Establishing ozone flux–response relationships for winter wheat: Analysis of uncertainties based on data for UK and Polish genotypes

The work outlined in this paper had three objectives. The first was to explore the effects of ozone pollution on grain yield and quality of commercially-grown winter wheat cultivars. The second was to derive a stomatal ozone flux model for winter wheat and compare with those already developed for spring wheat. The third was to evaluate exposure- versus flux–response approaches from a risk assessment perspective, and explore the implications of genetic variation in modelled ozone flux.Fifteen winter wheat cultivars were grown in open-top chambers where they were exposed to four levels of ozone. During fumigation, stomatal conductance measurements were made over the lifespan of the flag leaf across a range of environmental conditions. Although significant intra-specific variation in ‘ozone sensitivity’ (in terms of impacts on yield) was identified, yield was inversely related (R² = 0.63, P < 0.001) to the accumulated hourly averaged ozone exposure above 40 ppb during daylight hours (AOT40) across the dataset. The adverse effect of ozone on yield was principally due to a decline in seed weight. Algorithms defining the influence of environmental variables on stomatal uptake were subtly different from those currently in use, based on data for spring wheat, to map ozone impacts on pan-European cereal yield. Considerable intra-specific variation in phenological effects was identified. This meant that an ‘average behaviour’ had to be derived which reduced the predictive capability of the derived stomatal flux model (R² = 0.49, P < 0.001, 15 cultivars included). Indeed, given the intra-specific variability encountered, the flux model that was derived from the full dataset was no better in predicting O₃ impacts on wheat yield than was the AOT40 index. The study highlights the need to use ozone risk assessment tools appropriate to specific vegetation types when modelling and mapping ozone impacts at the regional level.     

The material resources for the iron and steel industries

The future supplies of iron ore, coking coal and ferrous scrap are discussed. There is no likelihood of the resources of iron ore being exhausted until well into the twenty-first century. Coking coal, on the other hand, is in shorter supply but it is being eked out by blending with non-coking coal and by making blast furnaces more efficient. Briquettes made completely from non-coking coal will play a part in iron making in the future. To ensure greater flexibility in steel making, hydrocarbons are being considered as possible substitutes for coal. Scrap has always played an important part in steel making and the amount recycled is increasing every year. But more effort is needed, for example, to ensure that the steel in car scrap is fully utilised and that refuse is efficiently recycled. Steel making increasingly demands the scrap to have few impurities and to be in uniform sized pieces. A cryogenic method of preparing such scrap is described. A futuristic way of extracting iron, non-ferrous metals and other saleeable by-products from refuse, by using redundant blast furnaces, is also discussed.     

Review of ozone and temperature lidar validations performed within the framework of the Network for the Detection of Stratospheric Change

The use of assimilation tools for satellite validation requires true estimates of the accuracy of the reference data. Since its inception, the Network for Detection of Stratospheric Change (NDSC) has provided systematic lidar measurements of ozone and temperature at several places around the world that are well adapted for satellite validations. Regular exercises have been organised to ensure the data quality at each individual site. These exercises can be separated into three categories: large scale intercomparisons using multiple instruments, including a mobile lidar; using satellite observations as a geographic transfer standards to compare measurements at different sites; and comparative investigations of the analysis software. NDSC is a research network, so each system has its own history, design, and analysis, and has participated differently in validation campaigns. There are still some technological differences that may explain different accuracies. However, the comparison campaigns performed over the last decade have always proved to be very helpful in improving the measurements. To date, more efforts have been devoted to characterising ozone measurements than to temperature observations. The synthesis of the published works shows that the network can potentially be considered as homogeneous within +/-2% between 20-35 km for ozone and +/-1 K between 35-60 km for temperature. Outside this altitude range, larger biases are reported and more efforts are required. In the lower stratosphere, Raman channels seem to improve comparisons but such capabilities were not systematically compared. At the top of the profiles, more investigations on analysis methodologies are still probably needed. SAGE II and GOMOS appear to be excellent tools for future ozone lidar validations but need to be better coordinated and take more advantage of assimilation tools. Also, temperature validations face major difficulties caused by atmospheric tides and therefore require intercomparisons with the mobile systems, at all sites.     

The importance of micro and macro morphological variation in the adaptation of a sublittoral demosponge to current extremes

Sponges are known to show morphological acclimation in response to habitat variation. However, previous studies have concentrated on only one aspect of morphological variation, either gross morphology or spicule morphology. Cliona celata (Grant) is common in a variety of different habitats on the south-west coast of Ireland and has been investigated with respect to morphological variability on both scales. C. celata exhibited six different gross morphological body forms (ridged, burrowing, massive, massive/chimneys, encrusting, encrusting/chimneys). The body form exhibited was correlated to local environment, showing the extent of morphological adaptation in C. celata. Sponge size varied (from 548ᇟ to 2,345녹 cm²) between sites, with the largest (2,345녹 cm²) being found at the most stable site where flow rates were <5 cm^-1 (F>23.24, P<0.05). This may seem paradoxical as growth conditions were considered poor, but mortality and damage from material in suspension was reduced at low energy sites. At the spicule level, morphological variation was also present. Spicules at high energy sites were significantly longer, narrower and less numerous than at low energy sites (F>15.36, P<0.05). Previously, spicule variation has been associated with increased stiffness in hostile environments. However, longer, thinner spicules, as found in C. celata, may result in a more flexible sponge. This is the first study to show both gross morphological (macro) and spicule (micro) variation in a single species of sponge. However, this study only reinforces some of the previously produced information on both of these adaptations of sponges to varying environments. This study also illustrates how the results of single studies should not be used to draw conclusions for group level adaptation.     

