Development and drift of northern shrimp larvae (<Emphasis Type="Italic">Pandalus borealis</Emphasis>) at West Greenland

This is the first study of the West Greenland offshore population of Pandalus borealis in recent history that covers all larval stages. Shrimp larvae were sampled on the fishing banks off the west coast of Greenland from 63.5°N to 67°N in May, June and July. Abundances decreased during the summer as did cumulated mortality rates [0.06 day^–1 (ZI) to 0.04 day^–1 (ZVI)]. Modelling stage development time as a function of temperature alone by means of the Blehrádek function gave decreasing stage durations from 22.7 to 16.7 days. Drift buoys showed a northbound current with an average velocity of 0.06 m s^–1. Potential spawning grounds of shrimp larvae were located from back-calculation by coupling development times and mortality rates with current velocity. This showed larval transport of up to 500 km. The adult female shrimp abundances were estimated to 0.12–96 females per 100 m², and locations of the estimated spawning stock agreed with observations from trawl surveys.Communicated by L. Hagerman, Helsingør     

Quantification of trypsin with a radioimmunoassay in herring larvae (Clupea harengus) compared with a highly sensitive fluorescence technique to determine tryptic enzyme activity

Enzymatic activity and quantity of the protease trypsin were measured in individual herring larvae (Clupea harengus L.). The enzymatic activity assay was done using a fluorescence technique, and a radioimmunoassay was used for quantification of trypsin. The results are compared and the differences between the techniques discussed. Both methods gave similar results, as high or low values in trypsin quantity were reflected in high or low values of tryptic activity. Quantity and activity were linearly and positively correlated, but small differences between methods were found at the lowest detection limits. Both techniques reflect high variability between individual larvae.     

Lead and polycyclic aromatic hydrocarbons (PAHs) in surface soil from day care centres in the city of Bergen, Norway

Surface soil (0-2cm) quality in 87 day care centres in the city of Bergen, Norway has been studied. Approximately 45% of the day care centres contained Pb and PAH values above recommended action levels. There are clear variations between different areas of the city. The old central part of the city hosts most of the contaminated day care centres. In suburban areas most of the day care centres have Pb and PAH concentrations below action levels. City fires, gas work emission, lead-based paint, and traffic are probably important anthropogenic contamination sources, together with uncontrolled transportation of soil from contaminated to clean areas. Geological or other natural sources are probably not an important contributor to the high levels of lead and PAH.     

Promise and performance of agricultural nutrient management policy: Lessons from the Baltic Sea

Following decades of international collaboration to restore the Baltic Sea, we provide an assessment of the domestic implementation of measures agreed to limit diffuse agricultural pollution and the patterns of policy instruments applied. Despite the Helsinki Convention being unusually specific in detailing what measures countries should introduce, we find many shortcomings. These are most pronounced in the larger countries (Poland, Germany and Russia), while smaller countries perform better, notably Sweden and Estonia. The patterns of policy instruments applied differ, influenced by domestic politics. The limited use of complementary policy instruments suggests that other priorities overrule full and effective implementation, with engagement mirroring the advantages that a restored Baltic Sea can bring to countries. Using the European Agricultural Fund for Rural Development to support farmers in managing nutrients, particularly advisory services and investments in modern manure management technologies, represents a significant opportunity for reducing agricultural pollution in most countries.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01549-3.     

The impact of visual factors on noise annoyance among people living in the vicinity of wind turbines

Wind turbines are highly visible objects and the response to wind turbine noise is possibly influenced by visual factors. In this study, visibility of the noise source, visual attitude and vertical visual angle (VVA) in different landscapes were explored. Data from two cross-sectional field studies carried out among people living near wind turbines (n=1095) were used for structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see vs. respondents who could not see wind turbines from their homes, living in flat vs. hilly/rocky terrain, and living in built-up vs. rural areas. Visual attitude towards the noise source was associated with noise annoyance to different degrees in different situations. A negative visual attitude, more than multi-modal effects between auditory and visual stimulation, enhanced the risk for noise annoyance and possibly also prevented psychophysiological restoration possibilities. Aesthetic evaluations of the noise source should be taken into account when exploring response to environmental noise.     

