Air‐Water Temperature Relationships in the Trout Streams of Southeastern Minnesota's Carbonate‐Sandstone Landscape

Carbonate‐sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface‐water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater‐fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air‐water temperature relationships for 40 GWFS in southeastern Minnesota. A 40‐stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R² of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface‐water dominated streams. Regression models for streams with high R² values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater‐fed systems, but will do so at a slower rate than surface‐water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.     

Is spread of invasive species regulated? Using ecological theory to interpret statistical analysis

We investigate a recent proposal that invasive species display patterns of spatial "spread regulation" analogous to density-dependent regulation of population abundances. While invasive species do offer valuable tests of ecological theories about spatial spread, we argue that the statistical approach used in the study is not useful, and that the proposed definition of "spread regulation" is likely to be confusing. While concepts of negative feedbacks in spatial spread may be reasonable, the proposed definition of "spread regulation" encompasses accelerating, constant, or decelerating spread. There is no compelling biological or practical reason to adopt such a definition. Moreover, we show that the statistical patterns (from time series of ratios of newly to recently invaded sites) proposed as evidence of spread regulation are predictable from basic diffusion models or other common models of constant spread with some stochasticity in dynamics and/or observations. Because such a wide range of processes would generate the observed patterns, no clear biological conclusions emerge from the proposed approach to spread analysis. When regarded in the context of the impacts and management of invasive species, the proposed regulation concept has the potential to create costly misunderstandings.     

The environmental audit. II. Application to stream network design

The planning and execution of water quality management programs requires careful collection and analysis of data coupled with a systematic review and analysis of programmatic success. The environmental audit is a tool which facilitates improved water quality planning and management. This article demonstrates the utility of the environmental audit by reviewing portions of a comprehensive review of the water quality management program for the state of Idaho. The audit is a tool which forces careful design of a sampling program before data are collected. In the audit approach, program objectives are clearly stated prior to initiation of sampling. Stated objectives are also evaluated regularly to identify tension points, that is, conflicts between expectations and reality. In the example taken from Idaho, a management review team followed a directive to redesign the water quality monitoring program. We present a summary of the redesign as proposed by that team, to illustrate the results of a typical review of monitoring programs. That summary is followed by an example of how the proposed program would differ if the audit approach had been used. The two approaches offered both coincident and conflicting recommendations. Management review team and audit recommendations for lake sampling programs were similar even though a different process was used to develop the recommendations. The most striking contrast between the two results lies in the review team's approach to the problem. The directives followed, and the team's responses, concentrate on tools, such as increasing biological monitoring or reliance on monthly BWMP stations. In contrast, the audit results stress addressing management questions for which clear objectives have been stated, depending on specific tools only as needed to meet stated objectives. Although the audit does integrate externalities in its structure, it is little affected by economic or political influences. A major strength of the audit approach is its ability to provide defensible data for management decision making.     

Ethnicity and hazard information dissemination

Citizens from two communities were questioned regarding the sources from which they have previously obtained information about environmental hazards and their preferences for different communication channels. Three ethnic groups—whites, blacks, and Mexican-Americans—were represented among those questioned. While all three ethnic groups described similar patterns of past information receipt, it was found that Mexican-Americans obtained more information through social network contacts than whites or blacks. Ethnic differentials emerged when citizens were asked about preferred sources for information receipt. While radio was identified as desirable by all three groups, only minority citizens expressed a preference for local television as a dissemination mode and only Mexican-Americans favored neighborhood meetings. Mailed dissemination and newspapers were preferred primarily by whites and blacks. The implications of the results for the conduct of hazard information dissemination are examined.     

The use of constructed wetlands in the treatment of acid mine drainage

US government regulations require that all effluents from industrial operations, including mining, meet certain water quality standards. Constructed wetlands have proven to be useful in helping to attain those standards. Application of this biotechnology to mine water drainage can reduce water treatment costs and improve water quality in streams and rivers adversely affected by acidic mine water drainage from abandoned mines. Over 400 constructed wetland water treatment systems have been built on mined lands largely as a result of research by the US Bureau of Mines. Wetlands are passive biological treatment systems that are relatively inexpensive to construct and require minimal maintenance. Chemical treatment costs are reduced sufficiently to repay the cost of construction in less than a year. The mine waste water is typically treated in a series of excavated ponds that resemble small marsh areas. The ponds are engineered to facilitate bacterial oxidation of iron. Ideally, the water then flows through a composted organic substrate supporting a population of sulphate-reducing bacteria which raises the pH. Constructed wetlands in the USA are described - their history, functions, construction methodologies, applicabilities, limitations and costs.     

