Effects of pollution on the structure and physiology of ecosystems

Thermal effect of the Middle Ural copper smelter (Russia) and growth of birch leaves

Toxic effects of industrial emissions on vegetation have been extensively studied, and at the same time indirect effects of pollution are less known. In 2011 and 2015, we studied temperature regime and leaf growth for Betula pubescens and B. pendula in deciduous forests near the Middle Ural copper smelter (MUCS). At two polluted sites (1 and 2 km from the smelter) and two unpolluted sites (16 and 27 km), we logged continuously air temperatures during the growing season (May-August) and measured leaves until completion of growth (May-June). Near MUCS, daily mean air temperatures were 0.7-1.0 °C higher with daily temperature range 2.2-2.7 °C greater than at distant sites. Daily air temperature range decreased from spring to midsummer, suggesting that the ability of vegetation to mitigate temperature variations increases with plant biomass, which peaks in midsummer. Growth of birch leaves near MUCS began 4-10 days earlier and completed 3-7 days earlier than far away. Thermal sum over the leaf growth period did not differ between areas in 2011, and in 2015 was lower in the polluted than in the unpolluted area. The earlier leaf growth completion near MUCS can be attributed to higher air temperatures and more rapid accumulation of required thermal sums.

Changes in spring arrival dates of Central European bird species over the past 100 years

Over the past decades, spring temperatures have increased in temperate regions, which resulted in birds arriving earlier in spring. Nonetheless, the timing of some species’ spring migration relies on endogenous rhythms that are not affected by climate change. In this study, we analysed changes in the spring arrival dates of 36 bird species over two periods in 22 towns and villages in Southeast Hungary and West Romania. The first period covered the national spring migration counts between 1894 and 1926, while the second period took place between 2005 and 2019 and is based on our recent observation data. Our results show, that the average spring arrival dates of most long-distance migrant species have not changed significantly over the past 100 years. In contrast, in cases of medium and short-distance migrants, most species arrive earlier recently than in the past. This may be caused by the fact, that the migration habit of long-distance migrants is characterized by strong genetic determinants, so they can not react as quickly to the warmer spring weather in Europe as the medium and short-distance migrants. However, in cases of some long-distance migrants, the timing of spring migration changed due to the drying of wintering grounds.

Urban ecosystem health assessment: perspectives and Chinese practice

The concept of ecosystem health is a way to assess the holistic operations and development potential of urban ecosystems. Accelerated by the practical need for integrated ecosystem management, assessment of urban ecosystem health has been greatly developed and extensively applied in urban planning and management. Development is aimed at comprehensively evaluating the performance of urban ecosystems, identifying the limiting factors, and providing suggestions for urban regulation. The time has come for reviewing and establishing an instructional framework for urban ecosystem health assessment to shed light on certain essential issues of urban ecosystem health. Based on literature reviews and series of practice, a holistic framework of urban ecosystem health assessment is proposed. The framework covers the essential elements of urban ecosystem health and integrates three dimensions: theoretical foundation, assessment method, and practical application. Concrete assessment methods are also established, focusing on both external performance and internal metabolic processes. The practice of urban ecosystem health assessment in China is illustrated to briefly demonstrate the application of the established framework and methods. Some prospects are discussed for urban ecosystem health assessment and its application in urban planning and management.

A MODEL FOR THE EFFECT OF POLLUTANT ON HUMAN POPULATION DEPENDENT ON A RESOURCE WITH ENVIRONMENTAL AND HEALTH POLICY

In this paper, a nonlinear mathematical model to study the effect of environmental pollution on resource biomass and human populations is proposed and analyzed. In modeling the system, it is considered that there is a limited budget to be spent on environmental cleanup and health policies. An optimal investment policy is also discussed using Pontryagin's Maximum Principle.

A second life for old data: global patterns in pollution ecology revealed from published observational studies

A synthesis of research on the responses of terrestrial biota (1095 effect sizes) to industrial pollution (206 point emission sources) was conducted to reveal regional and global patterns from small-scale observational studies. A meta-analysis, in combination with other statistical methods, showed that the effects of pollution depend on characteristics of the specific polluter (type, amount of emission, duration of impact on biota), the affected organism (trophic group, life history), the level at which the response was measured (organism, population, community), and the environment (biome, climate). In spite of high heterogeneity in responses, we have detected several general patterns. We suggest that the development of evolutionary adaptations to pollution is a common phenomenon and that the harmful effects of pollution on terrestrial ecosystems are likely to increase as the climate warms. We argue that community- and ecosystem-level responses to pollution should be explored directly, rather than deduced from organism-level studies.

