Plant-soil microorganism interactions: heritable relationship between plant genotype and associated soil microorganisms

Although soil microbial communities are known to play crucial roles in the cycling of nutrients in forest ecosystems and can vary by plant species, how microorganisms respond to the subtle gradients of plant genetic variation is just beginning to be appreciated. Using a model Populus system in a common garden with replicated clones of known genotypes, we evaluated microbial biomass and community composition as quantitative traits. Two main patterns emerged. (1) Plant genotype influenced microbial biomass nitrogen in soils under replicated genotypes of Populus angustifolia, F1, and backcross hybrids, but not P. fremontii. Genotype explained up to 78% of the variation in microbial biomass as indicated by broad-sense heritability estimates (i.e., clonal repeatability). A second estimate of microbial biomass (total phospholipid fatty acid) was more conservative and showed significant genotype effects in P. angustifolia and backcross hybrids. (2) Plant genotype significantly influenced microbial community composition, explaining up to 70% of the variation in community composition within P. angustifolia genotypes alone. These findings suggest that variation in above- and belowground traits of individual plant genotypes can alter soil microbial dynamics, and suggests that further investigations of the evolutionary implications of genetic feedbacks are warranted.     

Effectiveness of territorial polygyny and alternative mating strategies in northern fur seals, <Emphasis Type="Italic">Callorhinus ursinus</Emphasis>

We conducted a 6-year longitudinal behavioral and genetic investigation of a highly polygynous pinniped, the northern fur seal (Callorhinus ursinus), to determine the contribution of terrestrial polygyny to male fertilization success and to assess the occurrence of alternative mating strategies. Genetic samples from 37 adult males, 50 adult females, and 85 pups were collected and genotyped using five polymorphic microsatellite loci. Pup paternity was assigned using Cervus 2.0 at 99% confidence level. Paternity of 83 pups (98%) was assigned to terrestrial males who held territories or stayed temporarily in the study area during the breeding season when fertilization occurred. For 56 pups of which attendance records of their mothers were available, paternity of 45 pups (80%) was assigned to the associate males in whose territory their mothers stayed during the perioestrus period. In addition to defending breeding territories, territorial males have often been observed attempting to forcibly abduct adult females from adjacent territories (female stealing): We observed a total of 95 such cases, in which the stealers had significantly fewer females than the territorial males from whose territories they stole females. Our results indicate that terrestrial resource-defense polygyny is the major mating system in this species and that nonassociated paternity occurs mostly as a result of alternative mating strategies of less successful males. Male northern fur seals thus appear to adopt conditional alternative strategies that depend on their current social status to maximize their life-time reproductive success.     

Increasing litter species richness reduces variability in a terrestrial decomposer system

Debate on the relationship between diversity and stability has been driven by the recognition that species loss may influence ecosystem properties and processes. We conducted a litterbag experiment in the Scottish Highlands, United Kingdom, to examine the effects of altering plant litter diversity on decomposition, microbial biomass, and microfaunal abundance. The design of treatments was fully factorial and included five species from an upland plant community (silver birch, Betula pendula; Scots' pine, Pinus sylvestris; heather, Calluna vulgaris; bilberry, Vaccinium myrtillus; wavy-hair grass, Deschampsia flexuosa); species richness ranged from one to five species. We tested the effects of litter species richness and composition on variable means, whether increasing litter species richness reduced variability in the decomposer system, and whether any richness-variability relationships were maintained over time (196 vs. 564 days). While litter species composition effects controlled variable means, we revealed reductions in variability with increasing litter species richness, even after accounting for differences between litter types. These findings suggest that higher plant species richness per se may result in more stable ecosystem processes (e.g., decomposition) and decomposer communities. Negative richness-variation relationships generally relaxed over time, presumably because properties of litter mixtures became more homogeneous. However, given that plant litter inputs continue to enter the belowground system over time, we conclude that variation in ecosystem properties may be buffered by greater litter species richness.     

Application of tree-ring isotopic analyses to reconstruct historical water use of riparian trees.

