| 1. |
- Hubendick, Bengt, 1916-2012
(författare)
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Människa - miljö - överlevnad
- 1990
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Ingår i: Kulturmiljövård. - Stockholm : Riksantikvarieämbetet. - 1100-4800. ; [15]:2, s. 19-25
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 2. |
- Odén, Birgitta, 1921-2016
(författare)
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Miljön som historia
- 1990
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Ingår i: Kulturmiljövård. - Stockholm : Riksantikvarieämbetet. - 1100-4800. ; [15]:2, s. 9-18
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 3. |
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| 4. |
- Arsenie, Irina, et al.
(författare)
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Effects of Gamma Irradiation on an Aquatic Fulvic Acid
- 1991
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Ingår i: Humic substances in the aquatic and terrestrial environment : proceedings of an international symposium, Linköping, Sweden, August 21-23, 1989. - Berlin Heidelberg New York : Springer. - 3540537023 ; , s. 233-241
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Bokkapitel (refereegranskat)abstract
- An aquatic fulvic acid was irradiated with gamma radiation from a 60Co-source (dose range 0-48 Mrad), as part of a larger study of the transformation and decomposition of humic substances in natura! aquatic systems. Experiments were performed at two concentrations (1000 mg/l and 100 mg/l) and at various pH-values (2-10). The fulvic acid transformation was studied by monitoring optical density (UV-spectroscopy ), molecular weight distribution (GPC-technique) and total dissolved organic carbon (TOC). A general decrease in TOC with increasing radiation dose was observed: the initial G-value of about 5 decreased with the increasing dose to a minimum value of 0.2-0.3. A simultaneous increase in molecular weight (Mn rose from approximately 2000 to a maximum of about 4000) was observed in the acidic samples (pH 2-4) at a dose below 10 Mrad. Natural background radiation can significantly contribute to the degradation of dissolved humic substances in deep groundwaters, considering the observed G-value for low doses (about 5) and the otherwise high chemical stability of the fulvic acid fraction even after long residence times (103-104 y) in the ground.
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| 5. |
- Asplund, Gunilla, et al.
(författare)
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Soil Peroxidase-Mediated Chlorination of Fulvic Acid
- 1991
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Ingår i: Humic substances in the aquatic and terrestrial environment : proceedings of an international symposium, Linköping, Sweden, August 21-23, 1989. - Berlin Heidelberg New York : Springer. - 3540537023 ; , s. 474-483
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Bokkapitel (refereegranskat)abstract
- Humic matter has recently been shown to contain considerable quantities of naturally produced organohalogens. The present study investigated the possibility of a non-specific, enzymatically mediated halogenation of organic matter in soil. The results showed that, in the presence of chloride and hydrogen peroxide, the enzyme chloroperox1dase (CPO) from the fungus Caldariomyces fumago catalyzes chlorination of fulvic acid. At pH 2.5 - 6.0, the chlorine to fulvic acid ratio in the tested sample was elevated from 12 mg/g to approximately 40-50 mg/g. It was also shown that this reaction can take place at chloride and hydrogen peroxide concentrations found in the environment. An extract from spruce forest soil was shown to have a measurable chlorinating capacity. The activity of an extract of 0.5 kg soil corresponded to approximately 0.3 enzyme units, measured as CPO activity. Enzymatically mediated halogenation of humic substances may be one of the mechanisms explaining the w1despread occurrence of adsorbable organic halogens (AOX) in soil and water.
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| 6. |
- Colding, Johan
(författare)
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Analysis of hunting options by the use of general food taboos
- 1998
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Ingår i: Ecological Modelling. - 0304-3800 .- 1872-7026. ; 110:1, s. 5-17
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Tidskriftsartikel (refereegranskat)abstract
- A hypothetical model was built, using the STELLA II software program, to test several hunting options for a human hunting group. Different outcomes of possible hunting modes are analysed, such as a change in hunting rate, prey hunted, or species avoided or not avoided by taboos. The model consists of five sectors that reflect a short food chain in an upper Amazonian ecosystem. There is a vegetation sector, a predator sector, and two sectors consisting of browsers and grazers. The last sector represents a human group, known as the Ecuador Achuar. The critical factor analysed is how differences in hunting rate affect a target resource, and how this resource may be affected by general food taboos. The major results of the model are that general food taboos may not be an adaptive short term strategy for hunters, but that a 'moderate' hunting mode may be the most effective option for the human group. Since the model is a simplification of the real world, no general conclusions for management should be drawn from the results.
