dichloroethylene, trichloroethylene, tritium, and vinyl chloride, were detected at least once at concentrations greater than the method detection limit and least once at concentrations above the PDWS or the MCL. Based on differences in tritium concentrations at each location, it was determined that the sampling devices intercepted different groundwater flow paths. This negated direct comparison of analytical results between devices. However, when VOC concentrations measured at each well point and bucket location were normalized, resulting well point and bucket VOC concentrations were comparable in most cases. These results suggest that volatilization losses of VOCs from the buckets were negligible

Assessment of Wetland Valuation Processes for Compensation in ...

African Journals Online (AJOL)

The issue of compensation has been debated in various fora; however compensation on wetland resources has not been given the primary place. Wetland valuation like any other type of valuation requires going through stages, which may be more complex than real estate valuation for compensation. This study therefore ...

Identification and characterization of wetlands in the Bear Creek watershed

International Nuclear Information System (INIS)

Rosensteel, B.A.; Trettin, C.C.

1993-10-01

The primary objective of this study was to identify, characterize, and map the wetlands in the Bear Creek watershed. A preliminary wetland categorization system based on the Cowardin classification system (Cowardin et al. 1979) with additional site-specific topographic, vegetation, and disturbance characteristic modifiers was developed to characterize the type of wetlands that exist in the Bear Creek watershed. An additional objective was to detect possible relationships among site soils, hydrology, and the occurrence of wetlands in the watershed through a comparison of existing data with the field survey. Research needs are discussed in the context of wetland functions and values and regulatory requirements for wetland impact assessment and compensatory mitigation

Liquid neon heat intercept for superconducting energy storage magnets

International Nuclear Information System (INIS)

Khalil, A.; McIntosh, G.E.

1982-01-01

Previous analyses of heat intercept solutions are extended to include both insulation and strut heat leaks. The impact of using storable, boiling cryogens for heat intercept fluids, specifically liquid neon and nitrogen, is also examined. The selection of fluid for the heat intercepts is described. Refrigeration power for 1000 and 5000 MWhr SMES units is shown with optimum refrigeration power for each quantity shown in tables. Nitrogen and Neon cooled intercept location for minimum total refrigeration power for a 5000 MWhr SMES are each shown, as well as the location of nitrogen and neon cooled intercepts for minimum total refrigeration power for 5000 MWhr SMES. Cost comparisons are itemized and neon cost and availability discussed. For a large energy storage magnet system, liquid neon is a more effective heat intercept fluid than liquid nitrogen. Reasons and application of the conclusion are amplified

Placing prairie pothole wetlands along spatial and temporal continua to improve integration of wetland function in ecological investigations

Science.gov (United States)

Euliss, Ned H.; Mushet, David M.; Newton, Wesley E.; Otto, Clint R.V.; Nelson, Richard D.; LaBaugh, James W.; Scherff, Eric J.; Rosenberry, Donald O.

2014-01-01

We evaluated the efficacy of using chemical characteristics to rank wetland relation to surface and groundwater along a hydrologic continuum ranging from groundwater recharge to groundwater discharge. We used 27 years (1974–2002) of water chemistry data from 15 prairie pothole wetlands and known hydrologic connections of these wetlands to groundwater to evaluate spatial and temporal patterns in chemical characteristics that correspond to the unique ecosystem functions each wetland performed. Due to the mineral content and the low permeability rate of glacial till and soils, salinity of wetland waters increased along a continuum of wetland relation to groundwater recharge, flow-through or discharge. Mean inter-annual specific conductance (a proxy for salinity) increased along this continuum from wetlands that recharge groundwater being fresh to wetlands that receive groundwater discharge being the most saline, and wetlands that both recharge and discharge to groundwater (i.e., groundwater flow-through wetlands) being of intermediate salinity. The primary axis from a principal component analysis revealed that specific conductance (and major ions affecting conductance) explained 71% of the variation in wetland chemistry over the 27 years of this investigation. We found that long-term averages from this axis were useful to identify a wetland’s long-term relation to surface and groundwater. Yearly or seasonal measurements of specific conductance can be less definitive because of highly dynamic inter- and intra-annual climate cycles that affect water volumes and the interaction of groundwater and geologic materials, and thereby influence the chemical composition of wetland waters. The influence of wetland relation to surface and groundwater on water chemistry has application in many scientific disciplines and is especially needed to improve ecological understanding in wetland investigations. We suggest ways that monitoring in situ wetland conditions could be linked

North American Wetlands and Mosquito Control

Science.gov (United States)

Rey, Jorge R.; Walton, William E.; Wolfe, Roger J.; Connelly, Roxanne; O’Connell, Sheila M.; Berg, Joe; Sakolsky-Hoopes, Gabrielle E.; Laderman, Aimlee D.

2012-01-01

Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere. PMID:23222252

Treatment Wetlands

OpenAIRE

Dotro, Gabriela; Langergraber, Günter; Molle, Pascal; Nivala, Jaime; Puigagut, Jaume; Stein, Otto; Von Sperling, Marcos

2017-01-01

Overview of Treatment Wetlands; Fundamentals of Treatment Wetlands; Horizontal Flow Wetlands; Vertical Flow Wetlands; French Vertical Flow Wetlands; Intensified and Modified Wetlands; Free Water Surface Wetlands; Other Applications; Additional Aspects.

Indirect interception actions by blind and visually impaired perceivers: echolocation for interceptive actions.

Science.gov (United States)

Vernat, Jean-Philippe; Gordon, Michael S

2010-02-01

This research examined the acoustic information used to support interceptive actions by the blind. Congenitally blind and severely visually impaired participants (all wearing an opaque, black eye-mask) were asked to listen to a target ball rolling down a track. In response, participants rolled their own ball along a perpendicular path to intercept the target. To better understand what information was used the echoic conditions and rolling dynamics of the target were varied across test sessions. In addition the rolling speed of the target and the distance of the participant from the target were varied across trials. Results demonstrated that participants tended to perform most accurately at moderate speeds and distances, overestimating the target's arrival at the fastest speed, and underestimating it at the slowest speed. However, changes to the target's dynamics, that is, the amount of deceleration it underwent on approach, did not strongly influence performance. Echoic conditions were found to affect performance, as participants were slightly more accurate in conditions with faster, higher-intensity echoes. Based on these results blind individuals in this research seemed to be using spatial and temporal cues to coordinate their interceptive actions.

Estimation of Stormwater Interception Rate for various LID Facilities

Science.gov (United States)

Kim, S.; Lee, O.; Choi, J.

2017-12-01

In this study, the stormwater interception rate is proposed to apply in the design of LID facilities. For this purpose, EPA-SWMM is built with some areas of Noksan National Industrial Complex where long-term observed stormwater data were monitored and stormwater interception rates for various design capacities of various LID facilities are estimated. While the sensitivity of stormwater interception rate according to design specifications of bio-retention and infiltration trench facilities is not large, the sensitivity of stormwater interception rate according to local rainfall characteristics is relatively big. As a result of comparing the present rainfall interception rate estimation method which is officially operated in Korea with the one proposed in this study, it will be presented that the present method is highly likely to overestimate the performance of the bio-retention and infiltration trench facilities. Finally, a new stormwater interception rate formulas for the bio-retention and infiltration trench LID facilities will be proposed. Acknowledgement This research was supported by a grant (2016000200002) from Public Welfare Technology Development Program funded by Ministry of Environment of Korean government.

Planning of an interceptive movement in children

NARCIS (Netherlands)

van Kampen, P.M.; Ledebt, A.; Savelsbergh, G.J.P.

2010-01-01

In the present study, we examined the spatio-temporal organization of the walking and reaching behaviour during an interception task in younger (6-9 years old) and older (10-13 years old) children. To this end, eighteen children had to walk towards an interception point to grasp a moving ball under

Embedded Systems - Missile Detection/Interception

Directory of Open Access Journals (Sweden)

Luis Cintron

2010-01-01

Full Text Available Missile defense systems are often related to major military resources aimed at shielding a specific region from incoming attacks. They are intended to detect, track, intercept, and destruct incoming enemy missiles. These systems vary in cost, efficiency, dependability, and technology. In present times, the possession of these types of systems is associated with large capacity military countries. Demonstrated here are the mathematical techniques behind missile systems which calculate trajectories of incoming missiles and potential intercept positions after initial missile detection. This procedure involved the use of vector-valued functions, systems of equations, and knowledge of projectile motion concepts.

Large Pelagics Intercept Survey

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Large Pelagics Intercept Survey (LPIS) is a dockside survey of private and charterboat captains who have just completed fishing trips directed at large pelagic...

Spatio-temporal study of carbon sequestration through piscicultural practice at East Kolkata Wetland.

Science.gov (United States)

Pal, Sudin; Chattopadhyay, Buddhadeb; Mukhopadhyay, Subhra Kumar

2016-09-01

The present study focus the variation of carbon concentrations within three trophic level i.e., primary producer (phytoplankton), primary consumers (zooplankton) and secondary consumers (fish) in three selected ponds at East Kolkata Wetland area. Depending on the amount and frequency of wastewater input, physico-chemical characteristics of pond, species richness, predator-prey interactions and pond wise different piscicultural practices, the amount of carbon sequestration varied spatially. Significant temporal variations were also observed in each trophic level of these three selected East Kolkata Wetland pond ecosystems. On average primary producers were sequestered 2038.6 ± 244.8mg C m-3 d-1 whereas 307 ± 19.3 mg C m-3 and 11531.4 ± 318.2mg C m-3 was sequestered by primary and secondary consumers, respectively. In Kolkata and its nearby districts over 90% of the production was marked from the East Kolkata Wetland area. Consequently, a significant amount of sequestered carbon was exported from the East Kolkata Wetland ecosystem in the form of fish and this continuous system might increase the carbon sequestration efficiency of the aquatic ecosystem.

Wonderful Wetlands: An Environmental Education Curriculum Guide for Wetlands.

Science.gov (United States)

King County Parks Div., Redmond, WA.

This curriculum guide was designed to give teachers, students, and society a better understanding of wetlands in the hope that they learn why wetlands should be valued and preserved. It explores what is meant by wetlands, functions and values of wetlands, wetland activities, and wetland offerings which benefit animal and plant life, recreation,…

Interception of LPI radar signals

Science.gov (United States)

Lee, Jim P.

1991-11-01

Most current radars are designed to transmit short duration pulses with relatively high peak power. These radars can be detected easily by the use of relatively modest EW intercept receivers. Three radar functions (search, anti-ship missile (ASM) seeker, and navigation) are examined to evaluate the effectiveness of potential low probability of intercept (LPI) techniques, such as waveform coding, antenna profile control, and power management that a radar may employ against current Electronic Warfare (EW) receivers. The general conclusion is that it is possible to design a LPI radar which is effective against current intercept EW receivers. LPI operation is most easily achieved at close ranges and against a target with a large radar cross section. The general system sensitivity requirement for the detection of current and projected LPI radars is found to be on the order of -100 dBmi which cannot be met by current EW receivers. Finally, three potential LPI receiver architectures, using channelized, superhet, and acousto-optic receivers with narrow RF and video bandwidths are discussed. They have shown some potential in terms of providing the sensitivity and capability in an environment where both conventional and LPI signals are present.

How is rainfall interception in urban area affected by meteorological parameters?

Science.gov (United States)

Zabret, Katarina; Rakovec, Jože; Mikoš, Matjaž; Šraj, Mojca

2017-04-01

Rainfall interception is part of the hydrological cycle. Precipitation, which hits vegetation, is retained on the leaves and branches, from which it eventually evaporates into the atmosphere (interception) or reaches the ground by dripping from the canopy, falling through the gaps (throughfall) and running down the stems (stemflow). The amount of rainfall reaching the ground depends on various meteorological and vegetation parameters. Rainfall, throughfall and stemflow have been measured in the city of Ljubljana, Slovenia since the beginning of 2014. Manual and automatic measurements are performed regularly under Betula pendula and Pinus nigra trees in urban area. In 2014, there were detected 178 rainfall events with total amount of 1672.1 mm. In average B. pendula intercepted 44% of rainfall and P. nigra intercepted 72% of rainfall. In 2015 we have detected 117 events with 1047.4 mm of rainfall, of which 37% was intercepted by B. pendula and 60% by P. nigra. The effect of various meteorological parameters on the rainfall interception was analysed in the study. The parameters included in the analysis were rainfall rate, rainfall duration, drop size distribution (average drop velocity and diameter), average wind speed, and average temperature. The results demonstrate decreasing rainfall interception with longer rainfall duration and higher rainfall intensity although the impact of the latter one is not statistically significant. In the case of very fast or very slow rainfall drops, the interception is higher than for the mean rain drop velocity values. In the case of P. nigra the impact of the rain drop diameter on interception is similar to the one of rain drop velocity while for B. pendula increasing of drop diameter also increases the interception. As expected, interception is higher for warmer events. This trend is more evident for P. nigra than for B. pendula. Furthermore, the amount of intercepted rainfall also increases with wind although it could be

Rainfall interception of three trees in Oakland, California

Science.gov (United States)

Qingfu Xiao; E. Gregory McPherson

2011-01-01

A rainfall interception study was conducted in Oakland, California to determine the partitioning of rainfall and the chemical composition of precipitation, throughfall, and stemflow. Rainfall interception measurements were conducted on a gingko (Ginkgo biloba) (13.5 m tall deciduous tree), sweet gum (Liquidambar styraciflua) (8...

The role of interception in the hydrological cycle

NARCIS (Netherlands)

Gerrits, A.M.J.

2010-01-01

Interception is the part of the rainfall that is intercepted by the earth’s surface and which subsequently evaporates. In this definition the earth’s surface includes everything that becomes wet after a rainfall event and that dries out soon after. It includes: vegetation, soil surface, litter,

WHEN DEATH INTERCEPTS LIFE IN IMAGINATIVE WRITING

OpenAIRE

washington, gene

2014-01-01

The representation of death in imaginative writing is a "virtual" (as opposed to) an actual death. It always occurs in the context of a "virtual" (represented) life. In this text the author examines some of the ways death "intercepts" life in such writing. The subject is a vast, perhaps inexhaustible, one. The richest source, one the author dos not mine, is Shakespeare's interceptions of life by death.

Effects of Mediterranean shrub species on rainfall interception

International Nuclear Information System (INIS)

Garcia-Estringana, P.; Alonso-Blazquez, N.; Marques, M. J.; Bienes, R.; Alegre, J.

2009-01-01

Rainfall is intercepted by vegetation. Water intercepted could be evaporated, or it could drip from the leaves and stems to the soil or it could run down the stems to the base of the plant. In the Mediterranean, where water is a scant resource, interception loss could have an influence on hydrology. Water storage capacity depends on vegetation type. In the Mediterranean, there are many types of shrubs, and many of them are able to intercept large volumes of water depending on the shrub type. many lands of the Mediterranean basin of Europea Union have been abandoned in the last decades and consequently vegetation type changes too. This modifies hydrologic processes, changing the volume and the way in which the rainfall reaches the soil. The aim of this study was to characterize water storage capacity in 9 Mediterranean shrub species, working with the whole plant and comparing results obtained by two methods, rainfall simulation and submersion method in laboratory conditions. (Author) 12 refs.

Nitrate fate and transport through current and former depressional wetlands in an agricultural landscape, Choptank Watershed, Maryland, United States

Science.gov (United States)

Denver, J.M.; Ator, S.W.; Lang, M.W.; Fisher, T.R.; Gustafson, A.B.; Fox, R.; Clune, J.W.; McCarty, G.W.

2014-01-01

Understanding local groundwater hydrology and geochemistry is critical for evaluating the effectiveness of wetlands at mitigating agricultural impacts on surface waters. The effectiveness of depressional wetlands at mitigating nitrate (NO3) transport from fertilized row crops, through groundwater, to local streams was examined in the watershed of the upper Choptank River, a tributary of Chesapeake Bay on the Atlantic Coastal Plain. Hydrologic, geochemical, and water quality data were collected from January of 2008 through December of 2009 from surface waters and networks of piezometers installed in and around current or former depressional wetlands of three major types along a gradient of anthropogenic alteration: (1) natural wetlands with native vegetation (i.e., forested); (2) prior-converted croplands, which are former wetlands located in cultivated fields; and (3) hydrologically restored wetlands, including one wetland restoration and one shallow water management area. These data were collected to estimate the orientation of groundwater flow paths and likely interactions of groundwater containing NO3 from agricultural sources with reducing conditions associated with wetlands of different types. Natural wetlands were found to have longer periods of soil saturation and reducing conditions conducive to denitrification compared to the other wetland types studied. Because natural wetlands are typically located in groundwater recharge areas along watershed divides, nitrogen (N) from nearby agriculture was not intercepted. However, these wetlands likely improve water quality in adjacent streams via dilution. Soil and geochemical conditions conducive to denitrification were also present in restored wetlands and prior-converted croplands, and substantial losses of agricultural NO3 were observed in groundwater flowing through these wetland sediments. However, delivery of NO3 from agricultural areas through groundwater to these wetlands resulting in opportunities for

A randomized clinical study of two interceptive approaches to palatally displaced canines.

Science.gov (United States)

Baccetti, Tiziano; Leonardi, Maria; Armi, Pamela

2008-08-01

This study evaluated the effectiveness of two interceptive approaches to palatally displaced canines (PDC), i.e. extraction of the primary canines alone or in association with the use of a cervical-pull headgear. The randomized prospective design comprised 75 subjects with PDC (92 maxillary canines) who were randomly assigned to three groups: extraction of the primary canine only (EG), extraction of the primary canine and cervical-pull headgear (EHG), and an untreated control group (CG). Panoramic radiographs were evaluated at the time of initial observation (T1) and after an average period of 18 months (T2). At T2, an evaluation of the success of canine eruption was undertaken. Between-group statistical comparisons, Kruskal-Wallis test with Bonferroni correction, were performed on the T1-T2 changes of the diagnostic parameters on panoramic radiographs and the prevalence rates of success in canine eruption. A superimposition study on lateral cephalograms at T1 and T2 was carried out to evaluate the changes in the sagittal position of the upper molars in the three groups. The removal of the primary canine as an isolated measure to intercept palatal displacement of maxillary canines showed a success rate of 65.2 per cent, which was significantly greater than that in the untreated controls (36 per cent). The additional use of a headgear resulted in successful eruption in 87.5 per cent of the subjects, with a significant improvement in the measurements for intraosseous canine position. The cephalometric superimposition study showed a significant mesial movement of the upper first molars in the CG and EG when compared with the EHG.

Wetlands and Sustainability

Directory of Open Access Journals (Sweden)

Richard Smardon

2014-11-01

Full Text Available This editorial provides an overview of the special issue “Wetlands and Sustainability”. In particular, the special issue contains a review of Paul Keddy’s book “Wetland Ecology” with specific reference to wetland sustainability. It also includes papers addressing wetland data acquisition via radar and remote sensing to better understand wetland system dynamics, hydrologic processes linked to wetland stress and restoration, coastal wetlands land use conflict/management, and wetland utilization for water quality treatment.

Ohio Uses Wetlands Program Development Grants to Protect Wetlands

Science.gov (United States)

The wetland water quality standards require the use of ORAM score to determine wetland quality. OEPA has also used these tools to evaluate wetland mitigation projects, develop performance standards for wetland mitigation banks and In Lieu Fee programs an.

Visuo-motor coordination and internal models for object interception.

Science.gov (United States)

Zago, Myrka; McIntyre, Joseph; Senot, Patrice; Lacquaniti, Francesco

2009-02-01

Intercepting and avoiding collisions with moving objects are fundamental skills in daily life. Anticipatory behavior is required because of significant delays in transforming sensory information about target and body motion into a timed motor response. The ability to predict the kinematics and kinetics of interception or avoidance hundreds of milliseconds before the event may depend on several different sources of information and on different strategies of sensory-motor coordination. What are exactly the sources of spatio-temporal information and what are the control strategies remain controversial issues. Indeed, these topics have been the battlefield of contrasting views on how the brain interprets visual information to guide movement. Here we attempt a synthetic overview of the vast literature on interception. We discuss in detail the behavioral and neurophysiological aspects of interception of targets falling under gravity, as this topic has received special attention in recent years. We show that visual cues alone are insufficient to predict the time and place of interception or avoidance, and they need to be supplemented by prior knowledge (or internal models) about several features of the dynamic interaction with the moving object.

The cost of wetland creation and restoration. Final report

Energy Technology Data Exchange (ETDEWEB)

King, D.; Bohlen, C.

1995-08-01

This report examines the economics of wetland creation, restoration, and enhancement projects, especially as they are used within the context of mitigation for unavoidable wetland losses. Complete engineering-cost-accounting profiles of over 90 wetland projects were developed in collaboration with leading wetland restoration and creation practitioners around the country to develop a primary source database. Data on the costs of over 1,000 wetland projects were gathered from published sources and other available databases to develop a secondary source database. Cases in both databases were carefully analyzed and a set of baseline cost per acre estimates were developed for wetland creation, restoration, and enhancement. Observations of costs varied widely, ranging from $5 per acre to $1.5 million per acre. Differences in cost were related to the target wetland type, and to site-specific and project-specific factors that affected the preconstruction, construction, and post-construction tasks necessary to carry out each particular project. Project-specific and site-specific factors had a much larger effect on project costs than wetland type for non-agricultural projects. Costs of wetland creation and restoration were also shown to differ by region, but not by as much as expected, and in response to the regulatory context. The costs of wetland creation, restoration, and enhancement were also analyzed in a broader economic context through examination of the market for wetland mitigation services, and through the development of a framework for estimating compensation ratios-the number of acres of created, restored, or enhanced wetland required to compensate for an acre of lost natural wetland. The combination of per acre creation, restoration, and enhancement costs and the compensation ratio determine the overall mitigation costs associated with alternative mitigation strategies.

The influence of visual motion on interceptive actions and perception.

Science.gov (United States)

Marinovic, Welber; Plooy, Annaliese M; Arnold, Derek H

2012-05-01

Visual information is an essential guide when interacting with moving objects, yet it can also be deceiving. For instance, motion can induce illusory position shifts, such that a moving ball can seem to have bounced past its true point of contact with the ground. Some evidence suggests illusory motion-induced position shifts bias pointing tasks to a greater extent than they do perceptual judgments. This, however, appears at odds with other findings and with our success when intercepting moving objects. Here we examined the accuracy of interceptive movements and of perceptual judgments in relation to simulated bounces. Participants were asked to intercept a moving disc at its bounce location by positioning a virtual paddle, and then to report where the disc had landed. Results showed that interceptive actions were accurate whereas perceptual judgments were inaccurate, biased in the direction of motion. Successful interceptions necessitated accurate information concerning both the location and timing of the bounce, so motor planning evidently had privileged access to an accurate forward model of bounce timing and location. This would explain why people can be accurate when intercepting a moving object, but lack insight into the accurate information that had guided their actions when asked to make a perceptual judgment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Wetlands as energy-dissipating systems

Czech Academy of Sciences Publication Activity Database

Pokorný, J.; Květ, Jan; Rejšková, A.; Brom, J.

2010-01-01

Roč. 37, č. 12 (2010), s. 1299-1305 ISSN 1367-5435 Institutional research plan: CEZ:AV0Z60870520 Keywords : wetlands * vegetation * energy fluxes * primary production * landscape management Subject RIV: EF - Botanics Impact factor: 2.416, year: 2010 http://www.springerlink.com/content/y5t4750647q84553/

Water storage and evaporation as constituents of rainfall interception

NARCIS (Netherlands)

Klaassen, W; Bosveld, F; de Water, E

1998-01-01

Intercepted rainfall may be evaporated during or after the rain event. Intercepted rain is generally determined as the difference between rainfall measurements outside and inside the forest. Such measurements are often used to discriminate between water storage and evaporation during rain as well.

How might Australian rainforest cloud interception respond to climate change?

Science.gov (United States)

Wallace, Jim; McJannet, Dave

2013-02-01

SummaryThe lower and upper montane rainforests in northern Queensland receive significant amounts of cloud interception that affect both in situ canopy wetness and downstream runoff. Cloud interception contributes 5-30% of the annual water input to the canopy and this increases to 40-70% of the monthly water input during the dry season. This occult water is therefore an important input to the canopy, sustaining the epiphytes, mosses and other species that depend on wet canopy conditions. The potential effect of climate change on cloud interception was examined using the relationship between cloud interception and cloud frequency derived from measurements made at four different rainforest locations. Any given change in cloud frequency produces a greater change in cloud interception and this 'amplification' increases from 1.1 to 1.7 as cloud frequency increases from 5% to 70%. This means that any changes in cloud frequency will have the greatest relative effects at the higher altitude sites where cloud interception is greatest. As cloud frequency is also a major factor affecting canopy wetness, any given change in cloud frequency will therefore have a greater impact on canopy wetness at the higher altitude sites. These changes in wetness duration will augment those due to changes in rainfall and may have important implications for the fauna and flora that depend on wet canopy conditions. We also found that the Australian rainforests may be more efficient (by ˜50% on average) in intercepting cloud water than American coniferous forests, which may be due to differences in canopy structure and exposure at the different sites.

Gaze control during interceptive actions with different spatiotemporal demands.

NARCIS (Netherlands)

Navia, J.A.; Dicks, M.S.; van der Kamp, J; Ruiz, L.

It is widely accepted that the sources of information used to guide interceptive actions depend on conflicting spatiotemporal task demands. However, there is a paucity of evidence that shows how information pick-up during interceptive actions is adapted to such conflicting constraints. The present

Mapping wetlands and surface water in the Prairie Pothole Region of North America: Chapter 16

Science.gov (United States)

Rover, Jennifer R.; Mushet, David M.

2015-01-01

The Prairie Pothole Region (PPR) is one of the most highly productive wetland regions in the world. Prairie Pothole wetlands serve as a primary feeding and breeding habitat for more than one-half of North America’s waterfowl population, as well as a variety of songbirds, waterbirds, shorebirds, and other wildlife. During the last century, extensive land conversions from grassland with wetlands to cultivated cropland and grazed pastureland segmented and reduced wetland habitat. Inventorying and characterizing remaining wetland habitat is critical for the management of wetland ecosystem services. Remote sensing technologies are often utilized for mapping and monitoring wetlands. This chapter presents background specific to the PPR and discusses approaches employed in mapping its wetlands before presenting a case study.

Bioaccumulation of metals in constructed wetlands used to treat acid drainage

International Nuclear Information System (INIS)

Edwards, G.S.; Mays, P.A.

1994-01-01

Constructed wetlands are being used extensively as a potential mitigation for acid drainage. However, removal of metals to meet compliance requirements has varied among wetlands, ranging from partial to total success. In addition, wetlands are sinks for contaminants found in acid drainage, and bioaccumulation of these contaminants to levels that would adversely affect the food web is of growing concern. The primary objective of this project was to determine whether bioaccumulation of metals occurs in wetlands constructed for treatment of acid drainage. Water, sediment, plant and benthos samples were collected from two wetlands constructed by the Tennessee Valley Authority and a natural wetland in the spring and fall of 1992, and metal concentrations were determined. One of the constructed wetlands, Impoundment 1, has generally been in compliance for NPDES; the other, Widow's Creek, has never been in compliance. Preliminary results indicate similarities in sediment and plant metal concentrations between Impoundment 1 and the natural wetland and greater metal concentrations in the sediment and plants at Widow's Creek. Data also indicate that Mn, Zn, Cu, Ni, and Cr are being accumulated in the plants at each wetland. However, accumulation of metals by these plants probably accounts for only a small percentage of the removal of the annual metal load supplied to each wetland. Bioaccumulation of metals in the benthic organisms at each wetland is currently being investigated

Rainfall interception from a lowland tropical rainforest in Brunei

Science.gov (United States)

Dykes, A. P.

1997-12-01

Results from a programme of throughfall measurements in a lowland tropical rainforest in Brunei, northwest Borneo, indicate that interception losses amount to 18% of the gross incident rainfall. The high annual rainfall experienced by the study area results in annual interception losses of around 800 mm, which may result in total annual evapotranspiration losses significantly higher than in other rainforest locations. An improved version of Gash's analytical interception model is tested on the available data using assumed values for the "forest" parameters, and is found to predict interception losses extremely well. The model predictions are based on an estimated evaporation rate during rainfall of 0.71 mm h -1. This is significantly higher than has been reported in other tropical studies. It is concluded that these results are distinctive when compared with previous results from rainforests, and that further, detailed work is required to establish whether the enhanced evaporation rate is due to advective effects associated with the maritime setting of the study area.

Modeling natural wetlands: A new global framework built on wetland observations

Science.gov (United States)

Matthews, E.; Romanski, J.; Olefeldt, D.

2015-12-01

Natural wetlands are the world's largest methane (CH4) source, and their distribution and CH4 fluxes are sensitive to interannual and longer-term climate variations. Wetland distributions used in wetland-CH4 models diverge widely, and these geographic differences contribute substantially to large variations in magnitude, seasonality and distribution of modeled methane fluxes. Modeling wetland type and distribution—closely tied to simulating CH4 emissions—is a high priority, particularly for studies of wetlands and CH4 dynamics under past and future climates. Methane-wetland models either prescribe or simulate methane-producing areas (aka wetlands) and both approaches result in predictable over- and under-estimates. 1) Monthly satellite-derived inundation data include flooded areas that are not wetlands (e.g., lakes, reservoirs, and rivers), and do not identify non-flooded wetlands. 2) Models simulating methane-producing areas overwhelmingly rely on modeled soil moisture, systematically over-estimating total global area, with regional over- and under-estimates, while schemes to model soil-moisture typically cannot account for positive water tables (i.e., flooding). Interestingly, while these distinct hydrological approaches to identify wetlands are complementary, merging them does not provide critical data needed to model wetlands for methane studies. We present a new integrated framework for modeling wetlands, and ultimately their methane emissions, that exploits the extensive body of data and information on wetlands. The foundation of the approach is an existing global gridded data set comprising all and only wetlands, including vegetation information. This data set is augmented with data inter alia on climate, inundation dynamics, soil type and soil carbon, permafrost, active-layer depth, growth form, and species composition. We investigate this enhanced wetland data set to identify which variables best explain occurrence and characteristics of observed

Intercepting virtual balls approaching under different gravity conditions: evidence for spatial prediction.

Science.gov (United States)

Russo, Marta; Cesqui, Benedetta; La Scaleia, Barbara; Ceccarelli, Francesca; Maselli, Antonella; Moscatelli, Alessandro; Zago, Myrka; Lacquaniti, Francesco; d'Avella, Andrea

2017-10-01

To accurately time motor responses when intercepting falling balls we rely on an internal model of gravity. However, whether and how such a model is also used to estimate the spatial location of interception is still an open question. Here we addressed this issue by asking 25 participants to intercept balls projected from a fixed location 6 m in front of them and approaching along trajectories with different arrival locations, flight durations, and gravity accelerations (0 g and 1 g ). The trajectories were displayed in an immersive virtual reality system with a wide field of view. Participants intercepted approaching balls with a racket, and they were free to choose the time and place of interception. We found that participants often achieved a better performance with 1 g than 0 g balls. Moreover, the interception points were distributed along the direction of a 1 g path for both 1 g and 0 g balls. In the latter case, interceptions tended to cluster on the upper half of the racket, indicating that participants aimed at a lower position than the actual 0 g path. These results suggest that an internal model of gravity was probably used in predicting the interception locations. However, we found that the difference in performance between 1 g and 0 g balls was modulated by flight duration, the difference being larger for faster balls. In addition, the number of peaks in the hand speed profiles increased with flight duration, suggesting that visual information was used to adjust the motor response, correcting the prediction to some extent. NEW & NOTEWORTHY Here we show that an internal model of gravity plays a key role in predicting where to intercept a fast-moving target. Participants also assumed an accelerated motion when intercepting balls approaching in a virtual environment at constant velocity. We also show that the role of visual information in guiding interceptive movement increases when more time is available. Copyright © 2017 the American Physiological

Context effects on smooth pursuit and manual interception of a disappearing target.

Science.gov (United States)

Kreyenmeier, Philipp; Fooken, Jolande; Spering, Miriam

2017-07-01

In our natural environment, we interact with moving objects that are surrounded by richly textured, dynamic visual contexts. Yet most laboratory studies on vision and movement show visual objects in front of uniform gray backgrounds. Context effects on eye movements have been widely studied, but it is less well known how visual contexts affect hand movements. Here we ask whether eye and hand movements integrate motion signals from target and context similarly or differently, and whether context effects on eye and hand change over time. We developed a track-intercept task requiring participants to track the initial launch of a moving object ("ball") with smooth pursuit eye movements. The ball disappeared after a brief presentation, and participants had to intercept it in a designated "hit zone." In two experiments ( n = 18 human observers each), the ball was shown in front of a uniform or a textured background that either was stationary or moved along with the target. Eye and hand movement latencies and speeds were similarly affected by the visual context, but eye and hand interception (eye position at time of interception, and hand interception timing error) did not differ significantly between context conditions. Eye and hand interception timing errors were strongly correlated on a trial-by-trial basis across all context conditions, highlighting the close relation between these responses in manual interception tasks. Our results indicate that visual contexts similarly affect eye and hand movements but that these effects may be short-lasting, affecting movement trajectories more than movement end points. NEW & NOTEWORTHY In a novel track-intercept paradigm, human observers tracked a briefly shown object moving across a textured, dynamic context and intercepted it with their finger after it had disappeared. Context motion significantly affected eye and hand movement latency and speed, but not interception accuracy; eye and hand position at interception were

77 FR 18707 - USPS Package Intercept-New Product Offerings

Science.gov (United States)

2012-03-28

... commercial customers to register and request USPS Package Intercept service through the Business Customer... Intelligent Mail[supreg] package barcode will be included on the redirected new Priority Mail pieces. The USPS... requests are active for 10 business days from the date of the request. Interception of eligible mailpieces...

Wildlife health implications of sewage disposal in wetlands

Science.gov (United States)

Friend, M.; Godfrey, P.J.; Kaynor, E.R.; Pelczarski, S.

1985-01-01

Wildlife health concerns associated with disposal of sewage effluent in wetlands are of three primary types: (1) introduction of pathogens, (2) introduction of pollutants that adversely impact on host body defense mechanisms, and (3) changes in the physical and chemical properties of wetlands that favor the development and maintenance of disease problems. Unlike the situation with human health concerns, introduction of pathogens is not the major concern regarding wildlife health. Instead, the focus of attention needs to be directed at environmental changes likely to take place as a result of effluent discharges into different types of wetlands. Unless these changes are adequately addressed from a disease perspective, marshes utilized for sewage disposal could become disease incubators and wildlife death traps. This result would be unfortunate because the backlash would likely negate the potentially beneficial aspects of the use of sewage wastewater for the creation of new wetlands and have a severe impact on progress being made towards evaluation of the compatibility of wildlife and sewage effluents.

Investigating public decisions about protecting wetlands.

Science.gov (United States)

Getzner, Michael

2002-03-01

Quantitative analyses of species protection decisions taken by public authorities regularly show that ecological factors, such as the probability of extinction, often play a minor role in the decision-making process. The taxonomy of the species or its potential conflict with economic development is a more powerful factor. This paper presents quantitative empirical research on the protection of wetlands in Austria. Econometrically estimated models show that geographical and ecological factors (such as the size of the area, elevation and importance for biodiversity) play a significant role in the protection of wetlands. Additional influences include conflict variables encoding the negative effects of the primary economic sector (agriculture) or tourism.

Seasonal and spatial trends in production and stable isotope signatures of primary producers in Alberta oil sands reclamation wetlands

International Nuclear Information System (INIS)

Boutsivongsakd, M; Chen, H.; Legg, A.; Farwell, A.; Dixon, G.

2010-01-01

Oil sands processing produces large amounts of waste water that contains polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids (NAs). This study investigated the effects of exposure to PAHs and NA in aquatic organisms. The carbon and nitrogen dynamics in primary producers using stable isotopes in process-affected and reference wetlands were studied. Plankton and periphytic samples from artificial wetland substrates were collected and analyzed. Periphyton was collected in 14 to 20 day intervals for 5 different time periods in 2007 and 2008 in order to analyze seasonal trends in isotopic composition. Results of the study showed d15N enriched values for some consolidated tailings (CT) at sites in 2008. Other sites with mature fine tailings (MFT) as well as non-MFT sites did not have enriched d15N values. The study suggested that there are variations in ammonia levels in the CTs of different oil sands operators. Differences in the quality of the CT resulted in differences in d15N values of the periphyton-dominated by algae as well as in the periphyton dominated by microbes.

77 FR 63326 - Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland...

Science.gov (United States)

2012-10-16

..., consistent with sound principles of fish and wildlife management, conservation, legal mandates, and our... FXRS1265066CCP0] Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland Management District, SD; Final Comprehensive Conservation Plan and Finding of No Significant Impact for...

The specific interception potential of soils for radiocesium

International Nuclear Information System (INIS)

Sweeck, L.; Wauters, J.; Valcke, E.; Cremers, A.

1990-01-01

A simple methodology is presented for obtaining the specific interception potential for radiocesium, defined as the product of the number of specific sites times the Cs to K selectivity coefficient in these sites. This procedure is applied to a series of soils from a heavy clay to a podzol soil and it is shown that this interception potential may vary by some two orders of magnitude. On the basis of selectivity values of K and NH 4 -ions for the specific sites, it is demonstrated quantitatively that the specific sites are directly associated with the presence of micaceous clay minerals. In conclusion, a set of equations is developed for predicting the site K D - values of radiocesium on the basis of the specific radiocesium interception potential and the K and NH 4 -concentrations in the soil solution. (author)

Movement and Perceptual Strategies to Intercept Virtual Sound Sources.

Directory of Open Access Journals (Sweden)

Naeem eKomeilipoor

2015-05-01

Full Text Available To intercept a moving object, one needs to be in the right place at the right time. In order to do this, it is necessary to pick up and use perceptual information that specifies the time to arrival of an object at an interception point. In the present study, we examined the ability to intercept a laterally moving virtual sound object by controlling the displacement of a sliding handle and tested whether and how the interaural time difference (ITD could be the main source of perceptual information for successfully intercepting the virtual object. The results revealed that in order to accomplish the task, one might need to vary the duration of the movement, control the hand velocity and time to reach the peak velocity (speed coupling, while the adjustment of movement initiation did not facilitate performance. Furthermore, the overall performance was more successful when subjects employed a time-to-contact (tau coupling strategy. This result shows that prospective information is available in sound for guiding goal-directed actions.

Amazon River carbon dioxide outgassing fuelled by wetlands.

Science.gov (United States)

Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C; Savoye, Nicolas; Deborde, Jonathan; Souza, Edivaldo Lima; Albéric, Patrick; Landim de Souza, Marcelo F; Roland, Fabio

2014-01-16

River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.

East African wetland-catchment data base for sustainable wetland management

Science.gov (United States)

Leemhuis, Constanze; Amler, Esther; Diekkrüger, Bernd; Gabiri, Geofrey; Näschen, Kristian

2016-10-01

Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

East African wetland-catchment data base for sustainable wetland management

Directory of Open Access Journals (Sweden)

C. Leemhuis

2016-10-01

Full Text Available Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

Rainfall interception by two arboreal species in urban green area

Directory of Open Access Journals (Sweden)

Luzia Ferreira da Silva

2010-12-01

Full Text Available Rainfall interception by the two most usual species in forest urban spaces was analysed by measuring of interception (I or interception losses, through fall (Th, stem flow (St and gross precipitation (Pg. The chosen species were Caesalpinia pluviosa DC. (Fabaceae: Caesalpinoideae or sibipiruna, and Tipuana tipu O. Kuntze (Fabaceae: Faboideae or tipuana. The individuals analysed were more than 50 years old, with three separate individuals and three individuals in each studied group of species at the campus of ”Luiz de Queiroz” College of Agriculture (University of Sao Paulo, Piracicaba. The experiments were carried out from January to February 2007. Water was collected using seven-litre pails, in the edges and in the centre of the canopies. A high correlation of Th with Pg was observed on the centre of the crow of tipuana and by the edges of sibipiruna. St and I had low correlation with Pg for both species. The average of rain interception was greater in the edges of the crow of sibipiruna individuals, 60.6%, and in the centre of tipuana crow, 59.40%. Thus, both species intercepted up to 60% of the water rainfall, which indicates a great potential of both species for arborisation in urban environments.

Direct calculations of the odderon intercept in perturbative QCD

Energy Technology Data Exchange (ETDEWEB)

Braun, M.A.; Gauron, P.; Nicolescu, B

1999-03-08

The odderon intercept is calculated directly, from its expression via an average energy of the odderon Hamiltonian, using both trial wave functions in the variational approach and the wave function recently constructed by Janik and Wosiek. The results confirm their reported value for the energy. Variational calculations give energies some 30% higher. However, they also predict the odderon intercept to be quite close to unity. In fact, for realistic values of {alpha}{sub s}, the intercept calculated variationally is at most 2% lower than the exact one: 0.94 instead of 0.96. It is also found that the solution for q{sub 3} = 0 does not belong to the odderon spectrum. The diffusion parameter is found to be of the order 0.6.

On interception modelling of a lowland coastal rainforest in northern Queensland, Australia

Science.gov (United States)

Wallace, Jim; McJannet, Dave

2006-10-01

SummaryRecent studies of the water balance of tropical rainforests in northern Queensland have revealed that large fractions of rainfall, up to 30%, are intercepted by the canopy and lost as evaporation. These loss rates are much higher than those reported for continental rainforests, for example, in the Amazon basin, where interception is around 9% of rainfall. Higher interception losses have been found in coastal and mountain rainforests and substantial advection of energy during rainfall is proposed to account for these results. This paper uses a process based model of interception to analyse the interception losses at Oliver Creek, a lowland coastal rainforest site in northern Queensland with a mean annual rainfall of 3952 mm. The observed interception loss of 25% of rainfall for the period August 2001 to January 2004 can be reproduced by the model with a suitable choice of the three key controlling variables, the canopy storage capacity, mean rainfall rate and mean wet canopy evaporation rate. Our analyses suggest that the canopy storage capacity of the Oliver Creek rainforest is between 3.0 and 3.5 mm, higher than reported for most other rainforests. Despite the high canopy capacity at our site, the interception losses can only be accounted for with energy advection during rainfall in the range 40-70% of the incident energy.

Global estimate of lichen and bryophyte contributions to forest precipitation interception

Science.gov (United States)

Van Stan, John; Porada, Philipp; Kleidon, Axel

2017-04-01

Interception of precipitation by forest canopies plays an important role in its partitioning to evaporation, transpiration and runoff. Field observations show arboreal lichens and bryophytes can substantially enhance forests' precipitation storage and evaporation. However, representations of canopy interception in global land surface models currently ignore arboreal lichen and bryophyte contributions. This study uses the lichen and bryophyte model (LiBry) to provide the first process-based modelling approach estimating these organisms' contributions to canopy water storage and evaporation. The global mean value of forest water storage capacity increased significantly from 0.87 mm to 1.33 mm by the inclusion of arboreal poikilohydric organisms. Global forest canopy evaporation of intercepted precipitation was also greatly enhanced by 44%. Ratio of total versus bare canopy global evaporation exceeded 2 in many forested regions. This altered global patterns in canopy water storage, evaporation, and ultimately the proportion of rainfall evaporated. A sensitivity analysis was also performed. Results indicate rainfall interception is of larger magnitude than previously reported by global land surface modelling work because of the important role of lichen and bryophytes in rainfall interception.

Impact of Interception on Infiltration and Soil Moisture in Dipterocarp Forest and Oil Palm Plantations in Tasik Chini, Pahang

International Nuclear Information System (INIS)

Ata, F.M.; Mohd Ekhwan Toriman; Mohd Ekhwan Toriman

2015-01-01

In local water balance, the dipterocarp forest and oil palm plantation are two locations which demonstrated different processes in terms of interception, soil moisture and infiltration. To evaluate the process, this study was carried out at Tasik Chini watershed, Pahang, Malaysia for over ten months commencing April 2011 until January 2012. The main idea of this study is to study the characteristics of interception at two variants canopy and effect of interception on the infiltration process. The methodology used involves primary data including stremflow, through fall and soil moisture. 104 samples for stem flow and four samples for palm oil trees, 9 sets of through fall and 7 soil moisture stations were measured at dipterocarp forest and oil palm plantation, respectively the regression analysis was used to analyses the relationship between rate of infiltration and interception with soil moisture and rainfall. The result indicate that total interceptions were registered at 29.7 percent in Plot A, 29.1 percent in Plot B and 41.2 in oil palm plantation. The average for stem flow in the forest area is 8.65 mm per tree compared to 12.7 mm for every oil palm tree. Meanwhile, the average for through fall in oil palm plantation was higher compared to the forest area. This is about 0.49 mm and 0.42 mm respectively. The results of the interception at the Dipterocarp forest and palm areas were affected by physiographic characteristic such as the diameter size and branches of tree. The correlation coefficient between through fall and soil moisture in the oil palm plantation is r"2=0.49, in comparison to through fall and soil moisture in forest area is r"2=0.42. Positive correlation means that the amount of through fall increase than soil moisture will increase also. (author)

Estimating Vegetation Rainfall Interception Using Remote Sensing Observations at Very High Resolution

Science.gov (United States)

Cui, Y.; Zhao, P.; Hong, Y.; Fan, W.; Yan, B.; Xie, H.

2017-12-01

Abstract: As an important compont of evapotranspiration, vegetation rainfall interception is the proportion of gross rainfall that is intercepted, stored and subsequently evaporated from all parts of vegetation during or following rainfall. Accurately quantifying the vegetation rainfall interception at a high resolution is critical for rainfall-runoff modeling and flood forecasting, and is also essential for understanding its further impact on local, regional, and even global water cycle dynamics. In this study, the Remote Sensing-based Gash model (RS-Gash model) is developed based on a modified Gash model for interception loss estimation using remote sensing observations at the regional scale, and has been applied and validated in the upper reach of the Heihe River Basin of China for different types of vegetation. To eliminate the scale error and the effect of mixed pixels, the RS-Gash model is applied at a fine scale of 30 m with the high resolution vegetation area index retrieved by using the unified model of bidirectional reflectance distribution function (BRDF-U) for the vegetation canopy. Field validation shows that the RMSE and R2 of the interception ratio are 3.7% and 0.9, respectively, indicating the model's strong stability and reliability at fine scale. The temporal variation of vegetation rainfall interception loss and its relationship with precipitation are further investigated. In summary, the RS-Gash model has demonstrated its effectiveness and reliability in estimating vegetation rainfall interception. When compared to the coarse resolution results, the application of this model at 30-m fine resolution is necessary to resolve the scaling issues as shown in this study. Keywords: rainfall interception; remote sensing; RS-Gash analytical model; high resolution

The ecological value of constructed wetlands for treating urban runoff.

Science.gov (United States)

Pankratz, S; Young, T; Cuevas-Arellano-, H; Kumar, R; Ambrose, R F; Suffet, I H

2007-01-01

The Sweetwater Authority's urban runoff diversion system (URDS) comprises constructed wetlands on a hillside between the town of Spring Valley and the Sweetwater Reservoir, California, USA. The URDS were designed to divert dry-weather and first-flush urban runoff flows from the Sweetwater reservoir. However, these constructed wetlands have developed into ecologically valuable habitat. This paper evaluates the following ecological questions related to the URDS: (1) the natural development of the species present and their growth pattern; (2) the biodiversity and pollutant stress on the plants and invertebrates; and (3) the question of habitat provided for endangered species. The URDS wetlands are comprised primarily of rush (Scirpus spp.) and cattails (Typha spp.). This vegetative cover ranged from 39-78% of the area of the individual wetland ponds. Current analyses of plant tissues and wetland sediment indicates the importance of sediment sorption for metals and plant uptake of nutrients. Analyses of URDS water following runoff events show the URDS wetlands do reduce the amount of nutrients and metals in the water column. Invertebrate surveys of the wetland ponds revealed lower habitat quality and environmental stress compared to unpolluted natural habitat. The value of the wetlands as wildlife habitat is constrained by low plant biodiversity and pollution stress from the runoff. Since the primary Sweetwater Authority goal is to maintain good water quality for drinking, any secondary utilization of URDS habitat by species (endangered or otherwise) is deemed an added benefit.

Using Tradtional Ecological Knowledge to Protect Wetlands: the Swinomish Tribe's Wetland Cultural Assessment Project

Science.gov (United States)

Mitchell, T.

2017-12-01

"Traditional" wetland physical assessment modules do not adequately identify Tribal cultural values of wetlands and thus wetlands may not be adequately protected for cultural uses. This Swinomish Wetlands Cultural Assessment Project has developed a cultural resource scoring module that can be incorporated into wetland assessments to better inform wetland protections. Local native knowledge was gathered about the traditional uses of 99 native wetland plant species. A cultural scoring matrix was developed based on the presence of traditionally used plants in several use categories including: construction, ceremonial, subsistence, medicinal, common use, plant rarity, and place of value for each wetland. The combined score of the cultural and physcial modules provides an overall wetland score that relates to proscribed buffer protection widths. With this local native knowledge incorporated into wetland assessments, we are protecting and preserving Swinomish Reservation wetlands for both cultural uses and ecological functionality through the Tribe's wetland protection law.

Rainfall interception and spatial variability of throughfall in spruce stand

Czech Academy of Sciences Publication Activity Database

Dohnal, M.; Černý, T.; Votrubová, J.; Tesař, Miroslav

2014-01-01

Roč. 62, č. 4 (2014), s. 277-284 ISSN 0042-790X R&D Projects: GA TA ČR TA02021451 Institutional support: RVO:67985874 Keywords : Interception loss * Interception capacity * Free throughfall * Evaporation * Hydrological balance of vegetation cover Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.486, year: 2014

Two zero-flow pressure intercepts exist in autoregulating isolated skeletal muscle.

