Spawning behaviour and sex hormone levels in adult and precocious brown trout (Salmo trutta L.) males and the effect of anosmia

Summary. In the present experiment the behaviour and endocrine status of males of the brown trout, Salmo trutta L., (Salmoniformes: Salmonidae) were studied when males were kept in a stream tank with a nest digging female. Groups of mature adult males and precocious intact or anosmic male parr were placed with the nesting female so that the group resembled a natural spawning situation with big anadromous fish acting as dominant males and precocious parr acting as “sneakers”. A control experiment was also run with only males without a female present. In intact parr there were significant positive correlations between the per cent of the total observation time spent with a female, milt volume, and plasma concentration of 17α, 20β-dihydroxy-4-pregnen-3-one. Anosmic parr had significantly lower volumes of strippable milt and gonadal steroid hormone levels compared with intact parr. However, no differences were found in the control experiment. Significantly fewer anosmic parr attended and courted the nesting female and those anosmic fish that attended the female had significantly lower plasma levels of gonadal hormones. Intact parr also displayed a greater number of agonistic acts against other parr without any difference in fighting ability. No differences in aggression occured in the control experiment. In adult males together with a female, post-experimental gonadal steroid hormone levels were higher than pre-experimental levels. Positive correlations between aggression and androgen hormone levels were observed in adult males. No differences in plasma hormone levels were observed between adult males and intact precocious males. The results show that olfactory occlusion results in low steroid hormone levels and milt volumes in precocious males placed in a spawning situation. The courting behaviour was also affected by anosmia. Odours from the nesting female may have caused the enhanced plasma hormone levels and stimulated the males to attend the female. Received 15 May 1997; accepted 29 June 1997.     

A radical public administration? Green radicalism and policy influence among local environmental officials in Sweden

Green radicalism among local environmental officials in Sweden is examined with the aims of theoretically elaborating on different dimensions of Green radicalism in the context of public administration, exploring the dimensionality of Green radicalism among officials, and examining the extent to which Green radicalism is associated with policy influence. Three types of Green radicalism are identified: Green ethics, Green institutional change, and Green activism. Survey data (N = 701) show that the three theoretical dimensions are present among officials, and that there is no negative association between radicalism and influence. It is primarily officials with Green activism beliefs who perceive themselves as able to influence policy. These findings suggest a need for more nuanced understanding of and further studies into the role of public administration in the quest for more radical Green reforms.     

Cd-tolerant Suillus luteus: A fungal insurance for pines exposed to Cd

Soil metal pollution can trigger evolutionary adaptation in soil-borne organisms. An in vitro screening test showed cadmium adaptation in populations of Suillus luteus (L.: Fr.) Roussel, an ectomycorrhizal fungus of pine trees. Cadmium stress was subsequently investigated in Scots pine (Pinus sylvestris L.) seedlings inoculated with a Cd-tolerant S. luteus, isolated from a heavy metal contaminated site, and compared to plants inoculated with a Cd-sensitive isolate from a non-polluted area. A dose-response experiment with mycorrhizal pines showed better plant protection by a Cd-adapted fungus: more fungal biomass and a higher nutrient uptake at high Cd exposure. In addition, less Cd was transferred to aboveground plant parts. Because of the key role of the ectomycorrhizal symbiosis for tree fitness, the evolution of Cd tolerance in an ectomycorrhizal partner such as S. luteus can be of major importance for the establishment of pine forests on Cd-contaminated soils.     

The modelling of a hybrid combined cycle with pressurised fluidised bed combustion and CO2 capture

This study investigates the possibility of capturing CO₂ from flue gas under pressurised conditions, which could prove to be beneficial in comparison to working under atmospheric conditions. Simulations of two hybrid combined cycles with pressurised fluidised bed combustion and CO₂ capture are presented. CO₂ is captured from pressurised flue gas by means of chemical absorption after the boiler but before expansion. The results show a CO₂ capture penalty of approximately 8 percentage points (including 90% CO₂ capture rate and compression to 110 bar), which makes the efficiency for the best performing cycle 43.9%. It is 5.2 percentage points higher than the most probable alternative, i.e. using a natural gas fired combined cycle and a pulverised coal fired condensing plant separately with the same fuel split ratio. The largest part of the penalty is associated with the lower mass flow of flue gas after CO₂ capture, which leads to a decrease in work output in the expander and potential for feed water heating. The penalty caused by the regeneration of absorbent is quite low, since the high pressure permits the use of potassium carbonate, which requires less regeneration heat than for example the more commonly proposed monoethanolamine. Although the efficiencies of the cycles look promising it will be important to perform a cost estimate to be able to make a fair comparison with other systems. Such a cost estimate has not been done in this study. A significant drawback of these hybrid cycles in that respect is the complex nature of the systems that will have a negative effect on the economy.     

