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871.
Frédéric Gazeau Laura M. Parker Steeve Comeau Jean-Pierre Gattuso Wayne A. O’Connor Sophie Martin Hans-Otto Pörtner Pauline M. Ross 《Marine Biology》2013,160(8):2207-2245
Over the next century, elevated quantities of atmospheric CO2 are expected to penetrate into the oceans, causing a reduction in pH (?0.3/?0.4 pH unit in the surface ocean) and in the concentration of carbonate ions (so-called ocean acidification). Of growing concern are the impacts that this will have on marine and estuarine organisms and ecosystems. Marine shelled molluscs, which colonized a large latitudinal gradient and can be found from intertidal to deep-sea habitats, are economically and ecologically important species providing essential ecosystem services including habitat structure for benthic organisms, water purification and a food source for other organisms. The effects of ocean acidification on the growth and shell production by juvenile and adult shelled molluscs are variable among species and even within the same species, precluding the drawing of a general picture. This is, however, not the case for pteropods, with all species tested so far, being negatively impacted by ocean acidification. The blood of shelled molluscs may exhibit lower pH with consequences for several physiological processes (e.g. respiration, excretion, etc.) and, in some cases, increased mortality in the long term. While fertilization may remain unaffected by elevated pCO2, embryonic and larval development will be highly sensitive with important reductions in size and decreased survival of larvae, increases in the number of abnormal larvae and an increase in the developmental time. There are big gaps in the current understanding of the biological consequences of an acidifying ocean on shelled molluscs. For instance, the natural variability of pH and the interactions of changes in the carbonate chemistry with changes in other environmental stressors such as increased temperature and changing salinity, the effects of species interactions, as well as the capacity of the organisms to acclimate and/or adapt to changing environmental conditions are poorly described. 相似文献
872.
Marino Martini Luciano Giannini Antonella Buccianti Laura Maggi Franco Prati Paola Cellini Legittimo Paolo Iozzelli Bruno Capaccioni 《Chemistry and Ecology》1991,5(3):139-147
A major influence on the environment of active volcanic areas is expected from continuous input of chemical species pertaining to fumarolic activities occurring during inter-eruptive intervals.
The systematic investigations carried out during thirteen years in the island of Vulcano (Italy) showed also substantial contributions to phreatic waters and soils of minor constituents and trace metals from volcanic rocks with no negligible influence on growing crops.
Greater extents of these phenomena have been observed for products of hydromagmatic volcanic activity or of long-lasting weathering processes. 相似文献
The systematic investigations carried out during thirteen years in the island of Vulcano (Italy) showed also substantial contributions to phreatic waters and soils of minor constituents and trace metals from volcanic rocks with no negligible influence on growing crops.
Greater extents of these phenomena have been observed for products of hydromagmatic volcanic activity or of long-lasting weathering processes. 相似文献
873.
Microbial degradation of azo dyes usually starts in anaerobic conditions with a reductive cleavage of the azo bond, followed by an aerobic step necessary for the degradation of the aromatic amines formed. Because some reductive processes take place also in presence of molecular oxygen, a one-step azo dye degrading process has been investigated. A microbial consortium able to degrade ethyl orange in aerobic conditions has been selected and immobilized in alginate beads coated with polyacrylamide resin. Different concentrations of ethyl orange have been completely degraded in the presence of 1% glucose or starch as cosubstrates, and different beads preparation procedures have been studied to determine the best condition for microbial degradation. The catalytic activity of the immobilized consortium improved during five serial processes carried out for 30 days at room temperature. Three pure cultures were then isolated from the consortium. The one with the greatest degrading activity, a filamentous fungus, had a degradative capacity similar to that of the whole consortium. 相似文献
874.
875.
876.
Laura Toran David Grandstaff 《Journal of the American Water Resources Association》2007,43(3):630-641
Abstract: Use of lawn chemicals in residential areas may contribute nonpoint source (NPS) pollutants, such as nutrients, pesticides, and herbicides to streams. We conducted a 2‐year screening study of discharge in stormwater pipes in the Wissahickon Valley Watershed (suburban Philadelphia) using nitrogen as an indicator of lawn chemical use. Stormwater samples representing first flush and composite runoff were collected approximately twice a month using automatic samplers triggered by rise in water level during storms. The runoff collected by the stormpipes was from neighborhoods with 15‐100 residences, and from 2 to 18 ha (5‐45 acres). Several factors were examined to evaluate the effects on nitrate concentration. These factors included time of sampling (season), number of homes, total area, size of the storm, and time since last storm. Nitrate levels were generally less than 5 mg/l, but still above background in typical undeveloped areas. Concentrations were slightly higher in the first summer than during a drought in the second year, but the difference was not statistically significant. There was a positive correlation between size of the neighborhood (capture area) and peak concentration of nitrate. Storm characteristics (size of storm and time since last storm) did not correlate with nitrate concentrations. The variation in both space and time suggests that a more local control may be a factor. Although individual lawn chemical applications were not monitored, they may influence the timing of increased loading. Furthermore, the variability indicates that quarterly monitoring will not capture discharge characteristics of storm basins. 相似文献
877.