Science.gov (United States)

Braakman, R; Sipkema, P; Westerhof, N

1990-06-01

The autoregulating vascular bed of the isolated canine extensor digitorum longus muscle was investigated for the possible existence of two positive zero-flow pressure axis intercepts, a tone-dependent one and a tone-independent one. An isolated preparation, perfused with autologous blood, was used to exclude effects of collateral flow and nervous and humoral regulation while autoregulation was left intact [mean autoregulatory gain 0.50 +/- 0.24 (SD)]. In a first series of experiments, the steady-state (zero flow) pressure axis intercept [mean 8.9 +/- 2.6 (SD) mmHg, tone independent] and the instantaneous (zero flow) pressure axis intercept [mean 28.5 +/- 9.9 (SD) mmHg, tone dependent] were determined as a function of venous pressure (range: 0-45 mmHg) and were independent of venous pressure until the venous pressure exceeded their respective values. Beyond this point the relations between the venous pressure and the steady-state and instantaneous pressure axis intercept followed the line of identity. The findings agree with the predictions of the vascular waterfall model. In a second series it was shown by means of administration of vasoactive drugs that the instantaneous pressure axis intercept is tone dependent, whereas the steady-state pressure axis intercept is not. It is concluded that there is a (proximal) tone-dependent zero-flow pressure at the arteriolar level and a (distal) tone-independent zero-flow pressure at the venous level.

Non-intercepted dose errors in prescribing anti-neoplastic treatment

DEFF Research Database (Denmark)

Mattsson, T O; Holm, B; Michelsen, H

2015-01-01

BACKGROUND: The incidence of non-intercepted prescription errors and the risk factors involved, including the impact of computerised order entry (CPOE) systems on such errors, are unknown. Our objective was to determine the incidence, type, severity, and related risk factors of non-intercepted pr....... Strategies to prevent future prescription errors could usefully focus on integrated computerised systems that can aid dose calculations and reduce transcription errors between databases....

Quantifying Rainfall Interception Loss of a Subtropical Broadleaved Forest in Central Taiwan

Directory of Open Access Journals (Sweden)

Yi-Ying Chen

2016-01-01

Full Text Available The factors controlling seasonal rainfall interception loss are investigated by using a double-mass curve analysis, based on direct measurements of high-temporal resolution gross rainfall, throughfall and stemflow from 43 rainfall events that occurred in central Taiwan from April 2008 to April 2009. The canopy water storage capacity for the wet season was estimated to be 1.86 mm, about twice that for the dry season (0.91 mm, likely due to the large reduction in the leaf area index (LAI from 4.63 to 2.23 (m2·m−2. Changes in seasonal canopy structure and micro-meteorological conditions resulted in temporal variations in the amount of interception components, and rainfall partitioning into stemflow and throughfall. Wet canopy evaporation after rainfall contributed 41.8% of the wet season interception loss, but only 17.1% of the dry season interception loss. Wet canopy evaporation during rainfall accounted for 82.9% of the dry season interception loss, but only 58.2% of the wet season interception loss. Throughfall accounted for over 79.7% of the dry season precipitation and 76.1% of the wet season precipitation, possibly due to the change in gap fraction from 64.2% in the dry season to 50.0% in the wet season. The reduced canopy cover in the dry season also produced less stemflow than that of the wet season. The rainfall stemflow ratio ( P s f / P g was reduced from 12.6% to 8.9%. Despite relatively large changes in canopy structure, seasonal variation of the ratio of rainfall partitioned to interception was quite small. Rainfall interception loss accounted for nearly 12% of gross precipitation for both dry and wet seasons.

Proceedings of the Near-Earth-Object Interception Workshop

Science.gov (United States)

Canavan, G. J. (Editor); Solem, J. C. (Editor); Rather, John D. G. (Editor)

1993-01-01

The National Aeronautics and Space Administration Headquarters sponsored the Near-Earth-Object Interception Workshop hosted by the Los Alamos National Laboratory on 14-16 Jan. 1992 at the J. Robert Oppenheimer Study Center in Los Alamos, New Mexico. The Workshop evaluated the issues involved in intercepting celestial objects that could hit the Earth. It covered the technologies for acquiring, tracking, and homing, as well as those for sending interceptors to inspect, rendezvous with, land on, irradiate, deflect, or destroy them. This report records the presentations and technical options reviewed.

Detecting and classifying low probability of intercept radar

CERN Document Server

Pace, Phillip E

2003-01-01

The drive is on to devise LPI radar systems that evade hostile detection as well as develop non-cooperative intercept devices that outsmart enemy LPI radar. Based on the author's own design experience, this comprehensive, hands-on book gives you the latest design and development techniques to innovate new LPI radar systems and discover new ways to intercept enemy LPI radar. and help you visually identify waveform parameters. Filled with more than 500 equations that provide rigorous mathematical detail, this book can be used by both entry-level and seasoned engineers. Besides thoroughly treatin

Rainfall interception and spatial variability of throughfall in spruce stand

Directory of Open Access Journals (Sweden)

Dohnal Michal

2014-12-01

Full Text Available The interception was recognized as an important part of the catchment water balance in temperate climate. The mountainous forest ecosystem at experimental headwater catchment Liz has been subject of long-term monitoring. Unique dataset in terms of time resolution serves to determine canopy storage capacity and free throughfall. Spatial variability of throughfall was studied using one weighing and five tipping bucket rain gauges. The basic characteristics of forest affecting interception process were determined for the Norway spruce stand at the experimental area - the leaf area index was 5.66 - 6.00 m2 m-2, the basal area was 55.7 m2 ha-1, and the crown closure above individual rain gauges was between 19 and 95%. The total interception loss in both growing seasons analyzed was 34.5%. The mean value of the interception capacity determined was about 2 mm. Throughfall exhibited high variability from place to place and it was strongly affected by character of rainfall. On the other hand, spatial pattern of throughfall in average showed low variability.

Introduction to the Wetland Book 1: Wetland structure and function, management, and nethods

Science.gov (United States)

Davidson, Nick C.; Middleton, Beth A.; McInnes, Robert J.; Everard, Mark; Irvine, Kenneth; Van Dam, Anne A.; Finlayson, C. Max; Finlayson, C. Max; Everard, Mark; Irvine, Kenneth; McInnes, Robert J.; Middleton, Beth A.; Van Dam, Anne A.; Davidson, Nick C.

2016-01-01

The Wetland Book 1 is designed as a ‘first port-of-call’ reference work for information on the structure and functions of wetlands, current approaches to wetland management, and methods for researching and understanding wetlands. Contributions by experts summarize key concepts, orient the reader to the major issues, and support further research on such issues by individuals and multidisciplinary teams. The Wetland Book 1 is organized in three parts - Wetland structure and function; Wetland management; and Wetland methods - each of which is divided into a number of thematic Sections. Each Section starts with one or more overview chapters, supported by chapters providing further information and case studies on different aspects of the theme.

Vertical flow constructed wetlands: kinetics of nutrient and organic matter removal.

Science.gov (United States)

Pérez, M M; Hernández, J M; Bossens, J; Jiménez, T; Rosa, E; Tack, F

2014-01-01

The kinetics of organic matter and nutrient removal in a pilot vertical subsurface wetland with red ferralitic soil as substrate were evaluated. The wetland (20 m(2)) was planted with Cyperus alternifolius. The domestic wastewater that was treated in the wetland had undergone a primary treatment consisting of a septic moat and a buffer tank. From the sixth week of operation, the performance of the wetland stabilized, and a significant reduction in pollutant concentration of the effluent wastewater was obtained. Also a significant increase of dissolved oxygen (5 mg/l) was obtained. The organic matter removal efficiency was greater than 85% and the nutrient removal efficiency was greater than 75% in the vertical subsurface wetland. Nitrogen and biochemical oxygen demand (BOD) removal could be described by a first-order model. The kinetic constants were 3.64 and 3.27 d(-1) for BOD and for total nitrogen, respectively. Data on the removal of phosphorus were adapted to a second-order model. The kinetic constant was 0.96 (mg/l)(-1) d(-1). The results demonstrated the potential of vertical flow constructed wetlands to clean treated domestic wastewater before discharge into the environment.

Deriving Light Interception and Biomass from Spectral Reflectance Ratio

DEFF Research Database (Denmark)

Christensen, Svend; Goudriaan, J.

1993-01-01

was calculated as the ratio between infrared (790–810 nm) and red (640–660 nm) reflectance. The cultivars form a different canopy structure. However, a regression analysis did not show any cultivar effect on the relation between RVI and fPAR The predicted fPAR from frequently measured RVI was used to calculate...... the product of daily fPAR and incoming PAR (cumulative PAR interception) in all spring barley cultivars grown in monoculture and in mixture with oil seed rape (Brassica napus). A regression analysis showed that the relation between cumulative intercepted PAR and total above ground biomass was the same in all...... monocultures and mixtures. The ratio α of incremental dry matter and intercepted PAR was normally 2.4 g MJ−1, but it declined below this value when temperatures fell below 12°C....

A network model framework for prioritizing wetland conservation in the Great Plains

Science.gov (United States)

Albanese, Gene; Haukos, David A.

2017-01-01

ContextPlaya wetlands are the primary habitat for numerous wetland-dependent species in the Southern Great Plains of North America. Plant and wildlife populations that inhabit these wetlands are reciprocally linked through the dispersal of individuals, propagules and ultimately genes among local populations.ObjectiveTo develop and implement a framework using network models for conceptualizing, representing and analyzing potential biological flows among 48,981 spatially discrete playa wetlands in the Southern Great Plains.MethodsWe examined changes in connectivity patterns and assessed the relative importance of wetlands to maintaining these patterns by targeting wetlands for removal based on network centrality metrics weighted by estimates of habitat quality and probability of inundation.ResultsWe identified several distinct, broad-scale sub networks and phase transitions among playa wetlands in the Southern Plains. In particular, for organisms that can disperse >2 km a dense and expansive wetland sub network emerges in the Southern High Plains. This network was characterized by localized, densely connected wetland clusters at link distances (h) >2 km but <5 km and was most sensitive to changes in wetland availability (p) and configuration when h = 4 km, and p = 0.2–0.4. It transitioned to a single, large connected wetland system at broader spatial scales even when the proportion of inundated wetland was relatively low (p = 0.2).ConclusionsOur findings suggest that redundancy in the potential for broad and fine-scale movements insulates this system from damage and facilitates system-wide connectivity among populations with different dispersal capacities.

Reduction of neonicotinoid insecticide residues in Prairie wetlands by common wetland plants.

Science.gov (United States)

Main, Anson R; Fehr, Jessica; Liber, Karsten; Headley, John V; Peru, Kerry M; Morrissey, Christy A

2017-02-01

Neonicotinoid insecticides are frequently detected in wetlands during the early to mid-growing period of the Canadian Prairie cropping season. These detections also overlap with the growth of macrophytes that commonly surround agricultural wetlands which we hypothesized may reduce neonicotinoid transport and retention in wetlands. We sampled 20 agricultural wetlands and 11 macrophyte species in central Saskatchewan, Canada, over eight weeks to investigate whether macrophytes were capable of reducing movement of neonicotinoids from cultivated fields and/or reducing concentrations in surface water by accumulating insecticide residues into their tissues. Study wetlands were surrounded by clothianidin-treated canola and selected based on the presence (n=10) or absence (n=10) of a zonal plant community. Neonicotinoids were positively detected in 43% of wetland plants, and quantified in 8% of all plant tissues sampled. Three plant species showed high rates of detection: 78% Equisetum arvense (clothianidin, range: wetlands had higher detection frequency and water concentrations of clothianidin (β±S.E.: -0.77±0.26, P=0.003) and thiamethoxam (β±S.E.: -0.69±0.35, P=0.049) than vegetated wetlands. We assessed the importance of wetland characteristics (e.g. vegetative zone width, emergent plant height, water depth) on neonicotinoid concentrations in Prairie wetlands over time using linear mixed-effects models. Clothianidin concentrations were significantly lower in wetlands surrounded by taller plants (β±S.E.: -0.57±0.12, P≤0.001). The results of this study suggest that macrophytes can play an important role in mitigating water contamination by accumulating neonicotinoids and possibly slowing transport to wetlands during the growing season. Copyright © 2016 Elsevier B.V. All rights reserved.

Radiative transfer in shrub savanna sites in Niger: preliminary results from HAPEX-Sahel. 2. Photosynthetically active radiation interception of the woody layer

International Nuclear Information System (INIS)

Bégué, A.; Hanan, N.P.; Prince, S.D.

1994-01-01

Interception by the woody layer of photosynthetically active radiation (PAR) was measured and calculated for two Guiera senegalensis J.F. Gmel, shrub savannas in Ouallam, Western Niger, in 1991 as part of the HAPEX-Sahel experiment. Two different scales were considered. At the plant scale, PAR interception was measured throughout the day with amorphous silicon sensors, together with detailed measurements of the structure of the shrubs (size of the ‘envelope’ of the shrub, area index, and angular distribution of the leaves and the branches). These data permitted us to develop and validate a simple radiative transfer model in which the shrubs are represented by porous cylinders; the total transmissivity (or porosity) of the shrubs estimated by the model was approximately 0.4. It indicates that semi-arid shrubs cannot be considered opaque objects and that the fraction of ground covered with plants is a poor indicator of the PAR interception efficiency of the canopy. The model was also applied at a landscape scale to calculate the daily PAR interception of two shrub savanna sites. This value is needed to model primary production in conjunction with remotely sensed and production data acquired simultaneously on the sites. (author)

Fractional-Order Information in the Visual Control of Lateral Locomotor Interception

NARCIS (Netherlands)

Bootsma, Reinoud J.; Ledouit, Simon; Casanova, Remy; Zaal, Frank T. J. M.

Previous work on locomotor interception of a target moving in the transverse plane has suggested that interception is achieved by maintaining the target's bearing angle (often inadvertently confused and/or confounded with the target heading angle) at a constant value. However, dynamics-based model

Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders

Directory of Open Access Journals (Sweden)

Suet Wai Yuen

2017-12-01

Full Text Available Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator–prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception in Nephila pilipes orb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution’s disruption of species interactions.

Intercept Algorithm for Maneuvering Targets Based on Differential Geometry and Lyapunov Theory

Directory of Open Access Journals (Sweden)

Yunes Sh. ALQUDSI

2018-03-01

Full Text Available Nowadays, the homing guidance is utilized in the existed and under development air defense systems (ADS to effectively intercept the targets. The targets became smarter and capable to fly and maneuver professionally and the tendency to design missile with a small warhead became greater, then there is a pressure to produce a more precise and accurate missile guidance system based on intelligent algorithms to ensure effective interception of highly maneuverable targets. The aim of this paper is to present an intelligent guidance algorithm that effectively and precisely intercept the maneuverable and smart targets by virtue of the differential geometry (DG concepts. The intercept geometry and engagement kinematics, in addition to the direct intercept condition are developed and expressed in DG terms. The guidance algorithm is then developed by virtue of DG and Lyapunov theory. The study terminates with 2D engagement simulation with illustrative examples, to demonstrate that, the derived DG guidance algorithm is a generalized guidance approach and the well-known proportional navigation (PN guidance law is a subset of this approach.

Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders.

Science.gov (United States)

Yuen, Suet Wai; Bonebrake, Timothy C

2017-01-01

Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator-prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception in Nephila pilipes orb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings) and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution's disruption of species interactions.

Constructed Wetlands

Science.gov (United States)

these systems can improve water quality, engineers and scientists construct systems that replicate the functions of natural wetlands. Constructed wetlands are treatment systems that use natural processes

Quantifying interception associated with new urban vegetation canopies

Science.gov (United States)

Yerk, W.; Montalto, F. A.

2013-12-01

Interception of precipitation by vegetation canopies has long been recognized as an important component of the hydrologic cycle, though most research has been in closed or sparse canopy forests. Much less work has been published on interception by urban vegetation, and especially associated with the low growing shrubs commonly installed in green infrastructure program. To inform urban watershed model with vegetation-specific interception data, a field experiment was designed to directly measure canopy throughfall associated with two shrub species commonly included in urban greening programs. Data was collected at a high (e.g. five second) sampling frequency. A non-parametric Kruskal-Wallis test performed on data collected between August and October of 2012 demonstrated statistically significant (p= 0.0011) differences in recorded throughfall between two species (94% for Itea virginica, 86% for Cornus sericea). Additionally, the results suggested that the relationship of throughfall to rainfall intensity varied by species. For Itea, the ratio of throughfall to precipitation intensity was close to 1:1. However, for Cornus, the throughfall rate was on average slower (or 0.85 of the precipitation intensity). An improved and expanded set-up installed in 2013 added two additional species (Prunus laurocerasus and Hydrangea quercifolia). The 2013 results confirm interspecies differences in both throughfall amount, and in the relationship of throughfall rate to precipitation intensity. The results are discussed with respect to droplet splashing and enhanced evaporation within the canopy. Both years' findings suggest that the quantity of water intercepted by vegetation canopies exceeds the canopy storage capacity, as assumed in many conventional hydrologic models.

"Wetlands: Water Living Filters?",

OpenAIRE

Dordio, Ana; Palace, A. J.; Pinto, Ana Paula

2008-01-01

Human societies have indirectly used natural wetlands as wastewater discharge sites for many centuries. Observations of the wastewater depuration capacity of natural wetlands have led to a greater understanding of the potential of these ecosystems for pollutant assimilation and have stimulated the development of artificial wetlands systems for treatment of wastewaters from a variety of sources. Constructed wetlands, in contrast to natural wetlands, are human-made systems that are designed, bu...

The role of pH in structuring communities of Maine wetland macrophytes and chironomid larvae (Diptera)

Science.gov (United States)

Woodcock, T.S.; Longcore, J.R.; McAuley, D.G.; Mingo, T.M.; Bennatti, C.R.; Stromborg, K.L.

2005-01-01

Aquatic vascular plants, or macrophytes, are an important habitat component for many wetland organisms, and larvae of chironomid midges are ubiquitous components of wetland fauna. Many chironomids are primary consumers of algae and detritus and form an essential energetic link between allochthonous and autochthonous primary production and higher trophic levels, while others are predators and feed on smaller invertebrates. Live macrophytes serve mostly as habitat, whereas plant detritus serves as both habitat and as a food source. Assemblages of macrophytes and chironomid larvae were surveyed in ten Maine wetlands, five with low pH (5.5), and explained in terms of physical and chemical habitat variables. Macrophyte richness was significantly greater, and richness of chironomid larvae was lower, in low pH wetlands. There was no difference in chironomid abundance related to pH. However, community structure was related to pH, suggesting that competitive dominance of a few taxa was responsible for lower richness in low pH wetlands, whereas competition was weaker in high pH wetlands, making coexistence of more chironomid taxa possible. An examination of individual chironomid taxa by stepwise multiple regression showed that distribution of most taxa was controlled by water chemistry variables and macrophyte habit (i.e., floating, submergent).

Eye movements and manual interception of ballistic trajectories: effects of law of motion perturbations and occlusions.

Science.gov (United States)

Delle Monache, Sergio; Lacquaniti, Francesco; Bosco, Gianfranco

2015-02-01

Manual interceptions are known to depend critically on integration of visual feedback information and experience-based predictions of the interceptive event. Within this framework, coupling between gaze and limb movements might also contribute to the interceptive outcome, since eye movements afford acquisition of high-resolution visual information. We investigated this issue by analyzing subjects' head-fixed oculomotor behavior during manual interceptions. Subjects moved a mouse cursor to intercept computer-generated ballistic trajectories either congruent with Earth's gravity or perturbed with weightlessness (0 g) or hypergravity (2 g) effects. In separate sessions, trajectories were either fully visible or occluded before interception to enforce visual prediction. Subjects' oculomotor behavior was classified in terms of amounts of time they gazed at different visual targets and of overall number of saccades. Then, by way of multivariate analyses, we assessed the following: (1) whether eye movement patterns depended on targets' laws of motion and occlusions; and (2) whether interceptive performance was related to the oculomotor behavior. First, we found that eye movement patterns depended significantly on targets' laws of motion and occlusion, suggesting predictive mechanisms. Second, subjects coupled differently oculomotor and interceptive behavior depending on whether targets were visible or occluded. With visible targets, subjects made smaller interceptive errors if they gazed longer at the mouse cursor. Instead, with occluded targets, they achieved better performance by increasing the target's tracking accuracy and by avoiding gaze shifts near interception, suggesting that precise ocular tracking provided better trajectory predictions for the interceptive response.

Interception and retention of simulated cooling tower drift by vegetation

International Nuclear Information System (INIS)

Taylor, F.G. Jr.; Parr, P.D.

1978-01-01

A key issue concerning environmental impacts from cooling tower operation is the interception of drift by vegetation and the efficiency of plants in retaining the residue scavenged from the atmosphere. Chromated drift water, typical of the cooling towers of the Department of Energy's uranium enrichment facilities at Oak Ridge, Tennessee, was prepared using radio-labelled chromium. A portable aerosol generator was used to produce a spectrum of droplets with diameters (100 to 1300 μ) characteristic of cooling towers using state-of-the-art drift eliminators. Efficiency of interception by foliage varied according to leaf morphology with yellow poplar seedlings intercepting 72% of the deposition mass in contrast to 45% by loblolly pine and 24% by fescue grass. Retention patterns of intercepted deposition consisted of a short-time component (0 to 3 days) and a long-time component (3 to 63 days). Retention times, estimated from the regression equation of the long component, indicated that drift contamination from any deposition event may persist from between 8 and 12 weeks. In field situations adjacent to cooling towers, the average annual concentration of drift on vegetation at any distance remains relatively constant, with losses from weathering being compensated by chronic deposition

Random Intercept and Random Slope 2-Level Multilevel Models

Directory of Open Access Journals (Sweden)

Rehan Ahmad Khan

2012-11-01

Full Text Available Random intercept model and random intercept & random slope model carrying two-levels of hierarchy in the population are presented and compared with the traditional regression approach. The impact of students’ satisfaction on their grade point average (GPA was explored with and without controlling teachers influence. The variation at level-1 can be controlled by introducing the higher levels of hierarchy in the model. The fanny movement of the fitted lines proves variation of student grades around teachers.

Tropical wetlands: A missing link in the global carbon cycle?

Science.gov (United States)

Sjögersten, Sofie; Black, Colin R; Evers, Stephanie; Hoyos-Santillan, Jorge; Wright, Emma L; Turner, Benjamin L

2014-01-01

Tropical wetlands are not included in Earth system models, despite being an important source of methane (CH4) and contributing a large fraction of carbon dioxide (CO2) emissions from land use, land use change, and forestry in the tropics. This review identifies a remarkable lack of data on the carbon balance and gas fluxes from undisturbed tropical wetlands, which limits the ability of global change models to make accurate predictions about future climate. We show that the available data on in situ carbon gas fluxes in undisturbed forested tropical wetlands indicate marked spatial and temporal variability in CO2 and CH4 emissions, with exceptionally large fluxes in Southeast Asia and the Neotropics. By upscaling short-term measurements, we calculate that approximately 90 ± 77 Tg CH4 year−1 and 4540 ± 1480 Tg CO2 year−1 are released from tropical wetlands globally. CH4 fluxes are greater from mineral than organic soils, whereas CO2 fluxes do not differ between soil types. The high CO2 and CH4 emissions are mirrored by high rates of net primary productivity and litter decay. Net ecosystem productivity was estimated to be greater in peat-forming wetlands than on mineral soils, but the available data are insufficient to construct reliable carbon balances or estimate gas fluxes at regional scales. We conclude that there is an urgent need for systematic data on carbon dynamics in tropical wetlands to provide a robust understanding of how they differ from well-studied northern wetlands and allow incorporation of tropical wetlands into global climate change models. PMID:26074666

Performance of dryland and wetland plant species on extensive green roofs.

Science.gov (United States)

MacIvor, J Scott; Ranalli, Melissa A; Lundholm, Jeremy T

2011-04-01

Green roofs are constructed ecosystems where plants perform valuable services, ameliorating the urban environment through roof temperature reductions and stormwater interception. Plant species differ in functional characteristics that alter ecosystem properties. Plant performance research on extensive green roofs has so far indicated that species adapted to dry conditions perform optimally. However, in moist, humid climates, species typical of wetter soils might have advantages over dryland species. In this study, survival, growth and the performance of thermal and stormwater capture functions of three pairs of dryland and wetland plant species were quantified using an extensive modular green roof system. Seedlings of all six species were germinated in a greenhouse and planted into green roof modules with 6 cm of growing medium. There were 34 treatments consisting of each species in monoculture and all combinations of wet- and dryland species in a randomized block design. Performance measures were survival, vegetation cover and roof surface temperature recorded for each module over two growing seasons, water loss (an estimate of evapotranspiration) in 2007, and albedo and water capture in 2008. Over two seasons, dryland plants performed better than wetland plants, and increasing the number of dryland species in mixtures tended to improve functioning, although there was no clear effect of species or habitat group diversity. All species had survival rates >75 % after the first winter; however, dryland species had much greater cover, an important indicator of green roof performance. Sibbaldiopsis tridentata was the top performing species in monoculture, and was included in the best treatments. Although dryland species outperformed wetland species, planting extensive green roofs with both groups decreased performance only slightly, while increasing diversity and possibly habitat value. This study provides further evidence that plant composition and diversity can

An Introduction to the San Francisco Estuary Tidal Wetlands Restoration Series

Directory of Open Access Journals (Sweden)

Larry R. Brown

2003-10-01

Full Text Available Restoration of tidal wetlands may provide an important tool for improving ecological health and water management for beneficial uses of the San Francisco Estuary (hereafter “Estuary”. Given the large losses of tidal wetlands from San Francisco Bay and the Sacramento-San Joaquin Delta in the last 150 years, it seems logical to assume that restoring tidal wetlands will have benefits for a variety of aquatic and terrestrial native species that have declined during the same time period. However, many other changes have also occurred in the Estuary concurrent with the declines of native species. Other factors that might be important in species declines include the effects of construction of upstream dams, large and small water diversions within the Sacramento-San Joaquin Delta, agricultural pesticides, trace elements from industrial and agricultural activities, and invasions of alien species. Discussions among researchers, managers, and stakeholders have identified a number of uncertainties regarding the potential benefits of tidal wetland restoration. The articles of the Tidal Wetlands Restoration Series address four major issues of concern. Stated as questions, these are: 1. Will tidal wetland restoration enhance populations of native fishes? 2. Will wetland restoration increase rates of methylation of mercury? 3. Will primary production and other ecological processes in restored tidal wetlands result in net export of organic carbon to adjacent habitats, resulting in enhancement of the food web? Will the carbon produced contribute to the formation of disinfection byproducts when disinfected for use as drinking water? 4. Will restored tidal wetlands provide long-term ecosystem benefits that can be sustained in response to ongoing physical processes, including sedimentation and hydrodynamics? Reducing the uncertainty surrounding these issues is of critical importance because tidal wetland restoration is assumed to be a critical tool for

Catching what we can't see: manual interception of occluded fly-ball trajectories.

Science.gov (United States)

Bosco, Gianfranco; Delle Monache, Sergio; Lacquaniti, Francesco

2012-01-01

Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g) or increased gravity (2 g) at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses of subjects

Metro Multnomah Wetlands - Multnomah Channel Wetland Restoration Monitoring Project

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Multnomah Channel Wetland Restoration Monitoring Project characterizes wetlands use by juvenile salmonids and other fishes in the Multnomah Channel Marsh Natural...

Wetlands: The changing regulatory landscape

International Nuclear Information System (INIS)

Glick, R.M.

1993-01-01

Protection of wetlands became a national issue in 1988 when President George Bush pledged no net loss of wetlands in the US under his open-quotes environmental presidency.close quotes As wetlands became a national issue, the job of protecting them became an obligation for many groups, including hydro-power developers. Now, when a site selected for development includes an area that may be classified as a wetland, the developer quickly discovers the importance of recognizing and protecting these natural habitats. Federal legislation severely limits development of wetland, and most states increase the restrictions with their own wetlands regulations. The difficulty of defining wetlands complicates federal and state enforcement. Land that appears to be dry may in fact be classified as a wetland. So, even if a site appears dry, potential hydro developers must confirm whether or not any jurisdictional wetlands are present. Regulated lands include much more than marshes and swamps. Further complicating the definition of wetlands, a recent court decision found that even artificially created wetlands, such as man-made ponds, may be subject to regulation. Hydro developers must be aware of current regulatory requirements before they consider development of any site that may contain wetlands. To be certain that a site is open-quotes buildableclose quotes from the standpoint of wetlands regulation, a developer must verify (with the help of state agencies) that the property does not contain any jurisdictional wetlands. If it does, the regulatory process before development becomes much more complicated. For the short term, uncertainty abounds and extreme caution is in order. Because the regulatory process has become so complex and an agreeable definition of wetlands so elusive, the trend among the Corps and collaborating agencies is to constrict nationwide permits in favor of narrowing the jurisdictional definition of wetlands

Telecommunications (Interception and Access) and Its Regulation in Arab Countries

OpenAIRE

Kiswani, Nazzal

2010-01-01

Telecommunication has been a necessity in all countries this century. Communication has always been an essential part of our lives, education, family relations, business, government and other organizational activities. As telecommunication technology has advanced, so has the need for the interception of telecommunications and access by law enforcement authorities. In addition, lawful interception and the way it is performed have played an important role in the effectiveness of the monitoring ...

Forested wetland habitat

Science.gov (United States)

Duberstein, Jamie A.; Krauss, Ken W.; Kennish, Michael J.

2015-01-01

A forested wetland (swamp) is a forest where soils are saturated or flooded for at least a portion of the growing season, and vegetation, dominated by trees, is adapted to tolerate flooded conditions. A tidal freshwater forested wetland is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity of soil porewater less than 0.5 g/l. It is known locally as tidal várzea in the Amazon delta, Brazil. A tidal saltwater forested wetland (mangrove forest) is a forested wetland that experiences frequent but short-term surface flooding via tidal action, with average salinity often exceeding 3 g/l and reaching levels that can exceed seawater. Mangrove ecosystems are composed of facultative halophytes that generally experience better growth at moderate salinity concentrations.

National Wetlands Inventory Lines

Data.gov (United States)

Minnesota Department of Natural Resources — Linear wetland features (including selected streams, ditches, and narrow wetland bodies) mapped as part of the National Wetlands Inventory (NWI). The National...

Freshwater Wetlands: A Citizen's Primer.

Science.gov (United States)

Catskill Center for Conservation and Development, Inc., Hobart, NY.

The purpose of this "primer" for the general public is to describe the general characteristics of wetlands and how wetland alteration adversely affects the well-being of humans. Particular emphasis is placed on wetlands in New York State and the northeast. Topics discussed include wetland values, destruction of wetlands, the costs of…

Wise use of wetlands: current state of protection and utilization of Chinese wetlands and recommendations for improvement.

Science.gov (United States)

Wang, Yanxia; Yao, Yong; Ju, Meiting

2008-06-01

Wetland protection and utilization sometimes appear to be in conflict, but promoting the wise use of wetlands can solve this problem. All countries face the challenge of sustainable development of wetlands to a greater or lesser extent, but the problem is especially urgent in developing countries, such as China, that want to accelerate their economic development without excessive environmental cost. Chinese wetlands contribute greatly to economic development, but improper use of these natural resources has endangered their existence. It is thus necessary to provide scientific guidance to managers and users of wetlands. In this paper, we analyze the present status of Chinese wetland protection and utilization, and discuss problems in six categories: a lack of public awareness of the need for wetland protection; insufficient funding for wetland protection and management; an imperfect legal system to protect wetlands; insufficient wetland research; lack of coordination among agencies and unclear responsibilities; and undeveloped technologies related to wetland use and protection. The wise use of Chinese wetlands will require improvements in four main areas: increased wetland utilization research, scientific management of wetland utilization, improved laws and regulations to protect wetlands, and wider dissemination of wetland knowledge. Based on these categories, we propose a framework for the optimization of wetland use by industry to provide guidance for China and other countries that cannot sacrifice economic benefits to protect their wetlands.

Pipeline corridors through wetlands

International Nuclear Information System (INIS)

Zimmerman, R.E.; Wilkey, P.L.; Isaacson, H.R.

1992-01-01

This paper presents preliminary findings from six vegetational surveys of gas pipeline rights-of-way (ROW) through wetlands and quantifies the impacts of a 20-year-old pipeline ROW through a boreal forest wetland. Six sites of various ages were surveyed in ecosystems ranging from coastal marsh to forested wetland. At all sites except one, both the number and the percentage of wetland species on the Row approximated or exceeded those in the adjacent natural area. The boreal forest study showed that (1) adjacent natural wetland areas were not altered in type; (2) water sheet flow restriction had been reversed by nature; (3) no nonnative plant species invaded the natural area; (4) three-quarters of the ROW area was a wetland, and (5) the ROW increased diversity

National Wetlands Inventory Polygons

Data.gov (United States)

Minnesota Department of Natural Resources — Wetland area features mapped as part of the National Wetlands Inventory (NWI). The National Wetlands Inventory is a national program sponsored by the US Fish and...

Characteristic community structure of Florida's subtropical wetlands: the Florida wetland condition index

Science.gov (United States)

Depending upon the classification scheme applied, there are between 10 and 45 different wetland types in Florida. Land use and land cover change has a marked effect on wetland condition, and different wetland types are affected differentially depending on many abiotic and biotic ...

Determination of the health of Lunyangwa wetland using Wetland Classification and Risk Assessment Index

Science.gov (United States)

Wanda, Elijah M. M.; Mamba, Bhekie B.; Msagati, Titus A. M.; Msilimba, Golden

2016-04-01

Wetlands are major sources of various ecological goods and services including storage and distribution of water in space and time which help in ensuring the availability of surface and groundwater throughout the year. However, there still remains a poor understanding of the range of values of water quality parameters that occur in wetlands either in its impacted state or under natural conditions. It was thus imperative to determine the health of Lunyangwa wetland in Mzuzu City in Malawi in order to classify and determine its state. This study used the Escom's Wetland Classification and Risk Assessment Index Field Guide to determine the overall characteristics of Lunyangwa wetland and to calculate its combined Wetland Index Score. Data on site information, field measurements (i.e. EC, pH, temperature and DO) and physical characteristics of Lunyangwa wetland were collected from March, 2013 to February, 2014. Results indicate that Lunyangwa wetland is a largely open water zone which is dominated by free-floating plants on the water surface, beneath surface and emergent in substrate. Furthermore, the wetland can be classified as of a C ecological category (score = 60-80%), which has been moderately modified with moderate risks of the losses and changes occurring in the natural habitat and biota in the wetland. It was observed that the moderate modification and risk were largely because of industrial, agricultural, urban/social catchment stressors on the wetland. This study recommends an integrated and sustainable management approach coupled with continuous monitoring and evaluation of the health of the wetland for all stakeholders in Mzuzu City. This would help to maintain the health of Lunyangwa wetland which is currently at risk of being further modified due to the identified catchment stressors.

Wetland Hydrology

Science.gov (United States)

This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefit...

Light regimes in Populus plantations using the Voxel-based Light Interception Model

NARCIS (Netherlands)

Van der Zande, D.; Dieussart, K.; Stuckens, J.; Verstraeten, W.W.; Coppin, P.

2011-01-01

Three-dimensional light interception by three uniform Populus canopies was studied using the Voxel-based Light Interception Model (VLIM) in combination with ground-based Light Detection and Ranging (LiDAR) measurements. As the VLIM was developed and validated in a virtual environment to ensure

Constructed wetlands : the Canadian context

Energy Technology Data Exchange (ETDEWEB)

Speer, S.; Champagne, P. [Queen' s Univ., Kingston, ON (Canada). Dept. of Civil Engineering

2006-07-01

Large volumes of wastewater from livestock and production facilities must be treated to minimize the contamination of waterways in agricultural areas. This paper investigated the use of constructed wetlands as a lower-cost and efficient method of treating agricultural wastewaters. The study found that while constructed wetlands required limited maintenance, temperature dependency of the constructed wetlands systems is a limiting factor in their widespread implementation. Lower operating temperatures are only overcome by constructing larger wetlands systems, which require a substantial amount of land. The Canadian climate poses significant challenges to the implementation of constructed wetlands, which become inoperative during winter months. Plants and bacteria normally become dormant or die during winter months, which can create a lag in wetland treatment during the initial months of operation in the Spring. Snowmelt and added rainfall in the Spring can also create a high flow within the wetland cells, as many constructed wetlands rely on runoff as a feed source. Washout of bacteria can occur. Wastewater storage systems or further engineering of the wetlands may be required. It was concluded that insulating wetland cells will maintain a warmer operating temperature, while the addition of an aeration system will increase the treatment efficiency of the wetland during winter months. 17 refs., 5 tabs., 2 figs.

National Wetlands Inventory Points

Data.gov (United States)

Minnesota Department of Natural Resources — Wetland point features (typically wetlands that are too small to be as area features at the data scale) mapped as part of the National Wetlands Inventory (NWI). The...

Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico

Science.gov (United States)

Schellekens, J.; Scatena, F. N.; Bruijnzeel, L. A.; Wickel, A. J.

1999-12-01

Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location—the Luquillo Experimental Forest in eastern Puerto Rico—66 days of detailed throughfall and above-canopy climatic data were collected in 1996 and analysed using the Rutter and Gash models of rainfall interception. Throughfall occurred on 80% of the days distributed over 80 rainfall events. Measured interception loss was 50% of gross precipitation. When Penman-Monteith based estimates for the wet canopy evaporation rate (0.11 mm h -1 on average) and a canopy storage of 1.15 mm were used, both models severely underestimated measured interception loss. A detailed analysis of four storms using the Rutter model showed that optimizing the model for the wet canopy evaporation component yielded much better results than increasing the canopy storage capacity. However, the Rutter model failed to properly estimate throughfall amounts during an exceptionally large event. The analytical model, on the other hand, was capable of representing interception during the extreme event, but once again optimizing wet canopy evaporation rates produced a much better fit than optimizing the canopy storage capacity. As such, the present results support the idea that it is primarily a high rate of evaporation from a wet canopy that is responsible for the observed high interception losses.

Growth Responses of Three Dominant Wetland Plant Species to Various Flooding and Nutrient Levels

Science.gov (United States)

Barrett, S.; Shaffer, G. P.

2017-12-01

Coastal Louisiana is experiencing a greater rate of wetland loss than any other wetland system in the United States. This is primarily due to anthropogenic stressors such as flood control levees, backfilling and development of wetlands, and other hydrologic modifications. Methods employed to mitigate wetland loss include the construction of river diversions and assimilation wetlands, which can provide consistent sources of freshwater influx and nutrients to impounded swamps and marshes. It is well known that prolonged flooding causes strain on wetland plant communities and facilitates or exacerbates wetland degradation. However, because river diversions and assimilation wetlands bring high nutrient loads along with freshwater, there is debate over whether prolonged flooding or high influx of nutrients is the primary cause of stress in river diversion and assimilation wetland discharge areas. This mesocosm experiment addresses this question by isolating the effects of flooding and nutrients on the biomass of baldcypress (Taxodium distichum), maidencane (Panicum hemitomon), and cordgrass (Spartina patens) over the course of a growing season. The results of this study provide clarity as to whether flooding stress, high nutrient loads, or both cause a reduction in wetland plant productivity. By evaluating the growth responses of T. distichum, P. hemitomon, and S. patens at varying nutrient regimes, we gain insight on how these more dominant species will react to high nutrient discharges from large river diversions, such as those proposed in Louisiana's 2017 Master Plan.

Catching what we can't see: manual interception of occluded fly-ball trajectories.

Directory of Open Access Journals (Sweden)

Gianfranco Bosco

Full Text Available Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g or increased gravity (2 g at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses

Flora characteristics of Chenier Wetland in Bohai Bay and biogeographic relations with adjacent wetlands

Science.gov (United States)

Zhao, Yanyun; Lu, Zhaohua; Liu, Jingtao; Hu, Shugang

2017-12-01

A key step towards the restoration of heavily disturbed fragile coastal wetland ecosystems is determining the composition and characteristics of the plant communities involved. This study determined and characterized the community of higher plants in the Chenier wetland of Bohai Bay using a combination of field surveys, quadrat approaches, and multivariate statistical analyses. This community was then compared to other adjacent wetlands (Tianjin, Qinhuangdao, Laizhouwan, Jiaozhouwan, and Yellow River Delta wetland) located near the Huanghai and Bohai Seas using principal coordinate analysis (PCoA). Results showed a total of 56 higher plant species belonging to 52 genera from 20 families in Chenier wetland, the majority of which were dicotyledons. Single-species families were predominant, while larger families, including Gramineae, Compositae, Leguminosae, and Chenopodiaceae contained a higher number of species (each⩾6 species). Cosmopolitan species were also dominant with apparent intrazonality. Abundance (number of species) of temperate species was twice that of tropical taxa. Species number of perennial herbs, such as Gramineae and Compositae, was generally higher. Plant diversity in the Chenier wetland, based on the Shannon-Wiener index, was observed to be between the Qinhuangdao and Laizhouwan indices, while no significant difference was found in other wetlands using the Simpson index. Despite these slight differences in diversity, PCoA based on species abundance and composition of the wetland flora suggest that the Bohai Chenier community was highly similar to the coastal wetlands in Tianjin and Laizhouwan, further suggesting that these two wetlands could be important breeding grounds and resources for the restoration of the plant ecosystem in the Chenier wetland.

Macroinvertebrate abundance, water chemistry, and wetland characteristics affect use of wetlands by avian species in Maine

Science.gov (United States)

Longcore, J.R.; McAuley, D.G.; Pendelton, G.W.; Bennatti, C.R.; Mingo, T.M.; Stromborg, K.L.

2006-01-01

Our objective was to determine use by avian species (e.g., piscivores, marsh birds, waterfowl, selected passerines) of 29 wetlands in areas with low (chemistry, basin characteristics, and avian use of different wetland types. Shallow, beaver (Castor canadensis)-created wetlands with the highest phosphorus levels and abundant and varied macrophyte assemblages supported greater densities of macroinvertebrates and numbers of duck broods (88.3% of all broods) in contrast to deep, glacial type wetlands with sparse vegetation and lower invertebrate densities that supported fewer broods (11.7%). Low pH may have affected some acid-intolerant invertebrate taxa (i.e., Ephemeroptera), but high mean numbers of Insecta per wetland were recorded from wetlands with a pH of 5.51. Other Classes and Orders of invertebrates were more abundant on wetlands with pH > 5.51. All years combined use of wetlands by broods was greater on wetlands with pH ≤ 5.51 (77.4%) in contract to wetlands with pH > 5.51 that supported 21.8% of the broods. High mean brood density was associated with mean number of Insecta per wetland. For lentic wetlands created by beaver, those habitats contained vegetative structure and nutrients necessary to provide cover to support invertebrate populations that are prey of omnivore and insectivore species. The fishless status of a few wetlands may have affected use by some waterfowl species and obligate piscivores.

Wetlands & Deepwater Habitats - MO 2012 East West Gateway Wetlands (SHP)

Data.gov (United States)

NSGIC State | GIS Inventory — Cowardin’s Classification of Wetlands and Deep Water Habitats of the United States (http://www.npwrc.usgs.gov/resource/wetlands/classwet/index.htm), together with...

Bartlett correction in the stable AR(1) model with intercept and trend

NARCIS (Netherlands)

van Giersbergen, N.P.A.

2004-01-01

The Bartlett correction is derived for testing hypotheses about the autoregressive parameter ρ in the stable: (i) AR(1) model; (ii) AR(1) model with intercept; (iii) AR(1) model with intercept and linear trend. The correction is found explicitly as a function of ρ. In the models with deterministic

Wetlands Research Program. Wetland Evaluation Technique (WET). Volume 2. Methodology.

Science.gov (United States)

1987-10-01

to waves taller than I ft? • " Guidelines: 1 "Sufficient" is defined as the height of vegetation or relief multiplied * by length of vegetation or...Sci., Interim Rep. No. 3, Gloucester Point, VA. 52 pp. 203 VI. 4 WET 2.0 Simmons, E. G. 1957. An ecological survey of the Upper Laguna Madre of Texas...A wetland class characterized by vegetation that is 6 m or taller . Fringe Wetland - Fringe wetlands along a channel (i.e.. river, stream, etc.)are

Exploring the potential of the cosmic-ray neutron method to measure interception storage dynamics

Science.gov (United States)

Jakobi, Jannis; Bogena, Heye; Huisman, Johan Alexander; Diekkrüger, Bernd; Vereecken, Harry

2017-04-01

Cosmic-ray neutron soil moisture probes are an emerging technology that relies on the negative correlation between near-surface fast neutron counts and soil moisture content. Hydrogen atoms in the soil, which are mainly present as water, moderate the secondary neutrons on the way back to the surface. Any application of this method needs to consider the sensitivity of the neutron counts to additional sources of hydrogen (e.g. above- and below-ground biomass, humidity of the lower atmosphere, lattice water of the soil minerals, organic matter and water in the litter layer, intercepted water in the canopy, and soil organic matter). In this study, we analyzed the effects of canopy-intercepted water on the cosmic-ray neutron counts. For this, an arable field cropped with sugar beet was instrumented with several cosmic-ray neutron probes and a wireless sensor network with more than 140 in-situ soil moisture sensors. Additionally rainfall interception was estimated using a new approach coupling throughfall measurements and leaf wetness sensors. The derived interception storage was used to correct for interception effects on cosmic ray neutrons to enhance soil water content prediction. Furthermore, the potential for a simultaneous prediction of above- and below-ground biomass, soil moisture and interception was tested.

Managing wetlands for disaster risk reduction: A case study of the eastern Free State, South Africa

Directory of Open Access Journals (Sweden)

Johannes A. Belle

2018-03-01

Full Text Available This article investigated the knowledge and practice of a nature-based solution to reduce disaster risks of drought, veld fires and floods using wetlands in the eastern Free State, South Africa. A mixed research method approach was used to collect primary data using three data collection tools, namely questionnaires, interviews and field observations. Ninety-five wetlands under communal and private ownership as well as a few in protected areas were sampled, with their users completing questionnaires. The study showed that communal wetlands were more degraded, while wetlands in protected areas and in private commercial farms were in a good ecological state. An extensive literature review reveals that healthy wetlands are effective buffers in reducing disaster risks such as drought, veld fires and floods which are recurrent in the study area. Therefore, through better land-use and management practices, backed by education and awareness, wetlands could be good instruments to mitigate recurrent natural hazards in the agriculturally dominated eastern Free State in South Africa.

Use of multiple water surface flow constructed wetlands for non-point source water pollution control.

Science.gov (United States)

Li, Dan; Zheng, Binghui; Liu, Yan; Chu, Zhaosheng; He, Yan; Huang, Minsheng

2018-05-02

Multiple free water surface flow constructed wetlands (multi-FWS CWs) are a variety of conventional water treatment plants for the interception of pollutants. This review encapsulated the characteristics and applications in the field of ecological non-point source water pollution control technology. The roles of in-series design and operation parameters (hydraulic residence time, hydraulic load rate, water depth and aspect ratio, composition of influent, and plant species) for performance intensification were also analyzed, which were crucial to achieve sustainable and effective contaminants removal, especially the retention of nutrient. The mechanism study of design and operation parameters for the removal of nitrogen and phosphorus was also highlighted. Conducive perspectives for further research on optimizing its design/operation parameters and advanced technologies of ecological restoration were illustrated to possibly interpret the functions of multi-FWS CWs.

Rainfall Interception in Mangrove in the Southeastern Coast of Brazil

Directory of Open Access Journals (Sweden)

Emerson Galvani

2016-06-01

Full Text Available Mangroves are among the ecosystems biologically more productive and important in the world, providing unique goods and services to societies and coastal systems. These areas, however, are increasingly fragmented, contributing to the loss of their services and benefits. The rains have an important influence in this ecosystem is central to the dissolution of sea salts. This study investigated the total rainfall in the mangroves located in the Coastal System Cananeia-Iguape (SP at different time scales (daily, monthly, sea-sonal and annual and its interception by the mangrove canopy. It found an intercept of 8.8%, ranging from 13% to 4% in the annual scale, showing that the annual variation of rainfall, which reflects both its quantity and its intensity contributes to the percentage of that interception by the canopy. It was also found that as the intensity of precipitation increases, trapping the mangrove canopy reduces.

Kansas Playa Wetlands

Data.gov (United States)

Kansas Data Access and Support Center — This digital dataset provides information about the distribution, areal extent, and morphometry of playa wetlands throughout western Kansas. Playa wetlands were...

[Changes in vegetation and soil characteristics under tourism disturbance in lakeside wetland of northwest Yunnan Plateau, Southwest China].

Science.gov (United States)

Tang, Ming-Yan; Yang, Yong-Xing

2014-05-01

The characteristics of vegetation and soil were investigated in Bita Lake and Shudu Lake wetlands in northwest Yunnan Plateau under tourism disturbance. The 22 typical plots in the wetlands were classified into 4 types by TWINSPAN, including primary wetland, light degradation, moderate degradation, and severe degradation. Along the degradation gradient, the plant community density, coverage, species number and Shannon diversity index increased and the plant height decreased in Bita Lake and Shudu Lake wetlands, and Whittaker diversity index increased in Bita Lake wetland. Plant species number, soil organic matter, total nitrogen, porosity, available nitrogen, available phosphorus and available potassium contents were higher in Shudu Lake wetland than in Bita Lake wetland, but the plant density, height, soil total potassium and pH were opposite. Canonical correspondence analysis (CCA) by importance values of 42 plants and 11 soil variables showed that soil organic matter, total nitrogen and total potassium were the key factors on plant species distribution in Bita Lake and Shudu Lake wetlands under tourism disturbance. TWINSPAN classification and analysis of vegetation-soil characteristics indicated the effects of tourism disturbance in Bita Lake wetland were larger than in Shudu Lake wetland.

[Research progress on wetland ecotourism].

Science.gov (United States)

Wang, Li-Long; Lu, Lin

2009-06-01

Wetland is rich in biodiversity and cultural diversity, possessing higher tourism value and environmental education and community participation functions. Wetland ecotourism reflects the sustainable development of tourism economy and wetland protection, having received great concern from governments and scholars at home and abroad. This paper summarized the related theories and practices, discussed the research advances in wetland ecotourism from the aspects of significance, progress, contents, methods and results, and pointed out the important research fields in the future, aimed to accelerate the development of wetland ecotourism research and to provide reference about the resources exploitation, environment protection, and scientific administration of wetland and related scenic areas.