Oxidant effects on californian coastal sage scrub

Causes for the reduced cover of native species of coastal sage scrub in certain southern Californian sites wvere sought among 43 habitat variables. The mean annual concentration of oxidants (which averaged 18 parts per 100 million on the 11 most polluted sites) is statistically indicated as the most likely causal factor. Sites of high oxidant levels in the region are also characterized by declining species richness and equitability.

Urban ecosystem health assessment: a review

Due to the important role of cities for regional, national, and international economic development and the concurrent degradation of the urban environmental quality under rapid urbanization, a systematic diagnosis of urban ecosystem health for sustainable ecological management is urgently needed. This paper reviews the related research on urban ecosystem health assessment, beginning from the inception of urban ecosystem health concerns propelled by the development needs of urban ecosystems and the advances in ecosystem health research. Concepts, standards, indicators, models, and case studies are introduced and discussed. Urban ecosystem health considers the integration of ecological, economic, social and human health factors, and as such it is a value-driven concept which is strongly influenced by human perceptions. There is not an absolute urban ecosystem standard because of the uncertainty caused by the changing human needs, targets, and expectation of urban ecosystem over time; thus, suitable approaches are still needed to establish health standards of urban ecosystems. Several conceptual models and suitable indicator frameworks have been proposed to organize the multiple factors to represent comprehensively the health characteristics of an urban ecosystem, while certain mathematical methods have been applied to deal with the indicator information to get a clear assessment of the urban ecosystem health status. Instead of perceiving the urban ecosystem assessment as an instantaneous measurement of the health state, it is suggested to conceptualize the urban ecosystem health as a process, which impels us to focus more studies on the dynamic trends of health status and projecting possible development scenarios.

Height growth of northern red oak in relation to site and atmospheric deposition in Pennsylvania

A forest tree growth-response to atmospheric deposition is expected to arise indirectly through soil chemical changes and would probably be observable only in the long term. We examined this hypothesis by evaluating the relationship between periodic height growth of mature northern red oak (Quercus rubra L.) trees and soil, physiography and atmospheric sulfate deposition along a 170-km west-to-east gradient of decreasing sulfate deposition in north central Pennsylvania, USA. Height increments for three common 20-year periods beginning in 1929, 1949 and 1969 were estimated from exponential-monomolecular growth functions fitted to stem analysis data for each of 45 trees in 13 ecologically analogous stands along the deposition gradient. Canonical analysis was used to identify a statistically manageable subset of the original 48 independent soil, site and tree (age, crown width) variables strongly associated with height growth. Predictive models relating total (60-year) and the three 20-year height increments to the reduced variable set plus estimated average sulfate and nitrate deposition were derived by best subsets multiple regression. An inherent spatial gradient of decreasing height growth from western to eastern sites was apparent in even the earliest (1929-1948) increment. This inferred non-deposition-related spatial growth trend was accounted for in the 1949-1968 growth increment by introduction of the earliest (1929-1948) growth increment as a significant covariate in the regression model. The inherent growth largely disappeared by the 1969-1988 period as a probable consequence of converging growth rates reported to occur in oaks after age 60 years regardless of site quality. The 1969-1988 growth increment was not as strongly correlated with site factors as was growth in preceding periods, nor was early growth or sulfate deposition significantly related to this height increment. Growth effects from sulfate deposition, if any, would most likely occur within the recent (1969-1988) increment coincident with the period of naturally decreasing growth rate, when site differences and possibly environmental factors would have less influence on growth. Our results give no indication that wet sulfate inputs are affecting northern red oak height growth across the atmospheric deposition gradient.

Long-term biological consequences of nuclear war

Subfreezing temperatures, low light levels, and high doses of ionizing and ultraviolet radiation extending for many months after a large-scale nuclear war could destroy the biological support systems of civilization, at least in the Northern Hemisphere. Productivity in natural and agricultural ecosystems could be severely restricted for a year or more. Postwar survivors would face starvation as well as freezing conditions in the dark and be exposed to near-lethal doses of radiation. If, as now seems possible, the Southern Hemisphere were affected also, global disruption of the biosphere could ensue. In any event, there would be severe consequences, even in the areas not affected directly, because of the interdependence of the world economy. In either case the extinction of a large fraction of the Earth's animals, plants, and microorganisms seems possible. The population size of Homo sapiens conceivably could be reduced to prehistoric levels or below, and extinction of the human species itself cannot be excluded.

