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901.
902.
Twenty stomiatoid fish larvae (3.1 to 21,9 mm) belonging to the genera Bathophilus, Cyclothone, and Stomias were collected in plankton nets from surface waters over depths of 3 to 4 m from Biscayne Bay, Florida, USA. The adults are mesopelagic in the open water of the Florida Current and, therefore, these larvae were presumably advected in parcels of high salinity water into the shallows of Biscayne Bay by winds, tides, or currents. The presence of these larvae suggest that sewage discharged into the Florida Current may be recycling into coastal waters as well as into Biscayne Bay.Scientific Contribution No. 1403, University of Miami, Rosenstiel School of Marine and Atmospheric Science. The support of Environmental Protection Agency Contract FW QA 18050 DIU, Water Quality Office, Division of Water Quality Research is gratefully acknowledged.  相似文献   
903.
904.
In three delphinid species (Pacific spotted dolphin, Stenella attenuata; common dolphin, Delphinus delphis; harbor porpoise, Phocoena phocoena) the enzyme lysozyme and the peptide group -defensins are demonstrated for the first time in cetaceans as products of the thick integument. Lysozyme was found between the lamellae of the stratum corneum, in the cells of the stratum spinosum, free cells of the dermis, and in endothelial cells of dermal blood vessels. -defensins (especially type 3) were clearly located in cells of the upper stratum spinosum, and concentrated between the upper five or six layers of the stratum corneum. The occurrence and localization of such substances that may serve as a non-specific defense against bacteria, fungi, algae, and ectoparasites, was known until now only for haired marine mammals with typical skin glands, like in pinnipeds.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   
905.
In agricultural soil, a suite of anthropogenic events shape the ecosystem processes and populations. However, the impact from anthropogenic sources on the soil environment is almost exclusively assessed for chemicals, although other factors like crop and tillage practices have an important impact as well. Thus, the farming system as a whole should be evaluated and ranked according to its environmental benefits and impacts. Our starting point is a data set describing agricultural events and soil biological parameters. Using machine learning methods for inducing regression and model trees, we produce empirical models able to predict the soil quality from agricultural measures in terms of quantities describing the soil microarthropod community. We are also interested in discovering additional higher level knowledge. In particular, we have identified the most important factors influencing the population densities of springtails and mites and their biodiversity. We also identify to which agricultural actions different microarthropods react distinctly. To obtain this higher level knowledge, we employ multi-objective regression trees.  相似文献   
906.
贺词     
环境预防战略,无论是清洁生产、生态效益还是污染防治,是改变不可持续生产和消费方式的最佳战略.自从它被引入《21世纪议程》后,政府和工商业越来越多地采用了清洁生产观念,并且为完善这一概念做出了巨大的努力.  相似文献   
907.
Aerial surveys were conducted to estimate the abundance and distribution of loggerhead turtles (Caretta caretta) in the Columbretes Islands Marine Reserve and surrounding waters (western Mediterranean). Four surveys were carried out during 2000 and 2001, following the line transect methodology. Loggerheads appeared to be present at high densities in the area throughout the whole year, although density varied between seasons, being more abundant during the spring. Mean density in the study area was 0.322 turtles/km2 (range 0.200–0.516) and the mean abundance was 1,324 turtles (range 825–2,124). The turtles were distributed homogeneously throughout the study area, we found no difference in loggerhead density between the water around the reserve and that in the rest of the study area. Current conservation measures planned by the local authorities, which include increasing the area of the reserve, would be very positive for the conservation of this stock.Communicated by S.A. Poulet, Roscoff  相似文献   
908.
909.
Do female roe deer in good condition produce more sons than daughters   总被引:2,自引:0,他引:2  
In polygynous roe deer Capreolus capreolus, males are only slightly heavier than females and the overall sex ratio at birth is close to unity. We studied offspring sex ratio and litter size (range 1–4, n = 74) of culled females, in utero, which provided an opportunity to examine responses of sex ratio to maternal condition. Male embryos were heavier than their sisters, and male fawns (9 months old) heavier than female fawns, suggesting a higher growth rate in males. There was no evidence for differential mortality between the sexes from birth to 9 months old. Heavier adult females produced larger embryos than lighter, or primiparous females. The overall sex ratio of embryos did not differ from unity, but adult does had more male embryos (55%) than primiparous does (32%), and the proportion of male embryos in a litter increased with the mother's body mass. Litter size also tended to increase with maternal age and body mass. We argue that this pattern reflects adaptive variation in offspring sex ratio.  相似文献   
910.
Ye ZH  Lin ZQ  Whiting SN  de Souza MP  Terry N 《Chemosphere》2003,52(9):1571-1579
Wetland microcosms were used to evaluate the ability of constructed wetlands to remove extremely high concentrations of selenocyanate (SeCN-), arsenic (As), and boron (B) from wastewater generated by a coal gasification plant in Indiana. The wetland microcosms significantly reduced the concentrations of selenium (Se), As, B, and cyanide (CN) in the wastewater by 64%, 47%, 31%, and 30%, respectively. In terms of the mass of each contaminant, 79%, 67%, 57%, and 54% of the Se, As, B, and CN, respectively, loaded into the microcosms were removed from the wastewater. The primary sink for the retention of contaminants within the microcosms was the sediment, which accounted for 63%, 51%, and 36% of the Se, As, and B, respectively. Accumulation in plant tissues accounted for only 2-4%, while 3% of the Se was removed by biological volatilization to the atmosphere. Of the 14 plant species tested, cattail, Thalia, and rabbitfoot grass were highly tolerant of the contaminants and exhibited no growth retardation. Environmental toxicity testing with fathead minnow (Pimephales promelas) larvae confirmed that the water treated by the wetland microcosms was less toxic than untreated water. The data from the wetland microcosms support the view that constructed wetlands could be used to successfully reduce the toxicity of aqueous effluent contaminated with extremely high concentrations of SeCN-, As, and B, and that a pilot-scale wetland should therefore be constructed to test this in the field. Cattail, Thalia, and rabbitfoot grass would be suitable plant species to establish in such wetlands.  相似文献   
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