Wetland Hydrology | Science Inventory | US EPA

Science.gov (United States)

This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefits and types, and explains the role and importance of hydrology on wetland functioning. The chapter continues with the description of wetland hydrologic terms and related estimation and modeling techniques. The chapter provides a quick but valuable information regarding hydraulics of surface and subsurface flow, groundwater seepage/discharge, and modeling groundwater/surface water interactions in wetlands. Because of the aggregated effects of the wetlands at larger scales and their ecosystem services, wetland hydrology at the watershed scale is also discussed in which we elaborate on the proficiencies of some of the well-known watershed models in modeling wetland hydrology. This chapter can serve as a useful reference for eco-hydrologists, wetland researchers and decision makers as well as watershed hydrology modelers. In this chapter, the importance of hydrology for wetlands and their functional role are discussed. Wetland hydrologic terms and the major components of water budget in wetlands and how they can be estimated/modeled are also presented. Although this chapter does not provide a comprehensive coverage of wetland hydrology, it provides a quick understanding of the basic co

[Effect of air temperature and rainfall on wetland ecosystem CO2 exchange in China].

Science.gov (United States)

Chu, Xiao-jing; Han, Guang-xuan

2015-10-01

Wetland can be a potential efficient sink to reduce global warming due to its higher primary productivity and lower carbon decomposition rate. While there has been a series progress on the influence mechanism of ecosystem CO2 exchange over China' s wetlands, a systematic metaanalysis of data still needs to be improved. We compiled data of ecosystem CO2 exchange of 21 typical wetland vegetation types in China from 29 papers and carried out an integrated analysis of air temperature and precipitation effects on net ecosystem CO2 exchange (NEE), ecosystem respiration (Reco), gross primary productivity (GPP), the response of NEE to PAR, and the response of Reco to temperature. The results showed that there were significant responses (P0.05). Across different Chinese wetlands, both precipitation and temperature had no significant effect on apparent quantum yield (α) or ecosystem respiration in the daytime (Reco,day, P>0.05). The maximum photosynthesis rate (Amax) was remarkably correlated with precipitation (P 0.05). Precipitation was negatively correlated with temperature sensitivity of Reco (Q10, P<0.05). Furthermore, temperature accounted for 35% and 46% of the variations in temperature sensitivity of Reco (Q10) and basal respiration (Rref P<0.05), respectively.

Prospective Control in Catching : The Persistent Angle-of-Approach Effect in Lateral Interception

NARCIS (Netherlands)

Ledouit, Simon; Casanova, Remy; Zaal, Frank T. J. M.; Bootsma, Reinoud J.

2013-01-01

In lateral interception tasks balls converging onto the same interception location via different trajectories give rise to systematic differences in the kinematics of hand movement. While it is generally accepted that this angle-of-approach effect reflects the prospective (on-line) control of

Percent Wetland Cover

Data.gov (United States)

U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

Sorption-desorption of radiocesium interception potential in tropical soils

International Nuclear Information System (INIS)

Roque, Mario L.; Boaretto, Rodrigo M.; Boaretto, Antonio E.; Smolders, Erik E.T.

2000-01-01

A study of sorption of radiocaesium in soils of tropical climate (Brazil) was carried. The values of definitive fixation of the radiocaesium were determined by analytic methodology of sorption-desorption and the availability to plants were calculated by the determination of radiocesium interception potential (RIP). The values of sorption varied from 1,2 to 74,8% and the fixation varied from 3,2% to 32,2%. The results shown that the radiocaesium did remain adsorbed mainly to the frayed edge site. The low values of interception potential and definitive fixation demonstrated high capacity of the tropical soils in disposal the radionuclide for the solution and, consequently, to plants. (author)

Phytoremediation of explosives in groundwater using innovative wetlands-based treatment technologies

Energy Technology Data Exchange (ETDEWEB)

Sikora, F.J.; Behrends, L.L.; Coonrod, H.S.; Phillips, W.D. [Tennessee Valley Authority, Muscle Shoals, AL (United States). Environmental Research Center; Bader, D.F. [Army Environmental Center, Aberdeen Proving Ground, MD (United States)

1997-12-31

Many army ammunition plants across the country have problems with groundwater contaminated with explosives. A field demonstration was initiated at the Milan Army Ammunition Plant near Milan, Tennessee early in 1996 to demonstrate the feasibility of treating contaminated groundwater with constructed wetlands. Two different systems were designed and installed. A lagoon system consisted of two cells in series with each cell having dimensions of 24 x 9.4 x 0.6 m (L x W x H). A gravel-bed system consisted of three gravel-beds operated in series with a primary anaerobic cell having dimensions of 32 x 11 x 1.4 m (L x W x H), followed by a pair of secondary cells each with dimensions of 5.5 x 11 x 1.4 m (L x W x H). The primary cell is maintained anaerobic by adding powdered milk to the water every two weeks. The secondary cells are maintained aerobic via reciprocation, whereby water is pumped back and forth from one cell to another to cause a recurrent fill and drain action. The lagoons were planted with sago pond weed, water stargrass, elodea, and parrot feather. The gravel-bed wetlands were planted with canary grass, wool grass, sweet flag, and parrot feather. Water began flowing to each of the wetland treatment systems at 19 L min{sup {minus}1} starting in June 1996. The design hydraulic retention time through each treatment system was approximately 10 days. Influent and effluent water samples were collected every 2 weeks. Intensive sampling of water interior to the wetlands occurred every 2 months.

Neural network modelling of rainfall interception in four different forest stands

OpenAIRE

Ibrahim Yurtseven; Mustafa Zengin

2013-01-01

The objective of this study is to reveal whether it is possible to predict rainfall, throughfall and stemflow in forest ecosystems with less effort, using several measurements of rainfall interception (hereafter interception) and an artificial neural network based linear regression model (ANN model). To this end, the Kerpe Research Forest in the province of Kocaeli, which houses stands of mixed deciduous-broadleaf forest (Castanea sativa Mill., Fagus orientalis Lipsky, Quercus spp.), black pi...

Carbon dynamics in wetland restoration

Energy Technology Data Exchange (ETDEWEB)

Kovalenko, K.; Ciborowski, J.; Gardner-Costa, J.; Slama, C. [Windsor Univ., ON (Canada); Daly, C.; Hornung, J. [Suncor Energy, Calgary, AB (Canada); Dixon, G.; Farwell, A. [Waterloo Univ., ON (Canada); Foote, L.; Frederick, K.; Roy, M. [Alberta Univ., Edmonton, AB (Canada); Liber, K. [Saskatchewan Univ., Saskatoon, SK (Canada); Smits, J. [Calgary Univ., AB (Canada); Wytrykush, C. [Syncrude Canada Ltd., Edmonton, AB (Canada)

2010-07-01

This study focused on the reclamation of wetland ecosystems impacted by oil sands development in the boreal wetlands. Although these wetlands play an important role in global carbon balance, their ecosystem function is compromised by direct and regional anthropogenic disturbance and climate change. Large oil sand mining areas that require reclamation generate substantial quantities of extraction process-affected materials. In order to determine if the reclaimed wetlands were restored to equivalent ecosystem function, this study evaluated carbon flows and food web structure in oil sands-affected wetlands. The purpose was to determine whether a prescribed reclamation strategy or topsoil amendment accelerates reclaimed wetland development to produce self-sustaining peatlands. In addition to determining carbon fluxes, this study measured compartment standing stocks for residual hydrocarbons, organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, detritus, zoobenthos and aquatic-terrestrial exports. Most biotic 28 compartments differed between oil-sands-affected and reference wetlands, but the difference lessened with age. Macroinvertebrate trophic diversity was lower in oil sands-affected wetlands. Peat amendment seemed to speed convergence for some compartments but not others. These results were discussed in the context of restoration of ecosystem function and optimization of reclamation strategies.

Morphology of a Wetland Stream

Science.gov (United States)

Jurmu; Andrle

1997-11-01

/ Little attention has been paid to wetland stream morphology in the geomorphological and environmental literature, and in the recently expanding wetland reconstruction field, stream design has been based primarily on stream morphologies typical of nonwetland alluvial environments. Field investigation of a wetland reach of Roaring Brook, Stafford, Connecticut, USA, revealed several significant differences between the morphology of this stream and the typical morphology of nonwetland alluvial streams. Six morphological features of the study reach were examined: bankfull flow, meanders, pools and riffles, thalweg location, straight reaches, and cross-sectional shape. It was found that bankfull flow definitions originating from streams in nonwetland environments did not apply. Unusual features observed in the wetland reach include tight bends and a large axial wavelength to width ratio. A lengthy straight reach exists that exceeds what is typically found in nonwetland alluvial streams. The lack of convex bank point bars in the bends, a greater channel width at riffle locations, an unusual thalweg location, and small form ratios (a deep and narrow channel) were also differences identified. Further study is needed on wetland streams of various regions to determine if differences in morphology between alluvial and wetland environments can be applied in order to improve future designs of wetland channels.KEY WORDS: Stream morphology; Wetland restoration; Wetland creation; Bankfull; Pools and riffles; Meanders; Thalweg

Michigan Wetlands: Yours To Protect. A Citizen's Guide to Local Involvement in Wetland Protection. Second Edition.

Science.gov (United States)

Cwikiel, Wilfred

This guidebook is designed to assist concerned Michigan citizens, local governments, conservation organizations, landowners, and others in their efforts to initiate wetlands protection activities. Chapter 1 focuses on wetland functions, values, losses, and the urgent need to protect wetland resources. Chapter 2 discusses wetland identification and…

40 CFR 258.12 - Wetlands.

Science.gov (United States)

2010-07-01

... degraded wetlands or creation of man-made wetlands); and (5) Sufficient information is available to make a... expansions shall not be located in wetlands, unless the owner or operator can make the following...

Interception and retention of technetium by vegetation and soil

International Nuclear Information System (INIS)

Hoffman, F.O.; Garten, C.T. Jr.; Huckabee, J.W.; Lucas, D.M.

1982-01-01

Field experiments were performed to quantify the initial interception and retention of technetium (Tc) by herbaceous vegetation as a consequence of direct deposition and uptake from soil. A simulated rain containing a solution of 95 /sup m/TcO 4 - was applied to plots of bare soil and plots with standing vegetation. Vegetation emerging in the baresoil plots obtained Tc predominantly from root uptake. Vegetation standing during the initial application obtained Tc from both direct foliar interception and root uptake. For the plots with standing vegetation, the estimated initial interception fraction (r) ranged from 0.079 to 0.17. The mass interception factor (r/Y/sub v/) ranged from 0.65 to 1.1 m 2 /kg. The retention of Tc by vegetation receiving direct foliar contamination varied with environmental half-times (T/sub w/) ranging from 15.9 to 18.7 days. Adjusting for the effects of growth dilution increased the values of T/sub w/ (range 21.6-28.7 days). For vegetation emerging from the plots of initial bare soil, retention was equivalent to a T/sub w/ of 43 days. These data indicated that uptake of Tc from soil diminished with time and that Tc was removed from plant tissue. In soil, a downward movement was evident, because Tc in the top 2 cm decreased with time and concentrations at lower soil depths (6-8 and 14-15 cm) and increased with time. The application of these data to predict steady-state concentrations of Tc in vegetation resulting from continuous deposition does not differ substantially from predictions based on the use of generic-default parameter values recommend in Regulatory Guide 1.109 of the U. S. Nuclear Regulatory Commission

Evaluation of a market in wetland credits: entrepreneurial wetland banking in Chicago.

Science.gov (United States)

Robertson, Morgan; Hayden, Nicholas

2008-06-01

With the rise of market-led approaches to environmental policy, compensation for permitted discharge of dredge or fill material into wetlands under Section 404 of the U.S. Clean Water Act has been purchased increasingly from entrepreneurial third-party providers. The growth of this practice (i.e., entrepreneurial wetland banking) has resolved many challenges associated with wetland compensation. But it has also produced (1) quantifiable temporal loss of wetland ecological functions, (2) spatial redistribution of wetland area, and (3) a degree of regulatory instability that may pose a threat to entrepreneurial compensation as a sustainable component of wetland-compensation policy. We used achieved compensation ratios, lapse between bank credit sale and the attainment of performance standards, distance between impact and bank site, and changes in bank market area to examine these 3 factors. We analyzed data from a census of all such transactions in the Chicago District of the U.S. Army Corps of Engineers, compiled from site visits, Corps databases, and contacts with consultants and Section 404 permittees. Entrepreneurial banking provided compensation at a lower overall ratio than nonbank forms of compensation. Approximately 60% of bank credits were sold after site-protection standards were met but before ecological performance standards were met at the bank site. The average distance between bank and impact site was approximately 26 km. The area of markets within which established banks can sell wetland credits has fluctuated considerably over the study period. Comparing these data with similar data for other compensation mechanisms will assist in evaluating banking as an element of conservation policy. Data characterizing the performance of entrepreneurial wetland banks in actual regulatory environments are scarce, even though it is the most established of similar markets that have become instrumental to federal policy in administering several major environmental

Neural network modelling of rainfall interception in four different forest stands

Directory of Open Access Journals (Sweden)

Ibrahim Yurtseven

2013-12-01

Full Text Available The objective of this study is to reveal whether it is possible to predict rainfall, throughfall and stemflow in forest ecosystems with less effort, using several measurements of rainfall interception (hereafter ‘interception’ and an artificial neural network based linear regression model (ANN model. To this end, the Kerpe Research Forest in the province of Kocaeli, which houses stands of mixed deciduous-broadleaf forest (Castanea sativa Mill., Fagus orientalis Lipsky, Quercus spp., black pine (Pinus nigra Arnold, maritime pine (Pinus pinaster Aiton and Monterey pine (Pinus radiata D. Don, was selected study site. Four different forest stands were observed for a period of two years, during which rainfall, throughfall and stemflow measurements were conducted. These measurements were separately calculated for each individual stand, based on interception values and the use of stemflow data in strict accordance with the rainfall data, and the measured throughfall interception values were compared with values estimated by the ANN model. In this comparison, 70% of the total data was used for testing, and 30% was used for estimation and performance evaluation. No significant differences were found between values predicted with the help of the model and the measured values. In other words, interception values predicted by the ANN models were parallel with the measured values. In this study, the most success was achieved with the models of the Monterey pine stand (r2 = 0.9968; Mean Squared Error MSE = 0.16 and the mixed deciduous forest stand (r2 = 0.9964; MSE = 0.08, followed by models of the maritime pine stand (r2 = 0.9405; MSE = 1.27 and the black pine stand (r2 = 0.843, MSE = 17.36.

Mine-associated wetlands as avian habitat

International Nuclear Information System (INIS)

Horstman, A.J.; Nawrot, J.R.; Woolf, A.

1998-01-01

Surveys for interior wetland birds at mine-associated emergent wetlands on coal surface mines in southern Illinois detected one state threatened and two state endangered species. Breeding by least bittern (Ixobrychus exilis) and common moorhen (Gallinula chloropus) was confirmed. Regional assessment of potential wetland bird habitat south of Illinois Interstate 64 identified a total of 8,109 ha of emergent stable water wetlands; 10% were associated with mining. Mine-associated wetlands with persistent hydrology and large expanses of emergent vegetation provide habitat that could potentially compensate for loss of natural wetlands in Illinois

Operational, design and microbial aspects related to power production with microbial fuel cells implemented in constructed wetlands.

Science.gov (United States)

Corbella, Clara; Guivernau, Miriam; Viñas, Marc; Puigagut, Jaume

2015-11-01

This work aimed at determining the amount of energy that can be harvested by implementing microbial fuel cells (MFC) in horizontal subsurface constructed wetlands (HSSF CWs) during the treatment of real domestic wastewater. To this aim, MFC were implemented in a pilot plant based on two HSSF CW, one fed with primary settled wastewater (Settler line) and the other fed with the effluent of a hydrolytic up-flow sludge blanket reactor (HUSB line). The eubacterial and archaeal community was profiled on wetland gravel, MFC electrodes and primary treated wastewater by means of 16S rRNA gene-based 454-pyrosequencing and qPCR of 16S rRNA and mcrA genes. Maximum current (219 mA/m(2)) and power (36 mW/m(2)) densities were obtained for the HUSB line. Power production pattern correlated well with water level fluctuations within the wetlands, whereas the type of primary treatment implemented had a significant impact on the diversity and relative abundance of eubacteria communities colonizing MFC. It is worth noticing the high predominance (13-16% of relative abundance) of one OTU belonging to Geobacter on active MFC of the HUSB line that was absent for the settler line MFC. Hence, MFC show promise for power production in constructed wetlands receiving the effluent of a HUSB reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

Monitoring, interception and Big Boss in the workplace: is the devil in the details?

Directory of Open Access Journals (Sweden)

T Pistorius

2009-03-01

Full Text Available This article discusses the opposing dynamics in the modern workplace environment, specifically employees’ expectations of e-privacy and employers’ interception and monitoring of electronic communications. In terms of the Regulation of Interception of Communications and Provision of Communication-Related Information Act 70 of 2002 employees must take prior notice of or consent to the interception and monitoring of their e-communications. The article focuses on the extent to which click-wrap agreements and hypertext or XML links to e-workplace policies could meet these requirements.

Physical and biological controls over patterns of methane flux from wetland soils

Science.gov (United States)

Owens, S. M.; von Fischer, J. C.

2006-12-01

While methane (CH4) production and plant-facilitated gas transport both contribute to patterns of CH4 emissions from wetlands, the relative importance of each mechanism is uncertain. In flooded wetland soils, CH4 is produced by anaerobic methanogenic bacteria. In the absence of competing oxidizers (i.e. SO42-, NO3-, O2), CH4 production is limited by the availability of labile carbon, which is supplied from recent plant primary production (e.g. as root exudates) and converted by anaerobic fermenting bacteria into methanogenic substrate (e.g. acetate). Because diffusion of gases through saturated soils is extremely slow, the aerenchymous tissues of wetland plants provide the primary pathway for CH4 emissions in systems dominated by emergent vascular vegetation. Aerenchyma also function to shuttle atmospheric oxygen to belowground plant tissues for respiration. Consequentially, root radial oxygen loss results in an oxidized rhizosphere, which limits CH4 production and provides habitat for aerobic methanotrophic bacteria, potentially reducing CH4 emissions. To test the contribution of recent photosynthates on CH4 emissions, a shading experiment was conducted in a Juncus-dominated wetland in the Colorado Front Range. Shade treatments significantly reduced net ecosystem production (NEE) and gross primary production (GPP) compared to control plots (p=0.0194 and p=0.0551, respectively). While CH4 emissions did not significantly differ between treatments, CH4 flux rates were strongly correlated with NEE (p=0.0063) and GPP (p=0.0020), in support of the hypothesis that labile carbon from recent photosynthesis controls patterns of CH4 emissions. The relative importance of plant gas transport and methane consumption rates on CH4 emissions is not known. Methane flux is more tightly correlated with NEE than GPP, which may be explained by increased CH4 consumption or decreased CH4 production as a result of rhizospheric oxidation. The ability to predict future emissions of this

Interception of wet deposited atmospheric pollutants by herbaceous vegetation: Data review and modelling

Energy Technology Data Exchange (ETDEWEB)

Gonze, M.-A., E-mail: marc-andre.gonze@irsn.fr; Sy, M.M.

2016-09-15

Better understanding and predicting interception of wet deposited pollutants by vegetation remains a key issue in risk assessment studies of atmospheric pollution. We develop different alternative models, following either empirical or semi-mechanistic descriptions, on the basis of an exhaustive dataset consisting of 440 observations obtained in controlled experiments, from 1970 to 2014, for a wide variety of herbaceous plants, radioactive substances and rainfall conditions. The predictive performances of the models and the uncertainty/variability of the parameters are evaluated under Hierarchical Bayesian modelling framework. It is demonstrated that the variability of the interception fraction is satisfactorily explained and quite accurately modelled by a process-based alternative in which absorption of ionic substances onto the foliage surfaces is determined by their electrical valence. Under this assumption, the 95% credible interval of the predicted interception fraction encompasses 81% of the observations, including situations where either plant biomass or rainfall intensity are unknown. This novel approach is a serious candidate to challenge existing empirical relationships in radiological or chemical risk assessment tools. - Highlights: • Literature data on the interception of atmospheric pollutants by herbs were reviewed • Predictive models were developed and evaluated in the Bayesian modelling framework • Sensitivity of interception to environmental conditions was satisfactorily explained • 81% of the observations were satisfactorily predicted by a semi-mechanistic model • This model challenges empirical relationships currently used in risk assessment tools.

Development of a "Hydrologic Equivalent Wetland" Concept for Modeling Cumulative Effects of Wetlands on Watershed Hydrology

Science.gov (United States)

Wang, X.; Liu, T.; Li, R.; Yang, X.; Duan, L.; Luo, Y.

2012-12-01

Wetlands are one of the most important watershed microtopographic features that affect, in combination rather than individually, hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models, such as the Soil and Water Assessment Tool (SWAT), can be a best resort if wetlands can be appropriately represented in the models. However, the exact method that should be used to incorporate wetlands into hydrologic models is the subject of much disagreement in the literature. In addition, there is a serious lack of information about how to model wetland conservation-restoration effects using such kind of integrated modeling approach. The objectives of this study were to: 1) develop a "hydrologic equivalent wetland" (HEW) concept; and 2) demonstrate how to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba of Canada, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota of the United States. The HEWs were defined in terms of six calibrated parameters: the fraction of the subbasin area that drains into wetlands (WET_FR), the volume of water stored in the wetlands when filled to their normal water level (WET_NVOL), the volume of water stored in the wetlands when filled to their maximum water level (WET_MXVOL), the longest tributary channel length in the subbasin (CH_L1), Manning's n value for the tributary channels (CH_N1), and Manning's n value for the main channel (CH_N2). The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes

Wetland Management - A Success Story In Transition - Restoration of Bhoj Wetland, India

Science.gov (United States)

Mudgal, M. K.; Tech, B. M.; Miwwa

Wetlands are beautiful, biologically diverse, hydrologically disperse and ecological vibrant landscape world wide, embracing soils, water, plants, animals and human be- ing. The population growth in the catchment of wetlands led to multifarious human interventions for deriving maximum benefit from the wetlands and their catchments neglecting and disrespecting the principles of sustainability. This act of destruction has been pronounced in developing countries which are under the grip of poverty, illiteracy and lack of environmental education. SBhoj WetlandS is a Lake situated ´ in Central India, Earthen Dam across the river KOLANS in 1061 AD by then ruler king BHOJ. Till 1950 this Wetland was served as a principal source of water supply, even not requiring filtration. As the city grew and the wetland started getting encir- cled by habitation and urban development, the anthropogenic pressures on the lake increased, thus accelerating the process of eutrophication, making the water unfit for human consumption without due treatment due to deterioration of quality of water. For the conservation and management of Bhoj Wetland (Lake Bhopal) a project is under- taken in the financial assistance from Japan Bank for International Cooperation (JBIC, Japan). The project envisages tackle various issues of conservation and management ofn the wetlands under a multi prongs strategies and manner. Although these issues are deeply interrelated and interlinked but for operational and management ease, these issues have been divided into various sub projects which are being tackled indepen- dently, albeit with undercurrent knowledge and understanding of the related issues and interconnectivity with each other. The Project itself is an apt example of the spectrum of varied problems and issues that come to light when attempts are made for sustain- able conservation and management of a wetland. The Project as envisaged intends to conserve and manage through 14 sub projects as under:- Sub

Atrazine remediation in wetland microcosms.

Science.gov (United States)

Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

2001-05-01

Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column.

Pesticide concentrations in frog tissue and wetland habitats in alandscape dominated by agriculture

Science.gov (United States)

Smalling, Kelly L.; Reeves, Rebecca; Muths, Erin L.; Vandever, Mark W.; Battaglin, William A.; Hladik, Michelle; Pierce, Clay L.

2015-01-01

Habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline in agricultural landscapes. Conservation efforts have attempted to restore wetlands lost through landscape modifications to reduce contaminant loads in surface waters and providing quality habitat to wildlife. The benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the bioaccumulation of pesticides in the tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The median concentration of atrazine in surface water was 0.2 μg/L. Reproductive abnormalities in leopard frogs have been observed in other studies at these concentrations. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought lethal to frogs. Complex mixtures of pesticides including up to 8 fungicides, some previously unreported in tissue, were detected with concentrations ranging from 0.08 to 1500 μg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and

The cost of wetland creation and restoration. Final report, [February 12, 1992--April 30, 1994]- Draft

Energy Technology Data Exchange (ETDEWEB)

King, D.; Costanza, R.

1994-07-11

This report examines the economics of wetland creation, restoration, and enhancement projects, especially as they are used within the context of mitigation for unavoidable wetland losses. Complete engineering-cost-accounting profiles of over 90 wetland projects were developed in collaboration with leading wetland restoration and creation practitioners around the country to develop a primary source database. Data on the costs of over 1,000 wetland projects were gathered from published sources and other available databases to develop a secondary source database. Cases in both databases were carefully analyzed and a set of baseline cost per acre estimates were developed for wetland creation, restoration, and enhancement. Observations of costs varied widely, ranging from $5 per acre to $1.5 million per acre. Differences in cost were related to the target wetland type, and to site-specific and project-specific factors that affected the preconstruction, construction, and post-construction tasks necessary to carry out each particular project. Project-specific and site-specific factors had a much larger effect on project costs than wetland type for non-agricultural projects. Costs of wetland creation and restoration were also shown to differ by region, but not by as much as expected, and in response to the regulatory context. The costs of wetland creation, restoration, and enhancement were also analyzed in a broader economic context through examination of the market for wetland mitigation services, and through the development of a framework for estimating compensation ratios-the number of acres of created, restored, or enhanced wetland required to compensate for an acre of lost natural wetland. The combination of per acre creation, restoration, and enhancement costs and the compensation ratio determine the overall mitigation costs associated with alternative mitigation strategies.

Remotely sensed MODIS wetland components for assessing the variability of methane emissions in Indian tropical/subtropical wetlands

Science.gov (United States)

Bansal, Sangeeta; Katyal, Deeksha; Saluja, Ridhi; Chakraborty, Monojit; Garg, J. K.

2018-02-01

Temperature and area fluctuations in wetlands greatly influence its various physico-chemical characteristics, nutrients dynamic, rates of biomass generation and decomposition, floral and faunal composition which in turn influence methane (CH4) emission rates. In view of this, the present study attempts to up-scale point CH4 flux from the wetlands of Uttar Pradesh (UP) by modifying two-factor empirical process based CH4 emission model for tropical wetlands by incorporating MODIS derived wetland components viz. wetland areal extent and corresponding temperature factors (Ft). This study further focuses on the utility of remotely sensed temperature response of CH4 emission in terms of Ft. Ft is generated using MODIS land surface temperature products and provides an important semi-empirical input for up-scaling CH4 emissions in wetlands. Results reveal that annual mean Ft values for UP wetlands vary from 0.69 (2010-2011) to 0.71(2011-2012). The total estimated area-wise CH4 emissions from the wetlands of UP varies from 66.47 Gg yr-1with wetland areal extent and Ft value of 2564.04 km2 and 0.69 respectively in 2010-2011 to 88.39 Gg yr-1with wetland areal extent and Ft value of 2720.16 km2 and 0.71 respectively in 2011-2012. Temporal analysis of estimated CH4 emissions showed that in monsoon season estimated CH4 emissions are more sensitive to wetland areal extent while in summer season sensitivity of estimated CH4 emissions is chiefly controlled by augmented methanogenic activities at high wetland surface temperatures.

Marginal and Random Intercepts Models for Longitudinal Binary Data with Examples from Criminology

Science.gov (United States)

Long, Jeffrey D.; Loeber, Rolf; Farrington, David P.

2009-01-01

Two models for the analysis of longitudinal binary data are discussed: the marginal model and the random intercepts model. In contrast to the linear mixed model (LMM), the two models for binary data are not subsumed under a single hierarchical model. The marginal model provides group-level information whereas the random intercepts model provides…

Hydrogeology and hydrology of the Punta Cabullones wetland area, Ponce, southern Puerto Rico, 2007-08

Science.gov (United States)

Rodríguez-Martínez, Jesús; Soler-López, Luis R.

2014-01-01

, groundwater and surface water are hydraulically coupled. Locally, surface-hypersaline water sinks into the aquifer, providing recharge and serving as a mechanism to redistribute salt throughout the study area. The evapotranspiration in the wetland subarea is estimated at about 11 million gallons per day (Mgal/d) that is equivalent to about 12,586 acre-feet per year. The balance of evapotranspiration, in excess of the about 0.5 Mgal/d of groundwater flow within the wetland, is supplied by saline to hypersaline surface water that may include seawater and meteoric water highly affected by evaporation with dissolved salts. In one of the extreme scenarios in which no groundwater is intercepted by pumpage at the Restaurada well field, the amount of saline to hypersaline water in the wetland consumed by evapotranspiration is about 10.5 Mgal/d. In the opposite extreme in which the entire regional groundwater flow is intercepted by pumpage in the Restaurada well field, the entire evapotranpiration requirement is met by saline to hypersaline water. Hydrologic, isotopic, and chemical data indicate that all of, or a large portion of, the historical groundwater flow to Punta Cabullones is being captured by the Puerto Rico Aqueducts and Sewer Authority pumpage at the Restaurada well field at a rate of about 2 Mgal/d. As a consequence, seawater intrusion into the aquifer at the Punta Cabullones area seems to be occurring, while the current pumpage at the Restaurada well field is sustained by storage depletion of the aquifer.

Inter-Annual Variability of Area-Scaled Gaseous Carbon Emissions from Wetland Soils in the Liaohe Delta, China.

Science.gov (United States)

Ye, Siyuan; Krauss, Ken W; Brix, Hans; Wei, Mengjie; Olsson, Linda; Yu, Xueyang; Ma, Xueying; Wang, Jin; Yuan, Hongming; Zhao, Guangming; Ding, Xigui; Moss, Rebecca F

2016-01-01

Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling.

Human wetland dependency and socio-economic evaluation of wetland functions through participatory approach in rural India

Directory of Open Access Journals (Sweden)

Malabika Biswas

2010-12-01

Full Text Available Wetlands are an important source of natural resources upon which rural economies depend. They have increasingly been valuable for their goods and services, and the intrinsic ecological value they provide to local populations, as well as people living outside the periphery of the wetlands. Stakeholders' participation is essential to the protection and preservation of wetlands because it plays a very important role economically as well as ecologically in the wetland system. The objective of this study was to determine whether gender, educational status, mouzas (which are constituents of a block according to the land reform of the West Bengal Government in India, and wetland functions have any influence on the annual income of the local community. Considering a floodplain wetland in rural India, the focus was extended to recognize the pattern of wetland functions according to the nature of people's involvement through cluster analysis of the male and female populations. Using the statistical software R-2.8.1, an ANOVA (analysis of variance table was constructed. Since the p value (significance level was lower than 0.05 for each case, it can be concluded that gender, educational status, mouzas, and wetland functions have a significant influence on annual income. However, S-PLUS-2000 was applied to obtain a complete scenario of the pattern of wetland functions, in terms of involvement of males and females, through cluster analysis. The main conclusion is that gender, educational status, mouzas, and wetland functions have significant impacts on annual income, while the pattern of occupation of the local community based on wetland functions is completely different for the male and female populations.

Climate Change and Intertidal Wetlands

Directory of Open Access Journals (Sweden)

Pauline M. Ross

2013-03-01

Full Text Available Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause—the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the “squeeze” experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

Climate change and intertidal wetlands.

Science.gov (United States)

Ross, Pauline M; Adam, Paul

2013-03-19

Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause-the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the "squeeze" experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

SLOSS or Not? Factoring Wetland Size Into Decisions for Wetland Conservation, Enhancement, Restoration, and Creation

Science.gov (United States)

Mitigation or replacement of several small impacted wetlands or sites with fewer large wetlands can occur deliberately through the application of functional assessment methods (e.g., Adamus 1997) or coincidentally as the result of market-based mechanisms for wetland mitigation ba...

Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region

Science.gov (United States)

Zhao, Na; Xu, Mengzhen; Li, Zhiwei; Wang, Zhaoyin; Zhou, Hanmi

2017-09-01

The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

Working group report on wetlands and wildlife

International Nuclear Information System (INIS)

Teels, B.

1991-01-01

The results and conclusions of a working group held to discuss the state of knowledge and knowledge gaps concerning climatic change impacts on wetlands and wildlife are presented. Prairie pothole wetlands are extremely productive and produce ca 50% of all ducks in North America. The most productive, and most vulnerable to climate change, are small potholes, often less than one acre in area. Changes in water regimes and land use will have more impact on wildlife than changes in temperature. There are gaps in knowledge relating to: boreal wetlands and their wildlife, and response to climate; wetland inventories that include the smallest wetlands; coordinated schemes for monitoring status and trends of wetlands and wildlife; and understanding of ecological relationships within wetlands and their wildlife communities. Recommendations include: coordinate and enhance existing databases to provide an integrated monitoring system; establish research programs to increase understanding of ecological relationships within wetland ecosystems; evaluate programs and policies that affect wetlands; and promote heightened public awareness of general values of wetlands

Remote sensing of wetlands applications and advances

CERN Document Server

Tiner, Ralph W; Klemas, Victor V

2015-01-01

Effectively Manage Wetland Resources Using the Best Available Remote Sensing Techniques Utilizing top scientists in the wetland classification and mapping field, Remote Sensing of Wetlands: Applications and Advances covers the rapidly changing landscape of wetlands and describes the latest advances in remote sensing that have taken place over the past 30 years for use in mapping wetlands. Factoring in the impact of climate change, as well as a growing demand on wetlands for agriculture, aquaculture, forestry, and development, this text considers the challenges that wetlands pose for remote sensing and provides a thorough introduction on the use of remotely sensed data for wetland detection. Taking advantage of the experiences of more than 50 contributing authors, the book describes a variety of techniques for mapping and classifying wetlands in a multitude of environments ranging from tropical to arctic wetlands including coral reefs and submerged aquatic vegetation. The authors discuss the advantages and di...

Candidate soil indicators for monitoring the progress of constructed wetlands toward a natural state: a statistical approach

Science.gov (United States)

Stapanian, Martin A.; Adams, Jean V.; Fennessy, M. Siobhan; Mack, John; Micacchion, Mick

2013-01-01

A persistent question among ecologists and environmental managers is whether constructed wetlands are structurally or functionally equivalent to naturally occurring wetlands. We examined 19 variables collected from 10 constructed and nine natural emergent wetlands in Ohio, USA. Our primary objective was to identify candidate indicators of wetland class (natural or constructed), based on measurements of soil properties and an index of vegetation integrity, that can be used to track the progress of constructed wetlands toward a natural state. The method of nearest shrunken centroids was used to find a subset of variables that would serve as the best classifiers of wetland class, and error rate was calculated using a five-fold cross-validation procedure. The shrunken differences of percent total organic carbon (% TOC) and percent dry weight of the soil exhibited the greatest distances from the overall centroid. Classification based on these two variables yielded a misclassification rate of 11% based on cross-validation. Our results indicate that % TOC and percent dry weight can be used as candidate indicators of the status of emergent, constructed wetlands in Ohio and for assessing the performance of mitigation. The method of nearest shrunken centroids has excellent potential for further applications in ecology.

Engineered wetlands : an innovative environmental solution

International Nuclear Information System (INIS)

Wallace, S.; Davis, B.M.

2008-01-01

Engineered wetlands are now considered as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and waters. Engineered wetlands incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems in order to enhance oxygen delivery to the wetland's aerobic micro-organisms. The wetlands typically emphasize specific characteristics of wetland ecosystems to improve treatment capacities. This article discussed an engineered wetlands installed at a set of pipeline terminals as well as at a former British Petroleum (BP) refinery. The pipeline terminal generated contact wastewater containing BTEX and ammonia, and a subsurface engineered wetland was built in 1998. To date, the 16,000 2 foot wetland has treated a flow-equalized input of approximately 1.5 m 3 per day of contaminants. At the refinery, a wetland treatment system was designed to treat 6000 m 3 of benzene, toluene, ethylbenzene and xylene (BTEX) and volatile organic compounds (VOCs). The treatment site consists of a golf course, river front trails, and a white water kayak course. A cascade aeration system was used for iron oxidation and air-stripping. A soil matrix biofilter was used for passive gas phase benzene removal, as well as for the removal of ferric hydroxide precipitates. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 1 fig

Ecosystem stress response : understanding effects on the benthic invertebrate community of Alberta oil-sands wetlands

International Nuclear Information System (INIS)

Wytrykush, C.M.; Ciborowski, J.J.H.

2003-01-01

The environmental stress response of invertebrates was examined using wetlands in the Alberta oil-sands region as a model. Wetlands in this region occur naturally or they have been affected by oil-sands mining process materials such as mine-tailings, or saline process water. These materials can be toxic to aquatic organisms due to their high concentrations of sulphate ions, ammonia, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids. Wetlands are classified as either young or mature, and as having low or high sediment organic content. This study examined food web dynamics and structure in wetlands using stable isotopes to determine the effects of stress on ecological communities. Primary and secondary production in the wetlands was measured along with invertebrate diversity in order to determine a relationship. The maximum trophic position was determined using stable carbon and nitrogen isotopes to indicate food chain length which is influenced by energetic constraints, ecosystem size and stressors. The study quantifies the dynamics of vital links between the responses to environmental pressures in aquatic systems and the effects on terrestrial ecosystems

The nitrogen abatement cost in wetlands

International Nuclear Information System (INIS)

Bystroem, Olof

1998-01-01

The costs of abating agricultural nitrogen pollution in wetlands are estimated. By linking costs for construction of wetlands to the denitrification capacity of wetlands, an abatement cost function can be formed. A construction-cost function and a denitrification function for wetlands is estimated empirically. This paper establishes a link between abatement costs and the nitrogen load on wetlands. Since abatement costs fluctuate with nitrogen load, ignoring this link results in incorrect estimates of abatement costs. The results demonstrate that wetlands have the capacity to provide low cost abatement of nitrogen compounds in runoff. For the Kattegatt region in Sweden, marginal abatement costs for wetlands are shown to be lower than costs of land use changing measures, such as extended land under fallow or cultivation of fuel woods, but higher than the marginal costs of reducing nitrogen fertilizer

40 CFR 257.9 - Wetlands.

Science.gov (United States)

2010-07-01

... not locate such units in wetlands, unless the owner or operator can make the following demonstrations... actions (e.g., restoration of existing degraded wetlands or creation of man-made wetlands); and (5) Sufficient information is available to make a reasonable determination with respect to these demonstrations...

Conservation of Mexican wetlands: role of the North American Wetlands Conservation Act

Science.gov (United States)

Wilson, M.H.; Ryan, D.A.

1997-01-01

Mexico's wetlands support a tremendous biological diversity and provide significant natural resource benefits to local communities. Because they are also critical stopover and wintering grounds for much of North America's waterfowl and other migratory birds, Mexico has become an important participant in continental efforts to conserve these resources through the North American Wetlands Conservation Act. Funding from the Act has supported partnerships in a number of Mexico's priority wetlands to conduct data analyses and dissemination, mapping, environmental education, wetland restoration, development of sustainable economic alternatives for local people, and reserve planning and management. These partnerships, with the close involvement of Mexico's Federal Government authority, the Instituto Nacional de Ecologia, have advanced conservation in a uniquely Mexican model that differs from that employed in the United States and Canada.

Design-a-wetland: a tool for generating and assessing constructed wetland designs for wastewater treatment

International Nuclear Information System (INIS)

Casaril, Carolina J.

2007-01-01

Full text: Full text: The hydrological cycle is a key cycle affected by current and predicted climate change. Wetlands are one of the key ecosystems within the hydrological cycle and could contribute significantly in facing the challenges of climate change, such as water shortage. The impact of wetlands on greenhouse gas emissions is much debated and, conversely, the impact of climate change on wetlands also raises many questions. There have been many attempts to harness and integrate the natural capacities of wetlands into constructed systems. These systems are especially designed for multiple purposes. They can be used for wastewater treatment and reuse, and have the potential to increase sustainability by changing land and water use practices. This project generates a 'Design-A-Wetland' prototype model, designed to facilitate decision-making in the creation of constructed wetlands. Constructed wetlands are specifically tailored to their end use; water treatment fish and fowl habitat, flood buffer zones, or sequestration of greenhouse gases. This project attempts to answer the following questions: Can a single integrated decision model be created for the design and assessment of artificial wetlands, provided either entry or exit standards are known and specified?; Can the elements of a system of interfacing the model with public consultation be specified?; The project identifies model schematics and lays the groundwork for modelling suited to the wide variety of inputs required for decision making

Stochastic modeling of wetland-groundwater systems

Science.gov (United States)

Bertassello, Leonardo Enrico; Rao, P. Suresh C.; Park, Jeryang; Jawitz, James W.; Botter, Gianluca

2018-02-01

Modeling and data analyses were used in this study to examine the temporal hydrological variability in geographically isolated wetlands (GIWs), as influenced by hydrologic connectivity to shallow groundwater, wetland bathymetry, and subject to stochastic hydro-climatic forcing. We examined the general case of GIWs coupled to shallow groundwater through exfiltration or infiltration across wetland bottom. We also examined limiting case with the wetland stage as the local expression of the shallow groundwater. We derive analytical expressions for the steady-state probability density functions (pdfs) for wetland water storage and stage using few, scaled, physically-based parameters. In addition, we analyze the hydrologic crossing time properties of wetland stage, and the dependence of the mean hydroperiod on climatic and wetland morphologic attributes. Our analyses show that it is crucial to account for shallow groundwater connectivity to fully understand the hydrologic dynamics in wetlands. The application of the model to two different case studies in Florida, jointly with a detailed sensitivity analysis, allowed us to identify the main drivers of hydrologic dynamics in GIWs under different climate and morphologic conditions.

Effects of the interception of litterfall by the understory on carbon cycling in eucalyptus plantations of South China.

Science.gov (United States)

Yang, Long; Wang, Jun; Huang, Yuhui; Hui, Dafeng; Wen, Meili

2014-01-01

For the purposes of forest restoration, carbon (C) fixation, and economic improvement, eucalyptus (Eucalyptus urophylla) has been widely planted in South China. The understory of eucalyptus plantations is often occupied by a dense community of the fern Dicranopteris dichotoma, which intercepts tree canopy leaf litter before it reaches the ground. To understand the effects of this interception of litterfall on C cycling in eucalyptus plantations, we quantified the mass of intercepted litter and the influences of litterfall interception on litter decomposition and soil respiration. The total mass of E. urophylla litterfall collected on the understory was similar to that collected by the traditional litter trap method. All of the eucalyptus litterfall is intercepted by the D. dichotoma canopy. Of the litterfall that was intercepted by D. dichotoma, 20-40% and 60-80% was intercepted by the top (50-100 cm) and bottom (0-50 cm) of the understory canopy, respectively. Intercepted litterfall decomposed faster at the bottom of understory canopy (at the base of the plants) than at the top, and decomposition was slower on the soil surface in the absence of understory than on any location in the understory canopy. Soil respiration was highest when both the understory and litter were present and was lowest when both the understory and litter were absent. These results indicate that litterfall interception changed carbon flow between aboveground and belowground through litter decomposition and soil respiration, which changed carbon cycling in eucalyptus plantations. The effects of the understory on litter decomposition and soil respiration should be considered in ecosystem carbon models.

Effects of the interception of litterfall by the understory on carbon cycling in eucalyptus plantations of South China.

Directory of Open Access Journals (Sweden)

Long Yang

Full Text Available For the purposes of forest restoration, carbon (C fixation, and economic improvement, eucalyptus (Eucalyptus urophylla has been widely planted in South China. The understory of eucalyptus plantations is often occupied by a dense community of the fern Dicranopteris dichotoma, which intercepts tree canopy leaf litter before it reaches the ground. To understand the effects of this interception of litterfall on C cycling in eucalyptus plantations, we quantified the mass of intercepted litter and the influences of litterfall interception on litter decomposition and soil respiration. The total mass of E. urophylla litterfall collected on the understory was similar to that collected by the traditional litter trap method. All of the eucalyptus litterfall is intercepted by the D. dichotoma canopy. Of the litterfall that was intercepted by D. dichotoma, 20-40% and 60-80% was intercepted by the top (50-100 cm and bottom (0-50 cm of the understory canopy, respectively. Intercepted litterfall decomposed faster at the bottom of understory canopy (at the base of the plants than at the top, and decomposition was slower on the soil surface in the absence of understory than on any location in the understory canopy. Soil respiration was highest when both the understory and litter were present and was lowest when both the understory and litter were absent. These results indicate that litterfall interception changed carbon flow between aboveground and belowground through litter decomposition and soil respiration, which changed carbon cycling in eucalyptus plantations. The effects of the understory on litter decomposition and soil respiration should be considered in ecosystem carbon models.

Quantification of the interception and initial retention of radioactive contaminants deposited on pasture grass by simulated rain

International Nuclear Information System (INIS)

Hoffman, F.O.; Thiessen, K.M.; Frank, M.L.; Blaylock, B.G.

1992-01-01

Simulated rain containing both soluble radionuclides and insoluble particles labeled with radionuclides was applied to pasture-type vegetation under conditions similar to those found during convective storms. The fraction of material in rain intercepted by vegetation and initially retained was determined for three sizes of insoluble polystyrene microspheres, soluble 7 Be 2+ and soluble 131 I as periodate or iodide, over a range of rainfall amounts of both moderate- and high-intensity precipitation. Values for the interception and initial retention by vegetation (interception fractions) for soluble forms of 131 I in simulated rain are much less than those for insoluble particles and the reactive cation 7 Be 2+ . The interception fraction for soluble 131 I is an inverse function of rain amount. The mass interception factor (the interception fraction normalized for biomass) of 131 I is almost solely dependent on the amount of rain. The 131 I vegetation-to-rain concentration ratio is relatively constant at approximately 2.6 ι kg -1 . For 7 Be 2+ and the insoluble particles, the interception fractions range from 0.1 to 0.6 with geometric means of approximately 0.3. For these materials there is a greater dependence on biomass than on rain amount; the geometric means of the mass interception factors for these substances range from 0.99 to 2.4 m 2 kg -1 . These results indicate that anionic 131 I is essentially removed with the water once the vegetation surface becomes saturated and that the 7 Be cation and the insoluble particles are adsorbed to or settle out on the plant surface. (Author)

Engineered wetlands : an innovative environmental solution

Energy Technology Data Exchange (ETDEWEB)

Wallace, S.; Davis, B.M. [Jacques Whitford NAWE, White Bear Lake, MN (United States)

2008-03-15

Engineered wetlands are now considered as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and waters. Engineered wetlands incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems in order to enhance oxygen delivery to the wetland's aerobic micro-organisms. The wetlands typically emphasize specific characteristics of wetland ecosystems to improve treatment capacities. This article discussed an engineered wetlands installed at a set of pipeline terminals as well as at a former British Petroleum (BP) refinery. The pipeline terminal generated contact wastewater containing BTEX and ammonia, and a subsurface engineered wetland was built in 1998. To date, the 16,000{sup 2} foot wetland has treated a flow-equalized input of approximately 1.5 m{sup 3} per day of contaminants. At the refinery, a wetland treatment system was designed to treat 6000 m{sup 3} of benzene, toluene, ethylbenzene and xylene (BTEX) and volatile organic compounds (VOCs). The treatment site consists of a golf course, river front trails, and a white water kayak course. A cascade aeration system was used for iron oxidation and air-stripping. A soil matrix biofilter was used for passive gas phase benzene removal, as well as for the removal of ferric hydroxide precipitates. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 1 fig.

Wetlands and infectious diseases

Directory of Open Access Journals (Sweden)

Robert H. Zimmerman

2001-01-01

Full Text Available There is a historical association between wetlands and infectious disease that has led to the modification of wetlands to prevent disease. At the same time there has been the development of water resources projects that increase the risk of disease. The demand for more water development projects and the increased pressure to make natural wetlands economically beneficial creates the need for an ecological approach to wetland management and health assessment. The environmental and health interactions are many. There is a need to take into account the landscape, spatial boundaries, and cross-boundary interactions in water development projects as well as alternative methods to provide water for human needs. The research challenges that need to be addressed are discussed.

Methane emissions from global wetlands: An assessment of the uncertainty associated with various wetland extent data sets

Science.gov (United States)

Zhang, Bowen; Tian, Hanqin; Lu, Chaoqun; Chen, Guangsheng; Pan, Shufen; Anderson, Christopher; Poulter, Benjamin

2017-09-01

A wide range of estimates on global wetland methane (CH4) fluxes has been reported during the recent two decades. This gives rise to urgent needs to clarify and identify the uncertainty sources, and conclude a reconciled estimate for global CH4 fluxes from wetlands. Most estimates by using bottom-up approach rely on wetland data sets, but these data sets show largely inconsistent in terms of both wetland extent and spatiotemporal distribution. A quantitative assessment of uncertainties associated with these discrepancies among wetland data sets has not been well investigated yet. By comparing the five widely used global wetland data sets (GISS, GLWD, Kaplan, GIEMS and SWAMPS-GLWD), it this study, we found large differences in the wetland extent, ranging from 5.3 to 10.2 million km2, as well as their spatial and temporal distributions among the five data sets. These discrepancies in wetland data sets resulted in large bias in model-estimated global wetland CH4 emissions as simulated by using the Dynamic Land Ecosystem Model (DLEM). The model simulations indicated that the mean global wetland CH4 emissions during 2000-2007 were 177.2 ± 49.7 Tg CH4 yr-1, based on the five different data sets. The tropical regions contributed the largest portion of estimated CH4 emissions from global wetlands, but also had the largest discrepancy. Among six continents, the largest uncertainty was found in South America. Thus, the improved estimates of wetland extent and CH4 emissions in the tropical regions and South America would be a critical step toward an accurate estimate of global CH4 emissions. This uncertainty analysis also reveals an important need for our scientific community to generate a global scale wetland data set with higher spatial resolution and shorter time interval, by integrating multiple sources of field and satellite data with modeling approaches, for cross-scale extrapolation.

Percent Wetland Cover (Future)

Data.gov (United States)

U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

VSWI Wetlands Advisory Layer

Data.gov (United States)

Vermont Center for Geographic Information — This dataset represents the DEC Wetlands Program's Advisory layer. This layer makes the most up-to-date, non-jurisdictional, wetlands mapping avaiable to the public...

Baseline ecological risk assessment and remediation alternatives for a hydrocarbon-contaminated estuarine wetland

International Nuclear Information System (INIS)

Vedagiri, U.