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| 7. |
- Colding, Johan, et al.
(författare)
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The relations among threatened species, their protection, and taboos
- 1997
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Ingår i: Conservation Ecology. - 1195-5449. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the role of taboos for the protection of species listed as "threatened" by the World Conservation Union (IUCN), and also for species known to be endemic and keystone. The study was limited to taboos that totally avoid or prohibit any use of particular species and their populations. We call them specific-species taboos. Through a literature review, 70 currently existing examples of specific-species taboos were identified and analyzed. The species avoided were grouped into biological classes. Threat categories were determined for each species, based on the IUCN Red Data Book. We found that ≃ 30% of the identified taboos prohibit any use of species listed as threatened by IUCN. Of the specific-species taboos, 60% are set on reptiles and mammals. In these two classes, ≃ 50% of the species are threatened, representing all of the threatened species in our analysis, with the exception of one bird species. Both endemic and keystone species that are important for ecosystem functions are avoided by specific-species taboos. Specific-species taboos have important ecological ramifications for the protection of threatened and ecologically important populations of species. We do not suggest that specific-species taboos are placed on species because they are, or have been, endangered; instead, we emphasize that species are avoided for a variety of other reasons. It is urgent to identify and analyze resource practices and social mechanisms of traditional societies, such as taboos, and to investigate their possible ecological significance. Although it may provide insights of value for conservation, not only of species,
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| 8. |
- Grimvall, Anders, et al.
(författare)
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Phytotoxic Substances in Runoff from Forested Catchment Areas
- 1991
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Ingår i: Humic substances in the aquatic and terrestrial environment : proceedings of an international symposium, Linköping, Sweden, August 21-23, 1989. - Berlin Heidelberg New York : Springer. - 3540537023 ; , s. 397-406
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Bokkapitel (refereegranskat)abstract
- Runoff from different catchment areas in southem Sweden was tested in a root bioassay based on solution cultures of cucumber seedlings. Water samples from agricultural catchment areas produced no signs at all or only weak signs of inhibited root growth, whereas several water samples from catchmcnt areas dominated by mires or coniferous forests produced visible root injuries. The most severe root injuries (very short roots, discolouration, swelling of root tips and lack of root hairs) were caused by samples from a catchment area without local emissions and dominated by old stands of spruce. Fractionation by ultrafiltration showed that the phytotoxic effect of these samples could be attributed to organic matter with a nominal molecular-weight exceeding 1000 or to substances associated with organic macromolecules. Experiments aimed at concentrating phytotoxic compounds from surface water indicated that the observed growth inhibition was caused by strongly hydrophilic substances. Previous reports on phytotoxic, organic substances of natura! origin have emphasized interaction between plants growing close together. The presence of phytotoxic substances in runoff indicates that there is also a large-scale dispersion of such compounds.
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| 9. |
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| 10. |
- Härlin, Mikael
(författare)
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Tree-thinking and nemertean systematics, with a systematization of the Eureptantia
- 1998
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Ingår i: Hydrobiologia. - 0018-8158 .- 1573-5117. ; 365:1, s. 33-46
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Tidskriftsartikel (refereegranskat)abstract
- I review how some influential nemertean systematistshave perceived and illustrated phylogenetic trees andargue that the nineteenth century nemerteantaxonomists still influence many contemporarynemertean taxonomists to a high degree. By showing hownineteenth century systematics differs from moremodern views on trees, I hope to convey the advantagesof a cladistic approach to tree-thinking and nemerteansystematics. Furthermore I propose a systematizationof the Eureptantia that illustrates the cladisticapproach to tree-thinking but, more importantly, isalso a better representation of eureptantic phylogenythan previous classifications.
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