Historical patterns of water source use by trees inferred from long-term records of tree-ring stable isotopic content could assist in evaluating the impact of human alterations to natural stream flow regimes (e.g., water impoundments, stream flow diversions, and groundwater extraction). Our objective was to assess the utility of the hydrogen stable isotopic composition (SD) of tree rings as an index of historical water source use by riparian trees. We investigated the influence of site conditions that varied in climate and hydrology on the relationship between deltaD of Populus xylem water (deltaD(xyl)) and tree-ring cellulose (deltaD(cell)). deltaD(xyl) and deltaD(cell) were strongly correlated across sites (r2 = 0.89). However, the slope of this relationship was less than 1, indicating that factors other than deltaD(xyl) influenced deltaD(cell). Inverse modeling with an isotopic fractionation model for tree-ring cellulose suggested that the lack of one-to-one correspondence between deltaD(xyl) and deltaD(cell) was due to the influence of the hydrogen isotopic content of the atmospheric water vapor (deltaD(atm)). Empirically measured values of deltaD(cell) were typically within the seasonal range of deltaD(cell) predicted from the fractionation model. Sensitivity analyses showed that changes in deltaD(xyl) generally had a greater influence at high-elevation montane sites, whereas deltaD(xyl) and deltaD(atm) had about equal influence on deltaD(cell) at low-elevation desert sites. The intrasite relationship between deltaD(cell) and deltaD(xyl) among individual trees was poor, perhaps because of the within-site spatial variation in hydrologic conditions and associated tree physiological responses. Our study suggests that historical variation in deltaD(cell) of Populus provides information on historical variation in both time-integrated water source use and atmospheric conditions; and that the influence of atmospheric conditions is not consistent over sites with large differences in temperature and humidity. Reconstruction of xylem water sources of Populus in riparian ecosystems from deltaD(cell) will be more direct at higher elevation mountain sites than at low-elevation desert sites.     

Chemical characteristics of aerosols at coastal station in Hong Kong.Ⅱ.Environmental behavior of trace elements during the April 1995 to April 1996

An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 atcoastal region, Cape D'Aguilar, in Hong Kong. The trace element composition of aerosol particles(TSP and PM10)were measured and analyzed by using the Instrumental Neutron Activation Analysis (INAA) and Inductive CouplePlasma-Mass Spectrometry(ICP-MS) techniques. The results showed that the polluted elements such as: V, Zn,As, Pb, Cd, Sb, I, Se, Bi, with high enrichment factor( E. F) values, are derived from anthropogenic sources ,while Sc, Al, Fe, Mn, Sm, La, Sr are less than 10 in E. F, these elements are related the crust and soil. Theconcentration of the trace elements are present seasonal variation i.e. summer low and winter high, whereas the Vor noncrustal V(V* ) present summer high and winter low, this phenomenon might be explained by local or regionaloil combustion sources. Use three type of elemental ratio, e.g. La/Sm, Mn* /V* and Bi/Al indicate that both TSPand PM10 of La/Sm ratios are mainly related to soil and dust, Mn*/V* are probably represent fossil combustion andBi/Al are possibly associated with refuse incineration, ferromanganese alloys and aluminum production. The varimaxrotation factor analysis for trace elements was performed. By means of the absolute principal component analysis(APCA) and multiple regression, the contribution of trace elements to possible sources and overall means of traceelements were estimated. The results showed that the present station is impacted by the anthropogenic species,although the quantities are different during the summertime and wintertime.     

Developing a circumpolar programme for the monitoring of Arctic terrestrial biodiversity

The Arctic is undergoing biological and environmental changes, and a coordinated effort to monitor is critical to detect these changes. The Circumpolar Biodiversity Monitoring Programme (CBMP) of the Arctic Council biodiversity working group, Conservation of Arctic Flora and Fauna (CAFF), has developed pan-Arctic biodiversity monitoring plans that aims to improve the ability to detect and report on long-term changes. Whilst introducing this special issue, this paper also presents the making of the terrestrial monitoring plan and discusses how the plan follows the steps required for an adaptive and ecosystem-based monitoring programme. In this article, we discuss how data on key findings can be used to inform circumpolar and global assessments, including the State of the Arctic Terrestrial Biodiversity Report, which will be the first terrestrial assessment made by the CBMP. Key findings, advice for future monitoring and lessons learned will be used in planning next steps of pan-Arctic coordinated monitoring.     

Analytical management of SCR catalyst lifetimes and multipollutant performance

Selective catalytic reduction (SCR) catalysts are deactivated by several mineral and metallic trace elements at highly variable rates determined by fuel quality and furnace firing conditions. With a loss in activity, NO is reduced over a longer inlet length of the SCR monolith, which leaves a shorter trailing section to sustain the most favorable conditions to oxidize Hg⁰ and SO₂. Since virtually no operating SCR was designed for Hg oxidation and since different monoliths are routinely combined as layers in particular units, the Hg oxidation performance of any SCR fleet is largely unmanaged. The analysis in this paper directly relates a measurement or manufacturer’s forecast on the deterioration in NO reduction with age to corresponding estimates for oxidation of Hg⁰. It accommodates any number of catalyst layers with grossly different properties, including materials from different manufacturers and different ages. In this paper, the analysis is applied to 16 full-scale SCRs in the Southern Company fleet to demonstrate that catalyst deactivation disrupts even the most prominent connections among the Hg⁰ oxidation performance of commercial SCRs and the behavior of fresh catalysts at lab, pilot, and even full scale.