1993-01-01

Prior to a property transaction, the groundwater at an industrial refinery site in New Jersey was found to be contaminated with a variety of petroleum-based organic compounds. The highly built-up site included an on-site estuarine wetland and was located in a developed, industrialized area near ecologically important estuarine marshes. A preliminary ecological risk assessment was developed on the basis of available data on site contamination and ecological resources. The onsite wetland and its user fauna were identified as the sensitive receptors of concern and the primary contaminant pathways wee identified. The ecological significance of the contamination was assessed with regard to the onsite wetland and in the context of its position within the landscape and surrounding land uses. The wetland exhibited a combination of impact and vitality, i.e., there were clearly visible signs of contaminant impact as well as a relatively complex and abundant food web. Because of its position within the developed landscape, the onsite wetland appeared to function as a refugium for wildlife despite the level of disturbance. The feasibility of achieving regulatory compliance through natural remediation was also examined with respect to the findings of the risk assessment and the resultant conclusions are discussed

Pesticide concentrations in frog tissue and wetland habitats in a landscape dominated by agriculture.

Science.gov (United States)

Smalling, Kelly L; Reeves, Rebecca; Muths, Erin; Vandever, Mark; Battaglin, William A; Hladik, Michelle L; Pierce, Clay L

2015-01-01

Habitat loss and exposure to pesticides are likely primary factors contributing to amphibian decline in agricultural landscapes. Conservation efforts have attempted to restore wetlands lost through landscape modifications to reduce contaminant loads in surface waters and providing quality habitat to wildlife. The benefits of this increased wetland area, perhaps especially for amphibians, may be negated if habitat quality is insufficient to support persistent populations. We examined the presence of pesticides and nutrients in water and sediment as indicators of habitat quality and assessed the bioaccumulation of pesticides in the tissue of two native amphibian species Pseudacris maculata (chorus frogs) and Lithobates pipiens (leopard frogs) at six wetlands (3 restored and 3 reference) in Iowa, USA. Restored wetlands are positioned on the landscape to receive subsurface tile drainage water while reference wetlands receive water from overland run-off and shallow groundwater sources. Concentrations of the pesticides frequently detected in water and sediment samples were not different between wetland types. The median concentration of atrazine in surface water was 0.2 μg/L. Reproductive abnormalities in leopard frogs have been observed in other studies at these concentrations. Nutrient concentrations were higher in the restored wetlands but lower than concentrations thought lethal to frogs. Complex mixtures of pesticides including up to 8 fungicides, some previously unreported in tissue, were detected with concentrations ranging from 0.08 to 1,500 μg/kg wet weight. No significant differences in pesticide concentrations were observed between species, although concentrations tended to be higher in leopard frogs compared to chorus frogs, possibly because of differences in life histories. Our results provide information on habitat quality in restored wetlands that will assist state and federal agencies, landowners, and resource managers in identifying and implementing

Successful customer intercept interview recruitment outside small and midsize urban food retailers

Directory of Open Access Journals (Sweden)

Jennifer E. Pelletier

2016-10-01

Full Text Available Abstract Background Customer intercept interviews are increasingly used to characterize food purchases at retail food outlets and restaurants; however, methodological procedures, logistical issues and response rates using intercept methods are not well described in the food environment literature. The aims of this manuscript were to 1 describe the development and implementation of a customer intercept interview protocol in a large, NIH-funded study assessing food purchases in small and midsize food retailers in Minneapolis and St. Paul, Minnesota, 2 describe intercept interview response rates by store type and environmental factors (e.g., neighborhood socioeconomic status, day/time, weather, and 3 compare demographic characteristics (e.g., gender, race/ethnicity of participants versus non-participants. Methods After a pilot phase involving 28 stores, a total of 616 interviews were collected from customers exiting 128 stores in fall 2014. The number of eligible customers encountered per hour (a measure of store traffic, participants successfully recruited per hour, and response rates were calculated overall and by store type, neighborhood socio-economic status, day and time of data collection, and weather. Response rates by store type, neighborhood socio-economic status, time and day of data collection, and weather, and characteristics of participants and non-participants were compared using chi-square tests. Results The overall response rate was 35 %, with significantly higher response rates at corner/small grocery stores (47 % and dollar stores (46 % compared to food-gas marts (32 % and pharmacies (26 %, and for data collection between 4:00–6:00 pm on weekdays (40 % compared to weekends (32 %. The distribution of race/ethnicity, but not gender, differed between participants and non-participants (p < 0.01, with greater participation rates among those identified as Black versus White. Conclusions Customer intercept interviews can be

Lake Superior Coastal Wetland Fish Assemblages and ...

Science.gov (United States)

The role of the coastal margin and the watershed context in defining the ecology of even very large lakes is increasingly being recognized and examined. Coastal wetlands are both important contributors to the biodiversity and productivity of large lakes and important mediators of the lake-basin connection. We explored wetland-watershed connections and their relationship to wetland function and condition using data collected from 37 Lake Superior wetlands spanning a substantial geographic and geomorphic gradient. While none of these wetlands are particularly disturbed, there were nevertheless clear relationships between watershed landuse and wetland habitat and biota, and these varied consistently across wetland type categories that reflected the strength of connection to the watershed. For example, water clarity and vegetation structure complexity declined with decreasing percent natural land cover, and these effects were strongest in riverine wetlands (having generally large watersheds and tributary-dominated hydrology) and weakest in lagoon wetlands (having generally small watersheds and lake-dominate hydrology). Fish abundance and species richness both increased with decreasing percent natural land cover while species diversity decreased, and again the effect was strongest in riverine wetlands. Lagoonal wetlands, which lack any substantial tributary, consistently harbored the fewest species of fish and a composition different from the more watershed-lin

Diverse characteristics of wetlands restored under the Wetlands Reserve Program in the Southeastern United States

Science.gov (United States)

Diane De Steven; Joel M. Gramling

2012-01-01

The Wetlands Reserve Program (WRP) restores converted or degraded wetlands on private working lands; however, the nature and outcomes of such efforts are undocumented in the Southeastern U.S. Identification of wetland types is needed to assess the program's conservation benefits, because ecological functions differ with hydrogeomorphic (HGM) type. We reviewed...

The emergence of treatment wetlands

International Nuclear Information System (INIS)

Cole, S.

1998-01-01

Judging by the growing number of wetlands built for wastewater treatment around the world, this natural technology seems to have firmly established roots. After almost 30 years of use in wastewater treatment, constructed treatment wetlands now number over 500 in Europe and 600 in North America. Marsh-type surface flow systems are most common in North America, but subsurface flow wetlands, where wastewater flows beneath the surface of a gravel-rock bed, predominate in Europe. The inexpensive, low maintenance technology is in high demand in Central America, Eastern Europe, and Asia. New applications, from nitrate-contaminated ground water to effluent from high-intensity livestock operations, are also increasing. But in the United States, treatment-wetland technology has not yet gained national regulatory acceptance. Some states and EPA regions are eager to endorse them, but others are wary of this nontraditional method of treating wastewater. In part, this reluctance exists because the technology is not yet completely understood. Treatment wetlands also pose a potential threat to wildlife attracted to this new habitat -an ecosystem exposed to toxic compounds. New efforts are under way, however, to place the technology onto firmer scientific and regulatory ground. Long-term demonstration and monitoring field studies are currently probing the inner workings of wetlands and their water quality capabilities to provide better data on how to design more effective systems. A recent study of US policy and regulatory issues surrounding treatment wetlands has recommended that the federal government actively promote the technology and clear the regulatory roadblocks to enable wider use. Proponents argue that the net environmental benefits of constructed wetlands, such as restoring habitat and increasing wetlands inventory, should be considered. 8 refs., 6 photos

Multiple factors influence the vegetation composition of Southeast U.S. wetlands restored in the Wetlands Reserve Program

Science.gov (United States)

Diane De Steven; Joel M. Gramling

2013-01-01

Degradation of wetlands on agricultural lands contributes to the loss of local or regional vegetation diversity. The U.S. Department of Agriculture’s Wetlands Reserve Program (WRP) funds the restoration of degraded wetlands on private ‘working lands’, but these WRP projects have not been studied in the Southeast United States. Wetland hydrogeomorphic type influences...

Industry and forest wetlands: Cooperative research initiatives

International Nuclear Information System (INIS)

Shepard, J.P.; Lucier, A.A.; Haines, L.W.

1993-01-01

In 1989 the forest products industry responded to a challenge of the National Wetlands Policy Forum to initiate a cooperative research program on forest wetlands management organized through the National Council of the Paper Industry for Air and Stream Improvement (NCASI). The objective is to determine how forest landowners can manage wetlands for timber production while protecting other wetland functions such as flood storage, water purification, and food chain/wildlife habitat support. Studies supported by the NCASI in 9 states are summarized. Technical support on wetland regulatory issues to member companies is part of the research program. Since guidelines for recognizing wetlands for regulatory proposed have changed frequently, the NCASI has recommend an explicit link between wetland delineation and a classification system that considers difference among wetland types in vegetation, soils, hydrology, appearance, landscape position, and other factors. 16 refs

Global warming and prairie wetlands

International Nuclear Information System (INIS)

Poiani, K.A.; Johnson, W.C.

1991-01-01

In this article, the authors discuss current understanding and projections of global warming; review wetland vegetation dynamics to establish the strong relationship among climate, wetland hydrology, vegetation patterns and waterfowl habitat; discuss the potential effects of a greenhouse warming on these relationships; and illustrate the potential effects of climate change on wetland habitat by using a simulation model

Wetland soils, hydrology and geomorphology

Science.gov (United States)

C. Rhett Jackson; James A. Thompson; Randall K. Kolka

2014-01-01

The hydrology, soils, and watershed processes of a wetland all interact with vegetation and animals over time to create the dynamic physical template upon which a wetland's ecosystem is based (Fig. 2.1). With respect to many ecosystem processes, the physical factors defining a wetland environment at any particular time are often treated as independent variables,...

GlobWetland Africa: Implementing Sustainable Earth Observation Based Wetland Monitoring Capacity in Africa and Beyond

DEFF Research Database (Denmark)

Tottrup, Christian; Riffler, Michael; Wang, Tiejun

and decision support, [iii] receive a freely available, open, flexible and modifiable framework for easy establishment of new wetland observatories, for easy integration in existing observatory infrastructures and for easy adaptation to new requirements, e.g. changes in management processes.......Lack of data, appropriate information and challenges in human and institutional capacity put a serious constraint on effective monitoring and management of wetlands in Africa. Conventional data are often lacking in time or space, of poor quality or available at locations that are not necessarily...... for the conservation, wiseuse and effective management of wetlands in Africa and to provide African stakeholders with the necessary EO methods and tools to better fulfil their commitments and obligations towards the Ramsar Convention on Wetlands. The main objective of GlobWetland Africa (GW-A) is to provide the major...

National Wetland Condition Assessment 2011: A Collaborative Survey of the Nation's Wetlands

Science.gov (United States)

The National Wetland Condition Assessment 2011: A Collaborative Survey presents the results of an unprecedented assessment of the nation’s wetlands. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed to provide the publi...

Interception and translocation of radionuclides in major food crops for Koreans

International Nuclear Information System (INIS)

Choi, Y. H.; Lim, K. M.; Park, H. G.; Choi, H. J.; Lee, H. S.

2002-01-01

In order to investigate the direct plant contamination pathway of 54 Mn, 57 Co, 85 Sr, 103 Ru and 134 Cs in major food crops for Koreans, rice, soybean and radish plants at different growth stages were sprayed with radioactive solutions in a greenhouse. The interception factor and the translocation factor were quantified as the fraction of the total deposition that is initially retained on the aboveground plant surface and the fraction of the total initial plant activity that is contained in the edible part at harvest, respectively. In rice and radish, interception factors increased as plants grew old to harvest. In soybean, however, rapid defoliation in old plants made interception factors decrease with increasing age during the later part of the growth. There was little difference in the interception factor among radionuclides. Translocation factors decreased in the order of 134 Cs ≥> 57 Co > 54 Mn ≥ 85 Sr > 103 Ru in general and varied with radionuclides by factors of 6-4000, depending on application time and plant species. Translocation factors for rice seeds were the highest when radionuclides were applied at the active seed growth stage and those for soybean seeds were the highest following the application at the early pod-filling stage except for 103 Ru. For radish roots, translocation factors were on the whole the highest following the early- growth-stage application. The obtained data can be used for parameter values in food-chain dose assessment models especially for Koreans and many other Asian people

Interception and translocation of radionuclides in major food crops for Koreans

Energy Technology Data Exchange (ETDEWEB)

Choi, Y. H.; Lim, K. M.; Park, H. G.; Choi, H. J.; Lee, H. S. [KAERI, Daejon (Korea, Republic of)

2002-07-01

In order to investigate the direct plant contamination pathway of {sup 54}Mn, {sup 57}Co, {sup 85}Sr, {sup 103}Ru and {sup 134}Cs in major food crops for Koreans, rice, soybean and radish plants at different growth stages were sprayed with radioactive solutions in a greenhouse. The interception factor and the translocation factor were quantified as the fraction of the total deposition that is initially retained on the aboveground plant surface and the fraction of the total initial plant activity that is contained in the edible part at harvest, respectively. In rice and radish, interception factors increased as plants grew old to harvest. In soybean, however, rapid defoliation in old plants made interception factors decrease with increasing age during the later part of the growth. There was little difference in the interception factor among radionuclides. Translocation factors decreased in the order of {sup 134}Cs {>=}> {sup 57}Co > {sup 54}Mn {>=} {sup 85}Sr >{sup 103}Ru in general and varied with radionuclides by factors of 6-4000, depending on application time and plant species. Translocation factors for rice seeds were the highest when radionuclides were applied at the active seed growth stage and those for soybean seeds were the highest following the application at the early pod-filling stage except for {sup 103}Ru. For radish roots, translocation factors were on the whole the highest following the early- growth-stage application. The obtained data can be used for parameter values in food-chain dose assessment models especially for Koreans and many other Asian people.

Uncertainties in modelling CH4 emissions from northern wetlands in glacial climates: the role of vegetation parameters

Directory of Open Access Journals (Sweden)

J. van Huissteden

2011-10-01

Full Text Available Marine Isotope Stage 3 (MIS 3 interstadials are marked by a sharp increase in the atmospheric methane (CH4 concentration, as recorded in ice cores. Wetlands are assumed to be the major source of this CH4, although several other hypotheses have been advanced. Modelling of CH4 emissions is crucial to quantify CH4 sources for past climates. Vegetation effects are generally highly generalized in modelling past and present-day CH4 fluxes, but should not be neglected. Plants strongly affect the soil-atmosphere exchange of CH4 and the net primary production of the vegetation supplies organic matter as substrate for methanogens. For modelling past CH4 fluxes from northern wetlands, assumptions on vegetation are highly relevant since paleobotanical data indicate large differences in Last Glacial (LG wetland vegetation composition as compared to modern wetland vegetation. Besides more cold-adapted vegetation, Sphagnum mosses appear to be much less dominant during large parts of the LG than at present, which particularly affects CH4 oxidation and transport. To evaluate the effect of vegetation parameters, we used the PEATLAND-VU wetland CO2/CH4 model to simulate emissions from wetlands in continental Europe during LG and modern climates. We tested the effect of parameters influencing oxidation during plant transport (fox, vegetation net primary production (NPP, parameter symbol Pmax, plant transport rate (Vtransp, maximum rooting depth (Zroot and root exudation rate (fex. Our model results show that modelled CH4 fluxes are sensitive to fox and Zroot in particular. The effects of Pmax, Vtransp and fex are of lesser relevance. Interactions with water table modelling are significant for Vtransp. We conducted experiments with different wetland vegetation types for Marine Isotope Stage 3 (MIS 3 stadial and interstadial climates and the present-day climate, by coupling PEATLAND-VU to high resolution climate model simulations for Europe. Experiments assuming

Uncertainties in modelling CH4 emissions from northern wetlands in glacial climates: the role of vegetation parameters

Science.gov (United States)

Berrittella, C.; van Huissteden, J.

2011-10-01

Marine Isotope Stage 3 (MIS 3) interstadials are marked by a sharp increase in the atmospheric methane (CH4) concentration, as recorded in ice cores. Wetlands are assumed to be the major source of this CH4, although several other hypotheses have been advanced. Modelling of CH4 emissions is crucial to quantify CH4 sources for past climates. Vegetation effects are generally highly generalized in modelling past and present-day CH4 fluxes, but should not be neglected. Plants strongly affect the soil-atmosphere exchange of CH4 and the net primary production of the vegetation supplies organic matter as substrate for methanogens. For modelling past CH4 fluxes from northern wetlands, assumptions on vegetation are highly relevant since paleobotanical data indicate large differences in Last Glacial (LG) wetland vegetation composition as compared to modern wetland vegetation. Besides more cold-adapted vegetation, Sphagnum mosses appear to be much less dominant during large parts of the LG than at present, which particularly affects CH4 oxidation and transport. To evaluate the effect of vegetation parameters, we used the PEATLAND-VU wetland CO2/CH4 model to simulate emissions from wetlands in continental Europe during LG and modern climates. We tested the effect of parameters influencing oxidation during plant transport (fox), vegetation net primary production (NPP, parameter symbol Pmax), plant transport rate (Vtransp), maximum rooting depth (Zroot) and root exudation rate (fex). Our model results show that modelled CH4 fluxes are sensitive to fox and Zroot in particular. The effects of Pmax, Vtransp and fex are of lesser relevance. Interactions with water table modelling are significant for Vtransp. We conducted experiments with different wetland vegetation types for Marine Isotope Stage 3 (MIS 3) stadial and interstadial climates and the present-day climate, by coupling PEATLAND-VU to high resolution climate model simulations for Europe. Experiments assuming dominance of

Applicability Assessment of Uavsar Data in Wetland Monitoring: a Case Study of Louisiana Wetland

Science.gov (United States)

Zhao, J.; Niu, Y.; Lu, Z.; Yang, J.; Li, P.; Liu, W.

2018-04-01

Wetlands are highly productive and support a wide variety of ecosystem goods and services. Monitoring wetland is essential and potential. Because of the repeat-pass nature of satellite orbit and airborne, time-series of remote sensing data can be obtained to monitor wetland. UAVSAR is a NASA L-band synthetic aperture radar (SAR) sensor compact pod-mounted polarimetric instrument for interferometric repeat-track observations. Moreover, UAVSAR images can accurately map crustal deformations associated with natural hazards, such as volcanoes and earthquakes. And its polarization agility facilitates terrain and land-use classification and change detection. In this paper, the multi-temporal UAVSAR data are applied for monitoring the wetland change. Using the multi-temporal polarimetric SAR (PolSAR) data, the change detection maps are obtained by unsupervised and supervised method. And the coherence is extracted from the interfometric SAR (InSAR) data to verify the accuracy of change detection map. The experimental results show that the multi-temporal UAVSAR data is fit for wetland monitor.

Calculation of intercepted runoff depth based on stormwater quality and environmental capacity of receiving waters for initial stormwater pollution management.

Science.gov (United States)

Peng, Hai-Qin; Liu, Yan; Gao, Xue-Long; Wang, Hong-Wu; Chen, Yi; Cai, Hui-Yi

2017-11-01

While point source pollutions have gradually been controlled in recent years, the non-point source pollution problem has become increasingly prominent. The receiving waters are frequently polluted by the initial stormwater from the separate stormwater system and the wastewater from sewage pipes through stormwater pipes. Consequently, calculating the intercepted runoff depth has become a problem that must be resolved immediately for initial stormwater pollution management. The accurate calculation of intercepted runoff depth provides a solid foundation for selecting the appropriate size of intercepting facilities in drainage and interception projects. This study establishes a separate stormwater system for the Yishan Building watershed of Fuzhou City using the InfoWorks Integrated Catchment Management (InfoWorks ICM), which can predict the stormwater flow velocity and the flow of discharge outlet after each rainfall. The intercepted runoff depth is calculated from the stormwater quality and environmental capacity of the receiving waters. The average intercepted runoff depth from six rainfall events is calculated as 4.1 mm based on stormwater quality. The average intercepted runoff depth from six rainfall events is calculated as 4.4 mm based on the environmental capacity of the receiving waters. The intercepted runoff depth differs when calculated from various aspects. The selection of the intercepted runoff depth depends on the goal of water quality control, the self-purification capacity of the water bodies, and other factors of the region.

Wetland Mitigation Monitoring at the Fernald Preserve - 13200

Energy Technology Data Exchange (ETDEWEB)

Powell, Jane [Fernald Preserve Site Manager, DOE Office of Legacy Management, Harrison, Ohio (United States); Bien, Stephanie; Decker, Ashlee; Homer, John [Environmental Scientist, S.M. Stoller Corporation, Harrison, Ohio (United States); Wulker, Brian [Intern, S.M. Stoller Corporation, Harrison, Ohio (United States)

2013-07-01

The U.S. Department of Energy is responsible for 7.2 hectares (17.8 acres) of mitigation wetland at the Fernald Preserve, Ohio. Remedial activities affected the wetlands, and mitigation plans were incorporated into site-wide ecological restoration planning. In 2008, the Fernald Natural Resource Trustees developed a comprehensive wetland mitigation monitoring approach to evaluate whether compensatory mitigation requirements have been met. The Fernald Preserve Wetland Mitigation Monitoring Plan provided a guideline for wetland evaluations. The Ohio Environmental Protection Agency (Ohio EPA) wetland mitigation monitoring protocols were adopted as the means for compensatory wetland evaluation. Design, hydrologic regime, vegetation, wildlife, and biogeochemistry were evaluated from 2009 to 2011. Evaluations showed mixed results when compared to the Ohio EPA performance standards. Results of vegetation monitoring varied, with the best results occurring in wetlands adjacent to forested areas. Amphibians, particularly ambystomatid salamanders, were observed in two areas adjacent to forested areas. Not all wetlands met vegetation performance standards and amphibian biodiversity metrics. However, Fernald mitigation wetlands showed substantially higher ratings compared to other mitigated wetlands in Ohio. Also, soil sampling results remain consistent with other Ohio mitigated wetlands. The performance standards are not intended to be 'pass/fail' criteria; rather, they are reference points for use in making decisions regarding future monitoring and maintenance. The Trustees approved the Fernald Preserve Wetland Mitigation Monitoring Report with the provision that long-term monitoring of the wetlands continues at the Fernald Preserve. (authors)

Wetland Mitigation Monitoring at the Fernald Preserve - 13200

International Nuclear Information System (INIS)

Powell, Jane; Bien, Stephanie; Decker, Ashlee; Homer, John; Wulker, Brian

2013-01-01

The U.S. Department of Energy is responsible for 7.2 hectares (17.8 acres) of mitigation wetland at the Fernald Preserve, Ohio. Remedial activities affected the wetlands, and mitigation plans were incorporated into site-wide ecological restoration planning. In 2008, the Fernald Natural Resource Trustees developed a comprehensive wetland mitigation monitoring approach to evaluate whether compensatory mitigation requirements have been met. The Fernald Preserve Wetland Mitigation Monitoring Plan provided a guideline for wetland evaluations. The Ohio Environmental Protection Agency (Ohio EPA) wetland mitigation monitoring protocols were adopted as the means for compensatory wetland evaluation. Design, hydrologic regime, vegetation, wildlife, and biogeochemistry were evaluated from 2009 to 2011. Evaluations showed mixed results when compared to the Ohio EPA performance standards. Results of vegetation monitoring varied, with the best results occurring in wetlands adjacent to forested areas. Amphibians, particularly ambystomatid salamanders, were observed in two areas adjacent to forested areas. Not all wetlands met vegetation performance standards and amphibian biodiversity metrics. However, Fernald mitigation wetlands showed substantially higher ratings compared to other mitigated wetlands in Ohio. Also, soil sampling results remain consistent with other Ohio mitigated wetlands. The performance standards are not intended to be 'pass/fail' criteria; rather, they are reference points for use in making decisions regarding future monitoring and maintenance. The Trustees approved the Fernald Preserve Wetland Mitigation Monitoring Report with the provision that long-term monitoring of the wetlands continues at the Fernald Preserve. (authors)

Why are wetlands important?

Science.gov (United States)

Wetlands are among the most productive ecosystems in the world, comparable to rain forests and coral reefs. An immense variety of species of microbes, plants, insects, amphibians, reptiles, birds, fish, and mammals can be part of a wetland ecosystem.

Spectral data based vegetation indices to characterise crop growth parameters and radiation interception in brassica

International Nuclear Information System (INIS)

Kar, G.; Chakravarty, N.V.K.

2001-01-01

Four spectral data based vegetation indices viz., infra-red/red (IR/R) ratio, normalized difference (N.D.), greenness index (GNI) and brightness index (BNI) were derived to characterise leaf area index, above ground biomass production and intercepted photosynthetically active radiation in Brassica oilseed crop. It was found from correlation study among different spectral indices, plant growth parameters and radiation interception that there was strong relationship between infrared/red and normalized difference with green area index for all the three Brassica cultivars whereas these spectral were not significantly correlated with above ground biomass. On the other hand, the brightness and greenness indices were closely correlated with above groundry biomass as compared to infrared/red ratio and normalized difference. All the four spectral indices were correlated with intercepted photosynthetically active radiation (IP AR). The best fit equations relating them were derived, which can be incorporated in the algorithms of crop growth simulation model to estimate plant growth parameters and radiation interception using spectral indices

Comparison of Four Nitrate Removal Kinetic Models in Two Distinct Wetland Restoration Mesocosm Systems

Directory of Open Access Journals (Sweden)

Tiffany L. Messer

2017-07-01

Full Text Available The objective of the study was to determine the kinetic model that best fit observed nitrate removal rates at the mesocosm scale in order to determine ideal loading rates for two future wetland restorations slated to receive pulse flow agricultural drainage water. Four nitrate removal models were investigated: zero order, first order decay, efficiency loss, and Monod. Wetland mesocosms were constructed using the primary soil type (in triplicate at each of the future wetland restoration sites. Eighteen mesocosm experiments were conducted over two years across seasons. Simulated drainage water was loaded into wetlands as batches, with target nitrate-N levels typically observed in agricultural drainage water (between 2.5 and 10 mg L−1. Nitrate-N removal observed during the experiments provided the basis for calibration and validation of the models. When the predictive strength of each of the four models was assessed, results indicated that the efficiency loss and first order decay models provided the strongest agreement between predicted and measured NO3-N removal rates, and the fit between the two models were comparable. Since the predictive power of these two models were similar, the less complicated first order decay model appeared to be the best choice in predicting appropriate loading rates for the future full-scale wetland restorations.

Simulating the Effects of Sea Level Rise on the Resilience and Migration of Tidal Wetlands along the Hudson River.

Directory of Open Access Journals (Sweden)

Nava M Tabak

Full Text Available Sea Level Rise (SLR caused by climate change is impacting coastal wetlands around the globe. Due to their distinctive biophysical characteristics and unique plant communities, freshwater tidal wetlands are expected to exhibit a different response to SLR as compared with the better studied salt marshes. In this study we employed the Sea Level Affecting Marshes Model (SLAMM, which simulates regional- or local-scale changes in tidal wetland habitats in response to SLR, and adapted it for application in a freshwater-dominated tidal river system, the Hudson River Estuary. Using regionally-specific estimated ranges of SLR and accretion rates, we produced simulations for a spectrum of possible future wetland distributions and quantified the projected wetland resilience, migration or loss in the HRE through the end of the 21st century. Projections of total wetland extent and migration were more strongly determined by the rate of SLR than the rate of accretion. Surprisingly, an increase in net tidal wetland area was projected under all scenarios, with newly-formed tidal wetlands expected to comprise at least 33% of the HRE's wetland area by year 2100. Model simulations with high rates of SLR and/or low rates of accretion resulted in broad shifts in wetland composition with widespread conversion of high marsh habitat to low marsh, tidal flat or permanent inundation. Wetland expansion and resilience were not equally distributed through the estuary, with just three of 48 primary wetland areas encompassing >50% of projected new wetland by the year 2100. Our results open an avenue for improving predictive models of the response of freshwater tidal wetlands to sea level rise, and broadly inform the planning of conservation measures of this critical resource in the Hudson River Estuary.

Are isolated wetlands groundwater recharge hotspots?

Science.gov (United States)

Webb, A.; Wicks, C. M.; Brantley, S. T.; Golladay, S. W.

2017-12-01

Geographically isolated wetlands (GIWs) are a common landscape feature in the mantled karst terrain of the Dougherty Plain physiographic district in Southwestern Georgia. These wetlands support a high diversity of obligate/facultative wetland flora and fauna, including several endangered species. While the ecological value of these wetlands is well documented, the hydrologic effects of GIWs on larger watershed processes, such as water storage and aquifer recharge, are less clear. Our project seeks to understand the spatial and temporal variation in recharge across GIWs on this mantled karst landscape. In particular, our first step is to understand the role of isolated wetlands (presumed sinkholes) in delivering water into the underlying aquifer. Our hypothesis is that many GIWs are actually water-filled sinkholes and are locations of focused recharge feeding either the underlying upper Floridan aquifer or the nearby creeks. If we are correct, then these sinkholes should exhibit "drains", i.e., conduits into the limestone bedrock. Thus, the purposes of our initial study are to image the soil-limestone contact (the buried epikarstic surface) and determine if possible subsurface drains exist. Our field work was conducted at the Joseph W Jones Ecological Research Center. During the dry season, we conducted ground penetrating radar (GPR) surveys as grids and lines across a large wetland and across a field with no surface expression of a wetland or sinkhole. We used GPR (200 MHz antenna) with 1-m spacing between antenna and a ping rate of 1 ping per 40 centimeters. Our results show that the epikarstic surface exhibits a drain underneath the wetland (sinkhole) and that no similar feature was seen under the field, even though the survey grid and spacing were similar. As our project progresses, we will survey additional wetlands occurring across varying soil types to determine the spatial distribution between surface wetlands and subsurface drains.

Description of the Wetlands Research Programme

CSIR Research Space (South Africa)

Walmsley, RD

1988-01-01

Full Text Available This report presents a rationale to the development of a multidisciplinary South African Wetland Research Programme. A definition of what is meant by the term wetland is given along with a general description of what types of wetland occur in South...

Urban wetlands: restoration or designed rehabilitation?

Directory of Open Access Journals (Sweden)

Beth Ravit

2017-05-01

Full Text Available The continuing loss of urban wetlands due to an expanding human population and urban development pressures makes restoration or creation of urban wetlands a high priority. However, urban wetland restorations are particularly challenging due to altered hydrologic patterns, a high proportion of impervious surface and stormwater runoff, degraded urban soils, historic contamination, and competitive pressure from non-native species. Urban wetland projects must also consider human-desired socio-economic benefits. We argue that using current wetland restoration approaches and existing regulatory “success” criteria, such as meeting restoration targets for vegetation structure based on reference sites in non-urban locations, will result in “failed” urban restorations. Using three wetland Case Studies in highly urbanized locations, we describe geophysical tools, stormwater management methods, and design approaches useful in addressing urban challenges and in supporting “successful” urban rehabilitation outcomes. We suggest that in human-dominated landscapes, the current paradigm of “restoration” to a previous state must shift to a paradigm of “rehabilitation”, which prioritizes wetland functions and values rather than vegetation structure in order to provide increased ecological benefits and much needed urban open space amenities.

The study of Phosphorus distribution at Putrajaya Wetland

Science.gov (United States)

Mubin Zahari, Nazirul; Malek, Nur Farzana Fasiha Abdul; Fai, Chow Ming; Humaira Haron, Siti; Hafiz Zawawi, Mohd; Nazmi Ismail, Iszmir; Mohamad, Daud; Syamsir, Agusril; Sidek, Lariyah Mohd; Zakwan Ramli, Mohd; Ismail, Norfariza; Zubir Sapian, Ahmad; Noordin, Normaliza; Rahaman, Nurliyana Abdul; Muhamad, Yahzam; Mat Saman, Jarina

2018-04-01

This study is concerning phosphorus distribution in Putrajaya Wetland. Phosphorus is one of the important component in nutrients for living things be it aquatic or non – aquatic organisms. Total phosphorus (TP) results will give some information on the trophic status of surface water in water bodies. The focus of this study is to determine the total phosphorus concentration in Putrajaya Wetland which is in the inlet of the wetland then outlet of the wetland (Central Wetland Lake). The water sample is taken from Putrajaya Wetland and the test was conducted in the laboratory. The result from this study shows the results for total phosphorus according to month, sampling station and cells. Lowest total phosphate at the Central Wetland compare with all the wetland arms cells.

Development of an indicator to monitor mediterranean wetlands.

Science.gov (United States)

Sanchez, Antonio; Abdul Malak, Dania; Guelmami, Anis; Perennou, Christian

2015-01-01

Wetlands are sensitive ecosystems that are increasingly subjected to threats from anthropogenic factors. In the last decades, coastal Mediterranean wetlands have been suffering considerable pressures from land use change, intensification of urban growth, increasing tourism infrastructure and intensification of agricultural practices. Remote sensing (RS) and Geographic Information Systems (GIS) techniques are efficient tools that can support monitoring Mediterranean coastal wetlands on large scales and over long periods of time. The study aims at developing a wetland indicator to support monitoring Mediterranean coastal wetlands using these techniques. The indicator makes use of multi-temporal Landsat images, land use reference layers, a 50m numerical model of the territory (NMT) and Corine Land Cover (CLC) for the identification and mapping of wetlands. The approach combines supervised image classification techniques making use of vegetation indices and decision tree analysis to identify the surface covered by wetlands at a given date. A validation process is put in place to compare outcomes with existing local wetland inventories to check the results reliability. The indicator´s results demonstrate an improvement in the level of precision of change detection methods achieved by traditional tools providing reliability up to 95% in main wetland areas. The results confirm that the use of RS techniques improves the precision of wetland detection compared to the use of CLC for wetland monitoring and stress the strong relation between the level of wetland detection and the nature of the wetland areas and the monitoring scale considered.

Recreating wetland ecosystems in an oil sands disturbed landscape : Suncor consolidated-tailings demonstration wetlands

Energy Technology Data Exchange (ETDEWEB)

Daly, C. [Suncor Energy, Fort McMurray, AB (Canada). Aquatic Reclamation Research; Tedder, W.; Marlowe, P. [Golder Associates Ltd., Calgary, AB (Canada). Oil Sands Div.

2009-10-01

Open pit oil sands mining involves the disturbance of thin overburden covers of Boreal forest lands that must be returned to equivalent land capability after mining activities have ceased. Before mining starts, any wetlands are drained, timber is harvested, and peat, topsoils and subsoils are stockpiled for later use. This article discussed wetland reclamation activities conducted by Suncor Energy at its open pit mining operations. Research facilities were constructed in order to determine if wetlands constructed with consolidated tailings (CT) and pond effluent water (PEW) were able to support a sustainable vegetation community. Thirty-three cat-tail plots were established at the facility as well as unplanted plots in order to determine how quickly natural establishment occurred. Shoreline plug transplants and transplants from a natural saline lake were also introduced. Within 5 years, over 23 plant species had naturally colonized the CT wetlands. However, diversity was lower in CT and PEW-constructed wetlands. It was concluded that the application of a native peat-mineral mix soil may help to increase plant diversity. 20 refs., 5 figs.

Wetlands in changed landscapes: the influence of habitat transformation on the physico-chemistry of temporary depression wetlands.

Science.gov (United States)

Bird, Matthew S; Day, Jenny A

2014-01-01

Temporary wetlands dominate the wet season landscape of temperate, semi-arid and arid regions, yet, other than their direct loss to development and agriculture, little information exists on how remaining wetlands have been altered by anthropogenic conversion of surrounding landscapes. This study investigates relationships between the extent and type of habitat transformation around temporary wetlands and their water column physico-chemical characteristics. A set of 90 isolated depression wetlands (seasonally inundated) occurring on coastal plains of the south-western Cape mediterranean-climate region of South Africa was sampled during the winter/spring wet season of 2007. Wetlands were sampled across habitat transformation gradients according to the areal cover of agriculture, urban development and alien invasive vegetation within 100 and 500 m radii of each wetland edge. We hypothesized that the principal drivers of physico-chemical conditions in these wetlands (e.g. soil properties, basin morphology) are altered by habitat transformation. Multivariate multiple regression analyses (distance-based Redundancy Analysis) indicated significant associations between wetland physico-chemistry and habitat transformation (overall transformation within 100 and 500 m, alien vegetation cover within 100 and 500 m, urban cover within 100 m); although for significant regressions the amount of variation explained was very low (range: ∼2 to ∼5.5%), relative to that explained by purely spatio-temporal factors (range: ∼35.5 to ∼43%). The nature of the relationships between each type of transformation in the landscape and individual physico-chemical variables in wetlands were further explored with univariate multiple regressions. Results suggest that conservation of relatively narrow (∼100 m) buffer strips around temporary wetlands is likely to be effective in the maintenance of natural conditions in terms of physico-chemical water quality.

Wetlands in changed landscapes: the influence of habitat transformation on the physico-chemistry of temporary depression wetlands.

Directory of Open Access Journals (Sweden)

Matthew S Bird

Full Text Available Temporary wetlands dominate the wet season landscape of temperate, semi-arid and arid regions, yet, other than their direct loss to development and agriculture, little information exists on how remaining wetlands have been altered by anthropogenic conversion of surrounding landscapes. This study investigates relationships between the extent and type of habitat transformation around temporary wetlands and their water column physico-chemical characteristics. A set of 90 isolated depression wetlands (seasonally inundated occurring on coastal plains of the south-western Cape mediterranean-climate region of South Africa was sampled during the winter/spring wet season of 2007. Wetlands were sampled across habitat transformation gradients according to the areal cover of agriculture, urban development and alien invasive vegetation within 100 and 500 m radii of each wetland edge. We hypothesized that the principal drivers of physico-chemical conditions in these wetlands (e.g. soil properties, basin morphology are altered by habitat transformation. Multivariate multiple regression analyses (distance-based Redundancy Analysis indicated significant associations between wetland physico-chemistry and habitat transformation (overall transformation within 100 and 500 m, alien vegetation cover within 100 and 500 m, urban cover within 100 m; although for significant regressions the amount of variation explained was very low (range: ∼2 to ∼5.5%, relative to that explained by purely spatio-temporal factors (range: ∼35.5 to ∼43%. The nature of the relationships between each type of transformation in the landscape and individual physico-chemical variables in wetlands were further explored with univariate multiple regressions. Results suggest that conservation of relatively narrow (∼100 m buffer strips around temporary wetlands is likely to be effective in the maintenance of natural conditions in terms of physico-chemical water quality.

Wetlands - an underestimated economic resource?

International Nuclear Information System (INIS)

Gren, I.M.; Soederqvist, T.

1996-01-01

Wetlands are producing several valuable resources like fish, potential for recreation, water cleaning etc. These resources, and methods for assigning an economic value to them, are discussed in this article. Swedish and foreign empirical studies of the economic value of wetlands are reviewed. This review shows that socioeconomic estimates of the value of wetlands risk to be misleading if the direct and indirect values are not properly accounted for. 37 refs

Feasibility of using geothermal effluents for waterfowl wetlands

Energy Technology Data Exchange (ETDEWEB)

None

1981-09-01

This project was conducted to evaluate the feasibility of using geothermal effluents for developing and maintaining waterfowl wetlands. Information in the document pertains to a seven State area the West where geothermal resources have development potential. Information is included on physiochemical characteristics of geothermal effluents; known effects of constituents in the water on a wetland ecosystem and water quality criteria for maintaining a viable wetland; potential of sites for wetland development and disposal of effluent water from geothermal facilities; methods of disposal of effluents, including advantages of each method and associated costs; legal and institutional constraints which could affect geothermal wetland development; potential problems associated with depletion of geothermal resources and subsidence of wetland areas; potential interference (adverse and beneficial) of wetlands with ground water; special considerations for wetlands requirements including size, flows, and potential water usage; and final conclusions and recommendations for suitable sites for developing demonstration wetlands.

Eye movements in interception with delayed visual feedback.

Science.gov (United States)

Cámara, Clara; de la Malla, Cristina; López-Moliner, Joan; Brenner, Eli

2018-04-19

The increased reliance on electronic devices such as smartphones in our everyday life exposes us to various delays between our actions and their consequences. Whereas it is known that people can adapt to such delays, the mechanisms underlying such adaptation remain unclear. To better understand these mechanisms, the current study explored the role of eye movements in interception with delayed visual feedback. In two experiments, eye movements were recorded as participants tried to intercept a moving target with their unseen finger while receiving delayed visual feedback about their own movement. In Experiment 1, the target randomly moved in one of two different directions at one of two different velocities. The delay between the participant's finger movement and movement of the cursor that provided feedback about the finger movements was gradually increased. Despite the delay, participants followed the target with their gaze. They were quite successful at hitting the target with the cursor. Thus, they moved their finger to a position that was ahead of where they were looking. Removing the feedback showed that participants had adapted to the delay. In Experiment 2, the target always moved in the same direction and at the same velocity, while the cursor's delay varied across trials. Participants still always directed their gaze at the target. They adjusted their movement to the delay on each trial, often succeeding to intercept the target with the cursor. Since their gaze was always directed at the target, and they could not know the delay until the cursor started moving, participants must have been using peripheral vision of the delayed cursor to guide it to the target. Thus, people deal with delays by directing their gaze at the target and using both experience from previous trials (Experiment 1) and peripheral visual information (Experiment 2) to guide their finger in a way that will make the cursor hit the target.

Fingerponds: managing nutrients and primary productivity for enhanced fish production in Lake Victoria's wetlands, Uganda

NARCIS (Netherlands)

Kaggwa, R.S.

2006-01-01

Wetlands are of great ecological importance and have been described as the most important zone for freshwater fisheries. They can be exploited for agriculture and aquaculture through the integration of these activities. In Sub-Saharan Africa, emphasis has been put on agriculture and this has 1ed to

Evaporation of impact water droplets in interception processes: Historical precedence of the hypothesis and a brief literature overview

Science.gov (United States)

Dunkerley, David L.

2009-10-01

SummaryIntra-storm evaporation depths exceed post-storm evaporation depths in the interception of rainfall on plant canopies. An important fraction of the intra-storm evaporation may involve the small impact (or splash) droplets produced when raindrops, and perhaps gravity drops (drips released from plant parts), collide with wet plant surfaces. This idea has been presented as a new conception by Murakami [Murakami, S., 2006. A proposal for a new forest canopy interception mechanism: splash droplet evaporation. Journal of Hydrology 319, 72-82; Murakami, S., 2007a. Application of three canopy interception models to a young stand of Japanese cypress and interpretation in terms of interception mechanism. Journal of Hydrology 342, 305-319; Murakami, S., 2007b. A follow-up for the splash droplet evaporation hypothesis of canopy interception and remaining problems: why is humidity unsaturated during rainfall? In: Proceedings of the 20th Annual Conference. Japan Society of Hydrology and Water Resources (in Japanese). ] but was in fact advanced by Dunin [Dunin, F.X., O'Loughlin, E.M., Reyenga, W., 1988. Interception loss from eucalypt forest: lysimeter determination of hourly rates for long term evaluation. Hydrological Processes 2, 315-329] more than 20 years ago. In addition, Dunin et al. considered that canopy ventilation might be enhanced in intense rain. This note draws attention to the historical precedence of the work of Dunin et al. and also presents a short review of literature on impact droplet production, highlighting areas where data are still required for the full exploration of the role of droplet evaporation in canopy interception. Droplet production needs to be properly parameterised and included in models of interception processes and landsurface-atmosphere interactions.

7 CFR 1410.10 - Restoration of wetlands.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Restoration of wetlands. 1410.10 Section 1410.10... Restoration of wetlands. (a) An owner or operator who entered into a CRP contract on land that is suitable for restoration to wetlands or that was restored to wetlands while under such contract, may, if approved by CCC...

Variation of interception loss with different plant species at the ...

African Journals Online (AJOL)

USER

Department of Water Resources Management and Agrometeorology, University of ... Interception studies of six plants groups were carried out at the campus of University of Agriculture, ... species, leaf area, seasonal characteristics and leaf.

Simple measurement of light-interception by individual leaves in fruit vegetables by using an integrated solarimeter film

International Nuclear Information System (INIS)

Watanabe, S.; Nakano, Y.; Okano, K.

2001-01-01

Applicability of the integrated solarimeter film (Taisei Chemical Co. Ltd., Optleaf R-2D) for the measurement of amount of light-interception by individual leaves in fruit vegetables was investigated The fading rate of the film was highly correlated with the values measured by an integrated solarimeter at an open field, though the rate was depended on the air temperature during the measurement. Integrated solar radiation in a glasshouse could be estimated by the film as well as at an open field. Amount of light-interception by individual leaves of vertically trained watermelon plants could be measured by the film and light-interception characteristics of the plants could be expressed numerically. The integrated solarimeter film would be useful for analyzing light-interception characteristics in fruit vegetables

Electricity generation from wetlands with activated carbon bioanode

Science.gov (United States)

Sudirjo, E.; Buisman, C. J. N.; Strik, D. P. B. T. B.

2018-03-01

Paddy fields are potential non-tidal wetlands to apply Plant Microbial Fuel Cell (PMFC) technology. World widely they cover about 160 million ha of which 13.3 million ha is located in Indonesia. With the PMFC, in-situ electricity is generated by a bioanode with electrochemically active bacteria which use primary the organic matter supplied by the plant (e.g. as rhizodeposits and plant residues). One of limitations when installing a PMFC in a non-tidal wetland is the usage of “expensive” large amounts of electrodes to overcome the poor conductivity of wet soils. However, in a cultivated wetland such as rice paddy field, it is possible to alter soil composition. Adding a conductive carbon material such as activated carbon is believed to improve soil conductivity with minimum impact on plant vitality. The objective of this research was to study the effect of activated carbon as an alternative bioanode material on the electricity output and plants vitality. Lab result shows that activated carbon can be a potential alternative for bioanode material. It can continuously deliver current on average 1.54 A/m3 anode (0.26 A/m2 PGA or 66 mW/m2 PGA) for 98 days. Based on this result the next step is to do a test of this technology in the real paddy fields.

Wetland restoration, flood pulsing, and disturbance dynamics

Science.gov (United States)

Middleton, Beth A.

1999-01-01

While it is generally accepted that flood pulsing and disturbance dynamics are critical to wetland viability, there is as yet no consensus among those responsible for wetland restoration about how best to plan for those phenomena or even whether it is really necessary to do so at all. In this groundbreaking book, Dr. Beth Middleton draws upon the latest research from around the world to build a strong case for making flood pulsing and disturbance dynamics integral to the wetland restoration planning process.While the initial chapters of the book are devoted to laying the conceptual foundations, most of the coverage is concerned with demonstrating the practical implications for wetland restoration and management of the latest ecological theory and research. It includes a fascinating case history section in which Dr. Middleton explores the restoration models used in five major North American, European, Australian, African, and Asian wetland projects, and analyzes their relative success from the perspective of flood pulsing and disturbance dynamics planning.Wetland Restoration also features a wealth of practical information useful to all those involved in wetland restoration and management, including: * A compendium of water level tolerances, seed germination, seedling recruitment, adult survival rates, and other key traits of wetland plant species * A bibliography of 1,200 articles and monographs covering all aspects of wetland restoration * A comprehensive directory of wetland restoration ftp sites worldwide * An extensive glossary of essential terms

Photoinduced degradation of carbaryl in a wetland surface water.

Science.gov (United States)

Miller, Penney L; Chin, Yu-Ping

2002-11-06

The photoinduced degradation of carbaryl (1-naphthyl-N-methyl carbamate) was studied in a wetland's surface water to examine the photochemical processes influencing its transformation. For this particular wetland water, at high pH, it was difficult to delineate the photolytic contribution to the overall degradation of carbaryl. At lower pH values, the extent of the degradation attributable to indirect pathways, that is, in the presence of naturally occurring photosensitizers, increased significantly. Moreover, the photoenhanced degradation at the lower pH values was found to be seasonally and spatially dependent. Analysis of water samples revealed two primary constituents responsible for the observed indirect photolytic processes: nitrate and dissolved natural organic matter (NOM). Nitrate in the wetland appears at high concentrations (> or =1 mM) seasonally after the application of fertilizers in the watershed and promotes contaminant destruction through the photochemical production of the hydroxyl radical (HO*). The extent of the observed indirect photolysis pathway appears to be dependent upon the concentration of nitrates and the presence of HO* scavengers such as dissolved NOM and carbonate alkalinity. Paradoxically, during low-nitrate events (<50 microM), NOM becomes the principal photosensitizer through either the production of HO*, direct energy transfer from the excited triplet state, and/or production of an unidentified transient species.

78 FR 68719 - Floodplain Management and Protection of Wetlands

Science.gov (United States)

2013-11-15

... of wetlands in Sec. 55.2(b)(11) to cover manmade wetlands in order to ensure that wetlands built for...] RIN 2501-AD51 Floodplain Management and Protection of Wetlands AGENCY: Office of the Secretary, HUD... wetlands and floodplains. With respect to wetlands, the rule codifies existing procedures for Executive...

Functional roles of wetlands: a case study of the coastal wetlands of ...

African Journals Online (AJOL)

The Coastal Wetland of the study area is used extensively for a large number of activities. It is also threatened because of their vulnerability and attractiveness for development. These therefore prompted a study of the Wetlands for a period of 18 months (July 1997 – December 1998) to identify the functional roles that ...

Non-zero intercept frequency : an accurate method to determine the integral temperature of li-ion batteries

NARCIS (Netherlands)

Raijmakers, L.H.J.; Danilov, D.L.; van Lammeren, J.; Lammers, T.; Bergveld, H.J.; Notten, P.H.L.

2016-01-01

A new impedance-based approach is introduced in which the integral battery temperature is related to other frequencies than the recently developed zero-intercept frequency (ZIF). The advantage of the proposed non-zero-intercept frequency (NZIF) method is that measurement interferences, resulting

Primary Dentition Analysis: Exploring a Hidden Approach

OpenAIRE

Nuvvula, Sivakumar; Vanjari, Kalasandhya; Kamatham, Rekhalakshmi; Gaddam, Kumar Raja

2016-01-01

ABSTRACT Background: Accurate prediction of the mesiodistal widths (MDWs) of canines and premolars in children with primary dentition facilitates interception of malocclusion at an early age. Boston University (BU) approach is one, i.e., based on primary teeth for predicting canine and premolar dimensions. Aim: To predict the canine and premolar dimensions, in the contemporary population, using BU approach and compare with the values obtained using Tanaka-Johnston (T/J) approach. Design: Chil...

