Exploring the role of chitinolytic enzymes in the sea fan coral, <Emphasis Type="Italic">Gorgonia ventalina</Emphasis>

Chitinases are involved in defense against chitinaceous pathogens in both invertebrates and vertebrates. This study investigated whether sea fan corals, Gorgonia ventalina (Linnaeus) collected from the Florida Keys between the summer of 2002 and the summer of 2005 contain chitinases, and whether these enzymes could serve an analogous protective role against the fungal pathogen, Aspergillus sydowii (Thom et Church). Crude extracts of healthy sea fans contained detectible levels of exochitinase activity in an in vitro microplate assay using fluorogenic substrates. The exochitinase levels decreased upon injury, agitation, or manipulation of the tissue. A concurrent, transient increase of exochitinase in the surrounding water suggests that sea fans release chitinases as a response to these stresses. By contrast, endochitinase was detected in only 2 of 15 sea fans (13%), suggesting a high degree of variation for this enzyme. Sea fan chitinase-containing seawater and anion exchange chromatography fractions were both active against A. sydowii in an absorbance-based antifungal assay. The presence of chitinases in sea fan extracts, their release into the surrounding water upon stress, and their activity against A. sydowii suggests that further study of these enzymes in coral stress responses is warranted.     

Interaction between schools of fish and mysids

Summary A long-term daily census of 20 small patch reefs along the backreef of Tague Bay barrier reef, U.S. Virgin Islands, established that recently recruited postlarval French grunts, Haemulon flavolineatum, form mixed schools with at least two species of mysids (genus Mysidium). The formation of these taxonomically unrelated animals into socially interacting groups probably occurs because of the striking resemblance of postlarval grunts to mysids. Over a period of 5 d and as the postlarval grunts grow, these mixed associations break down, only to reform every 14–15 d as new postlarval grunts periodically recruit from the plankton. The fleeting but persistent formation of these mixedspecies schools is believed to initially provide protection to the grunts and, as the grunts grow, limited protection to the mysids. In additions, the grunts benefit trophically from the associations because they prey on the mysids.     

Energetics,reproductive suppression and obligate communal breeding in carnivores

Summary Leptogenys processionalis Jerdon forages on termites and other arthropods by raiding in branched trails. Growth and topology of these search trails were studied using Horton's (1945) technique orginally developed to analyze the branching pattern of river systems. Branching was always a bifurcating process and branches emerged symmetrically on either side of the main trail. Branching coefficients (R _b ) were similar to those of a few biological branching systems, such as lungs, that are considered to be non-random in their branching pattern. The R _b values indicated that the rate of branching and growth of trails remained constant within each foraging bout. The length of trails became shorter as they grew out and branched. The branching process was a function of the spatial separation of food patches in the terminal search field. Ants in the terminal search field send signals on encountering prey. The recruits cannot discriminate between these signals if they arise from two food patches situated <40 cm from each other, and hence converge on them in a single trail. However, discrimination is possible when food patches are >40 cm apart and hence recruits congregate on them separately in two trails, resulting in branching. Thus, the branching process is a result of independent decision by the ants conforming to certain simple rules and not a collective decision of the whole colony. We argue that mass recruiting ants selected to forage by branching pattern of trails because of its efficiency over other topologies (Stevens 1973) in minimizing the cost of travel, both from the nest to the food patches and between food patches. Further, the branch angles appear to be a trade-off to minimize travel cost and the resistance to the flow of ants comprising the column.Offprint requests to: T. Veena     

The decatur county landfill: One community turns over a clean sheet of paper

The Decatur County Landfill, a privately owned sanitary landfill, was shut down by Indiana officials in 1991. When the owner proved not to have the financial ability to close the site as required by law, state environmental officials turned to local businesses to remediate the landfill. In a pioneering effort at voluntary action, officials of the state, county, and city government worked in partnership with business and the local community to perform and fund closure and provide the postclosure care. This study illustrates the results that can be achieved when government and private parties work together.     

