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111.
The sensitivity of surface waters of Great Britain to acidification predicted from catchment characteristics 总被引:7,自引:0,他引:7
Hornung M Bull KR Cresser M Ullyett J Hall JR Langan S Loveland PJ Wilson MJ 《Environmental pollution (Barking, Essex : 1987)》1995,87(2):207-214
Using a combination of soil, land use and geological information, a map of Great Britain has been derived which indicates the sensitivity of surface waters to acidification. For the geological information, a slightly modified version of an available map was used which indicated the sensitivity of groundwaters to acidification. For soils, 1-km databases of soil information for England and Wales and for Scotland were employed to map the soil sensitivity as determined by buffering capacity. The derived soils map was modified to take account of agricultural liming in arable and managed grassland areas using the ITE Land Classification. The final map of surface water sensitivity was obtained by using a geographic information system overlay procedure which enabled each combination of soil and geology sensitivity to be uniquely defined. The final sensitivity classification was based upon expert knowledge and the experience of a similar sensitivity mapping exercise for Wales. 相似文献
112.
The effects of wet-deposited nitrogen on soil acidification and the health of Norway spruce were investigated in a pot experiment using an open-air spray/drip system. Nitrogen was applied as ammonium ((NH(4))(2)SO(4)) or nitrate (HNO(3)/NaNO(3)) in simulated rain to either the soil or the foliage. Symptoms of forest decline as observed in the field were not reproduced, and there was no evidence of direct toxicity. Treatments did, however, have significant effects on tree nutrition. Both NH(+)(4) and NO(-)(3) treatment applied to the foliage lowered foliar K concentrations. NH(+)(4) to a greater extent. Soil-applied NH(+)(4) reduced foliar Mg concentrations and increased foliar Al and Fe. Soil-applied NO(-)(3) significantly reduced foliar P concentrations, and at high doses prevented the alleviation of P deficiency by fertiliser. These effects could be important in some field situations. Ammonium deposition is predicted to be more damaging than nitrate deposition, although the latter may be critical for forests where P status is marginal, such as in parts of the British uplands. 相似文献
113.
The toxicity of leachate water from acid-sulphate soil to the early life stages of Australian bass, Macquaria novemaculeata, incubated in seawater was evaluated. Acid-sulphate soil leachate water (pH> or =6.8) delayed the hatching of fertilised eggs, but after 48 h the per cent hatching was normal. In comparison, acidic saline water (25 per thousand salinity) at pH 4.0 or less prevented embryos from hatching. The survival of yolk-sac larvae exposed to acid-sulphate soil leachate water at a concentration of 32% in seawater and an initial pH of 7.2, was significantly different to controls after 96 hours. In corresponding tests with only acidified saline water (20 per thousand salinity), pH levels equal to or below 5.0 killed yolk-sac larvae after 96 h exposure. Aluminum showed a pH dependent toxicity to yolk-sac larvae, with added aluminium as low as 200 microg litre(-1) having a significant effect on larval survival at pH 5.5, and concentrations of 600-800 microg litre(-1) having a significant effect on larval survival at an initial pH range of 6.0 < pH < 6.8. It was concluded that significant mortality of the early life stages of Australian bass would occur if they are exposed to acid-sulphate soil leachate that results in a pH in the receiving estuarine water below 5.5, or when the pH is below 6.8 and aluminium is present at a total concentration of 800 microg litre(-1) or greater. 相似文献
114.
Brown KA Freer-Smith PH Howells GD Skeffington RA Wilson RB 《Environmental pollution (Barking, Essex : 1987)》1988,54(3-4):285-295
This paper reports major points from the discussions which took place during the Workshop on Excess Nitrogen Deposition. 相似文献
115.
The effects of joint action of SO(2) and HF on three Eucalyptus species were studied by exposing them to combinations of < 13, 122 or 271 microg m(-3) of SO(2) and 0.03, 0.39 or 1.05 microg m(-3) of HF in open top chambers for 120 days. HF and SO(2) reduced the area and weight of immature leaves in all three species, but there were few interactive effects on immature leaves. The response of mature leaves to exposure differed among the species, with the greatest effects on E. calophylla and least effects on E. marginata. The interaction of HF + SO2 had no effect on leaf S concentrations in any of the species, but it reduced leaf F concentrations in E. calophylla and E. gomphocephala. HF increased leaf injury in E. calophylla and E. gomphocephala when simultaneously exposed to 271 microg m(-3) of SO(2), but had no effect at 122 microg m(-3), or on E. marginata. The addition of 271 microg m(-3) of SO(2) increased leaf injury when E. gomphocephala was exposed to 0.39 microg m(-3) of HF and when E. calophylla was exposed to 1.05 microg m(-3) of HF, despite reducing the leaf F concentrations. In some cases the interaction of the pollutants may increase susceptibility to visible injury. 相似文献
116.