Impact of rainfall interception on hydrologic partitioning and soil erosion in natural and managed seasonally dry ecosystems

Science.gov (United States)

Moura, A. E.; Montenegro, S. M.; Silva, B. B.; Bartlett, M. S.; Porporato, A. M.; Antonino, A. C.

2013-12-01

Quantifying the effects of land use change and rainfall variability in seasonal, dry ecosystems is crucial to sustainable management of soil and water resources. In particular, changes in rainfall interception effects on hydrologic partitioning and soil erosion due to land use change are among the least known processes, despite their importance for water resource managements, in terms of water availability for ecosystem and society and water quality and erosion problems. In this work we quantify the interception losses in different types of vegetation (coffee, lemon and vegetation of natural forest) found in the Tapacurá basin in the Pernambuco state of NE Brazil, coupling field experiments and analytical models. The interception losses were measured with rain gauges installed in three types of vegetation along with stemflow collectors. Close to the coffee plantation, a meteorological station was also installed for measurement of the necessary variables for the model calibrations. As expected, the results show that rainfall events of smaller magnitude proportionally have larger relative interception losses, with larger differences in the wet season. The model results also allow us to quantify the nonlinear behavior of the interception process, at the same time providing a valuable tool to estimate the interception loss due to changes in vegetation and rainfall regime and thus to improve water resource management in seasonally dry tropics .

Effects of leaf movement on radiation interception in field grown leguminous crops, 2: Soybean (Glycine max Merr.)

International Nuclear Information System (INIS)

Isoda, A.; Yoshimura, T.; Ishikawa, T.; Wang, P.; Nojima, H.; Takasaki, Y.

1993-01-01

The effects of the leaf movement on radiation interception were examined by a treatment which restrained the leaf movement in the upper layers of the canopy. Two determinate soybean cultivars with different canopy structures (c.v. Nanbushirome and Miyagishirome) were grown at two planting densities in the field. A pot experiment was also used to evaluate radiation interception under the conditions of no mutual shading. Intercepted radiation of every leaflet of two plants within the canopy and one plant in the pot experiment was measured by the integrated solarimeter films for two consecutive days. The amount of intercepted radiations per unit ground area in the treatments were larger than those in the controls of both cultivars and indicated the ineffectiveness of the leaf movement on radiation interception. In general, Nanbushirome intercepted larger amount of radiation in every layer of the canopy in both field and pot experiments. The differences between the control and the treatment in Nanbushirome were large as compared with Miyagishirome. The leaf temperature of the uppermost layer of the canopy in Nanbushirome was higher than the air temperature in the treatment, whereas it was at par with the air temperature in the control. The leaflets of the upper layer moved paraheliotropically to the sum rays during most of day time, it was therefore assumed that the leaf movement would regulate leaf temperature

Influence of Spatial and Temporal Factors in Determining Rainfall Interception at Dipterocarp Forest Canopy, Lake Chini, Pahang

International Nuclear Information System (INIS)

Nur Munirah Abdullah; Mohd Ekhwan Toriman; Haslinur Mohd Din

2013-01-01

The reduction of rainfall by interception process is influenced by two mechanisms namely climate and plant physiographic features. Climate features that affecting the interception loss including total rainfall (mm), wind speed (m/s) and temperature (degree Celsius). Meanwhile plant physiographic features that affect interception loss consists of trees height, skin, diameter, canopy, twigs and branches. Looking the role of climate and plant physiographic features in the interception process, this study was conducted in order to measure the throughfall, stem flow and interception loss and the factors that influence it. The assessment of throughfall and interception loss were carried out on study plot sized 100 x 100 meter in Dipterocarp Forest of Tasik Chini, Pahang. The study was conducted from October 2009 until January of 2010. Thirty tree samples are used and each tree is well-identified based on their species, family, diameter breast height (DBH), canopy size and its density. Four sets of throughfall were used to do throughfall measurements. Results of this study found that the value of throughfall and stem flow collected based on four rainfall events namely in October 2009 where 0.66 % (TF) and 99.34 % (SF), November 2009-0.54 % (TF) and 99.46 % (SF), December 2009-0.72 % (TF) and 99.28 % (SF) and January of 2010-0.49 % (TF) and 99.51 % (SF). Statistical analysis also indicates the existence of the relationship between total rainfall and interception loss with significant levels in 0.571 (r 2 ) in December of 2009. This study provides important information that related to the hydrological cycle and how plants canopy can be acted as a medium of water balance in the environment. (author)

Structural and functional loss in restored wetland ecosystems.

Directory of Open Access Journals (Sweden)

David Moreno-Mateos

2012-01-01

Full Text Available Wetlands are among the most productive and economically valuable ecosystems in the world. However, because of human activities, over half of the wetland ecosystems existing in North America, Europe, Australia, and China in the early 20th century have been lost. Ecological restoration to recover critical ecosystem services has been widely attempted, but the degree of actual recovery of ecosystem functioning and structure from these efforts remains uncertain. Our results from a meta-analysis of 621 wetland sites from throughout the world show that even a century after restoration efforts, biological structure (driven mostly by plant assemblages, and biogeochemical functioning (driven primarily by the storage of carbon in wetland soils, remained on average 26% and 23% lower, respectively, than in reference sites. Either recovery has been very slow, or postdisturbance systems have moved towards alternative states that differ from reference conditions. We also found significant effects of environmental settings on the rate and degree of recovery. Large wetland areas (>100 ha and wetlands restored in warm (temperate and tropical climates recovered more rapidly than smaller wetlands and wetlands restored in cold climates. Also, wetlands experiencing more (riverine and tidal hydrologic exchange recovered more rapidly than depressional wetlands. Restoration performance is limited: current restoration practice fails to recover original levels of wetland ecosystem functions, even after many decades. If restoration as currently practiced is used to justify further degradation, global loss of wetland ecosystem function and structure will spread.

Engineered wetlands for on-site groundwater remediation

International Nuclear Information System (INIS)

Wallace, S.; Davis, B.M.

2008-01-01

Engineered wetlands have been touted as an emerging technology for the in situ remediation of hydrocarbon-contaminated soil and water. They incorporate a horizontal subsurface flow gravel bed reactor lined with impermeable liners, and are equipped with forced bed aeration systems that enhance oxygen delivery to the wetland's aerobic micro-organisms. Engineered wetlands generally emphasize specific characteristics of wetland ecosystems to improve treatment capacities. Design parameters include biodegradation rate coefficients, flowrate, hydraulic residence time plus influent and required effluent concentrations. This paper described the installation of an engineered wetland system at a former British Petroleum (BP) refinery in Wyoming where a pipeline terminal generated contact wastewater containing benzene, toluene, ethylbenzene and xylene (BTEX) and ammonia. The wetland treatment system was designed to treat 6000 m 3 of contaminated ground water per day and has been in operation since May 2003. It was concluded that engineered wetlands can offer long-term solutions to site remediation challenges. 16 refs., 3 tabs., 6 figs

Wetland Restoration and Sediment Removal

Data.gov (United States)

Department of the Interior — In 2008, Minnesota’s Private Lands Program and Wetland Management Districts began to compare different methods of restoring prairie pothole wetlands to see if there...

Geographically isolated wetlands: Rethinking a misnomer

Science.gov (United States)

Mushet, David M.; Calhoun, Aram J.K.; Alexander, Laurie C.; Cohen, Matthew J.; DeKeyser, Edward S.; Fowler, Laurie G.; Lane, Charles R.; Lang, Megan W.; Rains, Mark C.; Walls, Susan

2015-01-01

We explore the category “geographically isolated wetlands” (GIWs; i.e., wetlands completely surrounded by uplands at the local scale) as used in the wetland sciences. As currently used, the GIW category (1) hampers scientific efforts by obscuring important hydrological and ecological differences among multiple wetland functional types, (2) aggregates wetlands in a manner not reflective of regulatory and management information needs, (3) implies wetlands so described are in some way “isolated,” an often incorrect implication, (4) is inconsistent with more broadly used and accepted concepts of “geographic isolation,” and (5) has injected unnecessary confusion into scientific investigations and discussions. Instead, we suggest other wetland classification systems offer more informative alternatives. For example, hydrogeomorphic (HGM) classes based on well-established scientific definitions account for wetland functional diversity thereby facilitating explorations into questions of connectivity without an a priori designation of “isolation.” Additionally, an HGM-type approach could be used in combination with terms reflective of current regulatory or policymaking needs. For those rare cases in which the condition of being surrounded by uplands is the relevant distinguishing characteristic, use of terminology that does not unnecessarily imply isolation (e.g., “upland embedded wetlands”) would help alleviate much confusion caused by the “geographically isolated wetlands” misnomer.

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang, E-mail: ywang@magnet.fsu.edu [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States); Gu, Binhe [South Florida Water Management District, West Palm Beach, FL 33406 (United States); Lee, Ming-Kuo [Department of Geology and Geography, Auburn University, Auburn, AL 36839 (United States); Jiang, Shijun, E-mail: sjiang@jnu.edu.cn [Institute of Hydrobiology/Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou, Guangdong 510632 (China); Xu, Yingfeng [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States)

2014-07-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

International Nuclear Information System (INIS)

Wang, Yang; Gu, Binhe; Lee, Ming-Kuo; Jiang, Shijun; Xu, Yingfeng

2014-01-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Schema generation in recurrent neural nets for intercepting a moving target.

Science.gov (United States)

Fleischer, Andreas G

2010-06-01

The grasping of a moving object requires the development of a motor strategy to anticipate the trajectory of the target and to compute an optimal course of interception. During the performance of perception-action cycles, a preprogrammed prototypical movement trajectory, a motor schema, may highly reduce the control load. Subjects were asked to hit a target that was moving along a circular path by means of a cursor. Randomized initial target positions and velocities were detected in the periphery of the eyes, resulting in a saccade toward the target. Even when the target disappeared, the eyes followed the target's anticipated course. The Gestalt of the trajectories was dependent on target velocity. The prediction capability of the motor schema was investigated by varying the visibility range of cursor and target. Motor schemata were determined to be of limited precision, and therefore visual feedback was continuously required to intercept the moving target. To intercept a target, the motor schema caused the hand to aim ahead and to adapt to the target trajectory. The control of cursor velocity determined the point of interception. From a modeling point of view, a neural network was developed that allowed the implementation of a motor schema interacting with feedback control in an iterative manner. The neural net of the Wilson type consists of an excitation-diffusion layer allowing the generation of a moving bubble. This activation bubble runs down an eye-centered motor schema and causes a planar arm model to move toward the target. A bubble provides local integration and straightening of the trajectory during repetitive moves. The schema adapts to task demands by learning and serves as forward controller. On the basis of these model considerations the principal problem of embedding motor schemata in generalized control strategies is discussed.

An integrated approach for estimation of methane emissions from wetlands and lakes in high latitude regions

Science.gov (United States)

Chiu, C.; Bowling, L. C.; Podest, E.; Bohn, T. J.; Lettenmaier, D. P.; Schroeder, R.; McDonald, K. C.

2009-04-01

In recent years, there has been increasing evidence of significant alteration in the extent of lakes and wetlands in high latitude regions due in part to thawing permafrost, as well as other changes governing surface and subsurface hydrology. Methane is a 23 times more efficient greenhouse gas than carbon dioxide; changes in surface water extent, and the associated subsurface anaerobic conditions, are important controls on methane emissions in high latitude regions. Methane emissions from wetlands vary substantially in both time and space, and are influenced by plant growth, soil organic matter decomposition, methanogenesis, and methane oxidation controlled by soil temperature, water table level and net primary productivity (NPP). The understanding of spatial and temporal heterogeneity of surface saturation, thermal regime and carbon substrate in northern Eurasian wetlands from point measurements are limited. In order to better estimate the magnitude and variability of methane emissions from northern lakes and wetlands, we present an integrated assessment approach based on remote sensing image classification, land surface modeling and process-based ecosystem modeling. Wetlands classifications based on L-band JERS-1 SAR (100m) and ALOS PALSAR (~30m) are used together with topographic information to parameterize a lake and wetland algorithm in the Variable Infiltration Capacity (VIC) land surface model at 25 km resolution. The enhanced VIC algorithm allows subsurface moisture exchange between surface water and wetlands and includes a sub-grid parameterization of water table position within the wetland area using a generalized topographic index. Average methane emissions are simulated by using the Walter and Heimann methane emission model based on temporally and spatially varying soil temperature, net primary productivity and water table generated from the modified VIC model. Our five preliminary study areas include the Z. Dvina, Upper Volga, Yeloguy, Syum, and Chaya

40 CFR 230.41 - Wetlands.

Science.gov (United States)

2010-07-01

... through secondary impacts. Discharging fill material in wetlands as part of municipal, industrial or recreational development may modify the capacity of wetlands to retain and store floodwaters and to serve as a...

Organic Carbon and Disinfection Byproduct Precursor Loads from a Constructed, Non-Tidal Wetland in California's Sacramento–San Joaquin Delta

Directory of Open Access Journals (Sweden)

Jacob A. Fleck

2007-05-01

Full Text Available Wetland restoration on peat islands in the Sacramento-San Joaquin Delta will change the quality of island drainage waters entering the Delta, a primary source of drinking water in California. Peat island drainage waters contain high concentrations of dissolved and particulate organic carbon (DOC and POC and organic precursors to drinking water disinfection byproducts, such as trihalomethanes (THMs. We quantified the net loads of DOC, POC, and THM-precursors from a constructed subsidence mitigation wetland on Twitchell Island in the Delta to determine the change in drainage water quality that may be caused by conversion of agricultural land on peat islands to permanently flooded, non-tidal wetlands. Creation of permanently flooded wetlands halts oxidative loss of the peat soils and thereby may mitigate the extensive land-surface subsidence of the islands that threatens levee stability in the Delta. Net loads from the wetland were dominated by DOC flushed from the oxidized shallow peat soil layer by seepage flow out of the wetland. The permanently flooded conditions in the overlying wetland resulted in a gradual evolution to anaerobic conditions in the shallow soil layer and a concomitant decrease in the flow could be minimized by reducing the hydraulic gradient between the wetland and the adjacent drainage ditch. Estimates of net loads from the wetland assuming efflux of surface water only were comparable in magnitude to net loads from nearby agricultural fields, but the wetland and agricultural net loads had opposite seasonal variations. Wetland surface water net loads of DOC, POC, and THM-precursors were lower during the winter months when the greatest amounts of water are available for diversion from the Delta to drinking water reservoirs.

On leadership and success in professional wetland science

Science.gov (United States)

The Society of Wetland Scientists and the wetland profession are fortunate to have an abundance of leaders. These leaders respond to the needs of the Society for guidance and direction. They also consistently advance wetland science and improve the quality of wetland management...

Dynamic characteristics of soil respiration in Yellow River Delta wetlands, China

Science.gov (United States)

Wang, Xiao; Luo, Xianxiang; Jia, Hongli; Zheng, Hao

2018-02-01

The stable soil carbon (C) pool in coastal wetlands, referred to as "blue C", which has been extensively damaged by climate change and soil degradation, is of importance to maintain global C cycle. Therefore, to investigate the dynamic characteristics of soil respiration rate and evaluate C budgets in coastal wetlands are urgently. In this study, the diurnal and seasonal variation of soil respiration rate in the reed wetland land (RL) and the bare wetland land (BL) was measured in situ with the dynamic gas-infrared CO2 method in four seasons, and the factors impacted on the dynamic characteristics of soil respiration were investigated. The results showed that the diurnal variation of soil respiration rate consistently presented a "U" curve pattern in April, July, and September, with the maximum values at 12:00 a.m. and the minimum values at 6:00 a.m. In the same season, the diurnal soil respiration rate in RL was significantly greater than those in BL (P respiration rate was 0.14, 0.42, and 0.39 μmol m-2 s-1 in RL, 0.05, 0.22, 0.13, and 0.01 μmol m-2 s-1 in BL, respectively. Soil surface temperature was the primary factor that influenced soil respiration, which was confirmed by the exponential positive correlation between the soil respiration rate and soil surface temperature in BL and RL (P respiration, confirming by the significantly negative correlation between soil respiration rate and the content of soluble salt. These results will be useful for understanding the mechanisms underlying soil respiration and elevating C sequestration potential in the coastal wetlands.

Wetland Program Development Grants (WPDGs)

Data.gov (United States)

U.S. Environmental Protection Agency — The Wetland Grant Database (WGD) houses grant data for Wetland Program Development Grants (created by EPA in 1990 under the Clean Water Act Section 104(b)(3)...

7 CFR 12.30 - NRCS responsibilities regarding wetlands.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false NRCS responsibilities regarding wetlands. 12.30 Section 12.30 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Wetland Conservation § 12.30 NRCS responsibilities regarding wetlands. (a) Technical and...

The effect of river pulsing on sedimentation and nutrients in created riparian wetlands.

Science.gov (United States)

Nahlik, Amanda M; Mitsch, William J

2008-01-01

Sedimentation under pulsed and steady-flow conditions was investigated in two created flow-through riparian wetlands in central Ohio over 2 yr. Hydrologic pulses of river water lasting for 6 to 8 d were imposed on each wetland from January through June during 2004. Mean inflow rates during pulses averaged 52 and 7 cm d(-1) between pulses. In 2005, the wetlands received a steady-flow regime of 11 cm d(-1) with no major hydrologic fluctuations. Thirty-two sediment traps were deployed and sampled once per month in April, May, June, and July for two consecutive years in each wetland. January through March were not sampled in either year due to frozen water surfaces in the wetlands. Gross sedimentation (sedimentation without normalizing for differences between years) was significantly greater in the pulsing study period (90 kg m(-2)) than in the steady-flow study period (64 kg m(-2)). When normalized for different hydrologic and total suspended solid inputs between years, sedimentation for April through July was not significantly different between pulsing and steady-flow study periods. Sedimentation for the 3 mo that received hydrologic pulses (April, May, and June) was significantly lower during pulsing months than in the corresponding steady-flow months. Large fractions of inorganic matter in collected sediments indicated that allochthonous inputs were the main contributor to sedimentation in these wetlands. Organic matter fractions of collected sediments were consistently greater in the steady-flow study period (1.8 g kg(-1)) than in the pulsed study period (1.5 g kg(-1)), consistent with greater primary productivity in the water column during steady-flow conditions.

Working group report on wetlands, wildlife and fisheries

International Nuclear Information System (INIS)

Maltby, L.

1990-01-01

A workshop was held to discuss the impacts of climatic change on wetlands, wildlife and fisheries. Impacts that could occur as a result of climatic change include: sea level rise affecting coastal wetlands by inundation, erosion and saltwater intrusion; temperature rise/moisture balance changes on other wetlands; lake level changes affecting shoreline wetlands; vegetation species/community modification of biological systems; and changes in values derived from wetlands impacting socio-economic systems. The Great Lakes shoreline is considered to be at high risk, and it is predicted that there will be profound effects on the ecological and socio-economic value of the Great Lakes wetlands. Presentations were given on wildlife as biological indicators, modelling the effects of climate warming on the stream habitats of brook trout, and the effects of an altered water regime on Great Lakes coastal wetlands. It was concluded that a fundamental research program of an interdisciplinary nature be established to determine current linkages of climatic variables to the function, distribution and productivity of wetlands and associated fish and wildlife resources. A national wetlands monitoring network should be established to trace the influence of climatic variables on wetlands and fish, to identify environmental indicators for reporting and to complement other monitoring programs

Aquatic macrophyte diversity of the Pantanal wetland and upper basin

Directory of Open Access Journals (Sweden)

VJ. Pott

Full Text Available This is a short review of the state of the art concerning diversity of aquatic macrophytes and the main aquatic vegetation types in the Brazilian Pantanal wetland and upper watershed. There are ca. 280 species of aquatic macrophytes on the Pantanal floodplain, with scarce endemism. On the upper watershed, Cerrado wetlands (veredas and limestone springs have a distinct flora from the Pantanal, with twice the species richness. As a representative case of aquatic habitats influenced by river flood, some primary data are presented for the Pantanal Matogrossense National Park and associated Acurizal Preserve, analysing the floristic similarity among aquatic vegetation types. We comment on problems of conservation and observe that Panicum elephantipes Nees is one of the few natives to compete with the invasive Urochloa arrecta (Hack. ex T. Durand & Schinz Morrone & Zuloaga.

A decision support system for adaptive real-time management ofseasonal wetlands in California

Energy Technology Data Exchange (ETDEWEB)

Quinn, Nigel W.T.; Hanna, W. Mark

2001-10-16

This paper describes the development of a comprehensive flow and salinity monitoring system and application of a decision support system (DSS) to improve management of seasonal wetlands in the San Joaquin Valley of California. The Environmental Protection Agency regulates salinity discharges from non-point sources to the San Joaquin River using a procedure known as the Total Maximum Daily Load (TMDL) to allocate the assimilative capacity of the River for salt among watershed sources. Management of wetland sources of salt load will require the development of monitoring systems, more integrative management strategies and coordination with other entities. To obtain local cooperation the Grassland Water District, whose primary function is to supply surface water to private duck clubs and managed wetlands, needs to communicate to local landowners the likely impacts of salinity regulation on the long term health and function of wildfowl habitat. The project described in this paper will also provide this information. The models that form the backbone of the DSS develop salinity balances at both a regional and local scale. The regional scale concentrates on deliveries to and exports from the Grasland Water District while the local scale focuses on an individual wetland unit where more intensive monitoring is being conducted. The design of the DSS is constrained to meet the needs of busy wetland managers and is being designed from the bottom up utilizing tools and procedures familiar to these individuals.

Measuring and modelling interception loss by an isolated olive tree in a traditional olive grove - pasture system

Science.gov (United States)

Nóbrega, Cristina; Pereira, Fernando L.; Valente, Fernanda

2015-04-01

Water losses associated to the rainfall interception process by trees can be an important component of the local hydrologic balance and must be accounted for when implementing any sustainable water management programme. In many dry areas of the Mediterranean region where agro-forestry systems are common, those programmes are crucial to foster adequate water conservation measures. Recent studies have shown that the evaluation of interception loss in sparse forests or tree plantations should be made for individual trees, being the total value determined as the sum of the individual contributions. Following this approach, rainfall interception was measured and modelled over two years, in an isolated Olea europeaea L. tree, in a traditional low-density olive grove in Castelo Branco, central Portugal. Total interception loss over the experimental period was 243.5 mm, on a tree crown projected area basis, corresponding to 18.0% of gross rainfall (Pg). Modelling made for each rainfall event using the sparse version of the Gash model, slightly underestimated interception loss with a value of 240.5 mm, i.e., 17.8 % ofPg. Modelling quality, evaluated according to a number of criteria, was good, allowing the conclusion that the methodology used was adequate. Modelling was also made on a daily basis, i.e., assuming a single storm per rainday. In this case, interception loss was overestimated by 12%, mostly because 72% of all rainfall events lasted for more than a day.

Mapping long-term wetland response to climate

Science.gov (United States)

Zhou, Q.; Gallant, A.; Rover, J.

2016-12-01

Wetlands provide unique feeding and breeding habitat for numerous waterfowl species. The distribution of wetlands has been considerably changed due to agricultural land conversion and hydrologic modification. Climate change may further impact wetlands through altered moisture regimes. This study characterized long-term variation in wetland conditions by using dense time series from all available Landsat data from 1985 to 2014. We extracted harmonic frequencies from 30 years to two years to delineate the long-term variation in all seven Landsat bands. A cluster analysis and unsupervised classification then enabled us to map different classes of wetland response. We demonstrated the method in the Prairie Pothole Region in North Dakota.

Pipeline corridors through wetlands - summary of seventeen plant-community studies at ten wetland crossings. Topical report, February 1990--August 1994

Energy Technology Data Exchange (ETDEWEB)

Van Dyke, G.D. [Argonne National Lab., IL (United States)]|[Trinity Christian College, Palos Heights, IL (United States); Shem, L.M.; Wilkey, P.L.; Zimmerman, R.E.; Alsum, S.K. [Argonne National Lab., IL (United States)

1994-12-01

As part of the Gas Research Institute Wetland Corridors Program, Argonne National Laboratory conducted field studies on 10 wetland crossings located in six states to document impacts of natural gas pipeline rights-of-way (ROWS) on 15 wetland plant communities. This study is unique in the number, range, ages, and variety of wetland crossings surveyed and compared. Vegetation data and recorded observations were analyzed to reveal patterns associated with age, installation technology, maintenance practices, and wetland type. This report summarizes the findings of this study. Results revealed that ROWs of pipelines installed according to recent wetland regulations rapidly revegetated with dense and diverse plant communities. The ROW plant communities were similar to those in the adjacent natural areas in species richness, wetland indicator values, and percentages of native species. The ROW plant communities developed from naturally available propagules without fertilization, liming, or artificial seeding. ROWs contributed to increased habitat and plant species diversity in the wetland. There was little evidence that they degrade the wetland by providing avenues for the spread of invasive and normative plant species. Most impacts are temporal in nature, decreasing rapidly during the first several years and more slowly thereafter to the extent permitted by maintenance and other ROW activities.

Yield accumulation in irrigated sugarcane. II. Utilization of intercepted radiation

International Nuclear Information System (INIS)

Muchow, R.C.; Evensen, C.I.; Osgood, R.V.; Robertson, M.J.

1997-01-01

Intercepted radiation is a major driving variable of crop production under high-input irrigated conditions. Quantitative information on the utilization of radiation in yield accumulation allows extrapolation beyond the current season and location, and when this information is incorporated into crop growth simulation models, the effect of crop age on the productivity of different cultivars can be examined under different climatic conditions. This paper examines the differential performance of high-yielding sugarcane (Saccharum spp. hybrids) crops in terms of the amount of short-wave solar radiation intercepted (Si) and the efficiency of use of intercepted radiation (RUE) in biomass production. Biomass accumulation during the 12- to 24-mo crop cycle was examined for two experiments conducted in Hawaii, and three experiments conducted in tropical Australia from 1991 to 1993. The analysis showed that (i) RUE was much less for growth after 12 mo than in the first 12 mo; (ii) maximum RUE of sugarcane approaches 2.0 g MJ(-1); (iii) biomass accumulation beyond 12 mo was not related directly to radiation utilization; and (iv) cultivars differed in Si, but differences in RUE could not be unequivocally assessed due to the confounding effect of variable recovery of trash in biomass estimates. It is concluded that stalk death and consequent biomass loss are important factors contributing to yield variation in sugarcane crops growing for 12 to 24 mo, with a yield plateau occurring at variable crop ages during the second year of growth

Variations in canopy and litter interception across a forest chronosequence in the southern Appalachian Mountains

Science.gov (United States)

Steven T. Brantley; Paul V. Bolstad; Stephanie H. Laseter; A. Christopher Oishi; Kimberly A. Novick; Chelcy F. Miniat

2016-01-01

Variations in evapotranspiration (ET) have been well documented across a variety of forest types and climates in recent decades; however, most of these data have focused on mature, secondgrowth stands. Here we present data on two important fluxes of water, canopy interception (Ic) and forest floor litter interception (Iff), across a chronosequence of forest age in the...

Solar radiation interception of various planting space patterns of maize and its relation to yields

International Nuclear Information System (INIS)

Akhir, N.

2003-01-01

A research was carried out to study solar radiation interception and its relation to yield of maize in various plant spacing patterns at high elevation. The goal of this research was to contribute the development of crop science, especially the plant ecophysiology. A field experiment was executed from March to August 1998 at Assessment Institute of Agricultural Technology, Sukarami, West Sumatra. The experiment was arranged in Randomized Block Design and each treatment was replicated three times. The experiment data was analyzed by ANOVA and path analysis. The results of experiment indicated that the percentage of solar radiation interception gave high contribution to the dry grain yield for Pioneer-7 cultivar, and the solar radiation interception was depend on LAI and leaf angle

Constructed Wetland Treatment Systems For Water Quality Improvement

International Nuclear Information System (INIS)

Nelson, E.

2010-01-01

The Savannah River National Laboratory implemented a constructed wetland treatment system (CWTS) in 2000 to treat industrial discharge and stormwater from the Laboratory area. The industrial discharge volume is 3,030 m 3 per day with elevated toxicity and metals (copper, zinc and mercury). The CWTS was identified as the best treatment option based on performance, capital and continuing cost, and schedule. A key factor for this natural system approach was the long-term binding capacity of heavy metals (especially copper, lead, and zinc) in the organic matter and sediments. The design required that the wetland treat the average daily discharge volume and be able to handle 83,280 m 3 of stormwater runoff in a 24 hour period. The design allowed all water flow within the system to be driven entirely by gravity. The CWTS for A-01 outfall is composed of eight one-acre wetland cells connected in pairs and planted with giant bulrush to provide continuous organic matter input to the system. The retention basin was designed to hold stormwater flow and to allow controlled discharge to the wetland. The system became operational in October of 2000 and is the first wetland treatment system permitted by South Carolina DHEC for removal of metals. Because of the exceptional performance of the A-01 CWTS, the same strategy was used to improve water quality of the H-02 outfall that receives discharge and stormwater from the Tritium Area of SRS. The primary contaminants in this outfall were also copper and zinc. The design for this second system required that the wetland treat the average discharge volume of 415 m 3 per day, and be able to handle 9,690 m 3 of stormwater runoff in a 24 hour period. This allowed the building of a system much smaller than the A-01 CWTS. The system became operational in July 2007. Metal removal has been excellent since water flow through the treatment systems began, and performance improved with the maturation of the vegetation during the first season of

CONSTRUCTED WETLAND TREATMENT SYSTEMS FOR WATER QUALITY IMPROVEMENT

Energy Technology Data Exchange (ETDEWEB)

Nelson, E.

2010-07-19

The Savannah River National Laboratory implemented a constructed wetland treatment system (CWTS) in 2000 to treat industrial discharge and stormwater from the Laboratory area. The industrial discharge volume is 3,030 m{sup 3} per day with elevated toxicity and metals (copper, zinc and mercury). The CWTS was identified as the best treatment option based on performance, capital and continuing cost, and schedule. A key factor for this natural system approach was the long-term binding capacity of heavy metals (especially copper, lead, and zinc) in the organic matter and sediments. The design required that the wetland treat the average daily discharge volume and be able to handle 83,280 m{sup 3} of stormwater runoff in a 24 hour period. The design allowed all water flow within the system to be driven entirely by gravity. The CWTS for A-01 outfall is composed of eight one-acre wetland cells connected in pairs and planted with giant bulrush to provide continuous organic matter input to the system. The retention basin was designed to hold stormwater flow and to allow controlled discharge to the wetland. The system became operational in October of 2000 and is the first wetland treatment system permitted by South Carolina DHEC for removal of metals. Because of the exceptional performance of the A-01 CWTS, the same strategy was used to improve water quality of the H-02 outfall that receives discharge and stormwater from the Tritium Area of SRS. The primary contaminants in this outfall were also copper and zinc. The design for this second system required that the wetland treat the average discharge volume of 415 m{sup 3} per day, and be able to handle 9,690 m{sup 3} of stormwater runoff in a 24 hour period. This allowed the building of a system much smaller than the A-01 CWTS. The system became operational in July 2007. Metal removal has been excellent since water flow through the treatment systems began, and performance improved with the maturation of the vegetation during

Hydraulic residence time and iron removal in a wetland receiving ferruginous mine water over a 4 year period from commissioning.

Science.gov (United States)

Kusin, F M; Jarvis, A P; Gandy, C J

2010-01-01

Analysis of residence time distribution (RTD) has been conducted for the UK Coal Authority's mine water treatment wetland at Lambley, Northumberland, to determine the hydraulic performance of the wetland over a period of approximately 4 years since site commissioning. The wetland RTD was evaluated in accordance with moment analysis and modelled based on a tanks-in-series (TIS) model to yield the hydraulic characteristics of system performance. Greater hydraulic performance was seen during the second site monitoring after 21 months of site operation i.e. longer hydraulic residence time to reflect overall system hydraulic efficiency, compared to wetland performance during its early operation. Further monitoring of residence time during the third year of wetland operation indicated a slight reduction in hydraulic residence time, thus a lower system hydraulic efficiency. In contrast, performance during the fourth year of wetland operation exhibited an improved overall system hydraulic efficiency, suggesting the influence of reed growth over the lifetime of such systems on hydraulic performance. Interestingly, the same pattern was found for iron (which is the primary pollutant of concern in ferruginous mine waters) removal efficiency of the wetland system from the second to fourth year of wetland operation. This may therefore, reflect the maturity of reeds for maintaining efficient flow distribution across the wetland to retain a longer residence time and significant fractions of water involved to enhance the extent of treatment received for iron attenuation. Further monitoring will be conducted to establish whether such performance is maintained, or whether efficiency decreases over time due to accumulation of dead plant material within the wetland cells.

44 CFR 10.14 - Flood plains and wetlands.

Science.gov (United States)

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood plains and wetlands. 10... Flood plains and wetlands. For any action taken by FEMA in a flood plain or wetland, the provisions of... Executive Order 11988, Flood Plain Management, and Executive Order 11990, Protection of Wetlands (44 CFR...

Is wetland mitigation successful in Southern California?

Science.gov (United States)

Cummings, D. L.; Rademacher, L. K.

2004-12-01

Wetlands perform many vital functions within their landscape position; they provide unique habitats for a variety of flora and fauna and they act as treatment systems for upstream natural and anthropogenic waste. California has lost an estimated 91% of its wetlands. Despite the 1989 "No Net Loss" policy and mitigation requirements by the regulatory agencies, the implemented mitigation may not be offsetting wetlands losses. The "No Net Loss" policy is likely failing for numerous reasons related to processes in the wetlands themselves and the policies governing their recovery. Of particular interest is whether these mitigation sites are performing essential wetlands functions. Specific questions include: 1) Are hydric soil conditions forming in mitigation sites; and, 2) are the water quality-related chemical transformations that occur in natural wetlands observed in mitigation sites. This study focuses on success (or lack of success) in wetlands mitigation sites in Southern California. Soil and water quality investigations were conducted in wetland mitigation sites deemed to be successful by vegetation standards. Observations of the Standard National Resource Conservation Service field indicators of reducing conditions were made to determine whether hydric soil conditions have developed in the five or more years since the implementation of mitigation plans. In addition, water quality measurements were performed at the inlet and outlet of these mitigation sites to determine whether these sites perform similar water quality transformations to natural wetlands within the same ecosystem. Water quality measurements included nutrient, trace metal, and carbon species measurements. A wetland location with minimal anthropogenic changes and similar hydrologic and vegetative features was used as a control site. All sites selected for study are within a similar ecosystem, in the interior San Diego and western Riverside Counties, in Southern California.

Wetlands Restoration Definitions and Distinctions

Science.gov (United States)

Ecological restoration is a valuable endeavor that has proven very difficult to define. The term indicates that degraded and destroyed natural wetland systems will be reestablished to sites where they once existed. But, what wetland ecosystems are we talki

Implications of agricultural encroachment on the carbon and greenhouse gas dynamics in tropical African wetlands.

Science.gov (United States)

Saunders, Matthew; Kansiime, Frank; Jones, Michael

2015-04-01

Cyperus papyrus L. (papyrus) wetlands dominate the permanently inundated wetlands of tropical East Africa and support the livelihoods of millions of people in rural sub-Saharan Africa through the provision of multiple ecosystem services such as the supply of drinking water, fish protein, building materials and biofuels. These wetlands are also extremely important in local and regional scale biogeochemical cycles due to their extensive spatial distribution, high rates of photosynthetic carbon dioxide (CO2) assimilation, long-term carbon (C) sequestration in the form of peat and the control of water loss through evapotranspiration. However, these wetlands are facing significant anthropogenic pressures due to the increasing demand for agricultural land where the papyrus plants are removed and replaced with subsistence crops such as cocoyam (Colocasia esculenta). Eddy covariance measurements were made on an undisturbed papyrus wetland and a cocoyam dominated wetland on the Ugandan shoreline of Lake Victoria to better understand the impacts of agricultural encroachment on the C sequestration potential of these wetlands. Peak rates of net photosynthetic CO2 assimilation at the papyrus wetland were over 40 μmol CO2 m-2 s-1, even under increasing vapour pressure deficit (≥2 kPa), while maximum rates of assimilation at the cocoyam site were 28 μmol CO2 m-2 s-1. Annual rates of papyrus net primary productivity (NPP) were amongst the highest recorded for wetland systems globally (3.09 kg C m-2 yr-1) and the continual regeneration of the papyrus plants, due to an absence of pronounced seasonal climatic variability, can lead to significant C accumulation in the above and belowground biomass (≥88 t C ha-1). Where these wetlands remain inundated and anaerobic conditions prevail, significant detrital and peat deposits can form further increasing the combined C sink capacity of these ecosystems to over 700 t C ha-1. The C sink strength of these wetlands is however offset by

Changes in Landscape Pattern of Wetland around Hangzhou Bay

Science.gov (United States)

Lin, Wenpeng; Li, Yuan; Xu, Dan; Zeng, Ying

2018-04-01

Hangzhou Bay is an important estuarial coastal wetland, which offers a large number of land and ecological resources. It plays a significant role in the sustainable development of resources, environment and economy. In this paper, based on the remote sensing images in 1996, 2005 and 2013, we extracted the coastal wetland data and analyzed the wetland landscape pattern of the Hangzhou Bay in the past 20 years. The results show that: (1) the area of coastal wetland is heading downwards in the recent decades. Paddy field and the coastal wetland diminish greatly. (2) the single dynamic degree of wetland of the Hangzhou Bay displays that paddy fields and coastal wetlands are shrinking, but lakes, reservoirs and ponds are constantly expanding. (3) the wetland landscape pattern index shows that total patch area of the coastal wetland and paddy fields have gradually diminished. The Shannon diversity index, the Shannon evenness index as well as the landscape separation index of the coastal wetlands in the Hangzhou Bay increase steadily. The landscape pattern in the study area has shown a trend of high fragmentation, dominance decreases, but some dominant landscape still exist in this region. (4) Urbanization and natural factors lead to the reduction of wetland area. Besides the pressure of population is a major threat to the wetland. The study will provide scientific basis for long-term planning for this region.

The Legal Structure of Taiwan’s Wetland Conservation Act

Directory of Open Access Journals (Sweden)

Yi-Yuan Su

2014-12-01

Full Text Available In July of 2013, Taiwan passed its Wetland Conservation Act and will begin the implementation of the Act on 2 February 2015. With this Act, Taiwan has become the second Asian country to have specific legislation on wetland conservation and protection. This new law enables the society to achieve sustainable utilization on wetland ecological services. The core concepts of the Wetland Conversation Act include biological diversity conservation and wise use of wetland resources. Special political circumstances prevent Taiwan from registering its wetlands as a conservation priority under the Ramsar Convention. This new law allows the government to evaluate and assign a specific area as a “Wetland of Importance.” Under this status, any development activities within the designated area shall be prohibited unless the developer prepares a usage plan for review. The usage plan and the original usage of the natural resources within the wetland area shall also follow the “wise use” principle to protect the wetland and biological service system. However, this new law does not provide clear separation between the two different “wise use” standards. If the development is deemed necessary, new law provides compensation mitigation measures to extend the surface of the wetland and provides additional habitats for various species. Wetland conservation and management rely heavily on systematic research and fundamental data regarding Taiwan’s wetlands. Determining how to adopt these scientific methodologies and transfer them into enforceable mechanisms is a sizeable challenge for both biologists and lawyers as the Wetland Conservation Act creates many legal norms without clarifying definitions. This article will review the current wetland regulations from the legal perspective and provide suggestions for enforcement in the future.

Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean–Orinoco Piedmont of Colombia?

Directory of Open Access Journals (Sweden)

Johanna I. Murillo-Pacheco

2016-08-01

Full Text Available Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean–Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1 type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms and (2 origins (natural, mixed and artificial. A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81% were considered species typical of the area (Meta Piedmont distribution. Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha, with a small area of surrounding forest (10 ± 8.6 ha supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account.

Hydrologic connectivity to streams increases nitrogen and phosphorus inputs and cycling in soils of created and natural floodplain wetlands

Science.gov (United States)

Wolf, Kristin L.; Noe, Gregory; Ahn, Changwoo

2013-01-01

Greater connectivity to stream surface water may result in greater inputs of allochthonous nutrients that could stimulate internal nitrogen (N) and phosphorus (P) cycling in natural, restored, and created riparian wetlands. This study investigated the effects of hydrologic connectivity to stream water on soil nutrient fluxes in plots (n = 20) located among four created and two natural freshwater wetlands of varying hydrology in the Piedmont physiographic province of Virginia. Surface water was slightly deeper; hydrologic inputs of sediment, sediment-N, and ammonium were greater; and soil net ammonification, N mineralization, and N turnover were greater in plots with stream water classified as their primary water source compared with plots with precipitation or groundwater as their primary water source. Soil water-filled pore space, inputs of nitrate, and soil net nitrification, P mineralization, and denitrification enzyme activity (DEA) were similar among plots. Soil ammonification, N mineralization, and N turnover rates increased with the loading rate of ammonium to the soil surface. Phosphorus mineralization and ammonification also increased with sedimentation and sediment-N loading rate. Nitrification flux and DEA were positively associated in these wetlands. In conclusion, hydrologic connectivity to stream water increased allochthonous inputs that stimulated soil N and P cycling and that likely led to greater retention of sediment and nutrients in created and natural wetlands. Our findings suggest that wetland creation and restoration projects should be designed to allow connectivity with stream water if the goal is to optimize the function of water quality improvement in a watershed.

Constructing a Baseline Model of Alpine Wetlands of the Uinta Mountains, Utah, USA

Science.gov (United States)

Matyjasik, M.; Ford, R. L.; Bartholomew, L. M.; Welsh, S. B.; Hernandez, M.; Koerner, D.; Muir, M.

2008-12-01

Alpine wetlands of the Uinta Mountains, northeastern Utah, contain a variety of groundwater-dependent ecosystems. Unlike their counterparts in other areas of the Rocky Mountains, these systems have been relatively unstudied. The Reader Lakes area on the southern slope of the range was selected for detailed study because of its variety of wetland plant communities, homogenous bedrock geology, and minimal human impact. The primary goal of this interdisciplinary study is to establish the functional links between the geomorphology and hydrogeology of these high mountain wetlands and their constituent plant communities. In addition to traditional field studies and water chemistry, geospatial technologies are being used to organize and analyze both field data (water chemistry and wetland vegetation) and archived multispectral imagery (2006 NAIP images). The hydrology of these wetlands is dominated by groundwater discharge and their surface is dominated by string-and-flark morphology of various spatial scales, making these montane wetlands classic patterned fens. The drainage basin is organized into a series of large-scale stair-stepping wetlands, bounded by glacial moraines at their lower end. Wetlands are compartmentalized by a series of large strings (roughly perpendicular to the axial stream) and flarks. This pattern may be related to small ridges on the underlying ground moraine and possibly modified by beaver activity along the axial stream. Small-scale patterning occurs along the margins of the wetlands and in sloping-fen settings. The smaller-scale strings and flarks form a complex; self-regulating system in which water retention is enhanced and surface flow is minimized. Major plant communities have been identified within the wetlands for example: a Salix planifolia community associated with the peaty strings; Carex aquatilis, Carex limosa, and Eriophorum angustifolium communities associated with flarks; as well as a Sphagnum sp.- rich hummocky transition zone

Value Assessment of Artificial Wetland Derived from Mining Subsided Lake: A Case Study of Jiuli Lake Wetland in Xuzhou

Directory of Open Access Journals (Sweden)

Laijian Wang

2017-10-01

Full Text Available Mining subsided lakes are major obstacles for ecological restoration and resource reuse in mining regions. Transforming mining subsided lakes into artificial wetlands is an ecological restoration approach that has been attempted in China in recent years, but a value assessment of the approach still needs systematic research. This paper considers Jiuli Lake wetland, an artificial wetland derived from restoration of a mining subsided lake in plain area, as a case study. A value assessment model for the artificial wetland was established based on cost–benefit analysis by means of field monitoring, social surveys, GIS geostatistics, raster calculation methods, etc. Empirical analysis and calculations were performed on the case study region. The following conclusions were drawn: (1 after ecological restoration, ecosystem services of Jiuli Lake wetland which has become a national level wetland park yield positive values; (2 the improved environment of the Jiuli Lake wetland has a spillover effect on the price of surrounding land, resulting in land price appreciation; (3 using GIS geostatistics and raster calculation methods, the impact range, strength, and value of the spillover effect can be explicitly measured; (4 through the establishment of a value assessment model of the artificial wetland, incomes of the ecological restoration was found to be sufficient to cover the implementation costs, which provides a research foundation for economic feasibility of ecological restoration of mining subsided lakes.

Winter Tourism and mountain wetland management and restoration

Science.gov (United States)

Gaucherand, S.; Mauz, I.

2012-04-01

The degradation and loss of wetlands is more rapid than that of other ecosystems (MEA 2005). In mountains area, wetlands are small and scattered and particularly sensitive to global change. The development of ski resorts can lead to the destruction or the deterioration of mountain wetlands because of hydrologic interferences, fill in, soil compression and erosion, etc. Since 2008, we have studied a high altitude wetland complex in the ski resort of Val Thorens. The aim of our study was to identify the impacts of mountain tourism development (winter and summer tourism) on wetland functioning and to produce an action plan designed to protect, rehabilitate and value the wetlands. We chose an approach based on multi-stakeholder participatory process at every stage, from information gathering to technical choices and monitoring. In this presentation, we show how such an approach can efficiently improve the consideration of wetlands in the development of a ski resort, but also the bottlenecks that need to be overcome. We will also discuss some of the ecological engineering techniques used to rehabilitate or restore high altitude degraded wetlands. Finally, this work has contributed to the creation in 2012 of a mountain wetland observatory coordinated by the conservatory of Haute-Savoie. The objective of this observatory is to estimate ecosystem services furnished by mountain wetlands and to find restoration strategies adapted to the local socio-economical context (mountain agriculture and mountain tourism).

Projecting the Hydrologic Impacts of Climate Change on Montane Wetlands

Science.gov (United States)

Hamlet, Alan F.; Palen, Wendy J.; Lawler, Joshua J.; Halabisky, Meghan

2015-01-01

Wetlands are globally important ecosystems that provide critical services for natural communities and human society. Montane wetland ecosystems are expected to be among the most sensitive to changing climate, as their persistence depends on factors directly influenced by climate (e.g. precipitation, snowpack, evaporation). Despite their importance and climate sensitivity, wetlands tend to be understudied due to a lack of tools and data relative to what is available for other ecosystem types. Here, we develop and demonstrate a new method for projecting climate-induced hydrologic changes in montane wetlands. Using observed wetland water levels and soil moisture simulated by the physically based Variable Infiltration Capacity (VIC) hydrologic model, we developed site-specific regression models relating soil moisture to observed wetland water levels to simulate the hydrologic behavior of four types of montane wetlands (ephemeral, intermediate, perennial, permanent wetlands) in the U. S. Pacific Northwest. The hybrid models captured observed wetland dynamics in many cases, though were less robust in others. We then used these models to a) hindcast historical wetland behavior in response to observed climate variability (1916–2010 or later) and classify wetland types, and b) project the impacts of climate change on montane wetlands using global climate model scenarios for the 2040s and 2080s (A1B emissions scenario). These future projections show that climate-induced changes to key driving variables (reduced snowpack, higher evapotranspiration, extended summer drought) will result in earlier and faster drawdown in Pacific Northwest montane wetlands, leading to systematic reductions in water levels, shortened wetland hydroperiods, and increased probability of drying. Intermediate hydroperiod wetlands are projected to experience the greatest changes. For the 2080s scenario, widespread conversion of intermediate wetlands to fast-drying ephemeral wetlands will likely reduce

Projecting the Hydrologic Impacts of Climate Change on Montane Wetlands.

Science.gov (United States)

Lee, Se-Yeun; Ryan, Maureen E; Hamlet, Alan F; Palen, Wendy J; Lawler, Joshua J; Halabisky, Meghan

2015-01-01

Wetlands are globally important ecosystems that provide critical services for natural communities and human society. Montane wetland ecosystems are expected to be among the most sensitive to changing climate, as their persistence depends on factors directly influenced by climate (e.g. precipitation, snowpack, evaporation). Despite their importance and climate sensitivity, wetlands tend to be understudied due to a lack of tools and data relative to what is available for other ecosystem types. Here, we develop and demonstrate a new method for projecting climate-induced hydrologic changes in montane wetlands. Using observed wetland water levels and soil moisture simulated by the physically based Variable Infiltration Capacity (VIC) hydrologic model, we developed site-specific regression models relating soil moisture to observed wetland water levels to simulate the hydrologic behavior of four types of montane wetlands (ephemeral, intermediate, perennial, permanent wetlands) in the U. S. Pacific Northwest. The hybrid models captured observed wetland dynamics in many cases, though were less robust in others. We then used these models to a) hindcast historical wetland behavior in response to observed climate variability (1916-2010 or later) and classify wetland types, and b) project the impacts of climate change on montane wetlands using global climate model scenarios for the 2040s and 2080s (A1B emissions scenario). These future projections show that climate-induced changes to key driving variables (reduced snowpack, higher evapotranspiration, extended summer drought) will result in earlier and faster drawdown in Pacific Northwest montane wetlands, leading to systematic reductions in water levels, shortened wetland hydroperiods, and increased probability of drying. Intermediate hydroperiod wetlands are projected to experience the greatest changes. For the 2080s scenario, widespread conversion of intermediate wetlands to fast-drying ephemeral wetlands will likely reduce

Review of Constructed Subsurface Flow vs. Surface Flow Wetlands

International Nuclear Information System (INIS)

HALVERSON, NANCY

2004-01-01

The purpose of this document is to use existing documentation to review the effectiveness of subsurface flow and surface flow constructed wetlands in treating wastewater and to demonstrate the viability of treating effluent from Savannah River Site outfalls H-02 and H-04 with a subsurface flow constructed wetland to lower copper, lead and zinc concentrations to within National Pollutant Discharge Elimination System (NPDES) Permit limits. Constructed treatment wetlands are engineered systems that have been designed and constructed to use the natural functions of wetlands for wastewater treatment. Constructed wetlands have significantly lower total lifetime costs and often lower capital costs than conventional treatment systems. The two main types of constructed wetlands are surface flow and subsurface flow. In surface flow constructed wetlands, water flows above ground. Subsurface flow constructed wetlands are designed to keep the water level below the top of the rock or gravel media, thus minimizing human and ecological exposure. Subsurface flow wetlands demonstrate higher rates of contaminant removal per unit of land than surface flow (free water surface) wetlands, therefore subsurface flow wetlands can be smaller while achieving the same level of contaminant removal. Wetlands remove metals using a variety of processes including filtration of solids, sorption onto organic matter, oxidation and hydrolysis, formation of carbonates, formation of insoluble sulfides, binding to iron and manganese oxides, reduction to immobile forms by bacterial activity, and uptake by plants and bacteria. Metal removal rates in both subsurface flow and surface flow wetlands can be high, but can vary greatly depending upon the influent concentrations and the mass loading rate. Removal rates of greater than 90 per cent for copper, lead and zinc have been demonstrated in operating surface flow and subsurface flow wetlands. The constituents that exceed NPDES limits at outfalls H-02 a nd H

Optimal Power Allocation Algorithm for Radar Network Systems Based on Low Probability of Intercept Optimization(in English

Directory of Open Access Journals (Sweden)

Shi Chen-guang

2014-08-01

Full Text Available A novel optimal power allocation algorithm for radar network systems is proposed for Low Probability of Intercept (LPI technology in modern electronic warfare. The algorithm is based on the LPI optimization. First, the Schleher intercept factor for a radar network is derived, and then the Schleher intercept factor is minimized by optimizing the transmission power allocation among netted radars in the network to guarantee target-tracking performance. Furthermore, the Nonlinear Programming Genetic Algorithm (NPGA is used to solve the resulting nonconvex, nonlinear, and constrained optimization problem. Numerical simulation results show the effectiveness of the proposed algorithm.

