SEARCH · PubMed Health

Results for “Ecosystem”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMedDate not supplied

[Development of a strategy for countermeasures application aimed at remediation of consequences of radioactive contamination of forest ecosystems].

The radiation situation has been assessed in forest ecosystems of the most affected by the Chernobyl accident region of the Russian Federation--Novozybkov district of the Bryansk region. Using a set of migration models and methods for estimating doses of external and internal irradiation of the population, predictive calculations have been made that demonstrated a need to implement countermeasures in forest ecosystems of the region. A strategy of countermeasures application was developed based on a conservative approach, which postulates priority of observance of the sanitary-hygienic standard--permissible exposure level for the population and need for invoking the economic indicators to optimize countermeasure option. The effectiveness of countermeasures has been assessed based on a multicriterium approach using a system of decision making PRIME Decisions. The derived results have been formalized as indices of countermeasures effectiveness for different combinations of criteria.

Cesium Radioisotopes↗

PubMed2004

Workshop 5 (synthesis): water pollution abatement as related to ecosystem protection.

Water pollution exerts major stress on water systems and the challenge is to ensure security in river basins for both water-dependent activities and for the aquatic ecosystems. The workshop focused on protection of good ecological status, quality criteria, priorities for action, and on achievement of sustainable improvements. The three keynote speakers presented the concept applied in the EU Water Framework Directive, the need for a multi-stakeholder collaboration in order to reach a good ecological status of waters and a concrete example of interactive planning of water protection measures in a transboundary lake. The additional paper presentations addressed specific pollution problems in catchments, the effect of environmental user fees and ecosystem indicators.

Ecology↗

PubMed2004

[Environmental quality assessment of regional agro-ecosystem in Loess Plateau].

Based on the detection and analysis of the contamination status of agro-ecosystem with apple-crops intercropping as the dominant cropping model in Loess Plateau, the individual factor and comprehensive environmental quality were assessed by multilevel fuzzy synthetic evaluation model, analytical hierarchy process(AHP), and improved standard weight deciding method. The results showed that the quality of soil, water and agricultural products was grade I, the social economical environmental quality was grade II, the ecological environmental quality was grade III, and the comprehensive environmental quality was grade I. The regional agro-ecosystem dominated by apple-crops intercropping was not the best model for the ecological benefits, but had the better social economical benefits.

Agriculture↗

PubMed2004

[Latest forty two years' sea surface temperature change of Weizhou Island and its influence on coral reef ecosystem].

Weizhou Island (109 degrees 00'-109 degrees 15'E, 21 degrees 00'-21 degrees 10'N) locates in the north coral reef distribution belt of the South China Sea. In such relatively high latitude area, sea surface temperature (SST) is an important factor affecting the development of coral reef ecosystem. Measurements of the latest 42 years' SST of Weizhou Island showed that with 3-4 years and 7-8 years fluctuating cycles, the SST almost had a synchronous increase with global warming, especially since the later 1980s. Overall, the coral reef of Weizhou Island could benefit from the SST warming, especially the cold months SST increase, because it's the north margin of tropical zone. But, the warming of the warmest month may be a thermal stress on the development of coral reef. It reaches the upper limits of coral reef development, and leads the coral reef bleaching. Mankind activities, including wide scale building, oil gas factory near the island, traveling, fishing and breeding, may be also the potential stresses on limiting the coral reef development. The combination of summer warming and mankind stress is possibly to destroy the coral reef ecosystem of Weizhou Island. Based on a detailed field investigation, the modern coral reef distribution map around Weizhou Island was described.

Animals↗

PubMed2004

[Application of energy theory in research of ecosystem stability].

According to the review of the research in ecosystem stability, the crucial reason of the debate was analyzed and the view that distinguishing two different kinds of stability as a starting point is advanced. The energy theory can be used as a sharp method to measure and assess the ecosystem stability in a relatively exact and quantitative way.

Ecosystem↗

PubMedDate not supplied

Ecosystem function in alluvial tailings after biosolids and lime addition.

