Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Four desert waters: Setting arid zone wetland conservation priorities through understanding patterns of endemism

Long-lasting surface water in arid-lands provide oases for aquatic biota, but their values as biological refugia have rarely been assessed. This study identified and mapped permanent natural wetlands across the Eastern Lake Eyre Basin in Australia and classified them into four types: riverine waterholes, rockholes, discharge springs and outcrop springs. Waterholes are the most widespread and numerous source of lasting water, while springs and rockholes are confined to relatively discrete clusters. The characteristics of each wetland type are summarised, and their biological values compared by examining various scales of endemism for vascular plant, fish and mollusc species. Discharge springs contain an exceptional concentration of endemic species across all three lifeforms at a range of scales. Waterholes are critical drought refugia for native fish species that also utilise a vast network of ephemeral streams during and after floods. Rockholes and outcrop springs do not contain any known specialised endemics, although the latter have disjunct populations of some plants and fish. The existing knowledge of antiquity, connectivity and habitat differentiation of the wetland types is compiled and their role in determining biological endemism is discussed. Exotic fish are a major conservation issue, the recovery of the discharge springs should be paramount, and the intact network of permanent waterholes should be preserved. A focus on endemism, combined with an understanding of the biogeographical processes underlying the observed patterns provides an effective and systematic approach to setting priorities for regional biodiversity conservation

Breeding Bird Diversity, Abundance and Density at Indian Cave and Ponca State Parks, Nebraska, 2012-2014

Indian Cave State Park (ICSP) and Ponca State Park (PSP) are important conservation properties in Nebraska that are owned and managed by the Nebraska Game and Parks Commission (NGPC). Both parks border the Missouri River and are two of the largest continuous tracts of undeveloped upland deciduous oak forest in Nebraska (Kaul and Rolfsmeier 1993). ICSP totals 1,336 hectares (ha) and is located in northeast Richardson and southeast Nemaha counties (Figure 1). PSP totals 813 ha and is located in northeast Dixon County. Both parks are part of Biologically Unique Landscapes identified by the Nebraska Natural Legacy Project (Schneider et al. 2011). Changes in grazing and fire regimes have altered oak forests, woodlands and savannas in the Midwestern United States (Apfelbaum and Haney 1987). Oak (Quercus spp.) woodlands and savannas are disturbance-mediated ecosystems that require periodic fires. Fires burn understory, foster oak regeneration and increase the density and diversity of ground-layer vegetation. A dense woody understory of shade-tolerant trees and shrubs will grow in absence of fire reducing oak regeneration. Fire has been absent at both ICSP and PSP for decades, if not over a century, and a dense understory of trees and shrubs has indeed developed. Furthermore, the understory has been invaded by non-native plants such as common buckthorn (Rhamnus catharitica), honeysuckles (Lonicera spp.) and garlic mustard (Allaria petiolata)

GNSS for sports - Sailing and rowing perspectives

This paper introduces two sport-related projects conducted by the Satellite Positioning and Orientation Research Team (SPORT) at RMIT University - speed sailing world record challenge and development of a smart GPS rower tracking system. In the first project, both traditional and contemporary surveying technologies are investigated to assist the Macquarie Speed Sailing Team to reliably record and subsequently claim a world speed sailing record. In the second project, an integrated rower tracking system has been developed in collaboration with other research partners and the system has been used prior to and during the Athens Olympic Games. Three Olympic rowing medals were won by Australia. The technology, research procedures and major developments are presented

Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions

Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae)

Plant responses to endophytic fungi and their effects on herbivorous insects

Communities of fungal endophytes are ubiquitous in above and below-ground tissues of probably all plants, where they live without causing any visible symptoms. Endophytes and plants have been found to interact on the molecular and biochemical level and, depending on the fungal species (or isolate) involved, the outcome of such interactions may even be beneficial to the colonized plant, leading to enhanced growth and stress tolerance. Plants and herbivorous insects also form intricate relationships and because plant chemistry is crucial for herbivore development and behaviour, endophyte-mediated responses may change the outcome of such plant-insect interactions. To shed some light on this question we studied the plant responses to three endophyte species with significantly different life histories: a ubiquitous, facultative root-colonizer (Trichoderma atroviride), a well-known insect pathogen (Beauveria bassiana), which was only recently described as capable of endophytic colonization, and the obligate shoot-colonizing grass endophyte Epichloë uncinatum. This talk will highlight some of the metabolic and transcriptional changes each fungus causes and will focus on the possible induction of plant defences against insects. Furthermore, data will be presented that demonstrate changes in volatile root compounds due to endophyte colonization and how this can affect the foraging behaviour of a soil insect. We conclude that endophytes interact directly with plants and indirectly with higher trophic levels thus playing important roles in the ecosystem. Understanding the mechanisms of these multitrophic interactions may help to manipulate crop plants for more sustainable pest and pathogen management