Noise and intercept point calculation for modern radio receiver planning

DEFF Research Database (Denmark)

Iversen, Christian Rye; Kolding, T. E.

2001-01-01

The paper presents analytical expressions for determining noise and intercept points for cascaded radio receiver stages. The theory allows for active receiver stages with frequency selectivity and flexible impedance levels. This makes the method highly usable for planning of modem receivers where...

Using dual classifications in the development of avian wetland indices of biological integrity for wetlands in West Virginia, USA.

Science.gov (United States)

Veselka, Walter; Anderson, James T; Kordek, Walter S

2010-05-01

Considerable resources are being used to develop and implement bioassessment methods for wetlands to ensure that "biological integrity" is maintained under the United States Clean Water Act. Previous research has demonstrated that avian composition is susceptible to human impairments at multiple spatial scales. Using a site-specific disturbance gradient, we built avian wetland indices of biological integrity (AW-IBI) specific to two wetland classification schemes, one based on vegetative structure and the other based on the wetland's position in the landscape and sources of water. The resulting class-specific AW-IBI was comprised of one to four metrics that varied in their sensitivity to the disturbance gradient. Some of these metrics were specific to only one of the classification schemes, whereas others could discriminate varying levels of disturbance regardless of classification scheme. Overall, all of the derived biological indices specific to the vegetative structure-based classes of wetlands had a significant relation with the disturbance gradient; however, the biological index derived for floodplain wetlands exhibited a more consistent response to a local disturbance gradient. We suspect that the consistency of this response is due to the inherent nature of the connectivity of available habitat in floodplain wetlands.

North Dakota Wetlands Discovery Guide. Photocopy Booklet.

Science.gov (United States)

Dietz, Nancy J., Ed.; And Others

This booklet contains games and activities that can be photocopied for classroom use. Activities include Wetland Terminology, Putting on the Map, Erosional Forces, Water in...Water out, Who Lives Here?, Wetlands in Disguise, Dichotomous Plant Game, Algae Survey, Conducting an Algal Survey, Water Quality Indicators Guide, Farming Wetlands, Wetlands…

7 CFR 1410.11 - Farmable Wetlands Program.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Farmable Wetlands Program. 1410.11 Section 1410.11... Wetlands Program. (a) In addition to other allowable enrollments, land may be enrolled in this program through the Farmable Wetlands Program (FWP) within the overall Conservation Reserve Program provided for...

The relationship between energy expenditure and speed during pedestrian locomotion in birds: a morphological basis for the elevated y-intercept?

Science.gov (United States)

Halsey, Lewis G

2013-06-01

The slope of the typically linear relationship between metabolic rate and walking speed represents the net cost of transport (NCOT). The extrapolated y-intercept is often greater than resting metabolic rate, thus representing a fixed cost associated with pedestrian transport including body maintenance costs. The full cause of the elevated y-intercept remains elusive and it could simply represent experimental stresses. The present literature-based study compares the mass-independent energetic cost of pedestrian locomotion in birds (excluding those with an upright posture, i.e. penguins), represented by the y-intercept, to a known predictor of cost of transport, hip height. Both phylogenetically informed and non-phylogenetically informed analyses were undertaken to determine if patterns of association between hip height, body mass, and the y-intercept are robust with respect to the method of analysis. Body mass and hip height were significant predictors of the y-intercept in the best phylogenetically-informed and non-phylogenetically informed models. Thus there is evidence that, in birds at least, the elevated y-intercept is a legitimate component of locomotion energy expenditure. Hip height is probably a good proxy of effective limb length and thus perhaps birds with greater hip heights have lower y-intercepts because their longer legs more efficiently accommodate body motion and/or because their limbs are more aligned with the ground reaction forces. Copyright © 2013 Elsevier Inc. All rights reserved.

Methodology and measurement of radiation interception by quantum sensor of the oil palm plantation

Directory of Open Access Journals (Sweden)

Johari Endan

2005-09-01

Full Text Available Interception of light by a canopy is a fundamental requirement for crop growth and is important for biomass production and plant growth modeling. Solar radiation is an important parameter for photosynthesis and evapotranspiration. These two phenomena are dependent not only on the intensity of radiation but also on the distribution of intercepted radiation within the canopy. In this study, two operational methods for estimating the amount of photosynthetically active radiation (PAR intercepted by a canopy of the oil palm are presented. LICOR radiation sensors, model LI-190SA and model LI-191SA were used for photosynthetically active radiation (PAR measurement above and below the canopy. We developed two methods, namely "Triangular" method and "Circular" method for PAR measurement. Results show that both methods were suitable for oil palm PAR measurement. The triangular method is recommended for PAR measurements with respect to the whole plantation and the circular method is recommended for specific purposes, such as growth analysis or growth modeling of the oil palm. However, practical considerations such as equipment availability, purpose of the measurement, age of the palm, and the number of measuring points to be sampled should be taken into account in the selection of a suitable method for a particular study. The results indicate that the interception of radiation was affected by spatial variation, and the radiation transmission decreased towards the frond tips.

Education and training of future wetland scientists and managers

Science.gov (United States)

Wilcox, D.A.

2008-01-01

Wetland science emerged as a distinct discipline in the 1980s. In response, courses addressing various aspects of wetland science and management were developed by universities, government agencies, and private firms. Professional certification of wetland scientists began in the mid-1990s to provide confirmation of the quality of education and experience of persons involved in regulatory, management, restoration/construction, and research involving wetland resources. The education requirements for certification and the need for persons with specific wetland training to fill an increasing number of wetland-related positions identified a critical need to develop curriculum guidelines for an undergraduate wetland science and management major for potential accreditation by the Society of Wetland Scientists. That proposed major contains options directed toward either wetland science or management. Both options include required basic courses to meet the general education requirements of many universities, required upper-level specialized courses that address critical aspects of physical and biological sciences applicable to wetlands, and a minimum of four additional upper-level specialized courses that can be used to tailor a degree to students' interests. The program would be administered by an independent review board that would develop guidelines and evaluate university applications for accreditation. Students that complete the required coursework will fulfill the education requirements for professional wetland scientist certification and possess qualifications that make them attractive candidates for graduate school or entry-level positions in wetland science or management. Universities that offer this degree program could gain an advantage in recruiting highly qualified students with an interest in natural resources. Alternative means of educating established wetland scientists are likewise important, especially to provide specialized knowledge and experience or

EnviroAtlas - Potential Wetland Areas - Contiguous United States

Data.gov (United States)

U.S. Environmental Protection Agency — The EnviroAtlas Potential Wetland Areas (PWA) dataset shows potential wetland areas at 30-meter resolution. Beginning two centuries ago, many wetlands were turned...

Growth, light interception, radiation use efficiency and productivity of ...

African Journals Online (AJOL)

The purpose of this study was to assess the influence of sowing date on growth, light interception, radiation use efficiency and productivity of mungbean cultivars. The experiment comprised four sowing dates at ten days interval, viz. 08, 18, 28 July and 07 August 2006 and two cultivars, viz. Gofa local and MH-97-6.

Roofvogels in de Nederlandse wetlands

NARCIS (Netherlands)

Dijkstra, Cornelis; Beemster, Nicolaas; Zijlstra, Menno; van Eerden, M; Daan, Serge

1995-01-01

Roofvogels in de Nederlandse wetlands (1995). C. Dijkstra, N. Beemster, M. Zijlstra, M. van Eerden, S. Daan RWS, RDIJ, Flevobericht nr. 381. ISBN 90-369-1147-8. Dit Flevobericht vormt de eindrapportage van het onderzoeksproject " De betekenis van grootschalige wetlands voor roofvogels". De verwerkte

Carbon Storage in US Wetlands.

Science.gov (United States)

Background/Question/Methods Wetland soils contain some of the highest stores of soil carbon in the biosphere. However, there is little understanding of the quantity and distribution of carbon stored in US wetlands or of the potential effects of human disturbance on these stocks. ...

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree

Directory of Open Access Journals (Sweden)

Agustina Ventre-Lespiaucq

2018-05-01

Full Text Available Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees (Psidium guajava L. growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of

Sediment diatom species and community response to nitrogen addition in Oregon (USA) estuarine tidal wetlands

Science.gov (United States)

Sediment microalgae play an important role in nutrient cycling and are important primary producers in the food web in Pacific Northwest estuaries. This study examines the effects of nitrogen addition to benthic microalgae in tidal wetlands of Yaquina Bay estuary on the Oregon c...

A Modified Gash Model for Estimating Rainfall Interception Loss of Forest Using Remote Sensing Observations at Regional Scale

Directory of Open Access Journals (Sweden)

Yaokui Cui

2014-04-01

Full Text Available Rainfall interception loss of forest is an important component of water balance in a forested ecosystem. The Gash analytical model has been widely used to estimate the forest interception loss at field scale. In this study, we proposed a simple model to estimate rainfall interception loss of heterogeneous forest at regional scale with several reasonable assumptions using remote sensing observations. The model is a modified Gash analytical model using easily measured parameters of forest structure from satellite data and extends the original Gash model from point-scale to the regional scale. Preliminary results, using remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS products, field measured rainfall data, and meteorological data of the Automatic Weather Station (AWS over a picea crassifolia forest in the upper reaches of the Heihe River Basin in northwestern China, showed reasonable accuracy in estimating rainfall interception loss at both the Dayekou experimental site (R2 = 0.91, RMSE = 0.34 mm∙d −1 and the Pailugou experimental site (R2 = 0.82, RMSE = 0.6 mm∙d −1, compared with ground measurements based on per unit area of forest. The interception loss map of the study area was shown to be strongly heterogeneous. The modified model has robust physics and is insensitive to the input parameters, according to the sensitivity analysis using numerical simulations. The modified model appears to be stable and easy to be applied for operational estimation of interception loss over large areas.

A Preliminary Study on Rainfall Interception Loss and Water Yield Analysis on Arabica Coffee Plants in Central Aceh Regency, Indonesia

Directory of Open Access Journals (Sweden)

Reza Benara

2012-12-01

Full Text Available Rainfall interception loss from plants or trees can reduce a net rainfall as source of water yield. The amount of rainfall interception loss depends on kinds of plants and hydro-meteorological characteristics. Therefore, it is important to study rainfall interception loss such as from Arabica Coffee plantation which is as main agricultural commodity for Central Aceh Regency. In this study, rainfall interception loss from Arabica Coffee plants was studied in Kebet Village of Central Aceh Regency, Indonesia from January 20 to March 9, 2011. Arabica coffee plants used in this study was 15 years old, height of 1.5 m and canopy of 4.567 m2. Rainfall interception loss was determined based on water balance approach of daily rainfall, throughfall, and stemflow data. Empirical regression equation between rainfall interception loss and rainfall were adopted as a model to estimate rainfall interception loss from Arabica Coffee plantation, which the coefficient of correlation, r is 0.98. In water yield analysis, this formula was applied and founded that Arabica Coffee plants intercept 76% of annual rainfall or it leaved over annual net rainfall 24% of annual rainfall. Using this net rainfall, water yield produced from Paya Bener River which is the catchment area covered by Arabica Coffee plantation was analyzed in a planning of water supply project for water needs domestic of 3 sub-districts in Central Aceh Regency. Based on increasing population until year of 2025, the results showed that the water yield will be not enough from year of 2015. However, if the catchment area is covered by forest, the water yield is still enough until year of 2025

Development of soil properties and nitrogen cycling in created wetlands

Science.gov (United States)

Wolf, K.L.; Ahn, C.; Noe, G.B.

2011-01-01

Mitigation wetlands are expected to compensate for the loss of structure and function of natural wetlands within 5–10 years of creation; however, the age-based trajectory of development in wetlands is unclear. This study investigates the development of coupled structural (soil properties) and functional (nitrogen cycling) attributes of created non-tidal freshwater wetlands of varying ages and natural reference wetlands to determine if created wetlands attain the water quality ecosystem service of nitrogen (N) cycling over time. Soil condition component and its constituents, gravimetric soil moisture, total organic carbon, and total N, generally increased and bulk density decreased with age of the created wetland. Nitrogen flux rates demonstrated age-related patterns, with younger created wetlands having lower rates of ammonification, nitrification, nitrogen mineralization, and denitrification potential than older created wetlands and natural reference wetlands. Results show a clear age-related trajectory in coupled soil condition and N cycle development, which is essential for water quality improvement. These findings can be used to enhance N processing in created wetlands and inform the regulatory evaluation of mitigation wetlands by identifying structural indicators of N processing performance.

Mapping the Dabus Wetlands, Ethiopia, Using Random Forest Classification of Landsat, PALSAR and Topographic Data

Directory of Open Access Journals (Sweden)

Pierre Dubeau

2017-10-01

Full Text Available The Dabus Wetland complex in the highlands of Ethiopia is within the headwaters of the Nile Basin and is home to significant ecological communities and rare or endangered species. Its many interrelated wetland types undergo seasonal and longer-term changes due to weather and climate variations as well as anthropogenic land use such as grazing and burning. Mapping and monitoring of these wetlands has not been previously undertaken due primarily to their relative isolation and lack of resources. This study investigated the potential of remote sensing based classification for mapping the primary vegetation groups in the Dabus Wetlands using a combination of dry and wet season data, including optical (Landsat spectral bands and derived vegetation and wetness indices, radar (ALOS PALSAR L-band backscatter, and elevation (SRTM derived DEM and other terrain metrics as inputs to the non-parametric Random Forest (RF classifier. Eight wetland types and three terrestrial/upland classes were mapped using field samples of observed plant community composition and structure groupings as reference information. Various tests to compare results using different RF input parameters and data types were conducted. A combination of multispectral optical, radar and topographic variables provided the best overall classification accuracy, 94.4% and 92.9% for the dry and wet season, respectively. Spectral and topographic data (radar data excluded performed nearly as well, while accuracies using only radar and topographic data were 82–89%. Relatively homogeneous classes such as Papyrus Swamps, Forested Wetland, and Wet Meadow yielded the highest accuracies while spatially complex classes such as Emergent Marsh were more difficult to accurately classify. The methods and results presented in this paper can serve as a basis for development of long-term mapping and monitoring of these and other non-forested wetlands in Ethiopia and other similar environmental settings.

Hurricane-induced failure of low salinity wetlands

Science.gov (United States)

Howes, Nick C.; FitzGerald, Duncan M.; Hughes, Zoe J.; Georgiou, Ioannis Y.; Kulp, Mark A.; Miner, Michael D.; Smith, Jane M.; Barras, John A.

2010-01-01

During the 2005 hurricane season, the storm surge and wave field associated with Hurricanes Katrina and Rita eroded 527 km2 of wetlands within the Louisiana coastal plain. Low salinity wetlands were preferentially eroded, while higher salinity wetlands remained robust and largely unchanged. Here we highlight geotechnical differences between the soil profiles of high and low salinity regimes, which are controlled by vegetation and result in differential erosion. In low salinity wetlands, a weak zone (shear strength 500–1450 Pa) was observed ∼30 cm below the marsh surface, coinciding with the base of rooting. High salinity wetlands had no such zone (shear strengths > 4500 Pa) and contained deeper rooting. Storm waves during Hurricane Katrina produced shear stresses between 425–3600 Pa, sufficient to cause widespread erosion of the low salinity wetlands. Vegetation in low salinity marshes is subject to shallower rooting and is susceptible to erosion during large magnitude storms; these conditions may be exacerbated by low inorganic sediment content and high nutrient inputs. The dramatic difference in resiliency of fresh versus more saline marshes suggests that the introduction of freshwater to marshes as part of restoration efforts may therefore weaken existing wetlands rendering them vulnerable to hurricanes. PMID:20660777

32 CFR 644.319 - Protection of wetlands.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Protection of wetlands. 644.319 Section 644.319... ESTATE HANDBOOK Disposal § 644.319 Protection of wetlands. The requirements of Executive Order 11990, Protection of Wetlands, 42 FR 26961, (24 May 1977) are applicable to the disposal of Federal lands and...

Tree rings record 100 years of hydrologic change within a wetland

Science.gov (United States)

Yanosky, Thomas M.; Kappel, William M.

1997-01-01

One of the primary responsibilities of the Water Resources Division of the United States Geological Survey is to monitor the amount and quality of waters in our rivers, lakes, and wetlands. Hydrologists can evaluate these important resources in the present day, but how can they determine what conditions were like in past decades or even centuries? Moreover, are conditions part of a natural cycle or caused primarily by human activities? It is sometimes possible to answer these questions by examining the annual growth rings of trees. Each ring can be assigned an exact year of formation, and yearly differences in ring widths can be used to compare past and present conditions on a flood plain, along a river, or within a wetland. Thus, tree rings provide information that otherwise might be difficult or even impossible to obtain.

High intensity beam profile monitors for the LAMPF primary beam lines

International Nuclear Information System (INIS)

Hoffman, E.W.; Macek, R.J.; van Dyck, O.; Lee, D.; Harvey, A.; Bridge, J.; Cainet, J.

1979-01-01

Two types of beam profile monitors are in use at LAMPF to measure the properties of the 800 MeV, 500 μA proton beam external to the linac. Both types use secondary electron emission from a wire to produce a current signal proportional to the amount of proton beam that intercepts the wire. The wire scanner system uses a pair of orthogonal wires which are passed through the beam and the harp system uses two fixed planes of parallel wires. Most of the harps are not retractable and are exposed continuously to the primary beam. The high beam intensities available lead to a number of technical problems for instruments that intercept the beam or are close to primary beam targets. The thermal, electrical, radiation-damage, and material selection problems encountered, and some solutions which have been implemented are discussed

THE PROBLEM OF INTERCEPTING PARKING SYSTEMS DESIGN IN CITIES

Directory of Open Access Journals (Sweden)

E. Hetsovych

2014-10-01

Full Text Available Consistent determination of the main problems concerning the system of intercepting parking – lot design with the purpose of transport systems improvement downtown is grounded. The given approach allows to fully satisfy the demand for parking-lots of urban transport systems in combination with the system of downtown parkings and the capacity of the highway network.

Composition of dissolved organic nitrogen in rivers associated with wetlands

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Akira, E-mail: akiraw@agr.nagoya-u.ac.jp [Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601 (Japan); Tsutsuki, Kiyoshi [Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan); Inoue, Yudzuru [Graduate School of Science and Engineering, Saitama University, Sakura, Saitama 338-8570 (Japan); Maie, Nagamitsu [School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628 (Japan); Melling, Lulie [Tropical Peat Research Laboratory Unit, Chief Minister' s Department, Jalan Badruddin 93400, Kuching, Sarawak (Malaysia); Jaffé, Rudolf [Southeast Environmental Research Center, Florida International University, 3000 NE 151 Str., Marine Sciences Building, North Miami, FL 33181 (United States); Department of Chemistry and Biochemistry, Florida International University, 3000 NE 151 Str., Marine Sciences Building, North Miami, FL 33181 (United States)

2014-09-15

As basic information for assessing reactivity and functionality of wetland-associated dissolved organic matter (DOM) based on their composition and structural properties, chemical characteristics of N in ultrafiltered DOM (UDON; > 1 kD) isolated from wetland-associated rivers in three climates (cool-temperate, Hokkaido, Japan; sub-tropical, Florida, USA; tropical, Sarawak, Malaysia) were investigated. The UDON was isolated during dry and wet seasons, or during spring, summer, and autumn. The proportion of UDON present as humic substances, which was estimated as the DAX-8 adsorbed fraction, ranged from 47 to 91%, with larger values in the Sarawak than at the other sites. The yield of hydrolyzable amino acid N ranged 1.24 to 7.01mg g{sup −1}, which correlated positively to the total N content of UDOM and tended to be larger in the order of Florida > Hokkaido > Sarawak samples. X-ray photoelectron N1s spectra of UDON showed a strong negative correlation between the relative abundances of amide/peptide N and primary amine N. The relative abundances of amide/peptide N and primary amine N in the Sarawak samples were smaller (70–76%) and larger (20–23%) respectively compared to those (80–88% and 4–9%) in the Florida and Hokkaido samples. Assuming terminal amino groups and amide N of peptides as major constituents of primary amine N and amide/peptide N, respectively, the average molecular weight of peptides was smaller in the Sarawak samples than that in the Florida and Hokkaido samples. Seasonal variations in UDON composition were scarce in the Sarawak and Florida samples, whereas the distribution of humic substance-N and nonhumic substance-N and compositions of amino acids and N functional groups showed a clear seasonality in the Hokkaido samples. While aromatic N increased from spring to autumn, contributions from fresh proteinaceous materials were also enhanced during autumn, resulting in the highest N content of UDOM for this season. - Highlights: • DON in

Composition of dissolved organic nitrogen in rivers associated with wetlands

International Nuclear Information System (INIS)

Watanabe, Akira; Tsutsuki, Kiyoshi; Inoue, Yudzuru; Maie, Nagamitsu; Melling, Lulie; Jaffé, Rudolf

2014-01-01

As basic information for assessing reactivity and functionality of wetland-associated dissolved organic matter (DOM) based on their composition and structural properties, chemical characteristics of N in ultrafiltered DOM (UDON; > 1 kD) isolated from wetland-associated rivers in three climates (cool-temperate, Hokkaido, Japan; sub-tropical, Florida, USA; tropical, Sarawak, Malaysia) were investigated. The UDON was isolated during dry and wet seasons, or during spring, summer, and autumn. The proportion of UDON present as humic substances, which was estimated as the DAX-8 adsorbed fraction, ranged from 47 to 91%, with larger values in the Sarawak than at the other sites. The yield of hydrolyzable amino acid N ranged 1.24 to 7.01mg g −1 , which correlated positively to the total N content of UDOM and tended to be larger in the order of Florida > Hokkaido > Sarawak samples. X-ray photoelectron N1s spectra of UDON showed a strong negative correlation between the relative abundances of amide/peptide N and primary amine N. The relative abundances of amide/peptide N and primary amine N in the Sarawak samples were smaller (70–76%) and larger (20–23%) respectively compared to those (80–88% and 4–9%) in the Florida and Hokkaido samples. Assuming terminal amino groups and amide N of peptides as major constituents of primary amine N and amide/peptide N, respectively, the average molecular weight of peptides was smaller in the Sarawak samples than that in the Florida and Hokkaido samples. Seasonal variations in UDON composition were scarce in the Sarawak and Florida samples, whereas the distribution of humic substance-N and nonhumic substance-N and compositions of amino acids and N functional groups showed a clear seasonality in the Hokkaido samples. While aromatic N increased from spring to autumn, contributions from fresh proteinaceous materials were also enhanced during autumn, resulting in the highest N content of UDOM for this season. - Highlights: • DON in

The perceptual control of goal-directed locomotion: a common control architecture for interception and navigation?

Science.gov (United States)

Chardenon, A; Montagne, G; Laurent, M; Bootsma, R J

2004-09-01

Intercepting a moving object while locomoting is a highly complex and demanding ability. Notwithstanding the identification of several informational candidates, the role of perceptual variables in the control process underlying such skills remains an open question. In this study we used a virtual reality set-up for studying locomotor interception of a moving ball. The subject had to walk along a straight path and could freely modify forward velocity, if necessary, in order to intercept-with the head-a ball moving along a straight path that led it to cross the agent's displacement axis. In a series of experiments we manipulated a local (ball size) and a global (focus of expansion) component of the visual flow but also the egocentric orientation of the ball. The experimental observations are well captured by a dynamic model linking the locomotor acceleration to properties of both global flow and egocentric direction. More precisely the changes in locomotor velocity depend on a linear combination of the change in bearing angle and the change in egocentric orientation, allowing the emergence of adaptive behavior under a variety of circumstances. We conclude that the mechanisms underlying the control of different goal-directed locomotion tasks (i.e. steering and interceptive tasks) could share a common architecture.

Prediction CH4 Emissions from the Wetlands in the Sanjiang Plain of Northeastern China in the 21st Century.

Directory of Open Access Journals (Sweden)

Tingting Li

Full Text Available The Sanjiang Plain has been experienced significant wetland loss due to expanded agricultural activities, and will be potentially restored by the China National Wetland Conservation Action Plan (NWCP in future. The objective of this study is to evaluate the impact of future climate warming and wetland restoration on wetland CH4 emissions in northeast China. We used an atmosphere-vegetation interaction model (AVIM2 to drive a modified biogeophysical model (CH4MODwetland, and projected CH4 flux variations from the Sanjiang Plain wetlands under different Representative Concentration Pathway scenarios throughout the 21st century. Model validation showed that the regressions between the observed and simulated CH4 fluxes by the modified model produced an R2 of 0.49 with a slope of 0.87 (p<0.001, n = 237. According to the AVIM2 simulation, the net primary productivity of the Sanjiang Plain wetlands will increase by 38.2 g m-2 yr-1, 116.6 g m-2 yr-1 and 250.4 g m-2 yr-1 under RCP 2.6, RCP 4.5 and RCP 8.5, respectively, by the end of this century. For RCP 2.6, 4.5 and 8.5 scenarios, the CH4 fluxes will increase by 5.7 g m-2 yr-1, 57.5 g m-2 yr-1 and 112.2 g m-2 yr-1. Combined with the wetland restoration, the regional emissions will increase by 0.18‒1.52 Tg. The CH4 emissions will be stimulated by climate change and wetland restoration. Regional wetland restoration planning should be directed against different climate scenarios in order to suppress methane emissions.

Floodplain and Wetland Assessment for the Mortandad Wetland Enhancement and the DP Dissipater Projects at Los Alamos National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Hathcock, Charles Dean [Los Alamos National Laboratory

2017-03-31

This floodplain and wetland assessment was prepared in accordance with 10 Code of Federal Regulations (CFR) 1022 Compliance with Floodplain and Wetland Environmental Review Requirements, which was promulgated to implement the U.S. Department of Energy (DOE) requirements under Executive Order 11988 Floodplain Management and Executive Order 11990 Wetlands Protection. According to 10 CFR 1022, a 100-year floodplain is defined as “the lowlands adjoining inland and coastal waters and relatively flat areas and flood prone areas of offshore islands” and a wetland is defined as “an area that is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs, and similar areas.” In this action, DOE is proposing two projects to improve wetland and floodplain function at Los Alamos National Laboratory (LANL). The proposed work will comply with corrective action requirements under the Settlement Agreement and Stipulated Final Compliance Order (Settlement Agreement)1 Number HWB-14-20. The first project is located in Technical Areas (TA)-03 in upper Mortandad Canyon. The upper Mortandad wetlands have existing stormwater controls that need to be rehabilitated. Head-cut formation is occurring at the downstream portion of the wetland. This project will repair damages to the wetland and reduce the future erosion potential. The second project is located in TA-21 in Delta Prime (DP) Canyon. The intent of the DP Dissipater Project in DP Canyon is to install stormwater control structures in DP Canyon to retain low channel flows and reduce downstream sediment transport as well as peak flows during low and moderate storm events. Due to increased erosion, the stream bank in this area has unstable vertical walls within the stream channel. The DOE prepared this floodplain and wetland

A Carbon Cycle Model for the Social-Ecological Process in Coastal Wetland: A Case Study on Gouqi Island, East China

Directory of Open Access Journals (Sweden)

Yanxia Li

2017-01-01

Full Text Available Coastal wetlands offer many important ecosystem services both in natural and in social systems. How to simultaneously decrease the destructive effects flowing from human activities and maintaining the sustainability of regional wetland ecosystems are an important issue for coastal wetlands zones. We use carbon credits as the basis for regional sustainable developing policy-making. With the case of Gouqi Island, a typical coastal wetlands zone that locates in the East China Sea, a carbon cycle model was developed to illustrate the complex social-ecological processes. Carbon-related processes in natural ecosystem, primary industry, secondary industry, tertiary industry, and residents on the island were identified in the model. The model showed that 36780 tons of carbon is released to atmosphere with the form of CO2, and 51240 tons of carbon is captured by the ecosystem in 2014 and the three major resources of carbon emission are transportation and tourism development and seawater desalination. Based on the carbon-related processes and carbon balance, we proposed suggestions on the sustainable development strategy of Gouqi Island as coastal wetlands zone.

A Carbon Cycle Model for the Social-Ecological Process in Coastal Wetland: A Case Study on Gouqi Island, East China

Science.gov (United States)

Xiong, Lihu; Zhu, Wenjia

2017-01-01

Coastal wetlands offer many important ecosystem services both in natural and in social systems. How to simultaneously decrease the destructive effects flowing from human activities and maintaining the sustainability of regional wetland ecosystems are an important issue for coastal wetlands zones. We use carbon credits as the basis for regional sustainable developing policy-making. With the case of Gouqi Island, a typical coastal wetlands zone that locates in the East China Sea, a carbon cycle model was developed to illustrate the complex social-ecological processes. Carbon-related processes in natural ecosystem, primary industry, secondary industry, tertiary industry, and residents on the island were identified in the model. The model showed that 36780 tons of carbon is released to atmosphere with the form of CO2, and 51240 tons of carbon is captured by the ecosystem in 2014 and the three major resources of carbon emission are transportation and tourism development and seawater desalination. Based on the carbon-related processes and carbon balance, we proposed suggestions on the sustainable development strategy of Gouqi Island as coastal wetlands zone. PMID:28286690

2011 Summary: Coastal wetland restoration research

Science.gov (United States)

Kowalski, Kurt P.; Wiley, Michael J.; Wilcox, Douglas A.; Carlson Mazur, Martha L.; Czayka, Alex; Dominguez, Andrea; Doty, Susan; Eggleston, Mike; Green, Sean; Sweetman, Amanda

2014-01-01

The Great Lakes Restoration Initiative (GLRI) projects currently taking place in Great Lakes coastal wetlands provide a unique opportunity to study ecosystem response to management actions as practitioners strive to improve wetland function and increase ecosystem services. Through a partnership between the U.S. Geological Survey – Great Lakes Science Center (GLSC), U.S. Fish and Wildlife Service (USFWS), and Ducks Unlimited, a GLRI-funded project has reestablished the hydrologic connection between an intensively managed impounded wetland (Pool 2B) and Crane Creek, a small Lake Erie tributary, by building a water-control structure that was opened in the spring of 2011. The study site is located within the USFWS Ottawa National Wildlife Refuge (ONWR) and lies within the boundaries of the U.S. Environmental Protection Agency (EPA)-designated Maumee River Area of Concern. The broad objective of the project is to evaluate how hydrologically reconnecting a previously diked wetland impacts fish, mollusks, and other biota and affects nutrient transport, nutrient cycling, water quality, flood storage, and many other abiotic conditions. The results from this project suggest large system-wide benefits from sustainable reestablishment of lake-driven hydrology in this and other similar systems. We comprehensively sampled water chemistry, fish, birds, plants, and invertebrates in Crane Creek coastal wetlands, Pool 2A (a reference diked wetland), and Pool 2B (the reconnected wetland) in 2010 and 2011 to: 1) Characterize spatial and seasonal patterns for these parameters. 2) Examine ecosystem response to the opening of a water-control structure that allows fish passage Our sampling efforts have yielded data that reveal striking changes in water quality, hydrology, and fish assemblages in our experimental unit (2B). Prior to the reconnection, the water chemistry in pools 2A and 2B were very similar. Afterwards, we found that the water chemistry in reconnected Pool 2B was more

Improving the representation of radiation interception and photosynthesis for climate model applications

International Nuclear Information System (INIS)

Mercado, Lina M.; Huntingford, Chris; Gash, John H.C.; Cox, Peter M.; Jogireddy, Venkata

2007-01-01

The Joint UK Land Environment Simulator (JULES) (which is based on Met Office Surface Exchange Scheme MOSES), the land surface scheme of the Hadley Centre General Circulation Models (GCM) has been improved to contain an explicit description of light interception for different canopy levels, which consequently leads to a multilayer approach to scaling from leaf to canopy level photosynthesis. We test the improved JULES model at a site in the Amazonian rainforest by comparing against measurements of vertical profiles of radiation through the canopy, eddy covariance measurements of carbon and energy fluxes, and also measurements of carbon isotopic fractionation from top canopy leaves. Overall, the new light interception formulation improves modelled photosynthetic carbon uptake compared to the standard big leaf approach used in the original JULES formulation. Additional model improvement was not significant when incorporating more realistic vertical variation of photosynthetic capacity. Even with the improved representation of radiation interception, JULES simulations of net carbon uptake underestimate eddy covariance measurements by 14%. This discrepancy can be removed by either increasing the photosynthetic capacity throughout the canopy or by explicitly including light inhibition of leaf respiration. Along with published evidence of such inhibition of leaf respiration, our study suggests this effect should be considered for inclusion in other GCMs

Gas Research Institute wetland research program

International Nuclear Information System (INIS)

Wilkey, P.L.; Zimmerman, R.E.; Isaacson, H.R.

1992-01-01

As part of three ongoing research projects, the Gas Research Institute (GRI) is studying the natural gas industry's impacts on wetlands and how to manage operations so that impacts can be minimized or eliminated. The objective of the first project is to gain a better understanding of the causes and processes of wetland loss in the Louisiana deltaic plain and what role gas pipeline canals play in wetland loss. On the basis of information gathered from the first projects, management and mitigation implications for pipeline construction and maintenance will be evaluated. The objective of the second project is to assess the floral and faunal communities on existing rights-of-way (ROWs) that pass through numerous types of wetlands across the United States. The emphasis of the project is on pipelines that were installed within the past five years. The objective of the third project is to evaluate the administrative, jurisdictional, technical, and economic issues of wetland mitigation banking. This paper discusses these projects, their backgrounds, some of the results to date, and the deliverables

Broken connections of wetland cultural knowledge

Science.gov (United States)

Middleton, Beth A.

2016-01-01

As global agriculture intensifies, cultural knowledge of wetland utilization has eroded as natural resources become more stressed, and marginal farmers move away from the land. The excellent paper by Fawzi et al. (2016) documents a particularly poignant case of traditional knowledge loss among the Marsh Arab women of Iraq. Through interviews, the authors document the breakdown of skill transfer from the older to younger generation of women. The authors link the loss of their cultural knowledge with the loss of wetlands in the region. Women no longer can help provide for their families using wetland products, and along with that, their ancient knowledge of plant usage is lost. These ancient skills included medicinal uses, and reed harvesting for weaving and water buffalo fodder. As, the majority of the Mesopotamian Marshes have dried, this way of life is being forgotten (Fawzi et al. 2015). The global tragedy is that while the careful alliance of wetlands and people have sustained human cultures for millennia, degraded wetlands lose their ability to provide these services (Maltby 1980).

Object-Based Image Analysis in Wetland Research: A Review

Directory of Open Access Journals (Sweden)

Iryna Dronova

2015-05-01

Full Text Available The applications of object-based image analysis (OBIA in remote sensing studies of wetlands have been growing over recent decades, addressing tasks from detection and delineation of wetland bodies to comprehensive analyses of within-wetland cover types and their change. Compared to pixel-based approaches, OBIA offers several important benefits to wetland analyses related to smoothing of the local noise, incorporating meaningful non-spectral features for class separation and accounting for landscape hierarchy of wetland ecosystem organization and structure. However, there has been little discussion on whether unique challenges of wetland environments can be uniformly addressed by OBIA across different types of data, spatial scales and research objectives, and to what extent technical and conceptual aspects of this framework may themselves present challenges in a complex wetland setting. This review presents a synthesis of 73 studies that applied OBIA to different types of remote sensing data, spatial scale and research objectives. It summarizes the progress and scope of OBIA uses in wetlands, key benefits of this approach, factors related to accuracy and uncertainty in its applications and the main research needs and directions to expand the OBIA capacity in the future wetland studies. Growing demands for higher-accuracy wetland characterization at both regional and local scales together with advances in very high resolution remote sensing and novel tasks in wetland restoration monitoring will likely continue active exploration of the OBIA potential in these diverse and complex environments.

VEGETATION MAPPING IN WETLANDS

Directory of Open Access Journals (Sweden)

F. PEDROTTI

2004-01-01

Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

76 FR 79145 - Floodplain Management and Protection of Wetlands

Science.gov (United States)

2011-12-21

...] RIN 2501-AD51 Floodplain Management and Protection of Wetlands Correction In proposed rule document... Type of proposed action Type of proposed action (new Wetlands or 100- Non-wetlands area reviewable... construction in wetlands locations. \\2\\ Or those paragraphs of Sec. 55.20 that are applicable to an action...

The Role of Driving Factors in Historical and Projected Carbon Dynamics in Wetland Ecosystems of Alaska

Science.gov (United States)

Lyu, Z.; Helene, G.; He, Y.; Zhuang, Q.; McGuire, A. D.; Bennett, A.; Breen, A. L.; Clein, J.; Euskirchen, E. S.; Johnson, K. D.; Kurkowski, T. A.; Pastick, N. J.; Rupp, S. T.; Wylie, B. K.; Zhu, Z.

2017-12-01

Wetlands are important terrestrial ecosystems in Alaska. It is important to understand and assess their role in the regional carbon dynamics in response to historical and projected environmental conditions. A coupled modeling framework that incorporates a fire disturbance model and two biogeochemical models was used to assess the relative influence of changing climate, atmospheric carbon dioxide (CO2) concentration, and fire regime on the historical and future carbon balance in wetland ecosystems of the four main Landscape Conservation Cooperatives (LCCs) of Alaska. Simulations were conducted for the historical period (1950-2009) and future projection period (2010-2099). These simulations estimate that the total carbon (C) storage in wetland ecosystems of Alaska is 5556 Tg C in 2009, with 89% of the C stored in soils. An estimated 175 Tg C was lost during the historical period, which is attributed to greater C lost from the Northwest Boreal LCC than C gained from the other three LCCs. The simulations for the projection period were conducted for six different scenarios driven by climate forcings from two different climate models for each of three CO2 emission scenarios. The mean total carbon storage increased 3.94 Tg C/yr by 2099, with variability among the simulations ranging from 2.02 Tg C/yr to 4.42 Tg C/yr. Across the four LCCs, the largest relative C storage increase occurred in the Arctic and North Pacific LCCs. These increases were primarily driven by increases in net primary production (NPP) that were greater than increases in heterotrophic respiration and fire emissions. Our analysis further indicates that NPP increase was primarily driven by CO2 fertilization ( 5% per 100 ppmv increase) as well as by increases in air temperature ( 1% per ° increase). Increases air temperature were estimated to be the primary cause for a projected 47.7% mean increase in wetlands biogenic CH4 emissions among the simulations ( 15% per ° increase). The combined effects of

Teacher Valuation and Use of Posters to Promote Sustainability of Wetlands in Kenya

Science.gov (United States)

Ndaruga, Ayub Macharia

2009-01-01

Posters have a long history of use as tools to promote awareness on diverse issues including environmental conservation. A study was done using 39 primary school teachers in Kenya to explore their valuation and use of a wetlands poster during their teaching at school and within the community. The teachers were sampled using a non-purposive,…

A simple method to estimate radiation interception by nursery stock conifers: a case study of eastern white cedar

NARCIS (Netherlands)

Pronk, A.A.; Goudriaan, J.; Stilma, E.S.C.; Challa, H.

2003-01-01

A simple method was developed to estimate the fraction radiation intercepted by small eastern white cedar plants (Thuja occidentalis 'Brabant'). The method, which describes the crop canopy as rows of cuboids, was compared with methods used for estimating radiation interception by crops with

Wetlands in a changing climate: Science, policy and management

Science.gov (United States)

Moomaw, William R.; Chmura, G.L.; Davies, Gillian T.; Finlayson, Max; Middleton, Beth A.; Natali, Sue M.; Perry, James; Roulet, Nigel; Sutton-Grier, Ariana

2018-01-01

Part 1 of this review synthesizes recent research on status and climate vulnerability of freshwater and saltwater wetlands, and their contribution to addressing climate change (carbon cycle, adaptation, resilience). Peatlands and vegetated coastal wetlands are among the most carbon rich sinks on the planet sequestering approximately as much carbon as do global forest ecosystems. Estimates of the consequences of rising temperature on current wetland carbon storage and future carbon sequestration potential are summarized. We also demonstrate the need to prevent drying of wetlands and thawing of permafrost by disturbances and rising temperatures to protect wetland carbon stores and climate adaptation/resiliency ecosystem services. Preventing further wetland loss is found to be important in limiting future emissions to meet climate goals, but is seldom considered. In Part 2, the paper explores the policy and management realm from international to national, subnational and local levels to identify strategies and policies reflecting an integrated understanding of both wetland and climate change science. Specific recommendations are made to capture synergies between wetlands and carbon cycle management, adaptation and resiliency to further enable researchers, policy makers and practitioners to protect wetland carbon and climate adaptation/resiliency ecosystem services.

Effects of sediment removal on vegetation communities in Rainwater Basin playa wetlands.

Science.gov (United States)

Beas, Benjamin J; Smith, Loren M; LaGrange, Theodore G; Stutheit, Randy

2013-10-15

Sedimentation from cultivated agricultural land use has altered the natural hydrologic regimes of depressional wetlands in the Great Plains. These alterations can negatively affect native wetland plant communities. Our objective was to determine if restored wetlands are developing plant communities similar to reference wetland conditions following hydrologic restoration. For this study, hydrology was restored via sediment removal. Thirty-four playa wetlands in reference, restored, and agricultural condition within the Rainwater Basin Region of Nebraska were sampled in 2008 and 2009. In 2008, reference and restored wetlands had higher species richness and more native, annual, and perennial species than agricultural wetlands. Restored wetlands had similar exotic species richness compared to reference and agricultural wetlands; however, reference wetlands contained more than agricultural wetlands. Restored wetlands proportion of exotics was 3.5 and 2 times less than agricultural wetlands and reference wetlands respectively. In 2009, reference and restored wetlands had higher species richness, more perennial species, and more native species than agricultural wetlands. Restored wetlands contained a greater number and proportion of annuals than reference and agricultural wetlands. Canonical Correspondence Analysis showed that reference, restored, and agricultural wetlands are dominated by different plant species and guilds. Restored wetland plant communities do not appear to be acting as intermediates between reference and agricultural wetland conditions or on a trajectory to reach reference conditions. This may be attributed to differing seed bank communities between reference and restored wetlands, dispersal limitations of perennial plant guilds associated with reference wetland conditions, and/or management activities may be preventing restored wetlands from reaching reference status. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydraulic and hydrological aspects of an evapotranspiration-constructed wetland combined system for household greywater treatment.

Science.gov (United States)

Filho, Fernando Jorge C Magalhães; Sobrinho, Teodorico Alves; Steffen, Jorge L; Arias, Carlos A; Paulo, Paula L

2018-05-12

Constructed wetlands systems demand preliminary and primary treatment to remove solids present in greywater (GW) to avoid or reduce clogging processes. The current paper aims to assess hydraulic and hydrological behavior in an improved constructed wetland system, which has a built-in anaerobic digestion chamber (AnC), GW is distributed to the evapotranspiration and treatment tank (CEvaT), combined with a subsurface horizontal flow constructed wetland (SSHF-CW). The results show that both the plants present in the units and the AnC improve hydraulic and volumetric efficiency, decrease short-circuiting and improve mixing conditions in the system. Moreover, the hydraulic conductivity measured on-site indicates that the presence of plants in the system and the flow distribution pattern provided by the AnC might reduce clogging in the SSHF-CW. It is observed that rainfall enables salt elimination, thus increasing evapotranspiration (ET), which promotes effluent reduction and enables the system to have zero discharge when reuse is unfeasible.

Hydrology and Ecology of Freshwater Wetlands in Central Florida - A Primer

Science.gov (United States)

Haag, Kim H.; Lee, Terrie M.

2010-01-01

Freshwater wetlands are an integral part of central Florida, where thousands are distributed across the landscape. However, their relatively small size and vast numbers challenge efforts to characterize them collectively as a statewide water resource. Wetlands are a dominant landscape feature in Florida; in 1996, an estimated 11.4 million acres of wetlands occupied 29 percent of the area of the State. Wetlands represent a greater percentage of the land surface in Florida than in any other state in the conterminous United States. Statewide, 90 percent of the total wetland area is freshwater wetlands and 10 percent is coastal wetlands. About 55 percent of the freshwater wetlands in Florida are forested, 25 percent are marshes and emergent wetlands, 18 percent are scrub-shrub wetlands, and the remaining 2 percent are freshwater ponds. Freshwater wetlands are distributed differently in central Florida than in other parts of the State. In the panhandle and in northern Florida, there are fewer isolated wetlands than in the central and southern parts of the State, and few of those wetlands are affected by activities such as groundwater withdrawals. In southern Florida, the vast wetlands of the Everglades and the Big Cypress Swamp blanket the landscape and form contiguous shallow expanses of water, which often exhibit slow but continuous flow toward the southwestern coast. In contrast, the wetlands of central Florida are relatively small, numerous, mostly isolated, and widely distributed. In many places, wetlands are flanked by uplands, generating a mosaic of contrasting environments-unique wildlife habitat often adjacent to dense human development. As the population of central Florida increases, the number of residents living near wetlands also increases. Living in close proximity to wetlands provides many Floridians with an increased awareness of nature and an opportunity to examine the relationship between people and wetlands. Specifically, these residents can observe

Nitrous oxide and methane emission in an artificial wetland treating polluted runoff from an agricultural catchment

Science.gov (United States)

Mander, Ülo; Tournebize, Julien; Soosaar, Kaido; Chaumont, Cedric; Hansen, Raili; Muhel, Mart; Teemusk, Alar; Vincent, Bernard

2015-04-01

An artificial wetland built in 2010 to reduce water pollution in a drained agricultural watershed showed real potential for pesticide and nitrate removal. The 1.2 ha off-shore wetland with a depth of from 0.1 to 1 m intercepts drainage water from a 450 ha watershed located near the village of Rampillon (03°03'37.3'' E, 48°32'16.7'' N, 70 km south-east of Paris, France). A sluice gate installed at the inlet makes it possible to close the wetland during the winter months (December - March), when no pesticides are applied and rainfall events are more frequent. The flow entering the wetland fluctuates from 0 to 120 L/s. The wetland is partially covered by Carex spp., Phragmites australis, Juncus conglomeratus, Typha latifolia and philamentous algae. Since 2011, an automatic water quality monitoring system measures water discharge, temperature, dissolved O2, conductivity pH, NO3- and DOC in both inlet and outlet. In May 2014, an automatic weather station and Campbell Irgason system for the measurement of CO2 and H2O fluxes were installed in the middle of the wetland. In May and November 2014 one-week high frequency measurement campaigns were conducted to study N2O and CH4 fluxes using 6 manually operated opaque floating static chambers and 12 floating automatic dynamic chambers. The latter were operated via multiplexer and had an incubation time of 5 minutes, whereas the gas flow was continuously measured using the Aerodyne TILDAS quantum cascade laser system. During the campaign, the reduction of NO3- concentration was measured in nine reactor pipes. Also, water samples were collected for N2O and N2 isotope analysis, and sediments were collected for potential N2 emission measurements. In May, the hydraulic retention time (HRT) was 30 days, and the average NO3- concentration decreased from 24 in the inflow to 0 mg/L in the outflow. Methane flux was relatively high (average 1446, variation 0.2-113990 μg CH4-C m-2 h-1), while about 2/3 was emitted via ebullition

When up is down in 0g: how gravity sensing affects the timing of interceptive actions.

Science.gov (United States)

Senot, Patrice; Zago, Myrka; Le Séac'h, Anne; Zaoui, Mohammed; Berthoz, Alain; Lacquaniti, Francesco; McIntyre, Joseph

2012-02-08

Humans are known to regulate the timing of interceptive actions by modeling, in a simplified way, Newtonian mechanics. Specifically, when intercepting an approaching ball, humans trigger their movements a bit earlier when the target arrives from above than from below. This bias occurs regardless of the ball's true kinetics, and thus appears to reflect an a priori expectation that a downward moving object will accelerate. We postulate that gravito-inertial information is used to tune visuomotor responses to match the target's most likely acceleration. Here we used the peculiar conditions of parabolic flight--where gravity's effects change every 20 s--to test this hypothesis. We found a striking reversal in the timing of interceptive responses performed in weightlessness compared with trials performed on ground, indicating a role of gravity sensing in the tuning of this response. Parallels between these observations and the properties of otolith receptors suggest that vestibular signals themselves might plausibly provide the critical input. Thus, in addition to its acknowledged importance for postural control, gaze stabilization, and spatial navigation, we propose that detecting the direction of gravity's pull plays a role in coordinating quick reactions intended to intercept a fast-moving visual target.

