20世纪瓦萨城市水保护发展阶段

位于波的尼亚湾的瓦萨是波罗的海沿岸有代表性的中等城市.本文论述了瓦萨对周围海域的影响,以及该市对海洋污染的反应.瓦萨的废水处理历史有力地表明,第一代的环境问题,如城市废水排放造成的污染问题,只是在一个漫长的发展过程之后作为最后的一着得到解决的.1953年建成了第一座废水处理厂.从长远来看,如果当初接受了建立中央处理厂的方案,那么城市政策不用为环境和城市本身付出那么大的代价了.在瓦萨,环境本身并没有起到激励作用,所发生的变化的诱因是城市废水排排放造成的健康危害、有害恶臭以及恶劣的户外游泳条件.最后万不得已时才采取了行动.本文还论述了环境研究的社会科学办法.     

波罗的海的鱼类类群:是有限资源还是无限资源?

人类引起的环境变化,特别是富营养化和由于气候变化和太阳活动而导致的自然环境条件的波动影响着波罗的海各鱼类和群体的繁殖和生长.在过去几十年间,人类影响的重要性明显增加,在很多情况下掩盖了自然因素.高速的开发降低了一些有价值的鱼的种类,影响了一些种类的支配层次.海洋深层的氧消耗使得某些海洋种类的生存条件日益恶化.随着船舶压舱水而引入的大量非本地种类严重地影响着生态系统和鱼类类群.对于海洋的这些变化的总体影响、残留的和淡水种类可能会产生预想不到的结果.鱼类资源应该根据其自然单元(种群)进行适当的评价和管理.根据全球气候过程的周期性波动,应该着手进行鱼类区系结构和丰度变化的长期预报工作.     

Female bank voles (Clethrionomys glareolus) prefer dominant males; but what if there is no choice?

Both intra-sexual competition between males and female mate choice have been found to affect mating behaviour in rodents. We studied female choice in the bank vole (Clethrionomys glareolus) under circumstances where male-male competition was excluded and the female could interact and mate freely with the males. Mating behaviour was observed in two situations: (1) the female encountered two males with a clear dominance relationship; and (2) the two males were equal in their social status. In all tests where a female in postpartum oestrus had a choice between males of different social rank she mated with the dominant one. When choosing between an even pair of males there was no difference in the frequency of lordotic responses, mounts or intromissions the female exhibited with either male before mating with one of them. The mean ejaculation latency was significantly longer in the tests with an even pair of males than in the tests where male hierarchy was clear. These results show that bank vole females are able to discriminate males according to their social status and strongly prefer dominant males as mating partners. However, when the females were presented with two equal males, they seemed to be unable to make a choice. The ability to choose the mating partner when the males are clearly different may be an important direct benefit for the female in terms of time saved during mating and thus decreased risk of predation and infanticide. Received: 16 March 1995/Accepted after revision: 11 February 1996     

Common goldeneyes adjust maternal effort in relation to prior brood success and not current brood size

Parental investment theory predicts that parental effort should be related to the reproductive value of the current brood. This depends on both the number of young and the survival prospects of each of them. Thus parents may provide more care to larger broods either because of (1) the direct effect of brood size per se on reproductive value (the “brood size” hypothesis) or because (2) past mortality, reflected in current brood size, predicts future mortality of the brood and hence its reproductive value (the “brood success” hypothesis). Earlier studies have not attempted to distinguish between these alternatives. We tested the hypotheses in the precocial, nidifugous common goldeneye Bucephala clangula, a species with uniparental female care. Maternal effort was measured as the time spent by the female in rearing the brood. We found that brood size itself is not associated with maternal effort, but that females modify their maternal effort according to the mortality already experienced by the brood, supporting the prediction of the brood success hypothesis. We also found that brood mortality varied considerably between broods and that previous mortality predicts future mortality within broods, basic assumptions of the brood success hypothesis. Received: 30 January 1996 / Accepted after revision: 27 October 1996     

Parasitic common goldeneye (<Emphasis Type="Italic">Bucephala clangula</Emphasis>) females lay preferentially in safe neighbourhoods

Nest predation has been suggested as an explanation of the adaptive significance and evolution of conspecific brood parasitism, an alternative reproductive tactic pursued by females in several animal taxa. I used new nest boxes that contained only decoy eggs and were erected on lakes differing in real nest predation risk to test this hypothesis in the common goldeneye (Bucephala clangula), a hole-nesting duck. I used broken eggs to simulate predation risk of the boxes to determine if parasites having no previous experience with the boxes discriminate between seemingly safe and risky nest sites. Parasites laid eggs in the experimental boxes independently of the simulated predation risk, suggesting that they do not use broken eggs or nest disarray as indicators of predation intensity. Parasites preferred experimental boxes on lakes where real nest predation risk was low, supporting the nest predation risk hypothesis. Assuming that females in high risk areas have had experience of nest predation, they may take this into account in selecting host nests.     

