LONG-TERM VARIATIONS IN SEASONAL WEATHER CONDITIONS IMPORTANT TO WATER RESOURCES IN ILLINOIS1

ABSTRACT: An analysis of historical relationships between seasonal weather conditions and water resource conditions in Illinois provides insights to the challenges of projecting such relationships under conditions of climate change. In Illinois for 1901–1997 there were major temporal shifts in types of seasonal conditions that have positive and negative effects on surface water and ground water supplies and their quality. Major seasonal effects came in the spring and summer seasons and when either wet-and-warm or dry-and-warm weather conditions prevailed in either season. Sixty percent of the summer seasons creating negative impacts occurred during only 40 years: 1911–1940 and 1951–1960. Seasons creating impacts relate well to the frequency of cyclone passages and to the incidence of El Niño or La Niña conditions. This reveals that future climate fluctuations that shift the frequency of cyclones and/or ENSO events will have profound effects on Midwestern seasonal conditions that affect water resources. Projecting future effects of climate change on water resources will need to consider how shifts in water use and water management technologies act to re-define the seasonal weather conditions that are critical.     

Field Trial of Biosparging with Oxygen for Bioremediation of Volatile Organic Compounds

Xpert Design & Diagnostics, LLC (XDD), & Conestoga‐Rovers and Associates (CRA) conducted a biosparging field trial at a Superfund site in New Jersey. The biosparging field trial proved that biosparging with oxygen was very effective in promoting the biological destruction of benzene. The approximately 265‐day period of oxygen injection successfully reduced benzene concentrations by several orders of magnitude, or even to non‐detect values, at least 40 feet from the point of injection. Through co‐precipitation of arsenic with oxidized iron, biosparging also effectively reduced total concentrations of arsenic and iron in groundwater. Based on the results of the biosparging field trial, the final remedy for the site has been amended to include the use of biosparging technology as an alternative to groundwater pumping and aboveground treatment in select locations. © 2001 John Wiley & Sons,Inc.     

Dredging impact on an urbanized Florida bayou: effects on benthos and algal-periphyton.

Environmental effects of dredging events have been uncommonly reported for shallow, residential estuaries characteristic of the Gulf of Mexico region. The objective of this study was to determine the impact of hydraulic dredging on an urbanized estuary. Physicochemical quality, benthic community composition, whole sediment toxicity, periphytic algal community composition and trace metal tissue quality were determined prior to and after dredging. The effects on surface water pH, dissolved oxygen, and temperature were negligible but photosynthetically active radiation was decreased at several stations. Dredging significantly reduced benthic diversity and density (P < 0.05). However, the sediments were not acutely toxic to the epibenthic, Americamysis bahia (formerly Mysidopsis bahia); survival averaged 93% (post-dredging) and to 98% (pre-dredging). There were several post-dredging taxonomic structural changes in the diatom-dominated, periphyton community but differences in mean density and three diversity indices were not significant. Trace metal concentration in periphyton after dredging were reduced from an average of 4-65% and significantly for mercury, zinc and chromium in several areas. It was concluded that the environmental impact of small-scale dredging events in urbanized near-coastal areas, based on the selected parameters, are likely to be localized and of short-term environmental consequence. The choice of the target biota, response parameters and chemical analysis are important considerations in the environmental impact assessment of these periodic episodic events.     

Lionfish alter benthic invertebrate assemblages in patch habitats of a subtropical estuary

Invasive lionfish (primarily Pterois volitans) have spread throughout the Caribbean region, Gulf of Mexico, and the Southeast US coast, and resulting impacts on reef fish populations have been well documented. We examined whether lionfish can likewise affect benthic invertebrate communities, using an in situ caging experiment, in the Loxahatchee Estuary, Florida, USA. We found that lionfish caused significant declines in the three most abundant benthic invertebrate species, driving an overall shift in assemblage composition. For example, grass shrimp (Palaemonidae) abundance was reduced by nearly 90 % in the presence of lionfish. Species richness of benthic organisms was significantly higher when lionfish were present, suggesting potentially complex emergent effects of lionfish predation on benthic assemblages. Despite the fact that this experiment was conducted in just a single location using relatively small experimental units, we show altered benthic invertebrate communities could well be an additional outcome of the lionfish invasion.     

Present and future economic impacts of climate extremes in the United States

Recent studies have yielded definitive information about the nation's economic impacts from extreme climates, although some sectoral values rely on educated estimates since hard data does not exist. Review of existing measures of the national impacts from weather—climate conditions reveals annual average losses of $36 billion from extremes and gains averaging $26 billion when conditions are favorable (good growing seasons, mild winters, etc.). Comparison of these values with various measures of the national economy reveals that the impacts are relatively small, typically about 1% of the Gross Domestic Product and less than 2% of the federal budget. The current impact information provides a basis for assessing various estimates of the nation's financial impacts resulting from a future climate change due to global warming. Most such estimates predict values similar to the magnitude of current climate impacts. Moreover, most economists attempting such estimates express a large degree of uncertainty about their projections.     

