Impact of osmolytes on buoyancy of marine phytoplankton

Marine phytoplanktonic cells can achieve neutral buoyancy only if the excess density of their relatively heavy structural materials (proteins, carbohydrates, silicate) is compensated for by the incorporation of materials that have densities less than seawater. We have calculated densities and osmotic concentrations for several marine algae, based on published values of structural materials and concentrations of inorganic ions and other osmolytes. The calculations, incorporating the partial molal volume, molecular mass, concentrations and osmotic coefficients, indicate that most published listings of intracellular osmolytes in marine algae are insufficient to provide the turgor known to exist. Similarly, the density of phytoplanktonic cells, calculated on the basis of known or estimated concentrations of cellular components, generally exceeds the density of seawater, which would cause negative buoyancy (sinking) throughout. We use models of osmotic concentration and cellular density in which we supplement known concentrations of osmolytes with proxy osmolytes. In particular, concentrations of some 100 mol m^-3 of quaternary ammonium derivatives can explain the deficits of both osmotic concentration and buoyancy.     

Use of Linkage Disequilibrium Data to Estimate Effective Size of Hatchery and Natural Fish Populations

A primary parameter in the assessment of the viability of a population is its effective population size ( Ne ). Allozyme analysis of four groups of fishes provided data on linkage disequilibrium, which were then used to estimate Ne . The groups included hatchery samples of juvenile white seabass, Atractoscion nobilis , juvenile rainbow trout, Oncorhynchus mykiss , from the Shasta Hatchery, and juvenile chinook salmon, O. tshawytscha , from the Coleman National Fish Hatchery. The fourth sample consisted of juvenile chinook salmon from the threatened winter run in the upper Sacramento River. The groups of fish were chosen to represent different applications of the methodology to conservation of fishes. For a variety of reasons. Ne may be considerably lower than census counts of fish present in the parental populations. The Ne of the hatchery broodstock that produced the sample of juvenile white seabass was estimated to be approximately 10, although 25 adult white seabass were present in a mass spawning tank. Ne estimates for the parental populations of the Shasta and Coleman Hatchery samples were 35.8 and 132.5, respectively. The actual number of fish spawned at the Shasta Hatchery was approximately 40, whereas nearly 10,000 salmon were spawned at the Coleman Hatchery. The threatened winter run of chinook salmon had an estimated Ne of 85.5 and an approximate run size of 2000 salmon. The method of estimating effective population size from linkage disequilibrium data appears to result in realistic estimates of effective population size when adequate sample size and a sufficient number of polymorphic loci are available.     

The relationship between emotional maturity and drinking-and-driving involvement among young adults

The relationship between emotional maturity and drinking-and-driving involvement among young adults aged 25–34 was investigated. The variables were sex, age broken down into two groups (25–29 and 30–39), and six drinking-and-driving categories. The Revised Huffman Inventory was used to measure emotional immaturity. The inventory was administered to graduate students enrolled at The University of Tennessee at Knoxville during the summer of 1981. A table of random numbers was used to obtain a sample of 326 subjects. A three-factor analysis of variance was used to test the hypotheses. If a difference among groups was significant (p< .05), Duncan's Multiple Range Test was applied to determine where those differences were. The conclusions were: (1) among females and males in the same age group, females are more emotionally mature than males; (2) age is a factor in emotional maturity in that emotional maturity increases with age; and (3) there appears to be a link between emotional maturity and drinking-and-driving involvement in that persons with lower emotional maturity are more likely to drive while under the influence of alcohol.     

EMPHASIS ON DISTRIBUTION: STRATEGIES FOR SMALL SCALE WATER RESOURCES DEVELOPMENT IN THAILAND1

This paper discusses strategies for the development of water resources, emphasizing the delivery of reliable water supplies, for both domestic and production purposes, to every village and to every farmer. This necessitates a shift of emphasis from the construction of large storage reservoirs to the construction, operation, and maintenance of water distribution systems capable of reaching the largest number of farms, and a shift from projects that benefit the few, to projects that benefit the many. Water distribution in this context takes on three interrelated meanings: a geographical meaning, a technical meaning, and an economic meaning. The geographical meaning focuses on the spatial distribution of the recipient population as a key to identifying the proper distribution of water projects in physical space. The technical meaning relates to the physical distribution of water through canal systems to the farmers' fields. The economic meaning refers to the equitable distribution of benefits from water projects. The paper provides an illustration of the need for an emphasis on distribution, using the state of development of water resources in northeast Thailand as an example, with a proposed program for the further development of these resources. The northeast, the poorest region in the country, has been recognized by the Government of Thailand as a priority area for accelerated regional development efforts.     