Inclusion of Riparian Wetland Module (RWM) into the SWAT model for assessment of wetland hydrological benefit

Science.gov (United States)

Wetlands are an integral part of many agricultural watersheds. They provide multiple ecosystem functions, such as improving water quality, mitigating flooding, and serving as natural habitats. Those functions are highly depended on wetland hydrological characteristics and their connectivity to the d...

Hydrologic connectivity to streams increases nitrogen and phosphorus inputs and cycling in soils of created and natural floodplain wetlands.

Science.gov (United States)

Wolf, Kristin L; Noe, Gregory B; Ahn, Changwoo

2013-07-01

Greater connectivity to stream surface water may result in greater inputs of allochthonous nutrients that could stimulate internal nitrogen (N) and phosphorus (P) cycling in natural, restored, and created riparian wetlands. This study investigated the effects of hydrologic connectivity to stream water on soil nutrient fluxes in plots ( = 20) located among four created and two natural freshwater wetlands of varying hydrology in the Piedmont physiographic province of Virginia. Surface water was slightly deeper; hydrologic inputs of sediment, sediment-N, and ammonium were greater; and soil net ammonification, N mineralization, and N turnover were greater in plots with stream water classified as their primary water source compared with plots with precipitation or groundwater as their primary water source. Soil water-filled pore space, inputs of nitrate, and soil net nitrification, P mineralization, and denitrification enzyme activity (DEA) were similar among plots. Soil ammonification, N mineralization, and N turnover rates increased with the loading rate of ammonium to the soil surface. Phosphorus mineralization and ammonification also increased with sedimentation and sediment-N loading rate. Nitrification flux and DEA were positively associated in these wetlands. In conclusion, hydrologic connectivity to stream water increased allochthonous inputs that stimulated soil N and P cycling and that likely led to greater retention of sediment and nutrients in created and natural wetlands. Our findings suggest that wetland creation and restoration projects should be designed to allow connectivity with stream water if the goal is to optimize the function of water quality improvement in a watershed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The significant surface-water connectivity of "geographically isolated wetlands"

Science.gov (United States)

Calhoun, Aram J.K.; Mushet, David M.; Alexander, Laurie C.; DeKeyser, Edward S.; Fowler, Laurie; Lane, Charles R.; Lang, Megan W.; Rains, Mark C.; Richter, Stephen; Walls, Susan

2017-01-01

We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be “geographically isolated” (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered to be “geographically isolated” shows the difficulties in grouping an ecological resource that does not reliably indicate lack of surface water connectivity in order to meet legal, regulatory, or scientific needs. Additionally, the practice of identifying “geographically isolated wetlands” based on distance from a stream can result in gross overestimates of the number of wetlands lacking ecologically important surface-water connections. Our findings do not support use of the overly simplistic label of “geographically isolated wetlands”. Wetlands surrounded by uplands vary in function and surface-water connections based on wetland landscape setting, context, climate, and geographic region and should be evaluated as such. We found that the “geographically isolated” grouping does not reflect our understanding of the hydrologic variability of these wetlands and hence does not benefit conservation of the Nation’s diverse wetland resources. Therefore, we strongly discourage use of categorizations that provide overly simplistic views of surface-water connectivity of wetlands fully embedded in upland landscapes.

China's natural wetlands: past problems, current status, and future challenges

Science.gov (United States)

Shuqing An; Harbin Li; Baohua Guan; Changfang Zhou; Zhongsheng Wang; Zifa Deng; Yingbiao Zhi; Yuhong Liu; Chi Xu; Shubo Fang; Jinhui Jiang; Hongli Li

2007-01-01

Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% coastal wetlands) because of the wetland reclamation during China's long history of civilization, and the...

Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.

Science.gov (United States)

Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R

2014-09-15

Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads. Copyright © 2014 Elsevier B.V. All rights reserved.

Deposition and interception of radionuclides. Current knowledge and future requirements

International Nuclear Information System (INIS)

1998-12-01

Following an accidental or routine release of radionuclides into the environment, a good knowledge of deposition processes is necessary in order to accurately predict the radiation dose to members of the public. In order to understand the environmental impact of released radionuclides and their transfer through the environment, including the food chain to man, there have been numerous studies on deposition of radionuclides to a range of surfaces such as bare soil, crops, forests, water bodies and urban surfaces. The RADREM committee provides a forum for liaison on UK research and monitoring in the areas of radioactive substances and radioactive waste management. RADREM has set up four sub-committees to cover issues related to radioactivity in the atmospheric, terrestrial and aquatic environments as well as those related radioactive waste management. One of the sub-committee tasks is to organise seminars and workshops on specific topics of interest. The first of these was the workshop on 'Deposition and Interception of Radionuclides: Current knowledge and future requirements' organised last year by the Ministry of Agriculture, Fisheries and Food (MAFF), acting as secretariat for the Terrestrial Environment Sub-Committee (TESC) of RADREM. The intent of this workshop was to provide an opportunity to exchange information on deposition-related aspects between representatives from various interested parties including government, regulatory bodies, industry and research organisations. Through presentations and discussions, this workshop addressed current developments in the areas of deposition and interception of radionuclides by various surfaces and served to identify areas which need further research. Papers were presented on various aspects of deposition and interception of radionuclides including deposition into grass, fruits and other crops as well as deposition into urban areas and forests

Use of created cattail ( Typha) wetlands in mitigation strategies

Science.gov (United States)

Dobberteen, Ross A.; Nickerson, Norton H.

1991-11-01

In order to balance pressures for land-use development with protection of wetland resources, artificial wetlands have been constructed in an effort to replace lost ecosystems. Despite its regulatory appeal and prominent role in current mitigation strategies, it is unclear whether or not created systems actually compensate for lost wetland resources. Mitigation predictions that rely on artificial wetlands must be analyzed critically in terms of their efficacy. Destruction of wetlands due to burial by coal fly ash at a municipal landfill in Danvers, Massachusetts, USA, provided an opportunity to compare resulting growth of created cattail ( Typha) marshes with natural wetland areas. Once the appropriate cattail species was identified for growth under disturbed landfill conditions, two types of artificial wetlands were constructed. The two systems differed in their hydrologic attributes: while one had a surface water flow characteristic of most cattail wetlands, the second system mimicked soil and water conditions found in naturally occurring floating cattail marshes. Comparison of plant growth measurements for two years from the artificial systems with published values for natural cattail marshes revealed similar structure and growth patterns. Experiments are now in progress to investigate the ability of created cattail marshes to remove and accumulate heavy metals from polluted landfill leachate. Research of the type reported here must be pursued aggressively in order to document the performance of artificial wetlands in terms of plant structure and wetland functions. Such research should allow us to start to evaluate whether artificial systems actually compensate for lost wetlands by performing similar functions and providing the concomitant public benefits.

Distribution and turnover of carbon in natural and constructed wetlands in the Florida Everglades

International Nuclear Information System (INIS)

Stern, J.; Wang, Y.; Gu, B.; Newman, J.

2007-01-01

Stable and radiocarbon isotopic contents of dissolved organic C (DOC), dissolved inorganic C (DIC), particulate organic C (POC) and plants were used to examine the source and turnover rate of C in natural and constructed wetlands in the Florida Everglades. DOC concentrations decreased, with P concentrations, along a water quality gradient from the agriculturally impacted areas in the northern Everglades to the more pristine Everglades National Park. δ 13 C values of DOC in the area reflect contributions of both wetland vegetation and sugarcane from agriculture. Radiocarbon ages of DOC, POC and DIC in the Everglades ranged from 2.01 ka BP to '>modern'. The old 14 C ages of DOC and POC were found in impacted areas near the Everglades Agricultural Area (EAA) in the northern Everglades. In contrast, DOC and POC in pristine marsh areas had near modern or '>modern' 14 C ages. These data indicate that a major source of POC and DOC in impacted areas is the degradation of historic peat deposits in the EAA. In the pristine areas of the marsh, DOC represents a mix of modern and historic C sources, whereas POC comes from modern primary production as indicated by positive Δ 14 C values, suggesting that DOC is transported farther away from its source than POC. High Δ 14 C values of DIC indicate that dissolution of limestone bedrock is not a significant source of DIC in the Everglades wetlands. As a restored wetland moves towards its 'original' or 'natural' state, the 14 C signatures of DOC should approach that of modern atmosphere. In addition, measurements of concentration and C isotopic composition of DOC in two small constructed wetlands (i.e., test cells) indicate that these freshwater wetland systems contain a labile DOC pool with rapid turnover times of 26-39 days and that the test cells are overall net sinks of DOC

Hydroclimate-driven changes in the landscape structure of the terminal lakes and wetlands of the China's Heihe River Basin.

Science.gov (United States)

Xiao, Shengchun; Xiao, Honglang; Peng, Xiaomei; Song, Xiang

2015-01-01

Changes in the landscape structure of terminal lakes and wetlands along inland rivers in arid areas are determined by the water balance in the river basins under the impacts of climate change and human activities. Studying the evolution of these landscapes and the mechanisms driving these changes is critical to the sustainable development of river basins. The terminal lakes and wetlands along the lower reaches of the Heihe River, an inland river in arid northwestern China, can be grouped into three types: runoff-recharged, groundwater-recharged, and precipitation-recharged. These water-recharge characteristics determine the degree to which the landscape structure of a terminal lake or wetland is impacted by climate change and human activities. An analysis of seven remote-sensing and hydroclimatic data sets for the Heihe River basin during the last 50 years indicates that hydrological changes in the basin caused by regional human activities were the primary drivers of the observed changes in the spatial and temporal landscape-structure patterns of the terminal lakes and wetlands of the Heihe River. In this warm, dry climatic context, the lakes and wetlands gradually evolved toward and maintained a landscape dominated by saline-alkaline lands and grasslands.

Retention and chemical speciation of uranium in an oxidized wetland sediment from the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Li, Dien; Seaman, John C.; Chang, Hyun-Shik; Jaffe, Peter R.; Koster van Groos, Paul; Jiang, De-Tong; Chen, Ning; Lin, Jinru; Arthur, Zachary; Pan, Yuanming; Scheckel, Kirk G.; Newville, Matthew; Lanzirotti, Antonio; Kaplan, Daniel I.

2014-05-01

Uranium speciation and retention mechanism onto Savannah River Site (SRS) wetland sediments was studied using batch (ad)sorption experiments, sequential extraction desorption tests and U L{sub 3}-edge X-ray absorption near-edge structure (XANES) spectroscopy of contaminated wetland sediments. U was highly retained by the SRS wetland sediments. In contrast to other similar but much lower natural organic matter (NOM) sediments, significant sorption of U onto the SRS sediments was observed at pH <4 and pH >8. Sequential extraction tests indicated that the U(VI) species were primarily associated with the acid soluble fraction (weak acetic acid extractable) and NOM fraction (Na-pyrophosphate extractable). Uranium L3- edge XANES spectra of the U-retained sediments were nearly identical to that of uranyl acetate. The primary oxidation state of U in these sediments was as U(VI), and there was little evidence that the high sorptive capacity of the sediments could be ascribed to abiotic or biotic reduction to the less soluble U(IV) species. The molecular mechanism responsible for the high U retention in the SRS wetland sediments is likely related to the chemical bonding of U to organic carbon.

Study of Wetland Ecosystem Vegetation Using Satellite Data

Science.gov (United States)

Dyukarev, E. A.; Alekseeva, M. N.; Golovatskaya, E. A.

2017-12-01

The normalized difference vegetation index (NDVI) is used to estimate the aboveground net production (ANP) of wetland ecosystems for the key area at the South Taiga zone of West Siberia. The vegetation index and aboveground production are related by linear dependence and are specific for each wetland ecosystem. The NDVI grows with an increase in the ANP at wooded oligotrophic ecosystems. Open oligotrophic bogs and eutrophic wetlands are characterized by an opposite relation. Maps of aboveground production for wetland ecosystems are constructed for each study year and for the whole period of studies. The average aboveground production for all wetland ecosystems of the key area, which was estimated with consideration for the area they occupy and using the data of satellite measurements of the vegetation index, is 305 g C/m2/yr. The total annual carbon accumulation in aboveground wetland vegetation in the key area is 794600 t.

Integrating geographically isolated wetlands into land management decisions

Science.gov (United States)

Golden, Heather E.; Creed, Irena F.; Ali, Genevieve; Basu, Nandita; Neff, Brian; Rains, Mark C.; McLaughlin, Daniel L.; Alexander, Laurie C.; Ameli, Ali A.; Christensen, Jay R.; Evenson, Grey R.; Jones, Charles N.; Lane, Charles R.; Lang, Megan

2017-01-01

Wetlands across the globe provide extensive ecosystem services. However, many wetlands – especially those surrounded by uplands, often referred to as geographically isolated wetlands (GIWs) – remain poorly protected. Protection and restoration of wetlands frequently requires information on their hydrologic connectivity to other surface waters, and their cumulative watershed‐scale effects. The integration of measurements and models can supply this information. However, the types of measurements and models that should be integrated are dependent on management questions and information compatibility. We summarize the importance of GIWs in watersheds and discuss what wetland connectivity means in both science and management contexts. We then describe the latest tools available to quantify GIW connectivity and explore crucial next steps to enhancing and integrating such tools. These advancements will ensure that appropriate tools are used in GIW decision making and maintaining the important ecosystem services that these wetlands support.

Arabian Gulf Maritime Interception Operations: Balancing the Ends, Ways, Means and Risks

National Research Council Canada - National Science Library

Shaw, Thomas

1999-01-01

.... Security Council Resolutions. Through the application of joint doctrine and operational art, USCINCCENT has determined that the military condition that will produce this strategic goal is an effective maritime interception...

Sand quarry wetlands provide high-quality habitat for native amphibians

Directory of Open Access Journals (Sweden)

M. Sievers

2017-05-01

Full Text Available Anthropogenic disturbances to habitats influence the fitness of individual animals, the abundance of their populations, and the composition of their communities. Wetlands in particular are frequently degraded and destroyed, impacting the animals that inhabit these important ecosystems. The creation of wetlands during and following sand extraction processes is inevitable, and thus, sand quarries have the potential to support aquatic animals. To determine how amphibians utilise these wetlands, I conducted nocturnal call surveys at wetlands within the Kables Sands quarry, New South Wales, Australia, and within surrounding reference wetlands, and quantified levels of developmental instability (DI as a proxy for fitness. Whilst quarry and reference wetlands were largely similar in terms of environmental characteristics, quarry wetlands consistently harboured more amphibian species and individuals. Using unsigned asymmetry as a measure of DI, frogs from the quarry sites exhibited significantly lower levels of DI compared to reference wetlands, indicating that quarry wetlands may be comparatively higher quality. Levels of DI within quarry wetlands also compared favourably to data from healthy frog populations extracted from the literature. Further enhancing the suitability of quarry wetlands would require minimal effort, with potentially significant increases in local and regional biodiversity. Documenting species presence and quantifying individual fitness by measuring limb lengths is an economically and logistically feasible method to assess the health of quarry wetlands. Overall, the methods outlined here provide a powerful, yet simple, tool to assess the overall health and suitability of quarry wetlands that could be easily adopted at quarries throughout the world.

Natural wetland in China | Pan | African Journal of Environmental ...

African Journals Online (AJOL)

As it is known to all, wetland is one of the most crucial ecosystems in the world, with large varieties in China. How to protect wetland in China has become a more serious problem and five typical wetlands were selected in the article to illustrate the condition. Through the comparison between the past and present of wetland, ...

Relating groundwater to seasonal wetlands in southeastern Wisconsin, USA

Science.gov (United States)

Skalbeck, J.D.; Reed, D.M.; Hunt, R.J.; Lambert, J.D.

2009-01-01

Historically, drier types of wetlands have been difficult to characterize and are not well researched. Nonetheless, they are considered to reflect the precipitation history with little, if any, regard for possible relation to groundwater. Two seasonal coastal wetland types (wet prairie, sedge meadow) were investigated during three growing seasons at three sites in the Lake Michigan Basin, Wisconsin, USA. The six seasonal wetlands were characterized using standard soil and vegetation techniques and groundwater measurements from the shallow and deep systems. They all met wetland hydrology criteria (e.g., water within 30 cm of land surface for 5% of the growing season) during the early portion of the growing season despite the lack of appreciable regional groundwater discharge into the wetland root zones. Although root-zone duration analyses did not fit a lognormal distribution previously noted in groundwater-dominated wetlands, they were able to discriminate between the plant communities and showed that wet prairie communities had shorter durations of continuous soil saturation than sedge meadow communities. These results demonstrate that the relative rates of groundwater outflows can be important for wetland hydrology and resulting wetland type. Thus, regional stresses to the shallow groundwater system such as pumping or low Great Lake levels can be expected to affect even drier wetland types. ?? Springer-Verlag 2008.

Nevada Test Site Wetlands Assessment

Energy Technology Data Exchange (ETDEWEB)

D. J. Hansen

1997-05-01

This report identifies 16 Nevada Test Site (NTS) natural water sources that may be classified by the U.S. Army Corps of Engineers (USACE) as jurisdictional wetlands and identifies eight water sources that may be classified as waters of the United States. These water sources are rare, localized habitats on the NTS that are important to regional wildlife and to isolated populations of water tolerant plants and aquatic organisms. No field investigations on the NTS have been conducted in the past to identify those natural water sources which would be protected as rare habitats and which may fall under regulatory authority of the Clean Water Act (CWA) of 1997. This report identifies and summarizes previous studies of NTS natural water sources, and identifies the current DOE management practices related to the protection of NTS wetlands. This report also presents management goals specific for NTS wetlands that incorporate the intent of existing wetlands legislation, the principles of ecosystem management, and the interests of regional land managers and other stakeholders.

Using Internet search behavior to assess public awareness of protected wetlands.

Science.gov (United States)

Do, Yuno; Kim, Ji Yoon; Lineman, Maurice; Kim, Dong-Kyun; Joo, Gea-Jae

2015-02-01

Improving public awareness of protected wetlands facilitates sustainable wetland management, which depends on public participation. One way of gauging public interest is by tracking Internet search behavior (ISB). We assessed public awareness of issues related to protected wetland areas (PWAs) in South Korea by examining the frequencies of specific queries (PWAs, Ramsar, Upo wetland, Sunchon Bay, etc.) using relative search volumes (RSVs) obtained from an Internet search engine. RSV shows how many times a search term is used relative to a second search term during a specific period. Public awareness of PWAs changed from 2007 to 2013. Initially the majority of Internet searches were related to the most well-known tidal and inland wetlands Sunchon Bay and Upo wetlands, which are the largest existing wetlands in Korea with the greatest historical exposure. Public awareness, as reflected in RSVs, of wetlands increased significantly following PWA designation for the wetlands in 2008, which followed the Ramsar 10th Conference of Contracting Parties to the Convention on Wetlands (COP10) meeting. Public interest was strongly correlated to the number of news articles in the popular media, as evidenced by the increase in Internet searches for specific wetlands and words associated with specific wetlands. Correspondingly, the number of visitors to specific wetlands increased. To increase public interest in wetlands, wetland aspects that enhance wetland conservation should be promoted by the government and enhanced via public education. Our approach can be used to gauge public awareness and participation in a wide range of conservation efforts. © 2014 Society for Conservation Biology.

Do geographically isolated wetlands influence landscape functions?

OpenAIRE

Cohen, Matthew J.; Creed, Irena F.; Alexander, Laurie; Basu, Nandita B.; Calhoun, Aram J. K.; Craft, Christopher; D’Amico, Ellen; DeKeyser, Edward; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lane, Charles R.; Lang, Megan

2016-01-01

Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bo...

Traveler information services in rural tourism areas : appendix A, tourist intercept surveys

Science.gov (United States)

2000-06-30

This document presents documentation regarding tourist intercept surveys for traveler information services in rural areas. It documents data collection functions and information dissemination functions, and provides an interpretive description of tra...

Tidal wetlands of the Yaquina and Alsea River estuaries, Oregon: Geographic Information Systems layer development and recommendations for National Wetlands Inventory revisions

Science.gov (United States)

Brophy, Laura S.; Reusser, Deborah A.; Janousek, Christopher N.

2013-01-01

Geographic Information Systems (GIS) layers of current, and likely former, tidal wetlands in two Oregon estuaries were generated by enhancing the 2010 National Wetlands Inventory (NWI) data with expert local field knowledge, Light Detection and Ranging-derived elevations, and 2009 aerial orthophotographs. Data were generated for two purposes: First, to enhance the NWI by recommending revised Cowardin classifications for certain NWI wetlands within the study area; and second, to generate GIS data for the 1999 Yaquina and Alsea River Basins Estuarine Wetland Site Prioritization study. Two sets of GIS products were generated: (1) enhanced NWI shapefiles; and (2) shapefiles of prioritization sites. The enhanced NWI shapefiles contain recommended changes to the Cowardin classification (system, subsystem, class, and/or modifiers) for 286 NWI polygons in the Yaquina estuary (1,133 acres) and 83 NWI polygons in the Alsea estuary (322 acres). These enhanced NWI shapefiles also identify likely former tidal wetlands that are classified as upland in the current NWI (64 NWI polygons totaling 441 acres in the Yaquina estuary; 16 NWI polygons totaling 51 acres in the Alsea estuary). The former tidal wetlands were identified to assist strategic planning for tidal wetland restoration. Cowardin classifications for the former tidal wetlands were not provided, because their current hydrology is complex owing to dikes, tide gates, and drainage ditches. The scope of this project did not include the field evaluation that would be needed to determine whether the former tidal wetlands are currently wetlands, and if so, determine their correct Cowardin classification. The prioritization site shapefiles contain 49 prioritization sites totaling 2,177 acres in the Yaquina estuary, and 39 prioritization sites totaling 1,045 acres in the Alsea estuary. The prioritization sites include current and former (for example, diked) tidal wetlands, and provide landscape units appropriate for basin

A simple method to estimate radiation interception by nursery stock conifers: a case study of eastern white cedar

International Nuclear Information System (INIS)

Pronk, A.A.; Goudriaan, J.; Stilma, E.; Challa, H.

2003-01-01

A simple method was developed to estimate the fraction radiation intercepted by small eastern white cedar plants (Thuja occidentalis ‘Brabant’). The method, which describes the crop canopy as rows of cuboids, was compared with methods used for estimating radiation interception by crops with homogeneous canopies and crops grown in rows. The extinction coefficient k was determined at different plant arrangements and an average k-value of 0.48 ± 0.03 (R 2 = 0.89) was used in the calculations. Effects of changing plant characteristics and inter- and intra-row plant distances were explored. The fraction radiation intercepted that was estimated with the method for rows of cuboids was up to 20% and for row crops up to 8% lower than estimated with the method for homogeneous canopies at low plant densities and a LAI of 1. The fraction radiation intercepted by small plants of Thuja occidentalis ‘Brabant’ was best estimated by the simple method described in this paper

Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional–structural plant model

Science.gov (United States)

Sarlikioti, V.; de Visser, P. H. B.; Marcelis, L. F. M.

2011-01-01

Background and Aims At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Methods Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional–structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Key Results Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north–south orientation of rows differed from east–west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Conclusions Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical

Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional-structural plant model.

Science.gov (United States)

Sarlikioti, V; de Visser, P H B; Marcelis, L F M

2011-04-01

At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional-structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north-south orientation of rows differed from east-west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical variation of photosynthesis in canopy is such that the

Icelandic Inland Wetlands: Characteristics and Extent of Draining

OpenAIRE

Gudmundsson, Jon; Brink, Sigmundur H.; Arnalds, Olafur; Gisladottir, Fanney O.; Oskarsson, Hlynur

2016-01-01

Iceland has inland wetland areas with soils exhibiting both Andosol and Histosol properties which are uncommon elsewhere on Earth. They are generally fertile, with higher bird-nest densities than in similar wetlands in the neighboring countries, with nutrients released by rapid weathering of aeolian materials of basaltic nature. Icelandic inland wetlands cover about 9000 km2 constituting 19.4 % of the vegetated surfaces of the island. The wetland soils are often 1–3 m thick and store 33 to >1...

Assessing the cumulative impacts of geographically isolated wetlands on watershed hydrology using the SWAT model coupled with improved wetland modules.

Science.gov (United States)

Lee, S; Yeo, I-Y; Lang, M W; Sadeghi, A M; McCarty, G W; Moglen, G E; Evenson, G R

2018-06-07

Despite recognizing the importance of wetlands in the Coastal Plain of the Chesapeake Bay Watershed (CBW) in terms of ecosystem services, our understanding of wetland functions has mostly been limited to individual wetlands and overall catchment-scale wetland functions have rarely been investigated. This study is aimed at assessing the cumulative impacts of wetlands on watershed hydrology for an agricultural watershed within the Coastal Plain of the CBW using the Soil and Water Assessment Tool (SWAT). We employed two improved wetland modules for enhanced representation of physical processes and spatial distribution of riparian wetlands (RWs) and geographically isolated wetlands (GIWs). This study focused on GIWs as their hydrological impacts on watershed hydrology are poorly understood and GIWs are poorly protected. Multiple wetland scenarios were prepared by removing all or portions of the baseline GIW condition indicated by the U.S. Fish and Wildlife Service National Wetlands Inventory geospatial dataset. We further compared the impacts of GIWs and RWs on downstream flow (i.e., streamflow at the watershed outlet). Our simulation results showed that GIWs strongly influenced downstream flow by altering water transport mechanisms in upstream areas. Loss of all GIWs reduced both water routed to GIWs and water infiltrated into the soil through the bottom of GIWs, leading to an increase in surface runoff of 9% and a decrease in groundwater flow of 7% in upstream areas. These changes resulted in increased variability of downstream flow in response to extreme flow conditions. GIW loss also induced an increase in month to month variability of downstream flow and a decrease in the baseflow contribution to streamflow. Loss of all GIWs was shown to cause a greater fluctuation of downstream flow than loss of all RWs for this study site, due to a greater total water storage capacity of GIWs. Our findings indicate that GIWs play a significant role in controlling hydrological

Socio-Economic Determinants of Wetland Cultivation in Kemise ...

African Journals Online (AJOL)

A study of wetland use in Kemise, central Illubabor, southwestern Ethiopia, shows food shortage as the main factor behind wetland cultivation in the locality. However, discriminant analysis results indicate that it is the wealthier farmers who tend to cultivate wetlands rather than the economically less fortunate ones.

HANDBOOK FOR CONSTRUCTED WETLANDS RECEIVING ACID MINE DRAINAGE

Science.gov (United States)

In the summer of 1987, a pilot constructed wetland was built at the Big Five Tunnel in Idaho Springs, Colorado. This report details the theory, design and construction of wetlands receiving acid mine drainages, based on the second and third year of operation of this wetland, whic...

Exploring drivers of wetland hydrologic fluxes across parameters and space

Science.gov (United States)

Jones, C. N.; Cheng, F. Y.; Mclaughlin, D. L.; Basu, N. B.; Lang, M.; Alexander, L. C.

2017-12-01

Depressional wetlands provide diverse ecosystem services, ranging from critical habitat to the regulation of landscape hydrology. The latter is of particular interest, because while hydrologic connectivity between depressional wetlands and downstream waters has been a focus of both scientific research and policy, it remains difficult to quantify the mode, magnitude, and timing of this connectivity at varying spatial and temporary scales. To do so requires robust empirical and modeling tools that accurately represent surface and subsurface flowpaths between depressional wetlands and other landscape elements. Here, we utilize a parsimonious wetland hydrology model to explore drivers of wetland water fluxes in different archetypal wetland-rich landscapes. We validated the model using instrumented sites from regions that span North America: Prairie Pothole Region (south-central Canada), Delmarva Peninsula (Mid-Atlantic Coastal Plain), and Big Cypress Swamp (southern Florida). Then, using several national scale datasets (e.g., National Wetlands Inventory, USFWS; National Hydrography Dataset, USGS; Soil Survey Geographic Database, NRCS), we conducted a global sensitivity analysis to elucidate dominant drivers of simulated fluxes. Finally, we simulated and compared wetland hydrology in five contrasting landscapes dominated by depressional wetlands: prairie potholes, Carolina and Delmarva bays, pocosins, western vernal pools, and Texas coastal prairie wetlands. Results highlight specific drivers that vary across these regions. Largely, hydroclimatic variables (e.g., PET/P ratios) controlled the timing and magnitude of wetland connectivity, whereas both wetland morphology (e.g., storage capacity and watershed size) and soil characteristics (e.g., ksat and confining layer depth) controlled the duration and mode (surface vs. subsurface) of wetland connectivity. Improved understanding of the drivers of wetland hydrologic connectivity supports enhanced, region

Observations On Some Upper Amazonian Wetlands of Southeastern Peru

Science.gov (United States)

Householder, J. E.; Muttiah, R.; Khanal, S.

2007-05-01

Upper Amazonian wetlands represent little studied, poorly understood, and grossly under protected systems. Scientific investigation of Amazonian wetlands is in its infancy; nor is there much known about their ecological services. Regionally, wetlands form a ubiquitous and significant component of floodplain habitat fed by perennial springs as well as overland runoff. Locally, wetland vegetation forms bewilderingly complex vegetation mosaics that seem to be governed by local topography and hydrology. Drawing upon intensive field campaigns and remotely sensed imagery, we summarize the results and experiences gathered in wetlands of southeastern Peru.

A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing Wetland Functions of Flats Wetlands in the Everglades

National Research Council Canada - National Science Library

Noble, Chris

2002-01-01

.... However, a variety of other potential uses have been identified, including the determination of minimal effects under the Food Security Act, design of wetland restoration projects, and management of wetlands...

Wetlands Assessment for site characterization, Advanced Neutron Source (ANS)

International Nuclear Information System (INIS)

Wade, M.C.; Socolof, M.L.

1994-10-01

This Wetlands Assessment has been prepared in accordance with the Department of Energy's (DOE) Code of Federal Regulations (CFR) 10 CFR 1022, Compliance with Floodplain/Wetlands Environmental Review Requirements, which established the policy and procedure for implementing Executive Order 11990, Protection of Wetlands. The proposed action is to conduct characterization activities in or near wetlands at the ANS site. The proposed action will covered under a Categorical Exclusion, therefore this assessment is being prepared as a separate document [10 CFR 1022.12(c)]. The purpose of this Wetlands Assessment is to fulfill the requirements of 10 CFR 1022.12(a) by describing the project, discussing the effects of the proposed action upon the wetlands, and considering alternatives to the proposed action

Echolocating bats use a nearly time-optimal strategy to intercept prey.

Directory of Open Access Journals (Sweden)

Kaushik Ghose

2006-05-01

Full Text Available Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of sports, such as tennis, football, Frisbee, and baseball. Studies of target pursuit in animals, ranging from dragonflies to fish and dogs to humans, have suggested that they all use a constant bearing (CB strategy to pursue prey or other moving targets. CB is best known as the interception strategy employed by baseball outfielders to catch ballistic fly balls. CB is a time-optimal solution to catch targets moving along a straight line, or in a predictable fashion--such as a ballistic baseball, or a piece of food sinking in water. Many animals, however, have to capture prey that may make evasive and unpredictable maneuvers. Is CB an optimum solution to pursuing erratically moving targets? Do animals faced with such erratic prey also use CB? In this paper, we address these questions by studying prey capture in an insectivorous echolocating bat. Echolocating bats rely on sonar to pursue and capture flying insects. The bat's prey may emerge from foliage for a brief time, fly in erratic three-dimensional paths before returning to cover. Bats typically take less than one second to detect, localize and capture such insects. We used high speed stereo infra-red videography to study the three dimensional flight paths of the big brown bat, Eptesicus fuscus, as it chased erratically moving insects in a dark laboratory flight room. We quantified the bat's complex pursuit trajectories using a simple delay differential equation. Our analysis of the pursuit trajectories suggests that bats use a constant absolute target direction strategy during pursuit. We show mathematically that, unlike CB, this approach minimizes the time it takes for a pursuer to intercept an unpredictably moving target. Interestingly, the bat's behavior is similar to the interception strategy

Echolocating bats use a nearly time-optimal strategy to intercept prey.

Science.gov (United States)

Ghose, Kaushik; Horiuchi, Timothy K; Krishnaprasad, P S; Moss, Cynthia F

2006-05-01

Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of sports, such as tennis, football, Frisbee, and baseball. Studies of target pursuit in animals, ranging from dragonflies to fish and dogs to humans, have suggested that they all use a constant bearing (CB) strategy to pursue prey or other moving targets. CB is best known as the interception strategy employed by baseball outfielders to catch ballistic fly balls. CB is a time-optimal solution to catch targets moving along a straight line, or in a predictable fashion--such as a ballistic baseball, or a piece of food sinking in water. Many animals, however, have to capture prey that may make evasive and unpredictable maneuvers. Is CB an optimum solution to pursuing erratically moving targets? Do animals faced with such erratic prey also use CB? In this paper, we address these questions by studying prey capture in an insectivorous echolocating bat. Echolocating bats rely on sonar to pursue and capture flying insects. The bat's prey may emerge from foliage for a brief time, fly in erratic three-dimensional paths before returning to cover. Bats typically take less than one second to detect, localize and capture such insects. We used high speed stereo infra-red videography to study the three dimensional flight paths of the big brown bat, Eptesicus fuscus, as it chased erratically moving insects in a dark laboratory flight room. We quantified the bat's complex pursuit trajectories using a simple delay differential equation. Our analysis of the pursuit trajectories suggests that bats use a constant absolute target direction strategy during pursuit. We show mathematically that, unlike CB, this approach minimizes the time it takes for a pursuer to intercept an unpredictably moving target. Interestingly, the bat's behavior is similar to the interception strategy implemented in some

Eco-geomorphological Response of an Estuarine Wetland to Changes in the Hydraulic Regime

Science.gov (United States)

Howe, A.; Rodrí Guez, J.

2006-12-01

In the Hunter Estuary, NSW, Australia, tidal regimes of numerous wetlands have been affected by extensive anthropomorphic intervention, including harbour dredging, land reclamation, and construction of infrastructure. The importance of these wetlands to ecosystem services such as primary productivity, flood attenuation and water quality enhancement has led to an increased effort to rehabilitate degraded sites by reintroduction of tidal flows. Because of the complex and dynamics interactions among hydraulic regime, vegetation and geomorphology, it is difficult to predict how wetlands will respond to the reintroduction of these flows and whether the resulting habitat distribution will achieve desired management outcomes. Eco-geomorphology research conducted at a rehabilitated wetland comprised of mangrove forest and saltmarsh has tracked the response of estuarine vegetation distribution and wetland geomorphology to reinstatement of tidal flows following removal of impediments in 1995. The wetland is an important site for migratory shorebirds and is highly compartmentalized due to the presence of roads and culverts. Our research methodology integrates historical analysis, field measurements and laboratory experiments. Historical analysis matched vegetation evolution obtained from aerial photography to bird roosting habitat use, which is in decline. Field data collection carried out in the last two years included topographic, vegetation and soil surveys; velocity, water quality and water level profiling; and high precision measurements of substrate shallow subsidence and vertical accretion. Laboratory studies focussed on the effects of estuarine vegetation on flow resistance. All this information has allowed for the characterization and conceptualization of the system, which includes zones with different tidal attenuation levels and vegetation distribution. It was found that an increased tidal frame resulting from hydraulic manipulation lead to a landward shift in

Accumulation and bioaccessibility of trace elements in wetland ...

African Journals Online (AJOL)

Accumulation of trace metals in sediment can cause severe ecological impacts. In this study, determination of elemental concentrations in water and sediment was done. Shadegan wetland is one of the most important wetlands in southwest of Iran and is among the Ramsar-listed wetlands. Wastewaters from industries ...

GLOBAL SOLAR RADIATION INTERCEPTION BY GRAPEVINES TRAINED TO A VERTICAL TRELLIS SYSTEM

Directory of Open Access Journals (Sweden)

CLAUDIA GUIMARÃES CAMARGO CAMPOS

2016-01-01

Full Text Available ABSTRACT In this paper we assess the utilization of radiant energy in the growing of grapevines (Cabernet Sauvignon trained to a vertical trellis system, and estimate the global solar radiation interception taking into account the physical characteristics of the training system at different phenological stages. The experiment was based on daily measurements of global solar radiation made by an automatic weather station placed at the vineyard of a winery located in the municipality of São Joaquim, in the southern Brazilian State of Santa Catarina (Villa Francioni winery, 28º 15’ 14” S, 49º 57’ 02” W, 1294m a.s.l.. Growth and phenological development of the shoots were evaluated. The global solar radiation is intercepted by the canopy (trained to a vertical trellis system in different orientations and the accumulated total is slightly greater on the east than on the west face of the canopy, especially after flowering. The daily variability of global solar radiation intercepted by the canopy is greater after flowering. The accumulated solar energy incident on the canopy increases until the onset of ripening. From the results, vineyards trained to a vertical trellis system in the north-south direction provide favorable sunlight exposure to leaves and fruits and are promising in quality and productivity.

Observation of Wetland Dynamics with Global Navigation Satellite Signals Reflectometry

Science.gov (United States)

Zuffada, C.; Shah, R.; Nghiem, S. V.; Cardellach, E.; Chew, C. C.

2015-12-01

Wetland dynamics is crucial to changes in both atmospheric methane and terrestrial water storage. The Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5) highlights the role of wetlands as a key driver of methane (CH4) emission, which is more than one order of magnitude stronger than carbon dioxide as a greenhouse gas in the centennial time scale. Among the multitude of methane emission sources (hydrates, livestock, rice cultivation, freshwaters, landfills and waste, fossil fuels, biomass burning, termites, geological sources, and soil oxidation), wetlands constitute the largest contributor with the widest uncertainty range of 177-284 Tg(CH4) yr-1 according to the IPCC estimate. Wetlands are highly susceptible to climate change that might lead to wetland collapse. Such wetland destruction would decrease the terrestrial water storage capacity and thus contribute to sea level rise, consequently exacerbating coastal flooding problems. For both methane change and water storage change, wetland dynamics is a crucial factor with the largest uncertainty. Nevertheless, a complete and consistent map of global wetlands still needs to be obtained as the Ramsar Convention calls for a wetlands inventory and impact assessment. We develop a new method for observations of wetland change using Global Navigation Satellite Signals Reflectometry (GNSS-R) signatures for global wetland mapping in synergy with the existing capability, not only as a static inventory but also as a temporal dataset, to advance the capability for monitoring the dynamics of wetland extent relevant to addressing the science issues of CH4 emission change and terrestrial water storage change. We will demonstrate the capability of the new GNSS-R method over a rice field in the Ebro Delta wetland in Spain.

Sustainable wetland management and support of ecosystem services

Science.gov (United States)

Smith, Loren M.; Euliss, Ned H.; Wilcox, Douglas A.; Brinson, Mark M.

2009-01-01

This article is a follow-up on a previous piece in the National Wetlands Newsletter in which we outlined problems associated with a static, local approach to wetland management versus an alternative that proposes a temporal and geomorphic approach (Euliss et al. 2009). We extend that concept by drawing on companion papers recently published in the journal Wetlands (Euliss et al. 2008, Smith et al. 2008). Here we highlight reasons for the failure of many managed wetlands to provide a suite of ecosystem services (e.g., carbon storage, diodiversity, ground-water recharge, contaminant filtering, floodwater storage). Our principal theme is that wetland management is best approached by giving consideration to the hydrogeomorphic processes that maintain productive ecosystems and by removing physical and social impediments to those processes. Traditional management actions are often oriented toward maintaining static conditions in wetlands without considering the temporal cycles that wetlands need to undergo or achieve productivity for specific groups of wildlife, such as waterfowl. Possibly more often, a manager's ability to influence hydrogeomorphic processes is restricted by activities in surrounding watersheds. These could be dams, for example, which do not allow management of flood-pulse processes essential to productivity of riparian systems. In most cases, sediments and nutrients associated with land use in contributing watersheds complicate management of wetlands for a suite of services, including wildlife. Economic or policy forces far-removed from a wetland often interact to prevent occurrence of basic ecosystem processes. Our message is consistent with recommendation of supply-side sustainability of Allen et al. (2002) in which ecosystems are managed "for the system that produces outputs rather than the outputs themselves."

Remote sensing of wetlands at the Savannah River Plant

International Nuclear Information System (INIS)

Christensen, E.J.; Jensen, J.R.; Sharitz, R.R.

1985-01-01

The Savannah River Plant (SRP) occupies about 300 sq mi along a 10-mile stretch of the Savannah River. Large areas of wetlands cover the site, especially along tributary stream floodplains and the Savannah River. Some of these areas have been altered by cooling water discharges from nuclear production reactors onsite. To assess the effects of current and future plant operations on SRP and regional wetlands, an accurate quantitative survey was needed. Several studies were initiated to provide wetland acreage and distribution information: regional wetland inventories were provided from an analysis of LANDSAT multispectral scanner (MSS) satellite data. Wetlands were mapped throughout the entire Savannah River watershed and in the Savannah River floodplain. SRP wetlands were identified using a combination of LANDSAT MSS and Thematic Mapper satellite data and aerial photography. Wetlands in the SRP Savannah River swamp and thermally affected areas were mapped using high resolution MSS data collected from a low-flying aircraft. Vegetation communities in areas receiving cooling water discharges were then compared to surface temperatures measured from the airborne scanner at the same time to evaluate plant temperature tolerance. Historic changes to SRP wetlands from cooling water discharges were tabulated using aerial photography

Microbial diversity in restored wetlands of San Francisco Bay

Energy Technology Data Exchange (ETDEWEB)

Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

2013-12-09

Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing Wetland Functions of Depression Wetlands in the Upper Des Plaines River Basin

Science.gov (United States)

2006-05-01

Wetlands and Coastal Ecology Branch; Dr. David J. Tazik, Chief, Eco- system Evaluation and Engineering Division; and Dr. Edwin A. Theriot, Direc- tor, EL...wetlands (Euliss and Mushet 1996, Azous and Horner 2001, Bhaduri et al. 1997) and nutrient loading into those wetlands. The overall LU score is...Euliss, N. H., and Mushet , D. M. (1996). “Water-level fluctuation in wetlands as a function of landscape condition in the prairie pothole region

The road to higher permanence and biodiversity in exurban wetlands.

Science.gov (United States)

Urban, Mark C; Roehm, Robert

2018-01-01

Exurban areas are expanding throughout the world, yet their effects on local biodiversity remain poorly understood. Wetlands, in particular, face ongoing and substantial threats from exurban development. We predicted that exurbanization would reduce the diversity of wetland amphibian and invertebrate communities and that more spatially aggregated residential development would leave more undisturbed natural land, thereby promoting greater local diversity. Using structural equation models, we tested a series of predictions about the direct and indirect pathways by which exurbanization extent, spatial pattern, and wetland characteristics might affect diversity patterns in 38 wetlands recorded during a growing season. We used redundancy, indicator species, and nested community analyses to evaluate how exurbanization affected species composition. In contrast to expectations, we found higher diversity in exurban wetlands. We also found that housing aggregation did not significantly affect diversity. Exurbanization affected biodiversity indirectly by increasing roads and development, which promoted permanent wetlands with less canopy cover and more aquatic vegetation. These pond characteristics supported greater diversity. However, exurbanization was associated with fewer temporary wetlands and fewer of the species that depend on these habitats. Moreover, the best indicator species for an exurban wetland was the ram's head snail, a common disease vector in disturbed ponds. Overall, results suggest that exurbanization is homogenizing wetlands into more permanent water bodies. These more permanent, exurban ponds support higher overall animal diversity, but exclude temporary wetland specialists. Conserving the full assemblage of wetland species in expanding exurban regions throughout the world will require protecting and creating temporary wetlands.

Coastal wetlands: an integrated ecosystem approach

Science.gov (United States)

Perillo, G. M. E.; Wolanski, E.; Cahoon, D.R.; Brinson, M.M.

2009-01-01

Coastal wetlands are under a great deal of pressure from the dual forces of rising sea level and the intervention of human populations both along the estuary and in the river catchment. Direct impacts include the destruction or degradation of wetlands from land reclamation and infrastructures. Indirect impacts derive from the discharge of pollutants, changes in river flows and sediment supplies, land clearing, and dam operations. As sea level rises, coastal wetlands in most areas of the world migrate landward to occupy former uplands. The competition of these lands from human development is intensifying, making the landward migration impossible in many cases. This book provides an understanding of the functioning of coastal ecosystems and the ecological services that they provide, and suggestions for their management. In this book a CD is included containing color figures of wetlands and estuaries in different parts of the world.

Two interceptive approaches to palatally displaced canines: a prospective longitudinal study.

Science.gov (United States)

Leonardi, Maria; Armi, Pamela; Franchi, Lorenzo; Baccetti, Tiziano

2004-10-01

This study evaluated the effectiveness of two interceptive approaches to palatally displaced canines (PDCs), ie, extraction of the deciduous canines alone and in association with the use of a cervical pull headgear. The prospective longitudinal design of the investigation included 46 subjects with PDC (62 maxillary canines) who were randomly assigned to one of three groups (1) a group that underwent the extraction of the deciduous canine only, (2) a group that received in addition the use of a cervical pull headgear, and (3) an untreated control group. Panoramic radiographs were evaluated at initial observation (T1) and after an average period of 18 months (T2). Cervical vertebral maturation was assessed on lateral cephalograms at T1. Successful or unsuccessful canine eruption was assessed 48 months after T1. The between-group statistical comparisons were performed on the T1-T2 changes in the diagnostic parameters on panoramic radiographs, the prevalence rates of successful canine eruption, and the amount of time for canine eruption. The removal of the deciduous canine as an isolated measure to intercept palatal displacement of maxillary canines showed a prevalence rate of 50% success, which was not significantly greater than the success rate in untreated controls. The use of a headgear in addition to the extraction of the deciduous canine induced successful eruption in 80% of the cases, with a significant improvement in the measures for intraosseous canine position. There was no significant difference between the two interceptive approaches in the time required for canine eruption.

Assessment of nutrient retention by Natete wetland Kampala, Uganda

Science.gov (United States)

Kanyiginya, V.; Kansiime, F.; Kimwaga, R.; Mashauri, D. A.

Natete wetland which is located in a suburb of Kampala city in Uganda is dominated by C yperus papyrus and covers an area of approximately 1 km 2. The wetland receives wastewater and runoff from Natete town which do not have a wastewater treatment facility. The main objective of this study was to assess nutrient retention of Natete wetland and specifically to: determine the wastewater flow patterns in the wetland; estimate the nutrient loads into and out of the wetland; determine the nutrient retention by soil, plants and water column in the wetland; and assess the above and belowground biomass density of the dominant vegetation. Soil, water and plant samples were taken at 50 m intervals along two transects cut through the wetland; soil and water samples were taken at 10 cm just below the surface. Physico-chemical parameters namely pH, electrical conductivity and temperature were measured in situ. Water samples were analyzed in the laboratory for ammonium-nitrogen, nitrate-nitrogen, total nitrogen, orthophosphate and total phosphorus. Electrical conductivity ranged between 113 μS/cm and 530 μS/cm and the wastewater flow was concentrated on the eastern side of the wetland. pH varied between 6 and 7, temperature ranged from 19 °C to 24 °C. NH 4-N, NO 3-N, and TN concentrations were retained by 21%, 98%, and 35% respectively. Phosphorus concentration was higher at the outlet of the wetland possibly due to release from sediments and leaching. Nutrient loads were higher at the inlet (12,614 ± 394 kgN/day and 778 ± 159 kgP/day) than the outlet (2368 ± 425 kgN/day and 216 ± 56 kgP/day) indicating retention by the wetland. Plants stored most nutrients compared to soil and water. The belowground biomass of papyrus vegetation in the wetland was higher (1288.4 ± 8.3 gDW/m 2) than the aboveground biomass (1019.7 ± 13.8 gDW/m 2). Plant uptake is one of the important routes of nutrient retention in Natete wetland. It is recommended that harvesting papyrus can be an

A novel algorithm for delineating wetland depressions and ...

Science.gov (United States)

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features that are seldom fully filled with water. For instance, wetland depressions in the Prairie Pothole Region (PPR) are seasonally to permanently flooded wetlands characterized by nested hierarchical structures with dynamic filling- spilling-merging surface-water hydrological processes. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution LiDAR data and aerial imagery. We proposed a novel algorithm delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost path algorithm. The resulting flow network delineated putative temporary or seasonal flow paths connecting wetland depressions to each other or to the river network at scales finer than available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow modeling and hydrologic connectivity analysis. Presentation at AWRA Spring Specialty Conference in Sn

Estimating restorable wetland water storage at landscape scales

Science.gov (United States)

Jones, Charles Nathan; Evenson, Grey R.; McLaughlin, Daniel L.; Vanderhoof, Melanie; Lang, Megan W.; McCarty, Greg W.; Golden, Heather E.; Lane, Charles R.; Alexander, Laurie C.

2018-01-01

Globally, hydrologic modifications such as ditching and subsurface drainage have significantly reduced wetland water storage capacity (i.e., volume of surface water a wetland can retain) and consequent wetland functions. While wetland area has been well documented across many landscapes and used to guide restoration efforts, few studies have directly quantified the associated wetland storage capacity. Here, we present a novel raster-based approach to quantify both contemporary and potential (i.e., restorable) storage capacities of individual depressional basins across landscapes. We demonstrate the utility of this method by applying it to the Delmarva Peninsula, a region punctuated by both depressional wetlands and drainage ditches. Across the entire peninsula, we estimated that restoration (i.e., plugging ditches) could increase storage capacity by 80%. Focusing on an individual watershed, we found that over 59% of restorable storage capacity occurs within 20 m of the drainage network, and that 93% occurs within 1 m elevation of the drainage network. Our demonstration highlights widespread ditching in this landscape, spatial patterns of both contemporary and potential storage capacities, and clear opportunities for hydrologic restoration. In Delmarva and more broadly, our novel approach can inform targeted landscape-scale conservation and restoration efforts to optimize hydrologically mediated wetland functions.

Book review: Southern Forested Wetlands: Ecology and Management

Science.gov (United States)

Carl C. Trettin

2000-01-01

The southern region has the largest proportion of wetlands in the conterminous US. The majority of that wetland resource is forested by diverse vegetation communities reflecting differences in soil, hydrology, geomorphology, climatic conditions and past management. Wetland resources in the southern US are very important to the economy providing both commodity and non-...