Lipid composition and partitioning of deepwater chondrichthyans: inferences of feeding ecology and distribution

The composition of lipids and fatty acids was determined for the livers, muscle, pancreas, kidney and stomach fluids of deepwater chondrichthyan species (including 11 squaliformes, 3 chimaeriformes, 1 hexanchiforme and 3 carcharhiniformes) caught as bycatch from continental waters off south-eastern Australia. The lipid class, fatty acid and fatty alcohol composition differed markedly in each tissue and in each species. The lipid and fatty acid composition of large, lipid-rich (38–70% wet weight, ww) livers demonstrated the multifunctional role of this organ in: lipid distribution, storage and biosynthesis, and buoyancy regulation. In the liver, the importance of certain lipids (including squalene, diacylglyceryl ethers, triacylglycerols and to a lesser extent wax esters) as mediators of buoyancy varied according to lifestyle and habitat. Less variability was observed in the muscle profiles, characterized by low lipid content (<1.0% ww) and high relative levels of polar lipids (>70%). The lipid and fatty acid profiles of the kidney and pancreas showed the highest intraspecific variability, suggesting these organs also have complex roles in lipid storage and metabolism. Overall intra- and interspecific differences in the tissue fatty acid profiles could be related to differences in a number of factors including phylogeny, habitat (depth), buoyancy regulation and diet and presumably also reflect different ecological roles. The lipid and fatty acid profiles are the first published for Rhinochimaera pacifica, Chimaera lignaria and Figaro boardmani and the first to demonstrate interspecific variation in lipid profiles of various tissues of deepwater chondrichthyans. The application of multivariate analysis to lipid class and fatty acid tissue profiles in chondrichthyans inferred dietary differences and metabolic preferences between species and habitats. These results have important implications for the future use of fatty acids as dietary tracers in chondrichthyan research.     

The potential and limitations of linking biological monitoring data and restoration needs of urbanized waterways: a case study

The implementation of effective strategies to mitigate the impacts of urbanization on waterways represents a major global challenge. Monitoring data plays an important role in the formulation of these strategies. Using monitoring and historical data compiled from around an urban area (Baltimore, USA), this paper is an assessment of the potential and limitations of the use of fish assemblage monitoring data in watershed restoration. A discriminant analysis between assemblages from urban and reference sites was used to determine faunal components which have been reduced or eliminated from Baltimore area waterways. This analysis produced a strong discrimination between fish assemblages from urban and reference sites. Species primarily associated with reference sites varied taxonomically and ecologically, were generally classified as pollution intolerant, and were native. Species associated with urbanized sites were also native, varied taxonomically and ecologically, and were mixed in pollution tolerance. One factor linking most species associated with reference sites was spawning mode (lithophilic). Spawning habitat limitations may be the mechanism through which these species have been reduced in the urbanized faunas. While this presents a strong general hypothesis, information regarding the specific habitat requirements and responses to urbanization of these species is limited. This represents a limitation to producing effective restoration strategies based on exact goals and targets. Without these, determining the type and number of restoration activities required to restore ecological communities remains problematic.     

Denitrification with carbon addition--kinetic considerations

The Blue Plains Advanced Wastewater Treatment Plant (Washington, D.C.) uses methanol as an external carbon source in a postdenitrification process, to achieve low effluent total nitrogen concentrations. This becomes more difficult in winter, at lower mixed liquor temperatures and higher flows, as a consequence of the kinetic behavior of the methanol-utilizing heterotrophs. The paper reports on an experimental batch test study conducted on Blue Plains postdenitrification sludge to investigate (1) the maximum specific growth rate of methanol-utilizing heterotrophs (Mu(METH)); (2) the temperature dependency of the growth rate; and (3) the efficacy of alternate substrates (ethanol, acetate, and sugar). A limited number of tests were conducted on sludge from two other treatment plants with methanol addition.     

Empirical Social-Ecological System Analysis: From Theoretical Framework to Latent Variable Structural Equation Model

The social-ecological system (SES) approach to natural resource management holds enormous promise towards achieving sustainability. Despite this promise, social-ecological interactions are complex and elusive; they require simplification to guide effective application of the SES approach. The complex, adaptive and place-specific nature of human-environment interactions impedes determination of state and trends in SES parameters of interest to managers and policy makers. Based on a rigorously developed systemic theoretical model, this paper integrates field observations, interviews, surveys, and latent variable modeling to illustrate the development of simplified and easily interpretable indicators of the state of, and trends in, relevant SES processes. Social-agricultural interactions in the Logone floodplain, in the Lake Chad basin, served as case study. This approach is found to generate simplified determinants of the state of SESs, easily communicable across the array of stakeholders common in human-environment interactions. The approach proves to be useful for monitoring SESs, guiding interventions, and assessing the effectiveness of interventions. It incorporates real time responses to biophysical change in understanding coarse scale processes within which finer scales are embedded. This paper emphasizes the importance of merging quantitative and qualitative methods for effective monitoring and assessment of SESs.