Reef development at Inhaca Island,Mozambique: coral communities and impacts of the 1999/2000 Southern African floods

Inhaca Island, southern Mozambique, is located towards the southerly latitudinal limits of coral reef growth. Reef development is restricted to the margins of channels which dissect intertidal flats on the Maputo Bay side of the island, and to depths of around 6 m. In contrast to lower latitude reefs, reef development is therefore both spatially and bathymetrically restricted (largely due to high turbidity levels). These natural stress levels were exacerbated, via increased freshwater and sediment discharge, during the severe floods of late 1999/early 2000. Flood impacts varied but were most significant on reefs on the inner (western) side of the island where live coral cover (LCC) decreased from 60.5% (1999) to 24.0% (2001). This is attributed to freshwater-induced bleaching. Dead in situ coral cover increased from 18.6% (1999) to 51.3% (2001). Reefs on the southern tip of the island, by contrast, were relatively unaffected. It is suggested that this largely reflects a closer proximity to the open Indian Ocean which mitigated the effects of freshwater dilution.     

The removal of phosphorus during wastewater treatment: a review

Phosphorus removal from wastewater can be achieved either through chemical removal, advanced biological treatment or a combination of both. The chemical removal of phosphorus involves the addition of calcium, iron and aluminium salts to achieve phosphorus precipitation by various mechanisms which are discussed. In addition, the effects of operating conditions, especially wastewater characteristics; sludge production in terms of quality and quantity; optimisation of chemical use and re-use; points of chemical addition combined with biological treatment; alternative chemical/physical treatments and examples of full-scale applications are also reviewed. Biological phosphorus removal is dependent upon the uptake of phosphorus in excess of normal bacterial metabolic requirements and is proposed as an alternative to chemical treatment. Early developments and the postulated removal mechanisms are reviewed; these include either natural chemical precipitation, enhanced biological removal, or a combination of both. The nature of excess biological phosphorus removal in activated sludge wastewater treatment plants is evaluated, considering various operating parameters, bacteriology and process designs.     

Reduction of hexachloroethane to tetrachloroethylene in groundwater

At the Canadian Forces Base, Borden, hexachloroethane (HCE) that was introduced into an unconfined sand aquifer disappeared rapidly, with a half-life of about 40 days. Laboratory-scale studies, initiated to help assess the fate of HCE, indicated that it is reductively biotransformed to tetrachloroethylene (PCE) both by aerobic cultures of wastewater microflora and by microcosms containing unhomogenized Borden aquifer material. The results also indicate that the agents involved in the aquifer transformation of HCE to PCE are not homogeneously distributed in the aquifer material.     

保护生物多样性应对农业生产者进行补偿

几千年以来，不同的社会都热衷于通过基因改良来改变物种以使其适应人们所处的环境条件。通过这种方式，人们已经持续改变了用于食物和农业的基因资源。现在的农业生产中所用的基因有一部分还是野生的，而另一部分则是人工培育或改变的基因。目前，人类食物供给的大部分是通过后一种方式获得的。所有物种，特别是那些野生物种为农业和食品生产的扩大和多样化提供了巨大潜力。     

Further studies on the influence of zeolite type A on metal transfer in the activated sludge process

Investigations were carried out to determine the effect of zeolite type A on metal removal by activated sludge using laboratory activated sludge simulations. They were operated at constant aerator sludge age and settler surface loading. Different concentrations of raw zeolite and zeolite extracted from washing powder (0, 15, 30, 60, 120 mgl^?1) were introduced into the simulations. The zeolite was added at two degrees of calcium exchanged for sodium, 25 and 75% of the maximum exchange capacity. Metals were added at concentrations typical of mixed domestic-industrial waste waters. The results show that there was no adverse effect on metal removal by the laboratory activated sludge simulations in the presence of zeolite type A.