Effects of environmental and temporal factors on Glomeromycotina spores in sand dunes along the Gulf of Valencia (Spain)

AMF symbiosis in sand dunes is the key for maintenance of stable vegetation. The main goal of this work was to determine the effects of environmental and temporal factors on AMF living in sand dunes (Gulf of Valencia, Spain). Soil samples were collected seasonally at 6 sites, during 2 yrs, from three habitats and four plant species and the frequency and relative abundance of AMF was examined. AMF were more frequent in mobile than in embryonic dunes, in spring and in sites with old vegetation. Ten AMF species were identified, their distribution depending mainly on the anthropogenic disturbance of the site. Gigasporaceae Cetraspora sp. and Dentiscutata sp. preferred undisturbed soil whereas Diversisporaceae, Glomeraceae and other Gigasporaceae were associated with recently restored soils. All AMF species were found in all plant species although Corymbiglomus corymbiforme was mainly associated with Echinophora spinosa. Our results might be of help for Mediterranean sand dune restoration.     

Energy release and countermeasures for sand casting explosion accidents

Abstract

Sand casting explosion accidents seriously threaten employees' lives and the harmony and stability of society, such as casualties, equipment trouble and environmental pollution. The main purpose of this study was to determine the water requirement for sand casting explosion accidents, and then corresponding safety measures were proposed to prevent such accidents. First, the relationship between the water condition and temperature for such accidents was achieved based on an energy release equation in compressed gas expansion and the ideal gas state equation. The volume of vapor expanded rapidly as the temperature rises, which was also the immediate cause of sand casting expansion accidents. Also, the water requirement for the sand casting expansion accidents decreased rapidly as the temperature rises. Then, a bow-tie model was adopted for preventing the causes and consequences of sand casting explosion accidents. Three main causes were identified, namely molten metal meeting ponding, failure of cavity exhaust and low strength sand of sand mold, and 11 prevention safety measures were adopted to prevent the causes of such accidents. In addition, three consequences were identified, namely casualties, equipment trouble and environment pollution, and ten mitigation safety measures were adopted to mitigate the consequences of such accidents.     

Effects of sand burial on purple sandgrass (Triplasis purpurea): the significance of seed heteromorphism

The effects of sand burial on seedling emergence, growth, and reproduction of the annual dune grass Triplasis purpurea (Walt.) Chapm. were examined. This species matures heteromorphic seeds on panicles enclosed by leaf sheaths along tiller nodes in a characteristic pattern: seeds at the lower nodes are heaviest, whilst those at the upper nodes are lightest. Field excavation of seedlings revealed that seedlings can emerge from seeds buried to 4 cm.In one experiment in an incubator, seeds collected from the upper and lower tiller nodes of glasshouse-grown parental plants were buried in sand at depths of 0, 3, and 6 cm. As expected, the effects of seed depth on seedling growth were due to delayed emergence for seedlings from buried seeds. However, seedlings from the larger seeds from the lower nodes of parental plants had significantly greater dry mass than those from the lighter seeds from upper nodes. Because lower node seeds are the most likely to become buried by sand in nature, the seed heteromorphism may be adaptive in the coastal environment.A second experiment involved the burial of seedlings to 0, 50, or 100% of their height. Although most seedlings did not survive complete burial (100% height), for partially buried seedlings (50% height) there was high survival and a marked stimulation of growth and eventual reproduction compared to unburied seedlings. This stimulation could be linked to increased root growth for seedlings that had been buried. The ability to respond positively to sand accumulation may represent an adaptation to the dynamic dune environment.     

Predicting the process of extinction in experimental microcosms and accounting for interspecific interactions in single‐species time series

Predicting population extinction risk is a fundamental application of ecological theory to the practice of conservation biology. Here, we compared the prediction performance of a wide array of stochastic, population dynamics models against direct observations of the extinction process from an extensive experimental data set. By varying a series of biological and statistical assumptions in the proposed models, we were able to identify the assumptions that affected predictions about population extinction. We also show how certain autocorrelation structures can emerge due to interspecific interactions, and that accounting for the stochastic effect of these interactions can improve predictions of the extinction process. We conclude that it is possible to account for the stochastic effects of community interactions on extinction when using single‐species time series.