Lime placement on subsoil as a strategy to reduce phosphorus leaching from agricultural soils

Leaching of phosphorus (P) from agricultural land is a major contributor to eutrophication of surface waters in many countries, and effective mitigation options to reduce P in leachate are needed. In this study, intact columns (0.77 m deep) of subsoil from three Swedish agricultural soils (one sand and two clay) were used to examine whether placing quicklime (calcium oxide, CaO) on the subsoil could reduce P leaching over a 3‐yr period. Leaching of particulate P (PP) was significantly less from clay soil columns with lime than from clay soil columns without (P < 0.001 and P < 0.05, respectively), with a relative reduction of 49 and 51% in the two soils. Leaching of dissolved reactive P (DRP) was less from sand columns with lime than from sand columns without, although not significantly so due to large variation in P leaching between columns. These results indicate that placement of lime on subsoil has potential to reduce P leaching, especially of PP from clay soils. However, more studies including both topsoil and subsoil and a range of soil types are needed to assess the full potential of this P mitigation option.     

Is tree growth in boreal coniferous stands on mineral soils affected by the addition of wood ash?

Increasing use of forest fuels for energy production is generating greater quantities of wood ash. In Sweden, it is recommended that this ash should be returned to the forest to counter soil acidification and avoid potential future nutrient deficiencies, but the effects on tree growth require clarification. Thus, 10 field experiments were established in Sweden in 1990–2006 to study the effects of adding wood ash of various origins, doses and combinations of both ash and nitrogen on stem growth in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) stands on mineral soil. Observations after 5–15 years show that growth responses were strongest when N was added, either alone or with wood ash. Growth responses to additions of wood ash without N were small and variable and statistically insignificant at all study sites. However, there were indications that adding wood ash may increase stem-wood growth at fertile sites and decrease it at less fertile sites. Hence, at fertile sites, it may compensate for the growth reductions that normally follow whole-tree harvests, at least temporarily, presumably due to its effects on soil N turnover. At less fertile sites, adding N is probably essential to counteract these growth reductions.     

Colloid Centrifugation Selects Normal Spermatozoa from Polymorphic Bull Ejaculates: A Case Study

Semen from a Western Finncattle bull exhibiting a highly polymorphic spermiogram was processed by colloid centrifugation using Androcoll‐B, a species‐specific silane‐coated silica colloid. In the first experiment, Single Layer Centrifugation (SLC) was used to identify which density colloids were needed to separate different cell populations. Colloids of the two chosen densities were then used in a density gradient resulting in two sperm subpopulations, one containing nearly all normally sized spermatozoa and the other enriched for the macrocephalic spermatozoa. Microcephalic spermatozoa did not appear in either of the selected subpopulations. Using a combination of SLC and DGC with this species‐specific colloid, it was possible to separate the spermatozoa into different subpopulations, that is, a subpopulation containing nearly all normally sized spermatozoa, and another one enriched for the macrocephalic spermatozoa. Thus, colloid centrifugation could be used to select sufficient normal spermatozoa from a highly polymorphic ejaculate for AI, if desired.     

Chromosome Y-specific DNA is transferred to the short arm of X chromosome in human XX males

Y-chromosomal DNA is present in the genomes of most human XX males. In these cases, maleness is probably due to the presence of the Y-encoded testis-determining factor (TDF). By means of in situ hybridization of a probe (pDP105) detecting Y-specific DNA to metaphases from three XX males, it was demonstrated that the Y DNA is located on the tip of the short arm of an X chromosome. This finding supports the hypothesis that XX maleness is frequently the result of transfer of Y DNA, including TDF, to a paternally derived X chromosome.     

Detection of a novel herpesvirus associated with squamous cell carcinoma in a free-ranging Blanding’s turtle

The spread of both infectious and noninfectious diseases through wildlife populations is of increasing concern. Neoplastic diseases are rarely associated with population-level impacts in wildlife; however, impacts on individual health can be severe and might reflect deteriorating environmental conditions. An adult male free-ranging Blanding’s turtle (Emydoidea blandingii) originally captured in 2005 and deemed healthy, was recaptured in 2018 with a 1 × 1.5 cm intra-oral broad-based right mandibular mass. An excisional biopsy was performed, and histopathology revealed squamous cell carcinoma (SCC). Consensus herpesvirus PCR identified a novel herpesvirus (proposed name Emydoidea herpesvirus 2 [EBHV-2]) within the tumor. EBHV-2 shares 85% sequence homology with Terrapene herpesvirus 2 (TerHV-2), a herpesvirus linked to fibropapillomas in eastern box turtles (Terrapene carolina carolina). Virus-associated fibropapillomas have been identified in multiple marine turtle species and have had debilitating effects on their populations, but to date, virus-associated SCCs are rarely reported.     