A tradeoff method to assess housing location preferences

In public decision making, tradeoffs between competing goods must be made by someone other than the user. A tradeoff technique provides a means both to allow users to participate in the decision making process and to educate users about the constraints involved in making such decisions. Seventy-two female public housing tenants were asked to describe their ideal housing location in terms of 20 attributes, including preferred distance to 16 facilities and preferred quality of four features of the environment. In the tradeoff situation, they were given constrained budgets and asked to ‘buy’ the most satisfactory location based on these 20 attributes. The ideal and tradeoff approaches show a general agreement about attributes that should be most heavily weighted in making decisions about public housing location. The rank order of the importance of the attributes differs, however, indicating that the tradeoff method should be used to weight the importance of each attribute. Residents' responses were influenced by the availability of an automobile but were relatively little affected by the personal characteristics of race, age of children and employment status.     

Theory and estimation of the household production function for wildlife recreation

The household production function is an intuitively appealing way to model man's interaction with nature. This paper models the interaction between the household's behavior and publicly provided inputs into wildlife recreation. The paper shows how to compute benefits, assuming that the household production function is known. The household production function approach collapses to the simple travel cost approach when households are unable to substitute their own inputs for publicly provided inputs. In addition, the paper demonstrates the conditions under which the parameters of cost and preference functions can be identified. The conditions for identification are quite restrictive when several choices are endogenous.     

Managing Alaska’s National Parks in an era of uncertainty: an evaluation of scenario planning workshops

Regional Environmental Change - Scenario planning is a flexible tool used to assess a broad range of plausible, relevant, divergent, and challenging futures, for short-term responses and long-term...     

The Lost Creek Fire: managing social relations under disaster conditions

This paper examines some of the social processes associated with disaster conditions. Utilising an asset‐based perspective of community capacity, it focuses on four types of normative systems to interpret the ability of communities to manage disasters through market‐, bureaucratic‐, associative‐, and communal‐based norms. Drawing on experience of a wildfire in the Crowsnest Pass region of southwest Alberta, Canada, in 2003, the tensions and compatibilities among these normative systems are evaluated through interviews with 30 community leaders. The results confirm the contributions of all types of social capital to resiliency, the necessity for rapid use of place‐based knowledge, and the importance of communication among all types and levels of agents. In addition, they point to the value of identifying and managing potential conflicts among the normative systems as a means to maximising their contributions. The integration of local networks and groups into the more general disaster response minimised the impacts on health and property.     

Surrogate Measures for Providing High Frequency Estimates of Total Suspended Solids and Total Phosphorus Concentrations1

Spackman Jones, Amber, David K. Stevens, Jeffery S. Horsburgh, and Nancy O. Mesner, 2010. Surrogate Measures for Providing High Frequency Estimates of Total Suspended Solids and Total Phosphorus Concentrations. Journal of the American Water Resources Association (JAWRA) 1‐15. DOI: 10.1111/j.1752‐1688.2010.00505.x Abstract: Surrogate measures like turbidity, which can be observed with high frequency in situ, have potential for generating high frequency estimates of total suspended solids (TSS) and total phosphorus (TP) concentrations. In the semiarid, snowmelt‐driven, and irrigation‐regulated Little Bear River watershed of northern Utah, high frequency in situ water quality measurements were recorded in conjunction with periodic chemistry sampling. Site‐specific relationships were developed using turbidity as a surrogate for TP and TSS at two monitoring locations. Methods are presented for employing censored data and for investigating categorical explanatory variables (e.g., hydrologic conditions). Turbidity was a significant explanatory variable for TP and TSS at both sites, which differ in hydrologic and water quality characteristics. The relationship between turbidity and TP was stronger at the upper watershed site where TP is predominantly particulate. At both sites, the relationships between turbidity and TP varied between spring snowmelt and base flow conditions while the relationships between TSS and turbidity were consistent across hydrological conditions. This approach enables the calculation of high frequency time series of TP and TSS concentrations previously unavailable using traditional monitoring approaches. These methods have broad application for situations that require accurate characterization of fluxes of these constituents over a range of hydrologic conditions.