Municipal biosolids and agricultural limestone were incorporated into the surface of alluvial highly acidic, metal-contaminated mine tailings in Leadville, CO, in 1998. Amended sites were seeded and a plant cover was subsequently established. A range of chemical and biological parameters were measured over time to determine if treatment was sufficient to restore ecosystem function. An uncontaminated upstream control (UUC), a contaminated vegetated area (CVA), and soils collected from the tailings deposits before amendment addition were used for comparison. Standard soil extracts showed decreases in extractable Pb, Zn, and Cd in the amended soils. Increased CO2 evolution, reduced N2O, and elevated NO3- in the amended tailings indicated an active microbial community. Levels of CO2 and NO3- were elevated in comparison with the CVA and UUC. Ryegrass (Lolium perenne L.) and earthworm (Eisenia foetida) survival and metal uptake values were similar in amended tailings to a laboratory control soil. Ryegrass and worms in unamended tailings died. Field plant diversity was lower in amended areas than in CVA or UUC, with a higher percentage of the vegetative cover consisting of grasses. Small mammal analysis showed a low potential for elevated body Cd and Pb in the amended tailings. A re-entrainment study using fathead minnows (Pimephales promelas) showed no danger for resuspended amended tailings, as survival of fish was similar to the laboratory control. Data suggest that ecosystem function has been restored to the amended tailings, but that these systems are not yet in equilibrium.

Animals↗

PubMedDate not supplied

Aquatic ecosystem as a bioreactor: water purification and some other functions.

A fundamental concept is proposed of aquatic ecosystem as a bioreactor that carries out the function of water purification in natural water bodies and streams. The ecosystem as a bioreactor has the following characteristic attributes: (1) it is a large-scale (large-volume) bioreactor; (2) it is a diversified (in terms of the number of taxa and the scope of functional activities) bioreactor; (3) it possesses a broad range of biocatalytic (chemical-transforming and degrading) capabilities. New experimental data on xenobiotics-induced inhibition of the functioning of the molluscs Unio tu- midus, U. pictorum, M. galloprovincialis and Limnaea stagnalis emphasize the potential ecological hazard from sublethal concentrations of pollutants (including those exemplified by synthetic surfactants and detergents).

Animals↗

PubMed2004

[Vegetation restoration in western Liaoning hilly region: a study based on succession theory and degradation degree of ecosystem].

Analysis with some habitat indexes of different succession stage, this paper quantitatively measured the degradation degree of degraded ecosystems in this region. The results showed that the average dissimilarities between natural Quercus forest, natural Chinese pine (Pinus tabulaeformis) forest and Populus-Quercus forest in Nanliuzhangzi forestry centre and Chinese pine plantations in Niuheliang region and Qitian forestry centre were 0.655, 0.665, 2.029 and 3.919, respectively, and as a whole, the dissimilarities represented the places of the forests in the process of ecosystem succession/degradation. It was also showed that most habitats were degraded to the stage between shrubbery and pioneer arbor forest, and closer to the succession stage of pioneer arbor forest. Some suggestions were made for the management of the existing plantation and the construction of mixed forest, e.g., to increase the proportion of shrubbery and pioneer arbor species, especially that of nitrogen fixation tree species. The plant species list of several main vegetation types in western Liaoning we offered could provide scientific reference for the vegetation restoration and the management of pure Chinese pine plantation in this region.

China↗

PubMedDate not supplied

Use of the ecosystem approach to population health: the case of mercury contamination in aquatic environments and riparian populations, Andean Amazon, Napo River Valley, Ecuador.

BACKGROUND: Driven by accelerating transformation of land use in the Amazon, studies addressing the impacts of deforestation and mercury (Hg) leaching on the geophysical, biological, social, health, economic and political systems of Amazonian countries are crucial to evaluate the population health risks of these rapid changes. METHODS: We used an ecosystem approach, integrating Hg measurements with socio-cultural and politico-economic elements, to provide an integral analysis and comprehensive solutions. RESULTS: Our interdisciplinary research in the Ecuadorian Andean Amazon has shown that comestible fish and riparian communities which rely on fish as a major protein source have mercury levels that could potentially cause subtle but deleterious population health alterations. A parallel study identified deforestation and soil erosion as a significant source of mercury to the aquatic ecosystem. INTERPRETATION: The analysis of these results in conjunction with the prevailing socio-cultural and politico-economic context allowed us to identify economic trends, and especially petroleum exploitation, as pivotal in the deforestation/mercury-exposure dynamic. In collaboration with public health authorities, we shared our results with local health stakeholders, including public health care staff, federal government agencies, researchers and local communities, in such a way as to promote sustainable land use practices and the nutritional benefits of fish eating while reducing toxic exposures.