Mercury in fish in Swedish lakes — Linkages to domestic and European sources of emission

The work deals primarily with data from 894 Swedish lakes. The following parameters are discussed: Hg- and Se-concentrations and Hg-quantity in the mor layer reflecting the atmospheric deposition of Hg and Se-, Hg- and S-emissions deposition from Swedish and continental sources, precipitation, Hg in pike, lake area, lake mean depth, pH, color, alkalinity, hardness, S and chloride in lake water. The results are focused on geographical variations and statistical correlations for the Hg-content in 1-kg pike (=FHg), and on computer simulations to get insights and data on the linkages between various historical Hg-emissions and FHg. Selected results: Increased FHg-values may be attributed to atmospheric emissions of Hg and to acid rain. Southern Sweden is significantly influenced by continental Hg-emissions. East Germany, Great Britain, West Germany and Poland seem to have contributed with the largest foreign Hg-amounts in the Swedish mor layer and, at the end, to increased Hg-concentrations in Swedish fish. We have calculated that there are about 10 300 Swedish lakes with FHg > 1 mg Hg kg^?1 (= the Swedish blacklisting limit). What would happen with FHg if atmospheric depositions of Hg and S were significantly reduced? Reductions of S would be beneficial primarily for lakes in S. Sweden. About 50% of the elevated levels of Hg in Swedish pike in the 1980s may be linked to Swedish Hg-emissions during the last 100 yr, about 10 to 15% could be attributed to foreign Hg-emissions and 35 to 40% to acid rain. There is a long lag phase between emission reduction and reduction of FHg. The known, major Swedish emissions of Hg have already been significantly reduced, but new point sources of Hg have appeared. There has been a significant change in the character of the Hg-emissions during the last decades. High FHg-values in fish in Swedish lakes will be a major environmental problem for decades to come.     

Application of Relaxed Eddy Accumulation Technique to Quantify Hg0 Fluxes Over Modified Soil Surfaces

Fluxes of mercury from a waste repository and from an agricultural field amended with sewage sludge were measured. The measurements were performed by utilising a Relaxed Eddy Accumulation (REA) system synchronously coupled to automated mercury cold vapour atomic fluorescence analysers (CVAFA). The waste repository was severely contaminated and fluxes of between 0.16μg m^?2 h^?1 and 29μg m^?2 h^?1 could be measured. Fluxes at the slightly contaminated agricultural field measured between 8 ng m^?2 h^?1 and 1.9μg m^?2 h^?1. The results showed that the REA-CVAFA system could be used for measurements above both severely-and slightly contaminated soils. The measurements at the chlor-alkali plant showed that temperature was the most important parameter controlling the release of mercury at this site. At the agricultural field, the measurements indicated that both solar radiation and temperature may have influenced the emissions. Most of the mercury added to the field was lost to the atmosphere during the summer season.     

Simultaneous determination of furanocoumarins in infusions and decoctions from "Carapiá" (dorstenia species) by high-performance liquid chromatography

The use of furanocoumarins, which are photosensitizing compounds, combined with exposure to UV-A radiation is a common treatment for vitiligo, psoriasis, and a number of other skin diseases. Although furanocoumarins plus UV-A treatment is highly effective, several studies have shown that exposure to high doses increases the risk to development of cutaneus carcinoma. Several Dorstenia species are used in folk medicine, mainly against skin diseases, because of the presence of biologically active compounds. We present here analysis of the chemical composition of furanocoumarins from infusion and decoction of "Carapiá" (Dorstenia species), which is used in Brazil against several diseases. We have employed high-performance liquid chromatography (HPLC) procedures for the quantitative determination of psoralen, bergapten, and isopimpinellin. The contents of furanocoumarins revealed an insignificant difference between infusion and decoction. Dorstenia tubicina and D. asaroides contained psoralen and bergapten only in the rhizomes, whereas D. vitifolia shows solely isopimpinellin in both rhizomes and aerial parts.