Effects of fertilization on understorey vegetation in a Norwegian Pinus sylvestris forest

Abstract. Boreal coniferous forests have been impacted by long distance airborne pollutant deposition for most of the 20th century. Changes in forest understorey vegetation attributable to N‐deposition have been observed in southern Sweden, but not so far in southern Norway. We recorded the quantity of all species of vascular plants, bryophytes and lichens in 144 plots in a fertilization experiment in a 35‐yr old Pinus sylvestris forest in Aust Agder County, southernNorway initiated 6 yr before our study. Each plot represented a combination of three levels of nitrogen, two levels of magnesium and two levels of phosphorus addition. Effects of fertilization on species quantity were tested by Kruskal‐Wallis one‐way analysis by ranks. For vascular plants, only small and hardly significant differences were found between treatments and control. Significant negative effects of N‐fertilization were found on both mosses and lichens. To some extent, these effects could be attributed to direct effects of application of the fertilizer, but were more likely to be due to a negative feedback response to the faster growth of pine trees in fertilized stands, reducing throughfall precipitation and increasing litter fall. Significant differences between Mg‐ and P‐fertilized sites and respective controls were found for too few species to be likely to represent an overall trend.     

A comparison of performance of WP2 and MOCNESS

Zooplankton biomass in the Barents Sea was monitored during1988–97 using WP2 and MOCNESS plankton nets. These twosampling gears differ in their size and mode of operation. Theplankton samples were size fractionated into three categoriesand the dry weight per square metre was calculated. The smallestand the medium size fractions (< 2000 µm) representedmainly copepods, and the larger size fraction (> 2000 µm)consisted mainly of macrozooplankton such as krill and amphipods.WP2 biomass values were higher for the smallest size fraction,whereas the MOCNESS tended to give higher values for the largestsize fraction However, the total amount of zooplankton biomass(g m^–1) obtained by these two methods was not significantlydifferent.     

Glucuronoyl esterases: diversity,properties and biotechnological potential. A review

Glucuronoyl esterases (GEs) belonging to the carbohydrate esterase family 15 (CE15) are involved in microbial degradation of lignocellulosic plant materials. GEs are capable of degrading complex polymers of lignin and hemicellulose cleaving ester bonds between glucuronic acid residues in xylan and lignin alcohols. GEs promote separation of lignin, hemicellulose and cellulose which is crucial for efficient utilization of biomass as an energy source and feedstock for further processing into products or chemicals. Genes encoding GEs are found in both fungi and bacteria, but, so far, bacterial GEs are essentially unexplored, and despite being discovered >10?years ago, only a limited number of GEs have been characterized. The first laboratory scale example of improved xylose and glucuronic acid release by the synergistic action of GE with cellulolytic enzymes was only reported recently (improved C5 sugar and glucuronic acid yields) and, until now, not much is known about their biotechnology potential. In this review, we discuss the diversity, structure and properties of microbial GEs and consider the status of their action on natural substrates and in biological systems in relation to their future industrial use.     

Prevalence of skull pathologies in European harbor seals (<Emphasis Type="Italic">Phoca vitulina</Emphasis>) during 1981–2014

Harbor seals (Phoca vitulina) inhabit the seas surrounding Denmark and are an important top predator in the marine food chain. This trophic position exposes them to environmental contaminants with disease epidemics and hunting being additional threats to this population. It is therefore important to study how environmental pollution at the current order of magnitude affects the health of the population. Earlier studies have shown that occurrence of periodontitis could be linked to the amount of pollution the seals were subjected to. In order to investigate this further, 380 skulls and 141 mandibles of harbor seals (Phoca vitulina) from the Wadden Sea, the Limfjord, and Kattegat collected during the period 1970–2014 were examined. The skulls were examined for pathological lesions. The Hounsfield Units (HU) which are correlated to the bone mineral density (BMD) were measured in a subsample (n = 34) using CT scans. The macroscopic examination revealed (with the exception of the Swedish part of Kattegat) a significant increase of pathological lesions over the study period of 1981–2014. The examination of HU showed that median HU measured at multiple sites was highest in the healthy skulls compared to the skulls with one or more of the lesions. A discriminant analysis allowed high discriminatory capacity to separate healthy skulls from the skulls with pathologies, simply by the utilization of the HU data. Former studies of BMD in marine mammals have shown that exposure to environmental chemicals alter BMD and cause periodontitis. The present study, based on temporal and spatial trends in BMD, confirms the results of previous studies.