Individual and combined effects of Ca/Mg ratio and water on trait expression in Mimulus guttatus

Low Ca/Mg ratios (a defining component of serpentine soils) and low water environmental conditions often co-occur in nature and are thought to exert strong selection pressures on natural populations. However, few studies test the individual and combined effects of these environmental factors. We investigated the effects of low Ca/Mg ratio and low water availability on plant leaf, stem, stolon, and floral traits of Mimulus guttatus, a bodenvag species, i.e., a species that occurs in serpentine and non-serpentine areas. We quantified genetic variation and genetic variation for plasticity for these leaf, stem, stolon, and floral traits at three hierarchical levels: field-habitat type, population, and family, and we evaluated the relative importance of local adaptation and plasticity. We chose two populations and 10 families per population from four distinct field "habitat types" in northern California: high Ca/Mg ratio (non-serpentine) and season-long water availability, high Ca/Mg ratio and seasonally drying, low Ca/Mg ratio (serpentine) and season-long water availability, and low Ca/Mg ratio and seasonally drying. Seedlings were planted into greenhouse treatments that mimicked the four field conditions. We only detected genetic variation for stem diameter and length of longest leaf at the field-habitat level, but we detected genetic variation at the family level for nearly all traits. Soil chemistry and water availability had strong phenotypic effects, alone and in combination. Our hypothesis of an association between responses to low water levels and low Ca/Mg ratio was upheld for length of longest leaf, stem diameter, corolla width, and total number of reproductive units, whereas for other traits, responses to Ca/Mg ratio and low water were clearly independent. Our results suggest that traits may evolve independently from Ca/Mg ratios and water availability and that our focal traits were not simple alternative measures of vigor. We found genetic variation for plasticity both at the field-habitat type and family levels for half of the traits studied. Phenotypic plasticity and genetic variation for plasticity appear to be more important than local adaptation in the success of these M. guttatus populations found across a heterogeneous landscape in northern California. Phenotypic plasticity is an important mechanism maintaining the broad ecological breadth of native populations of M. guttatus.     

Preliminary evaluation of septic-system absorption-field architecture types in a profile-limited soil

Managing household wastewater is an issue that affects hundreds of thousands of people in rural communities nationwide, many of whom rely on septic systems as their primary means of household wastewater disposal. Septic system absorption field products with architectures quite different from traditional pipe-and-gravel systems are being installed in many states with variances from initial design specifications. The objective of this study was to evaluate the performance, as measured by the in-product height of stored solution, of four differing absorption-field product architecture types in a profile-limited soil that was loaded at the maximum allowable rate based on soil morphology. Five chamber, two gravel-less pipe, two polystyrene aggregate, and four pipe-and-gravel systems were installed in a profile-limited, Captina silt loam soil (fine-silty, siliceous, active, mesic Typic Fragiudult) and dosed with raw effluent at rates determined by current State of Arkansas regulations via individual peristaltic pumps. Free-solution monitoring ports were installed within each product, where the depth to free solution was measured periodically and used to evaluate product performance. Data collected from January through August 2009 indicated that preliminary system performance was unaffected by product architecture type. All products performed similarly under dry soil conditions. However, differences among individual products were observed during periods of hydrologic stress (i.e., wet soil conditions). Surfacing of effluent was not observed atop any product, indicating that the current loading rate design method is functioning properly. Preliminary results indicate that some alternative absorption-field products perform similarly to the traditional pipe-and-gravel system, thus providing flexibility and options for homeowners.     

Spectroscopic approaches for phosphorus speciation in soils and other environmental systems

In the past decades, environmental scientists have become increasingly involved in developing novel approaches for applying emerging spectroscopic techniques to complex environmental matrices. The objective of this review is to convey the most common chemical species of phosphorus reported for soils, sediments, model systems, and waste materials based on analyses by four spectroscopic techniques: X-ray absorption near-edge structure, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and Raman spectroscopy. Unique information is provided by each technique at a level of specificity that depends in part on matrix complexity. The X-ray absorption near-edge structure and nuclear magnetic resonance techniques reveal inorganic and organic P species in intact environmental matrices or in chemical extracts, whereas the Fourier transform infrared and Raman techniques can provide more specific bonding information about mineral or adsorbed P species in model analogs of matrix components. The most common P species in soils and sediments as indicated by spectroscopy are hydroxyapatite and octacalcium phosphate minerals, phosphate adsorbed on Fe- and Al-oxides, pyrophosphates and polyphosphates, phosphate mono- and di-esters, and phosphonates. Continued advancements in spectroscopic methods should improve speciation-based models of P mobilization and transformations in the environment.     

