奥斯陆峡湾内部的污染与保护:重新确定20世纪废水处理政策的目标

20世纪奥斯陆峡湾内部的主要污染源是奥斯陆市的城市污水排放.20世纪初,污染只限于下水道出口附近的沿岸水域和奥斯陆的港区.细菌含量高造成健康危害,而城市当局试图通过建造一个污水系统.包括截流污水管和废水处理厂来减轻这种危害.由于人口的增长.日益增加的污水负荷的影响区域扩大.30年代,整个奥斯陆峡湾内部受到了影响.科学研究把城市污水排放与藻类生产量的增加联系起来.40年代,发现底层处于缺氧状态.奥斯陆下水处理机构意识到峡湾的污染,但认为有机质是主要的问题,并认为活化污泥法是最佳的解决办法.营养盐的作用一直到60年代末才得到普遍的承认.70年代去磷法开始采用.90年代又采用了去氮法.去除营养盐造成峡湾恢复缓慢.     

Light effects on nutrient-limited,oceanic primary production

Phytoplankton growth dynamics were investigated throughout the photic zone at three stations in the North Central Pacific Gyre south of the Hawaiian Islands. Ambient nutrients, vertical light profiles, phytoplankton biomass, and primary production were measured. Photosynthetically active radiation, measured with a submarine quantaspectrophotometer, illustrates vertical variations in photic spectral quality and is presented as incident quanta flux of visible light. Primary production was determined throughout the photic zone under conditions where the samples were collected, injected with ¹⁴C, and incubated under entirely in situ conditions to eliminate preincubation perturbation and to ensure representative response to both light quality and quantity. Oceanic phytoplankton activity is described as a continuous function of incident light under the prevailing low nutrient conditions, and the important rate constants are calculated based upon field data from oligotrophic regions. The vertical profiles of phytoplankton activity and incident quanta flux are analyzed in terms of a substrate-limited system according to the equqtion A _(z) = A _max (q (_(z) – q _o) [K + (q (_(z)) – q (_o], where q(_z) is the quanta flux at a given depth, and A(_z) is the phytoplankton assimilation number at that depth. This is done on the rationale that systematically declining levels of quanta flux, vertically, represent corresponding declines in the availability of substrate for the photochemical processes of photosynthesis. Comparison of data from isolated oceanic regions with those from a station located 15 miles off Oahu show that although large differences in the phytoplankton parameters are evident throughout the entire photic zones of these regions, the hyperbolic A(_z)-q(_z) relationship describes the data fairly well in both cases. The comparison suggests that this relationship may apply to the general case of an oligotrophic water column. These experiments show trends which may be useful for diagnosing phytoplankton activity in the field where N and P levels are low.Oceanic Institute Contribution No. 77-131.     

Environmental Services Provided from Riparian Forests in the Nordic Countries

Riparian forests (RF) growing along streams, rivers and lakes comprise more than 2% of the forest area in the Nordic countries (considering a 10 m wide zone from the water body). They have special ecological functions in the landscape. They receive water and nutrients from the upslope areas, are important habitats for biodiversity, have large soil carbon stores, but may emit more greenhouse gases (GHG) than the uplands. In this article, we present a review of the environmental services related to water protection, terrestrial biodiversity, carbon storage and greenhouse gas dynamics provided by RF in the Nordic countries. We discuss the benefits and trade-offs when leaving the RF as a buffer against the impacts from upland forest management, in particular the impacts of clear cutting. Forest buffers are effective in protecting water quality and aquatic life, and have positive effects on terrestrial biodiversity, particularly when broader than 40 m, whereas the effect on the greenhouse gas exchange is unclear.     

Public perceptions of planning objectives for regional level management of wild reindeer in Norway

We examined community perceptions of preferred objectives for wild reindeer management in Southern Norway as the former population-based model is being replaced with an area-based, multi-level regional management model spanning large mountain regions. Communally oriented objectives are favoured over economic benefits to landowners. Environmental attitudes discriminate on many of the issues and can be useful factors in sorting out levels of support for proposed management actions and compromises in land use decisions. The regional reindeer plans create a new political context for land use management across large mountain areas which will require better cooperation among municipalities.     

Pointing accuracy in children is dependent on age, sex and experience

We investigated the influence of age, sex and familiarity on spatial performance assessed with a pointing task in 84 children: 21 kindergartners, 21 first-graders, 21 fifth-graders and 21 sixth-graders. Spatial performance was assessed in the children's natural environment, their respective school or kindergarten. The children had to indicate the direction of prominent landmarks on the school campus while sitting in their classroom, drawing an arrow on a sheet of paper. Since the children had spent different amounts of time at their respective schools, experience with the environment was regarded as a covariate.Data analysis revealed significant effects for age, sex and experience. Fifth-graders aged around 10 years outperformed the younger children. Sex differences revealed male superiority at all ages. Experience with the environment was also shown to play a vital role. Children who had spent a longer time at the school were able to demonstrate better spatial knowledge by pointing more accurately towards unseen landmarks.     