Implications: Catalyst deactivation confounds even the most prominent connections among the Hg⁰ oxidation performance of commercial SCRs and the behavior of fresh catalyst at lab, pilot, and even full scale. The halogen dependence has been emphasized throughout the literature on catalytic Hg⁰ oxidation, based on a large database on fresh catalysts. But for deactivated catalysts in commercial SCRs, the number of layers is much more indicative of the Hg⁰ oxidation performance, in that SCRs with four layers perform better than those with three layers, and so on. The new qualified conclusion is that Hg⁰ oxidation is greater for progressively greater HCl concentrations only among SCRs with the same number of layers, even for an assortment of catalyst design specifications and operating conditions.     

Knowledge,agency and collective action as barriers to energy-saving behaviour

Energy saving is becoming a rising priority as a response to climate change and fossil fuel depletion in recent years. However, despite energy-related behaviour change being an important part of many environmental education initiatives, “energy literacy” among citizens remains patchy in both the USA and the UK, with evidence of strong positive attitudes but less consistent knowledge. Whilst it is clear that increasing knowledge does not automatically produce behaviour changes, potential questions must be asked about the logic of focusing solely on behaviour without simultaneously exploring and enhancing understanding of energy issues. This research, undertaken at a higher education institution with a strong focus on sustainability, illustrates the potential risks of targeting behaviour change and individual action at the expense of increasing knowledge, or encouraging collaborative and democratic endeavours. Results from an online survey indicate widespread misconceptions about energy which may reduce the effectiveness of energy-saving behaviours, alongside variable levels of motivation and engagement with energy issues. Respondents report a strong belief in the efficacy of personal changes, yet uncertainty about their capacity to influence business and government alongside a persistent faith in science to provide solutions to energy issues. The paper concludes by reflecting on the challenges arising from these findings for understanding agency and effectiveness in energy relationships.     

A New Open‐Access HUC‐8 Based Downscaled CMIP‐5 Climate Model Forecast Dataset for the Conterminous United States

Watershed‐scale hydrologic simulation models generally require climate data inputs including precipitation and temperature. These climate inputs can be derived from downscaled global climate simulations which have the potential to drive runoff forecasts at the scale of local watersheds. While a simulation designed to drive a local watershed model would ideally be constructed at an appropriate scale, global climate simulations are, by definition, arbitrarily determined large rectangular spatial grids. This paper addresses the technical challenge of making climate simulation model results readily available in the form of downscaled datasets that can be used for watershed scale models. Specifically, we present the development and deployment of a new Coupled Model Intercomparison Project phase 5 (CMIP5) based database which has been prepared through a scaling and weighted averaging process for use at the level of U.S. Geological Survey (USGS) Hydrologic Unit Code (HUC)‐8 watersheds. The resulting dataset includes 2,106 virtual observation sites (watershed centroids) each with 698 associated time series datasets representing average monthly temperature and precipitation between 1950 and 2099 based on 234 unique climate model simulations. The new dataset is deployed on a HydroServer and distributed using WaterOneFlow web services in the WaterML format. These methods can be adapted for downscaled General Circulation Model (GCM) results for specific drainage areas smaller than HUC‐8. Two example use cases for the dataset also are presented.     

On the scope and management of pesticide pollution of Swedish groundwater resources: The Scanian example

Twenty-three south-Swedish public supply wells were studied to assess pesticide pollution of regional groundwater resources. Relations between pesticide occurrence, hydrogeology, and land use were analyzed using Kohonen’s Self-Organizing Maps approach. Pesticides are demonstrated to be substantially present in regional groundwater, with detections in 18 wells. Concentrations above the drinking water threshold are confirmed for nine wells. Observations indicate considerable urban influence, and lagged effects of past, less restricted use. Modern, oxic waters from shallow, unconfined, unconsolidated or fracture-type bedrock aquifers appear particularly vulnerable. Least affected waters appear primarily associated with deeper wells, anoxic conditions, and more confined sediment aquifers lacking urban influence. Comprehensive, standardized monitoring of pesticides in groundwater need to be implemented nationwide to enable sound assessments of pollution status and trends, and to develop sound groundwater management plans in accordance with the Water Framework Directive. Further, existing water protection areas and associated regulations need to be reassessed.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0548-1) contains supplementary material, which is available to authorized users.