Perfluorinated phosphine oxide and sulfides as extractants for heavy metals and radionuclides

New highly fluorinated monodentate and bidentate phosphine oxide compounds of the type {CF(3)(CF(2))(n)CH(2)CH(2)}(3)PO (n = 5, 9) and [{CF(3)(CF(2))(5)CH(2)CH(2)}(2)P(O)CH(2)CH(2)P(O){CH(2)CH(2)(CF(2))(5)CF(3)}] have been prepared. Their ability to extract a number of metals and radionuclides from aqueous solutions into perfluorinated solvents has been established and the extractable species investigated. All extractants extract the metals As(V), Cd(II), Co(II), Cr(VI), Hg(II), Pb(II), and Sn(II) with >75% removal. In addition, the radioisotopes (90)Sr(II), (133)Ba(II), and U(VI) have been investigated, whilst (59)Fe(III) has been used to model the extraction of plutonium. (133)Ba(II) shows a high distribution ratio for monodentate phosphine oxides, whilst for UO(2)(2+) and (59)Fe(III) bidentate phosphine oxides are superior.     

Dopamine release by the green alga <Emphasis Type="Italic">Ulvaria obscura</Emphasis> after simulated immersion by incoming tides

Ulvaria obscura, a prominent component of green tide blooms in Washington, is unique among macroalgae because it contains dopamine. To examine dopamine release by U. obscura following simulated low tides, we conducted 6 field experiments in which algae were emersed for 75 min and then immersed in filtered seawater (FSW). Dopamine was measured in algal tissues prior to emersion and 3 h after immersion and in seawater for 3 h following immersion. In our experiments, algae released 7–100% of their tissue dopamine, resulting in average seawater concentrations of 3–563 μM. In 5 of 6 experiments, seawater dopamine concentrations were highest immediately after immersion, and then decreased over time. The percentages of dopamine released were not correlated with tissue dopamine concentrations, but were positively correlated with solar radiation during emersion. The release of dopamine, which is both cytotoxic and genotoxic, may explain the negative effects of U. obscura exudates on marine organisms.     

Age and sex influence marmot antipredator behavior during periods of heightened risk

Animals adjust their antipredator behavior according to environmental variation in risk, and to account for their ability to respond to threats. Intrinsic factors that influence an animal’s ability to respond to predators (e.g., age, body condition) should explain variation in antipredator behavior. For example, a juvenile might allocate more time to vigilance than an adult because mortality as a result of predation is often high for this age class; however, the relationship between age/vulnerability and antipredator behavior is not always clear or as predicted. We explored the influence of intrinsic factors on yellow-bellied marmot (Marmota flaviventris) antipredator behavior using data pooled from 4 years of experiments. We hypothesized that inherently vulnerable animals (e.g., young, males, and individuals in poor condition) would exhibit more antipredator behavior prior to and immediately following conspecific alarm calls. As expected, males and yearlings suppressed foraging more than females and adults following alarm call playbacks. In contrast to predictions, animals in better condition respond more than animals in below average condition. Interestingly, these intrinsic properties did not influence baseline time budgets; animals of all ages, sexes, and condition levels devoted comparable amounts of time to foraging prior to alarm calls. Our results support the hypothesis that inherent differences in vulnerability influence antipredator behavior; furthermore, it appears that a crucial, but poorly acknowledged, interaction exists between risk and state-dependence. Elevated risk may be required to reveal the workings of state-dependent behavior, and studies of antipredator behavior in a single context may draw incomplete conclusions about age- or sex-specific strategies.     

Behavioral and physiological factors associated with juvenile hormone in Polistes wasp foundresses

Although there is increasing interest in the evolution of endocrine systems, relatively little is known about the factors associated with natural endocrine variation in invertebrates. Here, we assess juvenile hormone (JH) titers among nest-founding queens of the wasp Polistes dominulus over 2 years. We allowed unfamiliar wasps to battle for dominance and examined the relationships between dominance rank, JH, ovarian development, and facial patterns. The relationship between JH-titer and dominance varied across years; there was a stronger relationship between JH-titer and dominance in 2006 than in 2008. Across years, wasps that won dominance contests had facial patterns with more broken black spots than wasps that lost dominance contests. There was no relationship between dominance rank and ovarian development. The individual characteristics associated with JH-titer were also tested; JH-titers were correlated with facial pattern brokenness and ovarian development. This study adds to previous work indicating that P. dominulus facial patterns function as a signal of fighting ability. Furthermore, the correlation between JH-titers and facial patterns parallels previous work on testosterone and vertebrate signals and suggests that links between signals of fighting ability and hormones that mediate fighting ability may be common across taxa. Overall, individual JH-titers vary, though they are typically associated with factors related to individual reproductive success, including dominance, fertility, and facial pattern brokenness. Future studies in additional contexts and taxa will be important to test how and why JH-titers vary.     

Physical,chemical, and mechanical properties of landfilled waste from Campina Grande,Brazil

Environmental Science and Pollution Research - The properties of municipal solid waste (MSW) in landfills vary considerably, depending on the waste’s composition, time, and density. This...