Carl E. Korschgen Gerry A. Jackson Laura F. Muessig Deborah C. Southworth 《Journal of the American Water Resources Association》1987,23(2):221-226
ABSTRACT: Sediment accumulation was evaluated in Lake Onalaska, a 2800-ha backwater impoundment on the Upper Mississippi River. Computer programs were used to process fathometric charts and generate an extensive data set on water depth for the lake. Comparison of 1983 survey data with pre-impoundment (before 1937) data showed that Lake Onalaska had lost less than 10 percent of its original mean depth in the 46 years since impoundment. Previous estimates of sedimentation rates based on Cesium-137 sediment core analysis appear to have been too high. 相似文献
878.
Laura Y. Sifuentes David W. Koenig Ronnie L. Phillips Kelly A. Reynolds Charles P. Gerba 《Food and environmental virology》2014,6(3):175-181
The goals of this study were to observe the spread of viruses in a hotel setting and to assess the effectiveness of a hygiene intervention in reducing their spread. Selected fomites in one hotel room were inoculated with bacteriophage ?x-174, and fomites in a conference center within the same hotel were inoculated using bacteriophage MS2. Cleaning of the contaminated room resulted in the spread of viruses to other rooms by the housekeeping staff. Furthermore, viruses were transferred by hotel guests to the conference center and a communal kitchen area. Additionally, conference attendees transferred viruses from the conference center to their hotel rooms and a communal kitchen area. This study demonstrated how viruses can be spread throughout a hotel setting by both housekeepers and guests. A hygiene intervention, which included providing hand hygiene products and facial tissues to the guests and disinfecting solutions with disposable wipes to the housekeeping staff, was successful in reducing the spread of viruses between the hotel guest rooms and conference center. The hygiene intervention resulted in significantly reduced transfer of the ?x-174 between the contaminated hotel room and other hotel rooms, communal areas, and the conference center (p = 0.02). 相似文献
879.
Sex identification in female crayfish is bimodal 总被引:1,自引:0,他引:1
Sex identification has been studied in several species of crustacean decapods but only seldom was the role of multimodality investigated in a systematic fashion. Here, we analyse the effect of single/combined chemical and visual stimuli on the ability of the crayfish Procambarus clarkii to identify the sex of a conspecific during mating interactions. Our results show that crayfish respond to the offered stimuli depending on their sex. While males rely on olfaction alone for sex identification, females require the combination of olfaction and vision to do so. In the latter, chemical and visual stimuli act as non-redundant signal components that possibly enhance the female ability to discriminate potential mates in the crowded social context experienced during mating period. This is one of the few clear examples in invertebrates of non-redundancy in a bimodal communication system. 相似文献
880.
Laura Domingo Stephen T. Grimes M. Soledad Domingo M. Teresa Alberdi 《Die Naturwissenschaften》2009,96(4):503-511
Expansion of C4 grasses during Late Miocene and Early Pliocene constitutes one of the most remarkable biotic events of the Cenozoic era.
The Teruel–Alfambra region (northeastern Spain) contains one of the most complete Miocene–Pliocene sequences of mammalian
fossil sites in the world. In this study, stable isotope (δ
13C and δ
18O) analyses have been performed on the tooth enamel from the equid Hipparion from 19 localities spanning a time interval from approximately 10.9 to 2.7 Ma. This time range starts with the first appearance
of this genus in Spain and ends at its extinction. An increase in δ
13C at about 4.2 Ma has been observed, indicative of a shift toward a more open habitat. This shift may be related to a large
scale vegetation change which occurred across the Miocene–Pliocene boundary when C4 grasses expanded. This expansion might in turn be linked to global tectonic events such as the uplift of the Himalaya and/or
the closure of the Panama Isthmus. However, other more regional factors may have ultimately enhanced the trend toward more
open habitats in the Western Mediterranean Basin. The Messinian Salinity Crisis was a major environmental event that may have
been responsible for the isotopic changes seen in the equid Hipparion from the Iberian Peninsula along with an increase in the aridity detected ~4.6 Ma ago in the Sahara. Even though the exact
factor triggering the isotopic change observed in the Hipparion enamel remains mostly unknown, this study demonstrates that the global environmental changes detected across the Miocene–Pliocene
boundary are also recorded in the realm of the Iberian Peninsula.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献