Heavy metals in flue gas cleaning residue

During combustion, most of the inorganic nutrients and trace elements in the fuel are retained and enriched in the ash. However, here we show that, due to the low total heavy metal concentrations, the flue gas cleaning residue (i.e. the fly ash) originating from the wet scrubber device at a medium-sized (32 MW) municipal district heating plant, is a potential forest fertilizer. Furthermore, the easily soluble calcium (1,980 mg kg⁻¹; d.w.) and phosphorus (50 mg kg⁻¹; d.w.) concentrations indicate that the flue gas cleaning residue is a potential agent for soil remediation and for improving soil fertility.     

Effects of changing climate on water and nitrogen availability with implications on the productivity of Norway spruce stands in Southern Finland

An integrated process-based model was used to study how the changing climate affects the availability of water and nitrogen, and consequently the dynamics of productivity of Norway spruce (Picea abies) on sites with different initial soil water conditions in southern Finland over a 100-year period. The sensitivity of the total stem volume growth in relation to short-term availability of water and nitrogen was also analyzed. We found that a high proportion (about 88–92%) of the total precipitation was lost in total evapotranspiration (incl. canopy evaporation (E_c), transpiration (E_t) and ground surface evaporation (E_g)), under both current and changing climate. Furthermore, under the changing climate the cumulative amount of E_c and E_g were significantly higher, while E_t was largely lower than under the current climate. Additionally, the elevated temperature and increased expansion of needle area index (L) enhanced E_c. Under the changing climate, the increasing soil water deficit (W_d) reduced the canopy stomatal conductance (g_cs), the E_t, humus yield (H, available nitrogen source) and nitrogen uptake (N_up) of the trees. During the latter phases of the simulation period, the canopy net photosynthesis (P_nc) was lower due to the reduced N_up and soil water availability. This also reduced the total stem volume production (V_s) on the site with the lower initial soil moisture content. The growth was slightly more sensitive to the change in precipitation than to the change in nitrogen content of the needles, when the elevated temperature was assumed. According to our findings, drought stress episodes may become more frequent under the changing climate. Thus, adaptive management strategies should be developed to sustain the productivity of Norway spruce in these conditions, and thus, to mitigate the adverse impacts of climate change.     

Warming autumns at high latitudes of Europe: an opportunity to lose or gain in cereal production?

Regional Environmental Change - Climate change is projected to prolong Finland’s short growing season at both ends though warming autumns are not expected to benefit arable crops such as...     

Market basket study on dietary intake of PCDD/Fs, PCBs, and PBDEs in Finland

We have measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDD/F), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDE) in 10 market baskets consisting of almost 4000 individual food samples representing 228 different food items, and also in the total diet basket. Lower bound concentrations of PCDD/Fs ranged between 0.0057 and 5.6 pg/g fresh weight in the market baskets and the corresponding values for PCBs from 39 to 25,000 pg/g. The fish basket contributed most to the concentrations of dioxins and PCBs, and also to concentrations of PBDEs in which the lower bound range was from 0.82 to 850 pg/g. We also assessed the average daily intakes of these substances by the Finnish adult population. The average daily intake of sum of PCDD/Fs and PCBs as WHO toxic equivalents was assessed to be 115 pg, which was 1.5 pg WHO-TEq/kg body weight using an average mean weight of 76 kg for the general population in Finland. The contribution of fish to the intake of PCDD/Fs was between 94% and 72%, depending on whether lower or upper bound concentrations were used. With respect to PCBs, the contribution of fish was 80%. The calculated intake of PBDEs of 44 ng/day was comparable to intake assessments from other countries. Fish also contributed most to the PBDE intake, but there was some other source of PBDEs that distinguishes the exposure to PBDEs from exposure to PCDD/Fs and PCBs. This additional source seemed to be found in the market basket that included beverages, spices, and sweets.     

A simple formula for calculating the ionization potential of two-electron ions

The ionization potential of one-electron ions can be calculated from a well-known simple equation, but no such equation has been available for calculating the ionization potential of multi-electron ions. I report here an equation that accurately gives the ionization potential of helium-like (i.e., two-electron) ions as a function of the atomic number, the relative difference from experimental values being below 1% for all ions for which reliable experimental data were found (Z = 3–29). The equation also predicts the stability of the negative hydrogen ion (the hydride ion), H⁻, although with twice too large a value for the ionization potential.