Mitigation of methane emission from Fakse landfill using a biowindow system

Landfills are significant sources of atmospheric methane (CH₄) that contributes to climate change, and therefore there is a need to reduce CH₄ emissions from landfills. A promising cost efficient technology is to integrate compost into landfill covers (so-called “biocovers”) to enhance biological oxidation of CH₄. A full scale biocover system to reduce CH₄ emissions was installed at Fakse landfill, Denmark using composted yard waste as active material supporting CH₄ oxidation. Ten biowindows with a total area of 5000 m² were integrated into the existing cover at the 12 ha site. To increase CH₄ load to the biowindows, leachate wells were capped, and clay was added to slopes at the site. Point measurements using flux chambers suggested in most cases that almost all CH₄ was oxidized, but more detailed studies on emissions from the site after installation of the biocover as well as measurements of total CH₄ emissions showed that a significant portion of the emission quantified in the baseline study continued unabated from the site. Total emission measurements suggested a reduction in CH₄ emission of approximately 28% at the end of the one year monitoring period. This was supported by analysis of stable carbon isotopes which showed an increase in oxidation efficiency from 16% to 41%. The project documented that integrating approaches such a whole landfill emission measurements using tracer techniques or stable carbon isotope measurements of ambient air samples are needed to document CH₄ mitigation efficiencies of biocover systems. The study also revealed that there still exist several challenges to better optimize the functionality. The most important challenges are to control gas flow and evenly distribute the gas into the biocovers.     

Cost–benefit analysis of beach-cast harvest: Closing land-marine nutrient loops in the Baltic Sea region

Harvesting beach-cast can help mitigate marine eutrophication by closing land-marine nutrient loops and provide a blue biomass raw material for the bioeconomy. Cost–benefit analysis was applied to harvest activities during 2009–2018 on the island of Gotland in the Baltic Sea, highlighting benefits such as nutrient removal from the marine system and improved recreational opportunities as well as costs of using inputs necessary for harvest. The results indicate that the activities entailed a net gain to society, lending substance to continued funding for harvests on Gotland and assessments of upscaling of harvest activities to other areas in Sweden and elsewhere. The lessons learnt from the considerable harvest experience on Gotland should be utilized for developing concrete guidelines for carrying out sustainable harvest practice, paying due attention to local conditions but also to what can be generalized to a wider national and international context.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01641-8.     

Butyltin compounds in sediment and molluscs from the shipping strait between Denmark and Sweden

The distribution of tributyltin (TBT) contamination in the subtidal zone of the waters between Denmark and Sweden was investigated in relation to major international shipping lanes. Sediment and different benthic molluscs were sampled in transects along and perpendicularly to the shipping lanes in the Sound (?resund) and the Kattegat/Skagerrak region. The samples were analysed for TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), using GC-PFPD. In sediments, the TBT concentration ranged from <1 to 19 ng g(-1) dry weight (dw) with a strong correlation between the TBT concentration and the organic fraction in sediment (r(2)=0.90) in the samples collected in the Sound, where the highest concentrations were found. This relationship was not observed in the samples from the Kattegat because the TBT concentration in most sediment samples was below the limit of detection. In the molluscs, TBT and its degradation products were detected in all samples from the entire area with concentrations ranging from 8.1 ng g(-1) dw in Buccinum undatum to 1316 ng g(-1) dw in Nuculana pernula. The deposit-feeding bivalve N. pernula was found to have a particularly high accumulation potential for TBT. In addition, a strong correlation between TBT concentrations in sediment and N. pernula was found. Therefore this species seems to be an ideal organism for monitoring sediment contamination. The TBT concentration in N. pernula was found to decrease gradually along the shipping lanes from the Sound, through the Kattegat and into the Skagerrak.