Water resources management in small island countries Cost recovery and demand management

The concepts of cost recovery and demand management in the context of water resources for small island countries are introduced. Water pricing mechanisms which could be used to achieve the goal of cost recovery are discussed. Regulatory and economic measures, and pricing policies for limiting increases in demand ('demand management') are also presented. Examples from island countries are used to illustrate the policies discussed.     

Using expert elicitation to define successful adaptation to climate change

This paper develops definitions of adaptation and successful adaptation to climate change, with a view to evaluating adaptations. There is little consensus on the definition of adapting to climate change in existing debates or on the criteria by which adaptation actions can be deemed successful or sustainable. In this paper, a variant of the Delphi technique is used to elicit expert opinion on a definition of successful adaptation to climate change. Through an iterative process, expert respondents coalesced around a definition based on risk and vulnerability and agreed that a transparent and acceptable definition should reflect impacts on sustainability. According to the final definition, agreed by the Delphi panel, successful adaptation is any adjustment that reduces the risks associated with climate change, or vulnerability to climate change impacts, to a predetermined level, without compromising economic, social, and environmental sustainability.     

Does hyperaccumulated nickel affect leaf decomposition? A field test using Senecio coronatus (Asteraceae) in South Africa

Summary. Nickel hyperaccumulator plants contain unusually elevated levels of Ni (>1,000 mg Ni kg⁻¹). The high Ni concentration of hyperaccumulator tissues may affect ecosystem processes such as decomposition, but this has yet to be studied under field conditions. We used Senecio coronatus Thunb. (Harv.) from two pairs of serpentine sites: one member of each pair contained a hyperaccumulator population and the other a non-hyperaccumulator population. Our main goal was to determine if leaf Ni status (hyperaccumulator or non-hyperaccumulator) affected leaf decomposition rate on serpentine sites. We also used a non-serpentine site on which leaves from all four S. coronatus populations were placed to compare decomposition at a single location. Dried leaf fragments were put into fine-mesh (0.1 mm) nylon decomposition bags and placed on field sites in mid-summer (early February) 2000. Sets of bags were recovered after 1, 3.5, and 8 months, their contents dried and weighed, and the Ni concentration and total Ni content of high-Ni leaves was measured. For the serpentine sites, there was no significant effect of leaf Ni status or site type on decomposition rates at 1 and 3.5 months. By 8 months, leaf Ni status and site type significantly influenced decomposition on one pair of sites: hyperaccumulator leaves decomposed more slowly than non-hyperaccumulator leaves, and leaves of both types decomposed more slowly on the non-hyperaccumulator site. At the non-serpentine site, the highest-Ni leaves (15,000 mg Ni kg⁻¹) decomposed more slowly than all others, but leaves containing 9,200 mg Ni kg⁻¹ did not decompose more slowly than non-hyperaccumulator leaves. Nickel in decomposing hyperaccumulator leaves was released rapidly: after 1 month 57–68% of biomass was lost and only 9–28% of original Ni content remained. We conclude that very high (>10,000 mg Ni kg⁻¹) leaf Ni concentrations may slow decomposition and that Ni is released at high rates that may impact co-occurring litter- and soil-dwelling organisms.     

Anticipatory governance for social-ecological resilience

Anticipation is increasingly central to urgent contemporary debates, from climate change to the global economic crisis. Anticipatory practices are coming to the forefront of political, organizational, and citizens’ society. Research into anticipation, however, has not kept pace with public demand for insights into anticipatory practices, their risks and uses. Where research exists, it is deeply fragmented. This paper seeks to identify how anticipation is defined and understood in the literature and to explore the role of anticipatory practice to address individual, social, and global challenges. We use a resilience lens to examine these questions. We illustrate how varying forms of anticipatory governance are enhanced by multi-scale regional networks and technologies and by the agency of individuals, drawing from an empirical case study on regional water governance of Mälaren, Sweden. Finally, we discuss how an anticipatory approach can inform adaptive institutions, decision making, strategy formation, and societal resilience.     

Linking chemical elements in forest floor humus (Oh-horizon) in the Czech Republic to contamination sources

While terrestrial moss and other plants are frequently used for environmental mapping and monitoring projects, data on the regional geochemistry of humus are scarce. Humus, however, has a much larger life span than any plant material. It can be seen as the “environmental memory” of an area for at least the last 60-100 years. Here concentrations of 39 elements determined by ICP-MS and ICP AES, pH and ash content are presented for 259 samples of forest floor humus collected at an average sample density of 1 site/300 km² in the Czech Republic. The scale of anomalies linked to known contamination sources (e.g., lignite mining and burning, metallurgical industry, coal fired power plants, metal smelters) is documented and discussed versus natural processes influencing humus quality. Most maps indicate a local impact from individual contamination sources: often more detailed sampling than used here would be needed to differentiate between likely sources.