Animals↗

PubMed2004

[Numerical simulation of interaction between forest ecosystem and atmosphere boundary layer].

Based on the basic principles of atmosphere boundary layer and plant canopy micrometeorology, a numerical model of the interaction between forest ecosystem and atmosphere boundary layer was built, and used to simulate the diurnal variations of heat balance in forest ecosystem, canopy temperature, air temperature in canopy, and ground surface temperature, as well as those of the profiles and temporal and spatial distributions of potential temperature, wind speed, specific humidity and turbulence exchange coefficient. It indicated that the model could be used to study the interaction between land surface process and atmospheric boundary layer over various underlying surface and regional climate effect, which supplied a solid base to the researches on coupling climate models with the biosphere.

Atmosphere↗

PubMed2004

[Response of soil-wheat ecosystem to soil magnetization and related ecological indicators].

By using outdoor pot-culture method combined with biological magnetic effect analysis, this paper studied the effect of soil magnetization on soil-wheat ecosystem health. It was showed that there was an improvement in soil-wheat ecosystem health after soil magnetization, e.g., the germination of wheat seeds promoted, and the seedling height, individuals of leaves and roots, overall and active absorption area of roots and their absorption rates, and biological yield of mature wheat were increased. The ecological indicators of magnetic health effect were also discussed. 200 mT was the best parameter of magnetic treatment for wheat growth.

Ecosystem↗

PubMed2004

[Host transfer of Beauveria bassiana population in pine stand ecosystem and impact of its genetic diversity on sustainable control of Masson's pine caterpillars].

In an anniversary investigation post inoculative release of Beauveria bassiana against Masson's pine caterpillars in a Masson's pine plantation, 119 strains were isolated from 30 host insects, soil, litter and air. Based on an esterase isozyme analysis, all these strains were assigned to 32 esterase types, suggesting abundant genetic diversity. The esterase type 2 was assigned including 18 other strains from 11 different host insects, indicating that the released strain had successfully survived in different insect populations and persisted in enzootic condition in 12 insect populations including pine caterpillars and grey pine weevils. Other host insects could maintain the food chain when the target insect population was low. The other esterase types included 1-23 strains. The anniversary host transfer dynamics further revealed that B. bassiana could transfer among different host insects in the pine ecosystem. The virulence of the strains of each esterase differed substantially, which suggested that B. bassiana persisted and dispersed along more than one route, and each esterase stood for at least one branch in the food web. Some hosts connected different esterase types at nodal points, making the food web very complicated. In addition, the strains isolated from soil, litter, forest crown and air belonged to different esterase types, suggesting that a complex of saprophytic food chains existed in the plantation, which made the food web more complicated, and benefited the sustainable control of the Masson's pine caterpillar and other pest insects in the ecosystem.

Animals↗

PubMed2005

[Relationships between net primary production and nitrogen cycling in Chinese forest ecosystems].

In order to better understand the relationships between net primary production (NPP) of forest ecosystem and nitrogen cycling, we studied and analyzed the relationships between NPP, litter nitrogen, plant nitrogen retention, and soil net nitrogen mineralization rate in Chinese forest ecosystems. The results indicated that NPP was linearly and positively related to litter nitrogen, plant nitrogen retention and soil net nitrogen mineralization rate, with the most correlation with soil net nitrogen mineralization rate (R2 = 0.74, n = 37), and the next with plant nitrogen retention (R2 = 0.60, n = 37).

Biomass↗

PubMed2005

[Assessing forest ecosystem health II. A case study].

On the bases of samples investment and related data collected by others, and with the method of health distance assessment and the ecosystem health index system of Korean pine and broad-leaved mixed forest established in prior paper, this paper attempted to assess the ecosystem health of Korean pine and broad-leaved mixed forest under various human disturbances. The results showed that the health degree was in the order of 20% intensity selective cutting stand (0.21) < 50% intensity selective cutting stand (0.44) < middle and mature birch stand (0.67) < youth birch stand (0.72) < Korean pine plantation (0.74) < larch plantation (0.77).