Diversity patterns of temporary wetland macroinvertebrate ...

African Journals Online (AJOL)

Although macroinvertebrates are potentially useful for assessing the condition of temporary wetlands, little is yet known about them. Macroinvertebrate assemblages were assessed in 138 temporary wetlands in the south-western Cape, recording 126 taxa. However, predicted richness estimates were all higher than the ...

Greenhouse gas flux dynamics in wetlands

Energy Technology Data Exchange (ETDEWEB)

Silvola, J; Alm, J; Saarnio, S [Joensuu Univ. (Finland). Dept. of Biology; Martikainen, P J [National Public Health Inst., Kuopio (Finland). Dept. of Environmental Microbiology

1997-12-31

Two important greenhouse gases, CO{sub 2} and CH{sub 4}, are closely connected to the carbon cycling of wetlands. Although virgin wetlands are mostly carbon accumulating ecosystems, major proportion of the CO{sub 2} bound annually in photosynthesis is released back to the atmosphere. Main portion of the carbon cycling in wetlands is quite fast while a small proportion of carbon diffusing from soil is released from organic matter, which may be ten thousand years old. Methane is formed in the anaerobic layers of wetlands, from where it is released gradually to the atmosphere. The decomposition in anaerobic conditions is very slow, which means that usually only a few percent of the annual carbon cycling takes place as methane. Research on CO{sub 2} fluxes of different virgin and managed peatlands was the main topic of this project during the first phase of SILMU. The measurements were made during two seasons in varying conditions in c. 30 study sites. In the second phase of SILMU the research topics were the spatial and temporal variation of CO{sub 2} and CH{sub 4} fluxes, the relationships between vegetation and gas fluxes as well as carbon balance studies in wetlands at some intensive sites

Greenhouse gas flux dynamics in wetlands

Energy Technology Data Exchange (ETDEWEB)

Silvola, J.; Alm, J.; Saarnio, S. [Joensuu Univ. (Finland). Dept. of Biology; Martikainen, P.J. [National Public Health Inst., Kuopio (Finland). Dept. of Environmental Microbiology

1996-12-31

Two important greenhouse gases, CO{sub 2} and CH{sub 4}, are closely connected to the carbon cycling of wetlands. Although virgin wetlands are mostly carbon accumulating ecosystems, major proportion of the CO{sub 2} bound annually in photosynthesis is released back to the atmosphere. Main portion of the carbon cycling in wetlands is quite fast while a small proportion of carbon diffusing from soil is released from organic matter, which may be ten thousand years old. Methane is formed in the anaerobic layers of wetlands, from where it is released gradually to the atmosphere. The decomposition in anaerobic conditions is very slow, which means that usually only a few percent of the annual carbon cycling takes place as methane. Research on CO{sub 2} fluxes of different virgin and managed peatlands was the main topic of this project during the first phase of SILMU. The measurements were made during two seasons in varying conditions in c. 30 study sites. In the second phase of SILMU the research topics were the spatial and temporal variation of CO{sub 2} and CH{sub 4} fluxes, the relationships between vegetation and gas fluxes as well as carbon balance studies in wetlands at some intensive sites

Hydrological science and wetland restoration: some case studies from Europe

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available Throughout the world, wetlands are increasingly being recognised as important elements of the landscape because of their high biodiversity and goods and services they provide to mankind. After many decades of wetland destruction and conversion, large areas of wetlands are now protected under the International Convention on Wetlands (Ramsar and regional or national legislation such as the European Union Habitats Directive. In many cases, there is a need to restore the ecological character of the wetland through appropriate water management. This paper provides examples of scientific knowledge of wetland hydrology that can guide such restoration. It focuses on the need for sound hydrological science on a range of issues including water level control, topography, flood storage, wetland connections with rivers and sustainability of water supply under climate change.

Interception of moving objects while walking in children with spastic hemiparetic cerebral palsy.

Science.gov (United States)

Ricken, Annieck X C; Savelsbergh, G J P; Bennett, S J

2007-01-15

The purpose of the study was to examine the coordination of reaching and walking behaviour when children with Spastic Hemiparetic Cerebral Palsy (SHCP) intercept an approaching and hence externally-timed object. Using either the impaired or non-impaired arm, children intercepted a ball approaching from a fixed distance with one of three velocities. Each participant's initial starting position was scaled to their maximum walking velocity determined prior to testing; for the medium ball velocity, participants would arrive at the point of interception at the correct time if they walked with their maximum velocity. Children with SHCP adapted their reaching and walking behaviour to the different ball approach velocities. These adaptations were exhibited when using the impaired and non-impaired arm, and resulted in similar outcome performance irrespective of which arm was used. Still, children with SHCP found it necessary to increase trunk movement to compensate for the decreased elbow excursion and a decreased peak velocity of the impaired arm. Children with SHCP exhibited specific adaptations to their altered movement capabilities when performing a behaviourally-realistic task. The provision of an external timing constraint appeared to facilitate both reaching and walking movements and hence could represent a useful technique in rehabilitation.

Advancing Wetlands Mapping and Monitoring with GNSS Reflectometry

Science.gov (United States)

Zuffada, Cinzia; Chew, Clara; Nghiem, Son V.; Shah, Rashmi; Podest, Erika; Bloom, A. Anthony; Koning, Alexandra; Small, Eric; Schimel, David; Reager, J. T.; Mannucci, Anthony; Williamson, Walton; Cardellach, Estel

2016-08-01

Wetland dynamics is crucial to address changes in both atmospheric methane (CH4) and terrestrial water storage. Yet, both spatial distribution and temporal variability of wetlands remain highly unconstrained despite the existence of remote sensing products from past and present satellite sensors. An innovative approach to mapping wetlands is offered by the Global Navigation Satellite System Reflectometry (GNSS-R), which is a bistatic radar concept that takes advantage of the ever increasing number of GNSS transmitting satellites to yield many randomly distributed measurements with broad-area global coverage and rapid revisit time. Hence, this communication presents the science motivation for mapping of wetlands and monitoring of their dynamics, and shows the relevance of the GNSS-R technique in this context, relative to and in synergy with other existing measurement systems. Additionally, the communication discusses results of our data analysis on wetlands in the Amazon, specifically from the initial analysis of satellite data acquired by the TechDemoSat-1 mission launched in 2014. Finally, recommendations are provided for the design of a GNSS-R mission specifically to address wetlands science issues.

Possible use of wetlands in ecological restoration of surface mined lands

International Nuclear Information System (INIS)

Atkinson, R.B.; Cairns, J. Jr.

1994-01-01

Surface mining for coal has dramatically altered millions of hectares throughout the Appalachian region of eastern North America. Flat benches and vertical high walls have replaced well-drained slopes, and wetlands have developed 'accidentally' on abandoned benches. Surface mining is continuing in this region, but new regulations do not include specifications for wetland construction in the reclamation process. Recent research has suggested that many ecosystem services appropriate for the Appalachian landscape could be performed by constructed wetlands. Inclusion of wetland construction in a reclamation plan could lead to a net increase in wetland acreage locally, as well as offset the loss of natural and/or accidental wetlands that are constructed to enhance nontreatment goals in reclamation. Study sites included 14 emergent wetlands in Wise County, Virginia. Sampling in June and August detected a total of 94 species in 36 vascular plant facilities. Obligate wetlands species, species that occur in wetlands over 99% of the time, were found in all 14 sites and included 26 species. The presence of so many wetland species without intentional management efforts suggests that wetland establishment could become a common component of mine reclamation. 18 refs., 2 tabs

Values of natural and human-made wetlands: A meta-analysis

NARCIS (Netherlands)

Ghermandi, A.; van den Bergh, J.C.J.M.; Brander, L.M.; de Groot, H.L.F.; Nunes, P.A.L.D.

2010-01-01

The values of goods and services provided by wetland ecosystems are examined through a meta-analysis of an expanded database of wetland value estimates and with a focus on human-made wetlands. This study extends and improves upon previous meta-analyses of the wetland valuation literature in terms of

Restoring Tides to Avoid Methane Emissions in Degraded Wetlands: A Potent and Untapped Climate Intervention

Science.gov (United States)

Kroeger, K. D.; Crooks, S.; Moseman-Valtierra, S.; Tang, J.

2016-12-01

To date, activity related to carbon (C) management in coastal marine ecosystems (sometimes referred to as "Blue Carbon") has been concerned primarily with preserving existing C stocks or creating new wetlands to increase CO2 uptake and sequestration. Here we show that the globally-widespread occurrence of hydrologically-altered, degraded wetlands, and associated enhanced GHG emissions, presents an opportunity to reduce an anthropogenic GHG emission through restoration. We model the climatic forcing associated with carbon sinks in natural wetlands and with GHG emissions in altered and degraded wetlands, as well as compile geographic data on tidal restrictions to show that substantial methane (CH4) and CO2 emission reductions can be achieved through restoration of saline tidal flows in diked, impounded and tidally-restricted coastal wetlands. Despite high rates of carbon storage in coastal ecosystems, tidal restoration has dramatically greater potential per unit area as a climate intervention than most other ecosystem management actions. We argue that such emissions reductions represent avoided anthropogenic emissions, equivalent in concept to reduced fossil fuel emissions. Once the emissions have been avoided, the benefit of that action cannot be eliminated, even if emissions resume in the future due to degradation of the ecosystem. The avoided emissions therefore have inherent "permanence", obviating concerns associated with vulnerability of C stocks in land-use based interventions that enhance C sequestration in wood or soil. Further, emissions reductions are likely to be rapid, and given the high radiative efficiency of avoided CH4, wetland tidal restorations can provide near-term climate benefit. The U.S. has recently initiated an effort to include coastal wetlands in the Inventory of U.S. Greenhouse Gas Emissions and Sinks, and the analysis presented here indicates that tidally restricted wetlands meet the primary criteria for inventoried ecosystems in that

Forested wetland area and distribution: A forest and paper industry policy

International Nuclear Information System (INIS)

Dubensky, M.M.; Berg, R.S.; Berry, W.S.

1993-01-01

The policy statement from the 1988 National Wetlands Policy Forum included the amorphous and ambiguous phase no overall net loss of the nation's remaining wetlands base. To industry and thousands of non-industrial landowners, timber production represents a major function of wetlands. The authors cover historical aspects of wetlands protection, the controversial and politicized issue of wetlands delineation, proposed revisions to the wetlands criteria, regulatory issues related to the US Corp of Engineers and EPA, and compensatory mitigation. A package of economic incentives, education, and favorable tax treatment to encourage landowners to maintain their forested wetlands is suggested. 5 refs

Value Assessment of Artificial Wetland Derived from Mining Subsided Lake: A Case Study of Jiuli Lake Wetland in Xuzhou

OpenAIRE

Laijian Wang; Lachun Wang; Pengcheng Yin; Haiyang Cui; Longwu Liang; Zhenbo Wang

2017-01-01

Mining subsided lakes are major obstacles for ecological restoration and resource reuse in mining regions. Transforming mining subsided lakes into artificial wetlands is an ecological restoration approach that has been attempted in China in recent years, but a value assessment of the approach still needs systematic research. This paper considers Jiuli Lake wetland, an artificial wetland derived from restoration of a mining subsided lake in plain area, as a case study. A value assessment model...

Stochastic and simulation models of maritime intercept operations capabilities

OpenAIRE

Sato, Hiroyuki

2005-01-01

The research formulates and exercises stochastic and simulation models to assess the Maritime Intercept Operations (MIO) capabilities. The models focus on the surveillance operations of the Maritime Patrol Aircraft (MPA). The analysis using the models estimates the probability with which a terrorist vessel (Red) is detected, correctly classified, and escorted for intensive investigation and neutralization before it leaves an area of interest (AOI). The difficulty of obtaining adequate int...

Analysis of wetland change in the Songhua River Basin from 1995 to 2008

International Nuclear Information System (INIS)

Yuan, L H; Jiang, W G; Liu, Y H; Luo, Z L; He, X H

2014-01-01

Wetlands in the Songhua River Basin in both 1995 and 2008 were mapped from land use/land cover maps generated from Landsat Thematic Mapper imagery. These maps were then divided into two categories, i.e. artificial wetland and natural wetland. From 1995 to 2008, the total area of wetland in the Songhua River Basin increased from 93 072.3 km 2 to 99 179.6 km 2 a net increase of 6107.3 km 2 . The area of natural wetland decreased by 4043.7 km 2 while the area of artificial wetland increased by 10 166.2 km 2 . Swamp wetland and paddy field wetland became the dominant wetlands and the swamp wetland in the east of the Heilong River system and the north of the Wusuli River system disappeared, being transformed into paddy field wetland. The diversity of wetland landscape is worsening and the distribution of wetland landscape is becoming more unbalanced; the fragmentation of natural wetland has intensified whereas the patch connectivity of artificial wetland has increased. Changes in natural wetlands were primarily caused by climate and socio-economic changes, while changes in artificial wetland were mainly caused by the growth of population and gross domestic product

A review of the ecohydrology of the Sakumo wetland in Ghana.

Science.gov (United States)

Nonterah, Cynthia; Xu, Yongxin; Osae, Shiloh; Akiti, Thomas T; Dampare, Samuel B

2015-11-01

The Sakumo wetland is an internationally recognized Ramsar site located in a largely urban area and provides essential ecological and social services to wetland community dwellers. Despite its importance, the wetland has over the years been subjected to human interference resulting in considerable risks of deteriorating water quality, biodiversity loss, and drying up of most parts of the wetland. The conversion of land for residential and agricultural uses has significantly altered the hydrological characteristics of the land surface and modified pathways and flow of water into the wetland. Other drivers identified included drainage (mainly as runoff from agricultural farms), anthropogenic pressure (waste discharge) due to infrastructure development associated with urbanization, chemical contamination as a result of industrial and household pollution, and unsustainable fishing practices (overfishing). The purpose of the study was to review some of the physical and chemical properties of the Sakumo wetland on the changing wetland resources with emphasis on water quality. Rapid urbanization, industrialization, and overexploitation of wetland resources were identified as key causative factors affecting the wetland functions. Their effects on the wetland among others include increased nutrient and toxic chemical load which has resulted in reduced wetland surface water quality and decrease in species diversity. pH of the wetland waters was generally alkaline which is characteristic of water bodies influenced by seawater under oxygenated conditions. The increasing trends of electrical conductivity, phosphates, ammonia, nitrate, and nitrite, though small, point to deteriorating water quality in the wetland. The lagoon water was observed to be heavily polluted with nutrients particularly phosphate. The sequence of nutrient in the wetland was found to be in the order of PO4-P>NH3-N>NO3-N>NO2-N. These, if not checked, will result in further deterioration of the wetland

Carbon Storage in US Wetlands. | Science Inventory | US EPA

Science.gov (United States)

Background/Question/Methods Wetland soils contain some of the highest stores of soil carbon in the biosphere. However, there is little understanding of the quantity and distribution of carbon stored in US wetlands or of the potential effects of human disturbance on these stocks. We provide unbiased estimates of soil carbon stocks for wetlands at regional and national scales and describe how soil carbon stocks vary by anthropogenic disturbance to the wetland. To estimate the quantity and distribution of carbon stocks in wetlands of the conterminous US, we used data gathered in the field as part of the 2011 National Wetland Condition Assessment (NWCA) conducted by USEPA. During the growing season, field crews collected soil samples by horizon from 120-cm deep soil pits at 967 randomly selected wetland sites. Soil samples were analyzed for bulk density and organic carbon. We applied site carbon stock averages by soil depth back to the national population of wetlands and to several subpopulations, including five geographic areas and anthropogenic disturbance level. Disturbance levels were categorized by the NWCA as least, intermediately, or most disturbed using a priori defined physical, chemical, and biological indicators that were observable at the time of the site visit.Results/Conclusions We find that wetlands in the conterminous US store a total of 11.52 PgC – roughly equivalent to four years of annual carbon emissions by the US, with the greatest soil ca

Conceptual hierarchical modeling to describe wetland plant community organization

Science.gov (United States)

Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

2010-01-01

Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

Pesticide mitigation capacities of constructed wetlands

Science.gov (United States)

Matthew T. Moore; Charles M. Cooper; Sammie Smith; John H. Rodgers

2000-01-01

This research focused on using constructed wetlands along field perimeters to buffer receiving water against potential effects of pesticides associated with storm runoff. The current study incorporated wetland mesocosm sampling following simulated runoff events using chlorpyrifos, atrazine, and metolachlor. Through this data collection and simple model analysis,...

Treatment of wastewater with the constructed wetland

International Nuclear Information System (INIS)

Fernandez, R.; Olivares, S.

2003-01-01

Constructed wetland is an environmental sound, actual and economic solution for the treatment of wastewater. The use of these constructed wetlands increased in the last few years, principally in developed countries. However there is not much information about the performance of these biological systems in tropical and subtropical climates. In these review the state of art of these technology is given, and also the advantage of the use of the constructed wetland for the wastewater treatment in our country

Mercury dilution by autochthonous organic matter in a fertilized mangrove wetland.

Science.gov (United States)

Machado, Wilson; Sanders, Christian J; Santos, Isaac R; Sanders, Luciana M; Silva-Filho, Emmanoel V; Luiz-Silva, Wanilson

2016-06-01

A dated sediment core from a highly-fertilized mangrove wetland located in Cubatão (SE Brazil) presented a negative correlation between mercury (Hg) and organic carbon contents. This is an unusual result for a metal with well-known affinity to organic matter. A dilution of Hg concentrations by autochthonous organic matter explained this observation, as revealed by carbon stable isotopes signatures (δ(13)C). Mercury dilution by the predominant mangrove-derived organic matter counterbalanced the positive influences of algal-derived organic matter and clay contents on Hg levels, suggesting that deleterious effects of Hg may be attenuated. Considering the current paradigm on the positive effect of organic matter on Hg concentrations in coastal sediments and the expected increase in mangrove organic matter burial due to natural and anthropogenic stimulations of primary production, predictions on the influences of organic matter on Hg accumulation in mangrove wetlands deserve caution. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Wetland landscape pattern change based on GIS and RS: a review].

Science.gov (United States)

Kong, Fan-Ting; Xi, Min; Li, Yue; Kong, Fan-Long; Chen, Wan

2013-04-01

Wetland is an ecological landscape with most biodiversity in nature, which has unique ecological structure and function, and contains abundant natural resources to provide material guarantee for human's living and development. Wetland landscape pattern is the comprehensive result of various ecological processes, and has become a hot issue in wetland ecological study. At present, the combination of geographic information system (GIS) and remote sensing (RS) technologies is an important way to study the wetland landscape pattern change. This paper reviewed the research progress in the wetland landscape change based on GIS and RS from the aspects of the research methods of wetland landscape pattern, index of wetland landscape pattern, and driving forces of wetland landscape pattern evolution, and discussed the applications of the combination of GIS and RS in monitoring the wetland landscape pattern change, the index selection of wetland landscape pattern, and the driving mechanisms of the combined action of human and nature. Some deficiencies in the current studies were put forward, and the directions of the future-studies were prospected.

A Fast Non Intercepting Linac Electron Beam Position and Current Monitor

DEFF Research Database (Denmark)

Hansen, Jørgen-Walther; Wille, Mads

1982-01-01

A non-intercepting beam monitor consisting of four detecting loops is used to determine the spatial postion and current of a pulsed beam from an electron linear accelerator. The monitor detects the magnetic field radiated by the substructure of the electron bunches created by the accelerating...

Responses of Isolated Wetland Herpetofauna to Upland Forest Management

International Nuclear Information System (INIS)

Russell, K.R.; Hanlin, H.G.; Wigley, T.B.; Guynn, D.C. Jr.

2002-01-01

Measurement of responses of herpetofauna at isolated wetlands in the Coastal Plain of South Carolina to disturbance of adjacent loblolly pine forest. Many species of isolated wetland herpetofauna in the Southeastern Coastal Plain may tolerate some disturbance in adjacent upland stands. Responses of isolated wetland herpetofauna to upland silviculture and the need for adjacent forested buffers likely depend on the specific landscape context in which the wetlands occur and composition of the resident herpetofaunal community

Replacing natural wetlands with stormwater management facilities: Biophysical and perceived social values.

Science.gov (United States)

Rooney, R C; Foote, L; Krogman, N; Pattison, J K; Wilson, M J; Bayley, S E

2015-04-15

Urban expansion replaces wetlands of natural origin with artificial stormwater management facilities. The literature suggests that efforts to mimic natural wetlands in the design of stormwater facilities can expand the provision of ecosystem services. Policy developments seek to capitalize on these improvements, encouraging developers to build stormwater wetlands in place of stormwater ponds; however, few have compared the biophysical values and social perceptions of these created wetlands to those of the natural wetlands they are replacing. We compared four types of wetlands: natural references sites, natural wetlands impacted by agriculture, created stormwater wetlands, and created stormwater ponds. We anticipated that they would exhibit a gradient in biodiversity, ecological integrity, chemical and hydrologic stress. We further anticipated that perceived values would mirror measured biophysical values. We found higher biophysical values associated with wetlands of natural origin (both reference and agriculturally impacted). The biophysical values of stormwater wetlands and stormwater ponds were lower and indistinguishable from one another. The perceived wetland values assessed by the public differed from the observed biophysical values. This has important policy implications, as the public are not likely to perceive the loss of values associated with the replacement of natural wetlands with created stormwater management facilities. We conclude that 1) agriculturally impacted wetlands provide biophysical values equivalent to those of natural wetlands, meaning that land use alone is not a great predictor of wetland value; 2) stormwater wetlands are not a substantive improvement over stormwater ponds, relative to wetlands of natural origin; 3) stormwater wetlands are poor mimics of natural wetlands, likely due to fundamental distinctions in terms of basin morphology, temporal variation in hydrology, ground water connectivity, and landscape position; 4) these

Predictive modelling of wetland occurrence in KwaZulu-Natal, South Africa

Directory of Open Access Journals (Sweden)

Jens Hiestermann

2015-07-01

Full Text Available The global trend of transformation and loss of wetlands through conversion to other land uses has deleterious effects on surrounding ecosystems, and there is a resultant increasing need for the conservation and preservation of wetlands. Improved mapping of wetland locations is critical to achieving objective regional conservation goals, which depends on accurate spatial knowledge. Current approaches to mapping wetlands through the classification of satellite imagery typically under-represents actual wetland area; the importance of ancillary data in improving accuracy in mapping wetlands is therefore recognised. In this study, we compared two approaches Bayesian networks and logistic regression to predict the likelihood of wetland occurrence in KwaZulu-Natal, South Africa. Both approaches were developed using the same data set of environmental surrogate predictors. We compared and verified model outputs using an independent test data set, with analyses including receiver operating characteristic curves and area under the curve (AUC. Both models performed similarly (AUC>0.84, indicating the suitability of a likelihood approach for ancillary data for wetland mapping. Results indicated that high wetland probability areas in the final model outputs correlated well with known wetland systems and wetland-rich areas in KwaZulu-Natal. We conclude that predictive models have the potential to improve the accuracy of wetland mapping in South Africa by serving as valuable ancillary data.

High temperature superconducting current lead test facility with heat pipe intercepts

International Nuclear Information System (INIS)

Blumenfeld, P.E.; Prenger, C.; Roth, E.W.; Stewart, J.A.

1998-01-01

A high temperature superconducting (HTS) current lead test facility using heat pipe thermal intercepts is under development at the Superconducting Technology Center at Los Alamos National Laboratory. The facility can be configured for tests at currents up to 1,000 A. Mechanical cryocoolers provide refrigeration to the leads. Electrical isolation is maintained by intercepting thermal energy from the leads through cryogenic heat pipes. HST lead warm end temperature is variable from 65 K to over 90 K by controlling heat pipe evaporator temperature. Cold end temperature is variable up to 30 K. Performance predictions in terms of heat pipe evaporator temperature as a function of lead current are presented for the initial facility configuration, which supports testing up to 200 A. Measurements are to include temperature and voltage gradient in the conventional and HTS lead sections, temperature and heat transfer rate in the heat pipes. as well as optimum and off-optimum performance of the conventional lead sections

Mean-intercept anisotropy analysis of porous media. II. Conceptual shortcomings of the MIL tensor definition and Minkowski tensors as an alternative.

Science.gov (United States)

Klatt, Michael A; Schröder-Turk, Gerd E; Mecke, Klaus

2017-07-01

Structure-property relations, which relate the shape of the microstructure to physical properties such as transport or mechanical properties, need sensitive measures of structure. What are suitable fabric tensors to quantify the shape of anisotropic heterogeneous materials? The mean intercept length is among the most commonly used characteristics of anisotropy in porous media, e.g., of trabecular bone in medical physics. Yet, in this series of two papers we demonstrate that it has conceptual shortcomings that limit the validity of its results. We test the validity of general assumptions regarding the properties of the mean-intercept length tensor using analytical formulas for the mean-intercept lengths in anisotropic Boolean models (derived in part I of this series), augmented by numerical simulations. We discuss in detail the functional form of the mean intercept length as a function of the test line orientations. As the most prominent result, we find that, at least for the example of overlapping grains modeling porous media, the polar plot of the mean intercept length is in general not an ellipse and hence not represented by a second-rank tensor. This is in stark contrast to the common understanding that for a large collection of grains the mean intercept length figure averages to an ellipse. The standard mean intercept length tensor defined by a least-square fit of an ellipse is based on a model mismatch, which causes an intrinsic lack of accuracy. Our analysis reveals several shortcomings of the mean intercept length tensor analysis that pose conceptual problems and limitations on the information content of this commonly used analysis method. We suggest the Minkowski tensors from integral geometry as alternative sensitive measures of anisotropy. The Minkowski tensors allow for a robust, comprehensive, and systematic approach to quantify various aspects of structural anisotropy. We show the Minkowski tensors to be more sensitive, in the sense, that they can

Constructed Wetlands as a Mitigation Strategy to Reduce Pesticide Loads in Agricultural Tailwater

OpenAIRE

Budd, Robert L.

2009-01-01

Pyrethroid and organophosphate pesticides have been found in numerous waterways throughout the United States. Monitoring studies within the San Diego Creek watershed in Orange County, California, confirmed that runoff from agricultural fields are a primary contributor to pesticide loads within these waterways. As a mitigation option for non-point pesticide pollution, constructed wetlands were investigated in this study to reduce pesticide loading in agricultural tailwaters. Multiple wetlan...

Floodwater utilisation values of wetland services - a case study in Northeastern China

Science.gov (United States)

Lü, S. B.; Xu, S. G.; Feng, F.

2012-02-01

Water plays a significant role in wetlands. Floodwater utilisation in wetlands brings a wide range of wetland services, from goods production and water regulation to animal protection and aesthetics related to water supply in wetlands. In this study, the floodwater utilisation values of wetland services were estimated within the Momoge wetland and Xianghai wetland in western Jilin province of northeastern China. From 2003 to 2008, the floodwater diverted from the Nenjiang and Tao'er River is 381 million m3, which translates into a monetary value of approximately 1.35 billion RMB in 2008 (RMB: Chinese Currency, RMB 6.80 = US 1), and the ratio of economic value, eco-environmental value, and social value is 1:12:2. Besides the monetary value of the water itself, excessive floodwater utilisation may bring losses to wetlands; the threshold floodwater utilisation volumes in wetlands are discussed. Floodwater utilisation can alleviate water shortages in wetlands, and the evaluation of floodwater utilisation in wetland services in monetary terms is a guide for the effective use of the floodwater resources and for the conservation of wetlands.

Flow regime in a restored wetland determines trophic links and species composition in the aquatic macroinvertebrate community

International Nuclear Information System (INIS)

González-Ortegón, E.; Walton, M.E.M.; Moghaddam, B.; Vilas, C.; Prieto, A.; Kennedy, H.A.; Pedro Cañavate, J.; Le Vay, L.

2015-01-01

In a restored wetland (South of Spain), where different flow regimes control water exchange with the adjacent Guadalquivir estuary, the native Palaemon varians coexists with an exotic counterpart species Palaemon macrodactylus. This controlled m/acrocosm offers an excellent opportunity to investigate how the effects of water management, through different flow regimes, and the presence of a non-native species affect the aquatic community and the trophic niche (by gut contents and C-N isotopic composition) of the native shrimp Palaemon varians. We found that increased water exchange rate (5% day −1 in mixed ponds vs. 0.1% day −1 in extensive ponds) modified the aquatic community of this wetland; while extensive ponds are dominated by isopods and amphipods with low presence of P. macrodactylus, mixed ponds presented high biomass of mysids, corixids, copepods and both shrimp species. An estuarine origin of nutrients and primary production might explain seasonal and spatial differences found among ponds of this wetland. A combined analysis of gut contents and isotopic composition of the native and the exotic species showed that: (1) native P. varians is mainly omnivorous (2) while the non-native P. macrodactylus is more zooplanktivorous and (3) a dietary overlap occurred when both species coexist at mixed ponds where a higher water exchange and high abundance of mysids and copepods diversifies the native species' diet. Thus differences in the trophic ecology of both species are clearly explained by water management. This experimental study is a valuable tool for integrated management between river basin and wetlands since it allows quantification of wetland community changes in response to the flow regime. - Highlights: • Flow regimen is a major determinant of physicochemical habitat of a wetland. • Water exchanges wetland-estuary modify its aquatic community and trophic links. • Omnivory and physiological tolerance key in the resistance of a wetland

Assessing Wetland Hydroperiod and Soil Moisture With Remote Sensing: A Demonstration for the NASA Plum Brook Station Year 2

Science.gov (United States)

Brooks, Colin; Bourgeau-Chavez, Laura; Endres, Sarah; Battaglia, Michael; Shuchman, Robert

2015-01-01

Primary Goal: Assist with the evaluation and measuring of wetlands hydroperiod at the PlumBrook Station using multi-source remote sensing data as part of a larger effort on projecting climate change-related impacts on the station's wetland ecosystems. MTRI expanded on the multi-source remote sensing capabilities to help estimate and measure hydroperiod and the relative soil moisture of wetlands at NASA's Plum Brook Station. Multi-source remote sensing capabilities are useful in estimating and measuring hydroperiod and relative soil moisture of wetlands. This is important as a changing regional climate has several potential risks for wetland ecosystem function. The year two analysis built on the first year of the project by acquiring and analyzing remote sensing data for additional dates and types of imagery, combined with focused field work. Five deliverables were planned and completed: 1) Show the relative length of hydroperiod using available remote sensing datasets 2) Date linked table of wetlands extent over time for all feasible non-forested wetlands 3) Utilize LIDAR data to measure topographic height above sea level of all wetlands, wetland to catchment area radio, slope of wetlands, and other useful variables 4) A demonstration of how analyzed results from multiple remote sensing data sources can help with wetlands vulnerability assessment 5) A MTRI style report summarizing year 2 results. This report serves as a descriptive summary of our completion of these our deliverables. Additionally, two formal meetings were held with Larry Liou and Amanda Sprinzl to provide project updates and receive direction on outputs. These were held on 2/26/15 and 9/17/15 at the Plum Brook Station. Principal Component Analysis (PCA) is a multivariate statistical technique used to identify dominant spatial and temporal backscatter signatures. PCA reduces the information contained in the temporal dataset to the first few new Principal Component (PC) images. Some advantages of PCA

Quarterly sampling of the wetlands along the old F Area effluent ditch: August 1994

International Nuclear Information System (INIS)

Cummins, C.L.; Dixon, K.L.

1994-08-01

In August 1994, well point water and near-surface water samples were collected to characterize tritium and volatile organic compounds (VOC) in the wetlands along the old F-Area effluent ditch south of 643-E (old burial ground). The August sampling event was the third in a series of eight events. Groundwater flow paths suggest that compounds detected in water table wells around 643-E migrate towards the old F-Area effluent ditch and Fourmile Branch. Recent analytical results from well point and near-surface water sampling in the wetlands that comprise the old F-Area effluent ditch have shown that tritium and small quantities of VOCs are outcropping in the area. For this study, seven locations along the old F-Area effluent ditch were selected to be sampled. Well point samples were collected from all seven locations and near-surface water samples were collected at four locations. A secondary objective of this project was to compare VOC concentrations between the well points installed to depths of 6 to 8 ft and the near-surface water sampling buckets installed to depths of 1 to 2 ft. Based on differences in tritium concentrations at each location, it was determined that the sampling devices intercepted different groundwater flow paths. This negated direct comparison of analytical results between devices. However, when VOC concentrations measured at each well point and bucket location were normalized, based on the percent differences observed in tritium concentrations at that location, the resulting well point and bucket VOC concentrations were comparable in most cases. These results are consistent with the results from the three previous sampling events, and suggest that volatilization losses of VOCs from the buckets may be negligible. Since the results from the two sampling methodologies are not directly comparable, further sampling of the buckets is not planned

Incorporating future change into current conservation planning: Evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios

Science.gov (United States)

Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.

2015-11-02

In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

Microbial diversity and carbon cycling in San Francisco Bay wetlands

Energy Technology Data Exchange (ETDEWEB)

Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

2014-03-21

Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.

Geographically Isolated Wetlands: Why We Should Keep the Term

Science.gov (United States)

Use of the term "isolated wetlands" in the U.S. Supreme Court’s SWANCC decision created confusion, since it could imply functional isolation. In response, the term "geographically isolated wetlands" (GIWs) - wetlands surrounded by uplands - was introduced in 2003. A recent arti...

Fish utilisation of wetland nurseries with complex hydrological connectivity.

Directory of Open Access Journals (Sweden)

Ben Davis

Full Text Available The physical and faunal characteristics of coastal wetlands are driven by dynamics of hydrological connectivity to adjacent habitats. Wetlands on estuary floodplains are particularly dynamic, driven by a complex interplay of tidal marine connections and seasonal freshwater flooding, often with unknown consequences for fish using these habitats. To understand the patterns and subsequent processes driving fish assemblage structure in such wetlands, we examined the nature and diversity of temporal utilisation patterns at a species or genus level over three annual cycles in a tropical Australian estuarine wetland system. Four general patterns of utilisation were apparent based on CPUE and size-structure dynamics: (i classic nursery utlisation (use by recently settled recruits for their first year (ii interrupted peristence (iii delayed recruitment (iv facultative wetland residence. Despite the small self-recruiting 'facultative wetland resident' group, wetland occupancy seems largely driven by connectivity to the subtidal estuary channel. Variable connection regimes (i.e. frequency and timing of connections within and between different wetland units (e.g. individual pools, lagoons, swamps will therefore interact with the diversity of species recruitment schedules to generate variable wetland assemblages in time and space. In addition, the assemblage structure is heavily modified by freshwater flow, through simultaneously curtailing persistence of the 'interrupted persistence' group, establishing connectivity for freshwater spawned members of both the 'facultative wetland resident' and 'delayed recruitment group', and apparently mediating use of intermediate nursery habitats for marine-spawned members of the 'delayed recruitment' group. The diversity of utilisation pattern and the complexity of associated drivers means assemblage compositions, and therefore ecosystem functioning, is likely to vary among years depending on variations in hydrological

Classification of Snowfall Events and Their Effect on Canopy Interception Efficiency in a Temperate Montane Forest.

Science.gov (United States)

Roth, T. R.; Nolin, A. W.

2015-12-01

Forest canopies intercept as much as 60% of snowfall in maritime environments, while processes of sublimation and melt can reduce the amount of snow transferred from the canopy to the ground. This research examines canopy interception efficiency (CIE) as a function of forest and event-scale snowfall characteristics. We use a 4-year dataset of continuous meteorological measurements and monthly snow surveys from the Forest Elevation Snow Transect (ForEST) network that has forested and open sites at three elevations spanning the rain-snow transition zone to the upper seasonal snow zone. Over 150 individual storms were classified by forest and storm type characteristics (e.g. forest density, vegetation type, air temperature, snowfall amount, storm duration, wind speed, and storm direction). The between-site comparisons showed that, as expected, CIE was highest for the lower elevation (warmer) sites with higher forest density compared with the higher elevation sites where storm temperatures were colder, trees were smaller and forests were less dense. Within-site comparisons based on storm type show that this classification system can be used to predict CIE.Our results suggest that the coupling of forest type and storm type information can improve estimates of canopy interception. Understanding the effects of temperature and storm type in temperate montane forests is also valuable for future estimates of canopy interception under a warming climate.

Sampling and analysis of water from Upper Three Runs and its wetlands near Tank 16 and the Mixed Waste Management Facility

Energy Technology Data Exchange (ETDEWEB)

Dixon, K.L.; Cummins, C.L.

1994-06-01

In April and September 1993, sampling was conducted to characterize the Upper Three Runs (UTR) wetland waters near the Mixed Waste Management Facility to determine if contaminants migrating from MWMF are outcropping into the floodplain wetlands. For the spring sampling event, 37 wetlands and five stream water samples were collected. Thirty-six wetland and six stream water samples were collected for the fall sampling event. Background seepline and stream water samples were also collected for both sampling events. All samples were analyzed for RCRA Appendix IX volatiles, inorganics appearing on the Target Analyte List, tritium, gamma-emitting radionuclides, and gross radiological activity. Most of the analytical data for both the spring and fall sampling events were reported as below method detection limits. The primary exceptions were the routine water quality indicators (e.g., turbidity, alkalinity, total suspended solids, etc.), iron, manganese, and tritium. During the spring, cadmium, gross alpha, nonvolatile beta, potassium-40, ruthenium-106, and trichloroethylene were also detected above the MCLs from at least one location. A secondary objective of this project was to identify any UTR wetland water quality impacts resulting from leaks from Tank 16 located at the H-Area Tank Farm.

Sampling and analysis of water from Upper Three Runs and its wetlands near Tank 16 and the Mixed Waste Management Facility

International Nuclear Information System (INIS)

Dixon, K.L.; Cummins, C.L.

1994-06-01

In April and September 1993, sampling was conducted to characterize the Upper Three Runs (UTR) wetland waters near the Mixed Waste Management Facility to determine if contaminants migrating from MWMF are outcropping into the floodplain wetlands. For the spring sampling event, 37 wetlands and five stream water samples were collected. Thirty-six wetland and six stream water samples were collected for the fall sampling event. Background seepline and stream water samples were also collected for both sampling events. All samples were analyzed for RCRA Appendix IX volatiles, inorganics appearing on the Target Analyte List, tritium, gamma-emitting radionuclides, and gross radiological activity. Most of the analytical data for both the spring and fall sampling events were reported as below method detection limits. The primary exceptions were the routine water quality indicators (e.g., turbidity, alkalinity, total suspended solids, etc.), iron, manganese, and tritium. During the spring, cadmium, gross alpha, nonvolatile beta, potassium-40, ruthenium-106, and trichloroethylene were also detected above the MCLs from at least one location. A secondary objective of this project was to identify any UTR wetland water quality impacts resulting from leaks from Tank 16 located at the H-Area Tank Farm

Structure and dynamics of basin forested wetlands in North America

International Nuclear Information System (INIS)

Brown, S.

1990-01-01

Freshwater basin wetlands are found in depressions of various depths, generally in areas where precipitation exceeds evapotranspiration or where the depression intersects the water table creating groundwater seeps or springs. Forested basins are those that contain woody vegetation with the potential for reaching tree stature; they do not include woody shrub wetlands. In North America these areas are mainly in the central and eastern region. Pertinent information and reviews on the distribution, floristic composition, structure and dynamics of basin forested wetlands are summarized. The major emphasis is on freshwater wetlands, but data for saltwater wetlands mainly from Florida and tropical America are included. The external factors affecting basin wetlands or the important components of a wetlands energy signature are described as well as the distribution and floristic composition of representative basin wetlands. Sections on structural characteristics, organic matter dynamics, and nutrient cycling comprise the bulk of quantitative information. The effects of disturbances, both natural and human induced, with varying degrees of impact depending upon the intensity and on the part of the ecosystem to which the stressor is applied are evaluated. Examples of stressors in basin wetlands include water impoundment, water diversion, thermal stress from hot water, sedimentation, addition of toxic substances, addition of wastewater, oil spills, and harvesting. 86 refs., 5 figs., 11 tabs

Hydrocarbon removal with constructed wetlands

OpenAIRE

Eke, Paul Emeka

2008-01-01

Wetlands have long played a significant role as natural purification systems, and have been effectively used to treat domestic, agricultural and industrial wastewater. However, very little is known about the biochemical processes involved, and the use of constructed treatment wetlands in the removal of petroleum aromatic hydrocarbons from produced and/or processed water. Wastewaters from the oil industry contain aromatic hydrocarbons such as benzene, toluene, ethylbenzene and x...

Seasonal variability of interception and water wettability of common oak leaves

Directory of Open Access Journals (Sweden)

Anna Klamerus-Iwan

2017-07-01

Full Text Available Wettability of leaves and the resulting amount of interception loss of tree crowns is an important component of the atmosphere-tree stand-soil system balance. In the study, we hypothesized that changes occurring in leaves during the vegetation period can significantly affect the amount of rainwater retained by plants and wettability of leaves which is expressed by the contact angle between drops and leaves. We evaluated the hypothesis based on measurement series, which combined direct spraying of leaves with water at different stages of development at a constant temperature with observations made with an electron scanner which was used to determine changes occurring within a leaf, while the photographic method was used to analyze the contact angle of drops. The study involved common oak (Quercus robur. Samples of twigs derived from this species were collected in the area of Przedbórz (Poland forest district, in particular from the trees with well-developed crowns. Twigs were collected from 10 trees of similar age (35–40 years. The resulting database contained experimental data on changes of raindrop adhesion on oak leaves throughout the growing season. The internal contact angle of drops was within the range of 150° on the upper side of the leaf and 160° on the underside in May, up to 15° and 35° in November on the upper and underside of the leaves. Loss of interception was established at 6% at the beginning of the growing season up to 22% in autumn. It was concluded that the wettability and the level of interception increases in line with the age of a leaf.

Neural network modelling of rainfall interception in four different forest stands

Directory of Open Access Journals (Sweden)

İbrahim Yurtseven

2013-11-01

Full Text Available The objective of this study is to reveal whether it is possible to predict rainfall, through fall and stem flow in forest ecosystems with less effort, using several measurements of rainfall interception (hereafter ‘interception’ and an artificial neural network based linear regression model (ANN model. To this end, the Kerpe Research Forest in the province of Kocaeli, which houses stands of mixed deciduous-broadleaf forest (Castanea sativa Mill., Fagusorientalis Lipsky, Quercus spp., black pine (Pinus nigra Arnold, maritime pine (Pinus pinaster Aiton and Monterey pine (Pinus radiata D. Don, was selected study site. Four different forest stands were observed for a period of two years, during which rainfall, throughfall and stemflow measurements were conducted. These measurements were separately calculated for each individual stand, based on interception values and the use of stemflow data in strict accordance with the rainfall data, and the measured throughfall interceptionvalues were compared with values estimated by the ANN model.In this comparison, 70% of the total data was used for testing, and 30% was used for estimation and performance evaluation. No significant differences were found between values predicted with the help of the model and the measured values. In other words, interception values predicted by the ANN models were parallel with the measured values. In this study, the most success was achieved with the models of the Monterey pine stand (r2 = 0.9968; Mean Squared Error MSE = 0.16 and the mixed deciduous forest stand (r2 = 0.9964; MSE = 0.08, followed by models of the maritime pine stand (r2 = 0.9405; MSE = 1.27 and the black pine stand (r2 = 0.843, MSE = 17.36.

Wetlands for Industrial Wastewater Treatment at the Savannah River Site

International Nuclear Information System (INIS)

Gladden, J.B.

2002-01-01

The A-01 effluent outfall, which collects both normal daily process flow and stormwater runoff from a industrial park area, did not meet the South Carolina Department of Health and Environmental Control (SCDHEC) National Pollutant Discharge Elimination System (NPDES) permit limits for metals, toxicity, and total residual chlorine at the outfall sampling point. Copper was the constituent of primary concern and the effluent consistently failed to meet that NPDES limit. Installation of a constructed wetland system including a basin to manage stormwater surges was required to reduce the problematic constituent concentrations to below the NPDES permit limits before the effluent reaches the sampling point. Both bench-scale and on-site pilot scale physical models were constructed to refine and optimize the preliminary design as well as demonstrate the effectiveness of this approach prior to construction, which was completed in October 2000. The constructed treatment wetlands system has prov en its ability to treat industrial wastewaters containing metals with low O and M costs since there are no mechanical parts. With an anticipated life of over 50 years, this system is exceptionally cost effective

Dynamics of carbon sequestration in a coastal wetland using radiocarbon measurements

Science.gov (United States)

Choi, Yonghoon; Wang, Yang

2004-12-01

Coastal wetlands are sensitive to global climate change and may play an important role in the global carbon cycle. However, the dynamics of carbon (C) cycling in coastal wetlands and its response to sea level change associated with global warming is still poorly understood. In this study, we estimated the long-term and short-term rates of C accumulation, using C and C isotopic measurements of peat cores collected along a soil chronosequence, in a coastal wetland in north Florida. The long-term C accumulation rates determined by examining the C inventory and the radioactive decay of radiocarbon as a function of depth in the peat cores decrease with time from ˜130 ± 9 g C/m2/yr over the last century to ˜13 ± 2 g C/m2/yr over the millennium timescale. The short-term C accumulation rates estimated by examining the differences in the radiocarbon and C contents of the surfacial peat between archived (1985, 1988) and present (1996 and 1997) samples range from 42 to 193 g C/m2/yr in low marsh, from 18 to 184 g C/m2/yr in middle marsh, and from -50 to 181 g C/m2/yr in high marsh. The high end-values of our estimated short-term C accumulation rates are comparable to the estimated rates of C sequestration in coastal wetlands reported by [2003], but are significantly higher than our estimated long-term rates in the marshes and are also much higher than the published rates of C sequestration in northern peatlands. The higher recent rates of C accumulation in coastal marshes, in comparison with the longer-term rates, are due to slow but continuous decomposition of organic matter in the peat over time. However, other factors such as increased primary production in the coastal wetland over the last decades or century, due to a rise in mean sea level and/or CO2 and nitrogen fertilization effect, could also have contributed to the large difference between the recent and longer-term rates. Our data indicate that salt marshes in this area have been and continue to be a sink for

Impacts of Intensified Agriculture Developments on Marsh Wetlands

Directory of Open Access Journals (Sweden)

Zhaoqing Luan

2013-01-01

Full Text Available A spatiotemporal analysis on the changes in the marsh landscape in the Honghe National Nature Reserve, a Ramsar reserve, and the surrounding farms in the core area of the Sanjiang Plain during the past 30 years was conducted by integrating field survey work with remote sensing techniques. The results indicated that intensified agricultural development had transformed a unique natural marsh landscape into an agricultural landscape during the past 30 years. Ninety percent of the natural marsh wetlands have been lost, and the areas of the other natural landscapes have decreased very rapidly. Most dry farmland had been replaced by paddy fields during the progressive change of the natural landscape to a farm landscape. Attempts of current Chinese institutions in preserving natural wetlands have achieved limited success. Few marsh wetlands have remained healthy, even after the establishment of the nature reserve. Their ecological qualities have been declining in response to the increasing threats to the remaining wetland habitats. Irrigation projects play a key role in such threats. Therefore, the sustainability of the natural wetland ecosystems is being threatened by increased regional agricultural development which reduced the number of wetland ecotypes and damaged the ecological quality.

The effects of nutrient enrichment on oil sands reclaimed wetlands : a field microcosm study

International Nuclear Information System (INIS)

Chen, H.; Farwell, A.; Dixon, G.

2010-01-01

Bitumen extraction processes generate large amounts of processed materials containing polycyclic aromatic hydrocarbons (PAHs), naphthenic acids (NA), and additional salts. The use of processed materials in reclaimed wetlands and lakes has an impact on aquatic faunal and floral colonization. This study investigated the effects on nutrient enrichment on reclaimed wetlands containing processed materials. Chlorophyll a and total biomass analyses were conducted in order to evaluate the influence of nutrient addition on primary production. The nutrients were added to microcosms with differing levels of fertility for 3 different water types with varying NA concentrations in 3 different reclamation substrates. Results of the study showed different levels of growth depending on both the water and substrate type. Combined planktonic and periphytic growth was highest in water with high levels of dissolved organic and inorganic carbon.

Designated Wetlands and Setback Distances in Iowa

Data.gov (United States)

Iowa State University GIS Support and Research Facility — This GIS layer depicts wetlands designated for protection in the state of Iowa. Designated wetland is defined in Iowa Code subsection 459.102(21) as follows: 21....

The importance of hydrology in restoration of bottomland hardwood wetland functions

Science.gov (United States)

Hunter, R.G.; Faulkner, S.P.; Gibson, K.A.

2008-01-01

Bottomland hardwood (BLH) forests have important biogeochemical functions and it is well known that certain structural components, including pulsed hydrology, hydric soils, and hydrophytic vegetation, enhance these functions. It is unclear, however, how functions of restored BLH wetlands compare to mature, undisturbed wetlands. We measured a suite of structural and functional attributes in replicated natural BLH wetlands (NAT), restored BLH wetlands with hydrology re-established (RWH), and restored BLH wetlands without hydrology re-established (RWOH) in this study. Trees were replanted in all restored wetlands at least four years prior to the study and those wetlands with hydrology re-established had flashboard risers placed in drainage ditches to allow seasonal surface flooding. Vegetation, soils, and selected biogeochemical functions were characterized at each site. There was a marked difference in woody vegetation among the wetlands that was due primarily to site age. There was also a difference in herbaceous vegetation among the restored sites that may have been related to differences in age or hydrology. Water table fluctuations of the RWH wetlands were comparable to those of the NAT wetlands. Thus, placing flashboard risers in existing drainage ditches, along with proper management, can produce a hydroperiod that is similar to that of a relatively undisturbed BLH. Average length of saturation within the upper 15 cm of soils was 37, 104, and 97 days for RWOH, RWH, and NAT, respectively. Soil moisture, denitrification potential, and soluble organic carbon concentrations differed among wetland sites, but soil carbon and nitrogen concentrations, heterotrophic microbial activity, and readily mineralizable carbon concentrations did not. Significant linear relationships were also found between soil moisture and heterotrophic microbial activity, readily mineralizable carbon, and soluble organic carbon. In addition, sedimentation rates were higher in NAT and RWH

Wetland forest statistics for the South Atlantic States