Modelling Acidification and Recovery of Swedish Lakes

The MAGIC model was calibrated to 143 lakes in Sweden, all of which are monitored in Swedish national monitoring programmes conducted by the University of Agricultural Sciences (SLU). Soil characteristics of the lake catchments were obtained from the National Survey of Forest Soils and Vegetation also carried out by SLU. Deposition data were provided by the Swedish Meteorological and Hydrological Institute (SMHI). The model successfully simulated the observed lake and soil chemistry at 133 lakes and their catchments. The fact that 85% of the lakes calibrated successfully without being treated in an individual way suggests that data gathered by the national monitoring programmes are suitable for modelling of soil and surface water recovery from acidification. The lake and soil chemistry data were then projected into the future under the deposition scenario based on emission reductions agreed in the Gothenburg protocol. Deposition of sulphur (sea salt corrected) was estimated to decrease from 1990 to 2010 by 65–73%; deposition of nitrogen was estimated to decrease by 53%. The model simulated relatively rapid improvements in lake water chemistry in response to the decline in deposition from 1990 to 2010, but the improvements levelled off once deposition stabilised at the lower value. There was a major improvement of simulated lake water charge balance acid neutralising capacity (ANC) from 1990 to 2010 in all lakes. The modelled lakes were divided into acidification sensitive and non-sensitive. The modelled sensitive lakes are representative of 20% of the most sensitive lakes in Sweden. By 2010, the ANC in the sensitive lakes was 10 to 50 μeq L^-1 below estimated pre-industrial levels and did not increase much further from 2010 to 2040. Soils at the majority of the modelled catchments continued to lose base cations even after the simulated decline in acid deposition was complete, i.e. after the year 2010. Based on this model prediction, the acidification of the Swedish soils will in general not be reversed by the deposition reduction experienced over the last 10 years and expected to occur by the year 2010.     

The potential of foliar treatments for enhanced phytoextraction of heavy metals from contaminated soil

Phytoextraction is the plant‐based removal of inorganic contaminants from the soil by root absorption and subsequent translocation to harvestable plant parts. The efficiency of this technique is limited by the phytoavailability of these contaminants in the soil and the root‐to‐shoot transport. To enhance the phytoextraction efficiency, the use of soil amendments has been widely investigated. Potential risks such as increased ecotoxicological effects and leaching of mobilized contaminants caution against the use of persistent mobilizing agents. The potential use of foliar amendments to enhance mineral absorption and/or translocation offers prospects for complementing or substituting soil amendments for enhanced phytoextraction purposes. This study presents an explorative screening to evaluate the feasibility of this approach. Helianthus annuus giganteus plants were grown in moderately contaminated dredged sediment for ten weeks, with daily foliar treatments from week six onward: (1) distilled water (control), (2) magnesium‐ethylenediaminetetraacetic acid (Mg‐EDTA), (3) diethylenetriaminepentaacetic acid (DTPA), (4) nitrilotriacetic acid (NTA), (5) citric acid, (6) oxalic acid, (7) calcium acetate, (8) ammonium thiocyanate (NH₄SCN), and (9) cystein. Applied doses varied between treatments based on plant tolerance: 15 μmol per plant for cystein, 60 μmol per plant for DTPA and NH₄SCN, 180 μmol per plant for Mg‐EDTA and NTA and 400 μmol per plant for the organic acids. At the end of the experiment, shoot accumulation of cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc was evaluated. © 2004 Wiley Periodicals, Inc.     

Roadmap for assessing regional trends in groundwater quality

Assessing regional trends in groundwater quality can be a difficult task. Data are often scattered in space and time, and the inertia of groundwater systems can create natural, seemingly persistent changes in concentration that are difficult to separate from anthropogenic trends. Here, we show how statistical methods and software for joint analysis of multiple time series can be integrated into a roadmap for trend analysis and critical examination of data quality. Ordinary and partial Mann–Kendall (MK) tests for monotonic trends and semiparametric smoothers for multiple time series constitute the cornerstones of our procedure. The MK tests include a simple and easily implemented method to correct for serial dependence, and the associated software is designed to enable convenient handling of numerous data series and to accommodate covariates and nondetects. The semiparametric smoothers are intended to facilitate detection of synchronous changes in a network of stations. A study of Swedish groundwater quality data revealed true upward trends in acid-neutralizing capacity and downward trends in sulfate but also a misleading shift in alkalinity level that would have been difficult to detect if the time series had been analyzed separately.     

