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Dagmar I. Werner Esmeralda M. Baker Elizabeth del C. Gonzalez Ines R. Sosa 《Behavioral ecology and sociobiology》1987,21(2):83-89
Summary The research addressed two questions: (1) doIguana iguana hatchlings recognize their kin, and (2) what are the recognition mechanisms? Eggs were collected from wild and captive-raised
females and hatched in semi-natural incubators. In the first experiment we used eggs from two females. One of the clutches
was subdivided to be placed in different incubators. Immediately after emergence one of these hatchling groups was introduced
into a 10 m x 10 m enclosure. At the same time we introduced hatchlings from another female. The remaining hatchling group
was kept separate for 3 weeks and was then introduced into the same cage. Unrelated hatchlings separated from each other.
Related but separated hatchlings grouped according to introduction date. In the second experiment we maintained eight kin
groups in individual cages and two hatchlings per kin group in an additonal cage. Hatchlings from the mixed group showed no
preference for their kin before physical contact with pure kin groups had occurred. After physical contact hatchling recognized
their kin by feces smell. Body odor is likely to be also involved. 相似文献
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Soil contaminations with the explosive 2,4,6-TNT are a major problem at many sites of former ammuniton plants in Germany. But only little is known about its environmental or metabolic fate in soil or plants. A field study was conducted on a former ammunition plant in Stadtallendorf/Hessen. Three areas with different TNT concentrations were planted with 8 different crops. After harvest plants were analyzed for TNT, ADNTs and DNTs. Soil contamination decreased in the rhizosphere compared to unplanted areas and there was a transfer of TNT from soil to the plants. Accumulation in plants was dependent on soil contamination and also specific for different plant parts or plant species. The contamination spectrum of TNT and derivatives was different in soil or plant tissue, respectively. After acid hydrolysis of bean roots, 2,6-DNT and 2,4-DNT could be identified in the extract. 相似文献
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Rainer Abendt Werner Balzer Jamshid Hosseinpour Peter Pluschke 《Environmental Sciences Europe》1993,5(5):246-251
In Nuremberg (Germany), each year about 25,000 tons (dry matter) of sewage sludge are obtained as by-product of waste water treatment. The digested sludge consists of 96% water. Until 1992 it was thermally stabilized using the Porteous procedure: the sludge was heated in an autoclave up to a temperature of 180–200 °C at a pressure of 28 bar. After pressure reduction and moving to a thickener, a substantial part of the liquid could be removed. After running through a chamber filter, the sludge contained only about 50% dry matter. This treatment does not only remove water; organic matter is also degraded or evaporated. Between November 1991 and May 1992, the sludge was analyzed four times before and after the drying process and examined for heavy metals (Pb, Cd, Cr, Cu, Ni, Hg, Zn), polychlorinated biphenyls (PCB) and PCDD/F. The concentration of heavy metals and PCB (related to dry matter) increased by a faktor of 1.3 after the drying process. This effect may be explained by the decrease of organic matter during drying. In the case of PCDD/F, the ITQ increased by a factor of 3.2, for some congeners even by a factor of 8. The only explanation can be that during thermal conditioning PCDD/F is formed by precursors as chlorophenols. This formation is probably catalyzed by metals as copper or nickel and sped up by the higher temperatures. 相似文献