Changes in water and sediment bacterial community structure in a lake receiving acid mine drainage

Water and sediment bacterial communities in a freshwater impoundment were studied over a 13-month period for stress-related responses to a point source of acid mine drainage (AMD). Comparisons of community structure were made on collections taken at the mouth of the acid stream, at a point 2 km downstream, and at the mouth of an uncontaminated stream. Monthly measurements of pH and specific conductance indicated the expected decrease in the AMD pollution with increasing distance from the source. Acridine orange direct counts did not differ significantly among the sites; however significantly fewer viable heterotrophs were observed by plate counts at the acid impacted station relative to the uncontaminated site. The diversity of the communities was significantly lower at the sites receiving mine drainage as compared with the unaffected station, and comparisons of community similarity showed that collections from the impacted sites were more like each other than like the control site. The assemblage at the latter site contained many bacterial guilds not found at the contaminated sites. The guilds unique to the control site showed a reduced in vitro ability to tolerate heavy metals as compared with the general community.

[The deterioration of the aquatic ecosystem because of civilization]

The surface waters of northwestern Europe belong to the most heavily loaded waters of the world. Within the last decades, pollution by non-biogenic organic substances has often become more important than pollution by domestic sewage. Ecologic concepts aid in understanding the various modes of disturbance of aquatic ecosystems. Stream pollution control consists not only of waste treatment.

Effects of PCB on interspecific competition in natural and gnotobiotic phytoplankton communities in continuous and batch cultures

The toxicity of polychlorinated biphenyls (PCB) to the diatomThalassiosira pseudonana (formerlyCyclotella nana), grown in pure and mixed cultures, was greatest when in competition with other species. Continuous cultures were superior to batch cultures for studying competitive interactions, and PCB caused greater alteration of species composition in continuous cultures than it did in batch cultures. Natural phytoplankton communities from Vineyard Sound, maintained in continuous culture, responded to PCB stress the same as did gnotobiotic communities, withT. pseudonana showing similar responses in both communities.A PCB concentration of 0.1 μg/liter (0.1 part per billion), a level not uncommon in natural waters, did not affect algal growth in pure cultures but caused substantial disruption of continuous culture communities. The possible impact of PCB pollution on natural phytoplankton communities is discussed.

Information and the Ecology of Scholars

Groups of scholars often behave in ways that are startlingly reminiscent of the behavior of groups of plants and animals in a biological ecosystem. I have tried to show that the parallel may have its basis in two fundamental considerations: (i) the similar properties of stable dissipative structures in a wide variety of contexts and (ii) the mathematical similarity of information to chemical (nutrient) free energy. A particularly intriguing problem is that of successional trends arising from the kinetic limitation of information flow through the intellectual and social structures created by scholars. The "strategy of ecosystem development" may have implications for the strategy of academic administration. In this connection, it is worth bearing in mind Marglef's dictum (6, p. 77): "Probably the hypothesis holds everywhere that the less mature ecosystem feeds the more mature structures around it."

Polychlorinated biphenyls and DDT alter species composition in mixed cultures of algae

Either DDT or polychlorinated biphenyls were added to mixed cultures containing a marine diatom and a marine green alga that were sensitive and resistant, respectively, to these organochlorine compounds. The diatom grew faster and was therefore dominant in control cultures, but its dominance diminished in treated cultures, even at concentrations of chlorinated hydrocarbons that had no apparent effect in pure cultures. Such stable pollutants could disrupt the species composition of phytoplankton communities, thereby affecting whole eco-systems.

DDT in the biosphere: where does it go?

The worldwide pattern of movement of DDT residues appears to be from the land through the atmosphere into the oceans and into the oceanic abyss. Calculations based on the fragmentary data available on. rates of movement and sizes of various pools of DDT residues lead to the conclusion that concentrations in the atmosphere and in the mixed layer of the oceans lag by only a few years behind the amounts of DDT used annually throughout the world. A model suggests that maximum concentrations of DDT residues occurred in air in 1966 and will occur in the mixed layer of the oceans in 1971. The biota probably contains in total less than 1/30 of 1 year's production of DDT during the mid-1960's, a very small amount in proportion to the total potentially available. The reason for the biota's failure to absorb larger quantities and to be affected much more severely is unclear. The analysis suggests that mere good fortune has protected man and the rest of the biota from much higher concentrations, thus emphasizing the need to determine the details of the movement of DDT residues and other toxins through the biosphere and to move swiftly to bring world use of such toxins under rational control based on firm knowledge of local and worldwide cycles and hazards.