Brenda DeZiel Lori Krider Brad Hansen Joseph Magner Bruce Wilson Geoff Kramer John Nieber 《Journal of the American Water Resources Association》2019,55(1):154-188
Water quality and stream habitat in agricultural watersheds are under greater scrutiny as hydrologic pathways are altered to increase crop production. Ditches have been traditionally constructed to remove water from agricultural lands. Little attention has been placed on alternative ditch designs that are more stable and provide greater habitat diversity for wildlife and aquatic species. In 2009, 1.89 km of a conventional drainage ditch in Mower County, Minnesota, was converted to a two‐stage ditch (TSD) with small, adjacent floodplains to mimic a natural system. Cross section surveys, conducted pre‐ and post‐construction, generally indicate a stable channel with minor adjustments over time. Vegetation surveys showed differences in species composition and biomass between the slopes and the benches, with changes ongoing. Longitudinal surveys demonstrated a 12‐fold increase in depth variability. Fish habitat quality improved with well‐sorted gravel riffles and deeper pool habitat. The biological response to improved habitat quality was investigated using a Fish Index of Biological Integrity (FIBI). Our results show higher FIBI scores post‐construction with scores more similar to natural streams. In summary, the TSD demonstrated improvements in riparian and instream habitat quality and fish communities, which showed greater fish species richness, higher percentages of gravel spawning fish, and better FIBI scores. This type of management tool could benefit ditches in other regions where gradient and geology allow. 相似文献
117.
The morphology and ultrastructure of the otolith settlement-mark was examined in 44 tropical reef-fish species spanning nine
families. A classification scheme based on similar otolith characteristics is presented. Three major categories are identified
based on changes in increment width and optical qualities of the settlement-mark. Of the 44 species examined, 39 possessed
“abrupt” settlement-marks (Type I) characterised by a rapid decrease in increment width (up to 50% reduction) over settlement.
Type I settlement-marks were found in all nine families examined. The 39 species spanned the whole range of possible larval
durations (Pomacentrus moluccensis, 15 d ± 0 SE; Naso hexacanthus, 91.2 d ± 2.97 SE). Four of the 44 species possessed “zonal” settlement-marks (Type II), featuring a band of increments that
are wider than pre-settlement increments. Species in this category are the labrids Corisaygula, Thalassoma bifasciatum, T. lunare and an unidentified acanthurid (Acanthurus sp. 2). One species of acanthurid (N. brevirostris) possessed a “gradual” settlement-mark (Type III), manifest as a gradual decrease in increment width during the settlement
period. A possible fourth type was identified from the literature. Gnatholepis thompsoni and Coryphopterus glaucofraenum possessed a settlement-mark with increment widths that increased post-settlement. Available data suggest a poor relationship
between the structure of the settlement-mark and the magnitude of metamorphosis (previously reported as internal and external
morphological change). Evidence suggests that the increment profile over early development and the increment transitions associated
with the settlement event are taxon-specific and may enable late-larval stage fishes to be identified to species level.
Received: 21 May 1997 / Accepted: 3 February 1999 相似文献
118.
119.
F. A. Hockley C. A. M. E. Wilson N. Graham J. Cable 《Behavioral ecology and sociobiology》2014,68(9):1513-1520
Group living in fish can provide benefits of protection from predators and some parasites, more efficient foraging for food, increased mating opportunities and enhanced energetic benefit when swimming. For riverine species, shoaling behaviour can be influenced by various environmental stressors, yet little is known how flow rate might influence the shoaling of diseased fish shoals. In view of the increasingly unpredictable flow rates in streams and rivers, this study aimed to assess the combined effect of flow condition and parasitism on the shoaling behaviour of a model fish species. Shoal size, shoal cohesion and time spent shoaling of female guppies Poecilia reticulata were compared when infected with the directly transmitted ectoparasite Gyrodactylus turnbulli under flow and static conditions. Flow condition was an important factor in influencing shoaling behaviour of guppies with the fish forming larger shoals in the absence of flow. When a shoal member was infected with G. turnbulli, shoal cohesion was reduced, but the magnitude of this effect was dependent on flow condition. In both flow and static conditions, bigger fish formed larger shoals than smaller counterparts. Future changes to stream hydrology with more frequent flooding and drought events will affect the shoaling tendency of fish. During high-flow events, diseased fish may not be able to keep up with shoal mates and therefore have a higher risk of predation. Additionally, these findings may be important for aquaria and farmed species where an increase in flow rate may reduce aggregation in fish. 相似文献
120.
V.M. Sadagoparamanujam Damalia T. Wilson Crystal L. Ramanujam Regina P. Lederman James J. Grady Nancy W. Alcock 《毒物与环境化学》2013,95(10):2098-2110
The study examined the stage of clean-up of the Port Lavaca bay sites in Texas, which were polluted during the early 1990's by effluent containing mercury (Hg) from a chloralkali plant. In addition to Hg intoxication through environmental contaminations, human exposure through dietary fish and other seafoods occurred. Bacteria converts inorganic Hg to alkyl organic compounds and subsequently the metal crosses the blood brain barrier thus exerting adverse effects on the fetal developing nervous system. In order to conduct a survey of dietary Hg exposure, blood was collected from pregnant women and those of childbearing age at routine clinic visits at each of three centers in South Texas cities (Galveston, Texas City, Port Lavaca/Victoria, TX). A questionnaire sought dietary and lifestyle information including consumption, sources of fish and other seafoods. A significant number of subjects (119 out of 175, 68%) ate fish caught locally. The blood Hg concentrations (µg?L?1) range varied with the location of the study centers: City of Galveston 2.6–62; Texas City 2.8–111.8; and the Port Lavaca areas 3.02–126.7. The concentrations of blood Hg was directly proportional to the number of fish meals consumed for each species considered. Mean blood Hg concentrations for no fish meals per week were: Port Lavaca 4.5 (N?=?3), Galveston 4.3 (N?=?3), Texas City 3.5 (N?=?10). For >3 fish meals per week, the mean blood Hg concentrations were: Port Lavaca, 48.0 (N?=?53), Galveston 29.1 (N?=?35), Texas City, 36.1 (N?=?31). Data show that residues of Hg were still present in 1994 despite the clean-up efforts. 相似文献