Variation in Organic Matter and Water Color in Lake Mälaren during the Past 70 Years

Interest in long time series of organic matter data has recently increased due to concerns about the effects of global climate change on aquatic ecosystems. This study presents and evaluates unique time series of chemical oxygen demand (COD) and water color from Lake Mälaren, Sweden, stretching almost seven decades (1935–2004). A negative linear trend was found in COD, but not in water color. The decrease was mainly due to installation of sewage works around 1970. Time series of COD and water color had cyclic pattern. It was strongest for COD, with 23 years periodicity. Similar periodicity observed in air temperature and precipitation in Sweden has been attributed to the North Atlantic Oscillation index and solar system orbit, suggesting that COD in Lake Mälaren is partly derived from algae. Discharge influenced water color more than COD, possibly because water color consists of colored substances brought into the lake from surrounding soils.     

Energy consumption in the Norwegian fisheries

Energy use is of great concern within fisheries, due to both associated environmental effects and the cost of fuel to fishermen. This article explores the scale of energy consumed by most segments of the Norwegian fishing fleet for gadoid fish and for parts of the pelagic fleet for the period 1980–2005. Fuel use is assigned to the different species caught and different fishing gears using economic and mass-based allocation, where data permit. Correlations between variations in energy use and changing catch rates, quotas and oil prices are found. Inverse correlations are found between fuel consumption per kilogram of fish and catch rates on a yearly basis and between fuel consumption and oil prices on a longer term basis. A long term trend towards increased fuel consumption and reduced real prices is observed from the mid 1980s until 2000. This may indicate that low fuel prices do not motivate the development of energy efficient technology in the long run. Increased fuel use may further be used as an indication of over fishing as the correlation between low catch rates and increased fuel consumption is rather strong. Possible means of reducing energy use and emissions are discussed including changing operational strategies, hull forms and the use of alternative energy carriers. A comparison with measures taken in connection with the previous oil crisis around 1980 is done.     

Environmental impact of packaging and food losses in a life cycle perspective: a comparative analysis of five food items

The environmental concern and development issues regarding packaging has for 20 years to a high extent been on packaging when it has become waste. To reduce the environmental impact from the whole food packaging system it is also important to develop the packaging’s ability to reduce food waste. In some cases it may be necessary to increase the environmental impact of packaging in order to reduce food waste. In this paper, the environmental impact of packaging and food losses and the balance between the two has been examined for five different food items. The results show that packaging’s that reduce food waste can be an important tool to reduce the total environmental impact, even if there is an increase in impact from the packaging itself. This is especially true for food items where the environmental impact of the food is high relative the packaging, for example cheese, and for food items with high losses, for example bread. It is important to analyse the risk of increasing food losses when packaging design changes, for example, when the aim is less packaging material, which is the main intention of the packaging and packaging waste directive of the European Union.     

Long-term prediction of traffic accident record from bus driver celeration behavior.

Driver celeration (speed change) behavior of bus drivers measured a number of times was used to predict their culpable accidents over increasing time periods. It was found that predictive power was considerable (>.30 correlation) over 5 years of time with aggregated celeration (mean of repeated measurements) as independent variables, and there were also indications that power reached even further, although too low Ns made these results unreliable. Similarly, there were indications of even stronger correlations with increased aggregation of celeration values. The results were discussed in terms of the methodology needed to bring out such results, and the stability of accident-causing behavior over time.     