Territory ownership and familiarity status affect how much male root voles (Microtus oeconomus) invest in territory defence

Neighbour–stranger discrimination occurs when individuals respond with more aggression to strangers than to territorial neighbours—a phenomenon termed the “dear enemy phenomenon” (DEP). We investigated the DEP with male and female root voles (Microtus oeconomus Pallas 1776) using field dyadic arena tests conducted in enclosures where we could test for the effects of familiarity (familiar versus stranger), ownership (resident versus intruder status) and resource-holding potential (body mass) on territorial behaviours. The results showed that males put more effort into territorial defence than females, and males could discriminate between neighbours and strangers. In males, aggressiveness was influenced by a significant two-way interaction between treatment and ownership. Male residents were more aggressive towards stranger intruders than towards neighbour intruders, while male intruders were less aggressive towards stranger residents than towards neighbour residents. In females, neither treatment nor ownership status had a significant effect on aggressiveness. Familiar males performed more social behaviours but less non-social behaviours than stranger males. Furthermore, there was a clear dominance hierarchy between residents and intruders in stranger dyads, with the male territory holders dominating the intruder in pairwise interactions. To our knowledge, these results demonstrate for the first time DEP in a small mammal with a known pedigree and present the first evidence for “prior resident advantage” in voles. We argue that both ownership status and familiarity status affect how much an individual invests in territory defence. The benefits of neighbour–stranger discrimination for male root voles and the absence of neighbour–stranger discrimination in female root voles are discussed.     

Male turnover reduces population growth: an enclosure experiment on voles

Turnover of individuals is assumed to cause disruptions of social organization, followed by reduced reproduction and survival. We tested how male turnover (removal of resident males and their replacement by unfamiliar males) affected population performance in experimental root vole (Microtus oeconomus) populations. The treatment simulated predation of adult males, with the subsequent replacement by immigrants, and provided insight into the interaction between extrinsic (i.e., predation) and intrinsic (i.e., social organization) factors. We showed that recruitment and female survival dramatically declined and that reproduction commenced slightly later in treatment populations compared with control populations. The treatment nearly halved the population growth rate. We suspect that recruitment failed due to infanticidal immigrating males. Reduced female survival was particularly apparent in treatment populations in which females exhibited a high degree of spatial overlap. Our experimental results show how males may significantly shape population dynamics and suggest how predation and social factors interact mechanistically.     

POP exposure from fish liver consumption and risk of cancer--the Norwegian Women and Cancer Study

The aim of the study was to investigate the hypothesis that consumption of fish liver increases cancer risk in humans due to increased intake of persistent organic pollutants (POPs). This study is based on data from the Norwegian Women and Cancer Study (NOWAC). The study has a prospective cohort design with questionnaire data from 64 285 randomly selected Norwegian women (aged 40-70 at baseline) and linkage to the Norwegian Cancer Registry. Cox proportional hazards regression was used to calculate risk ratios associated with consumption of fish liver and total cancer and cancer in breast, uterus, and colon. Fish liver consumption was, after adjusting for known risk factors, associated with a significant reduced risk for total cancer (RR = 0.92, 95% CI: 0.85, 0.99), and non-significant reduced risk for breast cancer (RR = 0.90, 95% CI: 0.78, 1.04), and colon cancer (RR = 0.82, 95% CI: 0.63, 1.07). Relative risk for uterus cancer was 0.82 (95% CI: 0.61-1.12). No significant dose-response effect was found for frequency of fish liver consumption (when divided into three intake groups) and total cancer, nor for any of the other cancer sites.We have concluded that in Norwegian women, fish liver consumption was not associated with an increased cancer risk in breast, uterus, or colon. In contrast, a decreased risk for total cancer was found.     

Forest Ecosystem Responses to Atmospheric Pollution: Linking Comparative With Experimental Studies

The impact on an ecosystem of an environmental stress, such as climate change or air pollution, can be studied through experimentation, through comparisons of sites across a gradient of the stress, through long-term studies at a single site, or through theoretical or modelling approaches. Although the former three techniques often are used to develop and test models, it is much rarer to explicitly link experimental, comparative or long-term studies together. Here we present a concept for combining experimental and comparative research to assess the direction and rate of change, the expected long-term state, and the rate at which the long-term state is achieved after an ecosystem is exposed to an environmental stress. We do this by comparing the response of a forest in Denmark to experimentally increased N deposition with the expected long-term response based on a European database of forests exposed to different levels of N deposition over long time periods. The analysis suggests that if N deposition were to increase by 3-fold to about 50 kg N ha^-1 a^-1 at the Danish site, and remain at this level, the N concentration in needles would respond within 2–4 yr after the onset of the enhanced N deposition, and would rapidly plateau to an expected mean value of 18.0 mg N g^-1 dry mass (95% confidence interval ± 2.5 mg g^-1). The N concentration of new litter also would respond rapidly (1–2 yr) to reach an expected value of 16.6 mg N kg^-1 dry mass (± 3). The N concentration of the organic layer in the soil would increase much more slowly, but a significant increase would be expected within 5–10 yr. Mineral soil pH would take more than 7 yr to change. Finally, the flux of dissolved inorganic N in leachate wouldbegin to increase immediately, but would take many years to reach the expected level of 22.4 kg N ha^-1 a^-1(± 4).