Age and seasonal variability of polybrominated diphenyl ethers in free-ranging East Greenland polar bears (Ursus maritimus)

Polybrominated diphenyl ethers (PBDEs) were analysed in adipose tissue from 92 East Greenland polar bears (Ursus maritimus) sampled during 1999-2001. Mean SigmaPBDE concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. Of the 32 analysed PBDE congeners; BDE47, BDE153, BDE99 and BDE100 dominated, and comprised 99.6% of the SigmaPBDE concentration. The SigmaPBDE concentration had a highly significant correlation with SigmaPCB, SigmaCHL, dieldrin, HCB and SigmaHCH concentrations. We found a seasonal pattern of median SigmaPBDE concentration with 1.2 to 1.8 times higher concentrations in March to July than the rest of the year. The seasonal variation also provides a clue to the seasonal exposure, bio-availability, toxic exposure and degradation. We suggest that future geographical PBDE data comparisons may not need corrections for sex or age, but such data sets should be corrected for seasonal variability, using the presented correctional trigonometric regression.     

Living in an oasis: Rapid transformations,resilience, and resistance in the North Water Area societies and ecosystems

Based on lake sediment data, archaeological findings, and historical records, we describe rapid transformations, resilience and resistance in societies and ecosystems, and their interactions in the past in the North Water area related to changes in climate and historical events. Examples are the formation of the polynya itself and the early arrival of people, ca. 4500 years ago, and later major human immigrations (different societies, cultural encounters, or abandonment) from other regions in the Arctic. While the early immigrations had relatively modest and localised effect on the ecosystem, the later-incoming culture in the early thirteenth century was marked by extensive migrations into and out of the area and abrupt shifts in hunting technologies. This has had long-lasting consequences for the local lake ecosystems. Large natural transformations in the ecosystems have also occurred over relatively short time periods related to changes in the polynya. Finally, we discuss the future perspectives for the North Water area given the many threats, but also opportunities.     

Hypoxia in the Baltic Sea: Biogeochemical Cycles, Benthic Fauna, and Management

Hypoxia has occurred intermittently over the Holocene in the Baltic Sea, but the recent expansion from less than 10 000 km² before 1950 to >60 000 km² since 2000 is mainly caused by enhanced nutrient inputs from land and atmosphere. With worsening hypoxia, the role of sediments changes from nitrogen removal to nitrogen release as ammonium. At present, denitrification in the water column and sediments is equally important. Phosphorus is currently buried in sediments mainly in organic form, with an additional contribution of reduced Fe-phosphate minerals in the deep anoxic basins. Upon the transition to oxic conditions, a significant proportion of the organic phosphorus will be remineralized, with the phosphorus then being bound to iron oxides. This iron-oxide bound phosphorus is readily released to the water column upon the onset of hypoxia again. Important ecosystems services carried out by the benthic fauna, including biogeochemical feedback-loops and biomass production, are also lost with hypoxia. The results provide quantitative knowledge of nutrient release and recycling processes under various environmental conditions in support of decision support tools underlying the Baltic Sea Action Plan.     

Reduction of Baltic Sea Nutrient Inputs and Allocation of Abatement Costs Within the Baltic Sea Catchment

The Baltic Sea Action Plan (BSAP) requires tools to simulate effects and costs of various nutrient abatement strategies. Hierarchically connected databases and models of the entire catchment have been created to allow decision makers to view scenarios via the decision support system NEST. Increased intensity in agriculture in transient countries would result in increased nutrient loads to the Baltic Sea, particularly from Poland, the Baltic States, and Russia. Nutrient retentions are high, which means that the nutrient reduction goals of 135 000 tons N and 15 000 tons P, as formulated in the BSAP from 2007, correspond to a reduction in nutrient loadings to watersheds by 675 000 tons N and 158 000 tons P. A cost-minimization model was used to allocate nutrient reductions to measures and countries where the costs for reducing loads are low. The minimum annual cost to meet BSAP basin targets is estimated to 4.7 billion €.