Key considerations and challenges in the application of social-network research for environmental decision making

Attempts to better understand the social context in which conservation and environmental decisions are made has led to increased interest in human social networks. To improve the use of social-network analysis in conservation, we reviewed recent studies in the literature in which such methods were applied. In our review, we looked for problems in research design and analysis that limit the utility of network analysis. Nineteen of 55 articles published from January 2016 to June 2019 exhibited at least 1 of the following problems: application of analytical methods inadequate or sensitive to incomplete network data; application of statistical approaches that ignore dependency in the network; or lack of connection between the theoretical base, research question, and choice of analytical techniques. By drawing attention to these specific areas of concern and highlighting research frontiers and challenges, including causality, network dynamics, and new approaches, we responded to calls for increasing the rigorous application of social science in conservation.     

Extension rate: A primary control on the isotopic composition of West Indian (Jamaican) scleractinian reef coral skeletons

Large variations in skeletal microarchitecture, and in the carbon and oxygen isotopic composition of the skeleton, exist within single calices and over the surfaces of single colonies of various species of West Indian (Jamaican) scleractinian reef corals. Rapidly extending parts of individual colonies are depleted in both C¹³ and O¹⁸ regardless of the abundance of zooxanthellae in the overlying tissues. We suggest that this relationship is due to active translocation of organic compounds to sites of rapid calcification. Considerable variation in isotopic composition is found in skeletons of different specimens of the same species even when the skeletons are sampled in a consistent manner, come from the same locality and depth, and have a comparable growth history. The isotopic composition of the scleractinian skeleton is vastly more complex than has heretofore been realized.     

Sublittoral epifaunal communities at Signy Island,Antarctica. II. Below the ice-foot zone

Photographic samples were taken every 5 m along two 40 m transects on mostly rock face at Signy Island, Antarctica, during the austral winter of 1991. Dense and taxonomically rich communities of benthos occurred at most of the sublittoral study locations. These communities, however, varied significantly with substratum type, substratum profile and depth. Algae were generally the largest occupiers of space, but the area of substratum colonised by animal taxa increased whenever the profile approached vertical. Shallower than 15 m, disturbance effects, largely from ice, restricted community development to a high degree, but the frequency of disturbance at 25 m appeared to maintain high diversity by preventing domination of the assemblage by a few competitively superior taxa. Bryozoans, and to a lesser extent sponges, were the most abundant animal phyla. Among the bryozoans, species with an encrusting growth form occurred at the shallowest depths followed by encrusting massive/folaceous species and, at 40 m, the erect flexible forms. The ratio of encrusting to erect bryozoan species changed rapidly over the 0 to 50 m depth zone, from exclusively encrusting at 0 to 5 m to approaching 1 at 50 m. The erect bryozoans studied, from the shallow sublittoral to 290 m, could be classified as encrusting massive (foliaceous), erect flexible or erect rigid forms. There was some suggestion, despite the overlap between groups and considerable intra-group variation, that encrusting massive forms were abundant in the shallowest water, followed by erect flexible forms and then erect rigid forms with increasing depth. Some species which occurred as encrusting massive/foliaceous forms in deeper water occurred mostly in encrusting form only in shallow water (<15 m).     

Interaction between ozone and winter stress

In some countries, ozone (O3) is primarily a summer pollutant, but in much of Europe, elevated concentrations occur outside the growing season so perennials and over-wintering annuals may be subjected to the combined stresses of pollution, plus chilling, freezing, and winter desiccation. It is recognised that some air pollutants modify the response of plants to environmental stress, but little is known of interactions involving O3. This paper is part of a programme concerned with the effects of O3 on resistance to chilling, freezing, and winter desiccation. Pea (Pisum sativum L.) was used as a convenient model to confirm that O3 affects freezing resistance. The experiment also served as a further evaluation of the use of induced chlorophyll fluorescence kinetics to detect latent O3 injury. Two cultivars, 'Feltham First' and 'Conquest', were fumigated for 7 days, 7 h day(-1). Diffusive resistance and induced fluorescence were recorded daily during the period, then the plants were hardened at 4 degrees C day/2 degrees C night before exposure to 0, -2, -4, -6 and -8 degrees C. Ozone (0.075 ppm; 150 microg O3 m(-3)) caused stomatal closure in both cultivars, but the response was more rapid in 'Conquest'. There were also rapid effects on fluorescence kinetics, and it was concluded that FR, the rate of rise of induced fluorescence, is a useful parameter for indicating latent injury and for distinguishing between cultivars of different sensitivity. Exposure to O3 increased freezing injury and led to greater electrolyte leakage. The freezing resistance of 'Feltham First' was more affected than that of 'Conquest', probably because of the slower stomatal response to the pollutant leading to greater flux of O3 to the internal tissues. It is concluded that interactions involving pollutants and winter stress have implications for crop loss assessment. Perennials and over-wintering annuals should be exposed to the full range of environmental stresses.     

A status report on the U.S. national dioxin study

In 1983, the US Environmental Protection Agency (EPA) embarked on an extensive investigation of the presence and extent of contamination of the national environment by CDDs/CDFs. This status report is a prelude to a final report to be delivered to the US Congress in December, 1985.