Biomass↗

PubMed2005

Tracing the influence of sewage nitrogen in a coastal ecosystem using stable nitrogen isotopes.

This paper reviews the use of stable nitrogen isotopes (delta15N) to delineate the influence of sewage nitrogen (N) in coastal ecosystems, drawing extensively on the case of Himmerfjärden, a Baltic Sea bay that receives 15N-enriched tertiary treated sewage that is discharged mainly as dissolved inorganic N (DIN). Gradients of delta15N in macroalgae (Fucus vesiculosus) and surface sediments traced sewage-derived N to 24 km from the outfall but elevated delta15N values (> 7 per thousand) indicated that the sewage influence was most pronounced within 10 km. Comparison of macroalgal delta15N values before and after enhanced tertiary treatment showed a decrease in the spatial impact of sewage N from about 24 km to 12 km from the outfall and a decrease to more marine delta15N values in more recent growth tissues. Sedimentary delta15N records showed that sewage has had a dominant influence on organic matter production in the bay with dramatic increases in sedimentary delta15N during the years of maximum sewage N loads. In cases where sewage N introduces a distinct isotopic signature into a system and where it has had a dominant influence on organic matter production, delta15N values in biota and sediments can be used to trace the spatial and temporal influence of sewage N in aquatic ecosystems.

Ecosystem↗

PubMed2005

[Nitrogen bio-cycle in the alpine tundra ecosystem of Changbai Mountain and its comparison with arctic tundra].

The nitrogen bio-cycle was discussed in the alpine tundra ecosystem of Changbai Mountain through compartment model. The alpine tundra of Changbai Mountain was compared with Arctic tundra by the common ratio of genus and species in this paper. It was found that the 89.3% of genus and 58.6% of species was the common between Changbai alpine tundra and Arctic tundra while 95.5% of lichen genus and 58.7% lichen species, 82.1% of moss genus and 76.3% of moss species, 93.1% of vascular bundle genus and 40.5% of vascular bundle species were the common, respectively, which made vegetation type or community to be similar between Changbai alpine tundra and Arctic tundra. The total storage of nitrogen was 65220.6 t in the vegetation-plant system of Changbai Mountain, of which soil pool amounted to 99.3%. The nitrogen storage of each compartment was as follows: the vegetation pool, litterfall pool and soil pool were 237.4 t, 145.3 t and 64837.9 t respectively. The transferable amounts of nitrogen were 131.7 t x a(-1), 58 t/a and 73.7 t x a(-1) in the aboveground plant, belowground root system and litterfall of alpine tundra ecosystem of Changbai Mountain.

Arctic Regions↗

PubMed2005

[Willingness to pay for ecosystem services of urban river in Shanghai].

The contingent valuation method (CVM) is one of the most dominating and standard techniques for eliciting the willingness to pay (WTP) for the ecosystem services provided by environment and resources. Taking Zhangjiabang Creek, a model project in the comprehensive management of urban river in China, as a case study, 800 payment card CVM questionnaires were surveyed and 646 as useful questionnaires were feed back in August 2003, then, the mean WTP, 195.07 - 253.04 Yen per person every year in the future 3 years, to the ecosystem services of the urban river was got in the payment card CVM study, and the figure was compared to some other river CVM studies. Distribution shape and range of WTP were probed, and the regression relationship between respondents WTP and their socioeconomic information such as income, education level, donation experience, and environmental attitude was discussed, what's important, an environmental economics explanation was given to the regression results. Some biases which influence the mean WTP of payment card CVM are inspected and corresponding countermeasures were seriously noticed and implemented in the survey. Finally the critiques and controversies that CVM is faced with were advanced, but the reliability of CVM is also given based upon environmental decision-making theory.

China↗

PubMed2006

[Profit and loss of nutrients in crop-fruit ecosystems].

The analysis on the balance of nutrient's profit and loss in crop-fruit ecosystems of three villges in middle-south Loess Plateau showed that fertilization was the main input of nutrients, of which, chemical fertilizer occupied a larger proportion, while organic manure was relatively insufficient. The quantity of N, P and K spent in interior circulation was far less than that exported from the ecosystem. The ratio of nutrient's output and input in three test villages was differed, but all at a low level.

Crops, Agricultural↗