Comparison of exergy found by a classical thermodynamic approach and by the use of the information stored in the genome

It is possible to calculate the exergy for organisms based on classic thermodynamics as already demonstrated by Mejer and Jorgensen [Mejer, H., Jorgensen, S.E., 1979. Exergy and ecological buffer capacity. State-of-the-art in Ecol. Model. 7, 829–846]. The calculation of exergy as eco-exergy, which is based on the information stored in the genome, has lately been proposed by Jørgensen and co-workers. Recently, Ludovisi [Ludovisi, A., 2009. Exergy vs information in ecological successions: interpreting community changes by a classical thermodynamic approach. Ecol. Model. 220, 1566–1577] has put forward a method based on classical thermodynamics, which leads to the calculation of “virtual” values of concentration at equilibrium for a number of organic compounds (VEC) and freshwater organisms (VECE). This paper compares the two approaches by analysing the correlation existing between the VECE- and the β-values derived by Jørgensen et al. [Jørgensen, S.E., Ladegaard, N., Debeljak, M., Marques, J.C., 2005. Calculations of exergy for organisms. Ecol. Model. 185, 165–175]. It was found that there was a good correlation, which can be useful for estimating β-values for organisms whose genome is not known in a sufficient detail. The relationship between VECE- and β-values suggests that two proposed thermodynamic orientors based on these quantities – the eco-exergy index and the structural information – should lead to coherent results when applied to the evaluation of the development state of ecosystems. A numerical simulation shows that this expectation is verified in a major case, but also that different, even opposite, responses can arise, depending on the biological composition of the biocoenosis investigated.     

Seasonal and decadal changes in distribution patterns of Halobates (Hemiptera: Gerridae) populations in the eastern tropical Pacific

Five species of the marine insect Halobates share similar ecology but have distinct biogeographic ranges in the eastern tropical Pacific, a region from approximately 75°W–160°W and 10°S–35°N. Between 2001 and 2010, the Sea Education Association collected Halobates from 682 neuston tows (surface net 1 m × 0.5 m, 335-μm mesh) during fifteen cruises between San Diego, USA, Mexico and Tahiti. Total Halobates spp. densities varied substantially from year to year, but our data do not show a sustained change from a data set collected 40 years earlier from 1967 to 1968 (Cheng and Shulenberger in Fish Bull 78(3):579–591, 1980). Halobates are sensitive to sea surface temperature and we observed significant differences in species distributions over time, but these were not due to differences in water temperature or climate change. Our analyses show that the patterns observed are attributable to substantial but previously undescribed seasonal shifts that occur each year in the ranges for both Halobates sobrinus and Halobates micans. There is substantial overlap in ranges during seasonal shifts, but very little co-occurrence of H. sobrinus and H. micans in individual net tows, suggesting biological mechanisms rather than physical factors are restricting distribution and co-occurrence of these two species.     

Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair

Sexual selection may drive speciation, but most research focuses on pre-copulatory sexual selection, overlooking post-copulatory processes. Post-copulatory sexual selection in allopatric populations could drive divergence in post-copulatory pre-zygotic (PCPZ) phenotypes, limiting gene flow upon secondary contact. Here, we performed in vitro experiments examining one potential PCPZ barrier between two closely related passerine species, house sparrows (Passer domesticus) and Spanish sparrows (Passer hispaniolensis). In birds, crossing in the vagina may be particularly challenging for sperm, so we tested the effect of female reproductive tract fluids on sperm swimming speed and motility. If a PCPZ barrier exists at this stage of the fertilization process, heterospecific female fluids are predicted to reduce sperm swimming speed or motility relative to conspecific female fluid. We found that house sparrow female fluids affected the two species’ sperm asymmetrically, depending on the control sperm velocity and male species. Overall, however, sperm performed equally in conspecific and heterospecific female fluids, and the species had similar sperm morphology and sperm swimming performance. Low divergence in PCPZ phenotypes between species, perhaps because post-copulatory sexual selection is stabilizing or only moderately strong in these taxa, may be insufficient to cause an overall PCPZ barrier. Reinforcement may be unlikely to drive PCPZ barriers for this species pair, because relatively effective pre-copulatory barriers exist between the species, and because hybrids can be quite successful. Testing the role of PCPZ barriers in birds with more divergent PCPZ phenotypes will improve our understanding of speciation in passerines.