Expedition to the volcanoes of the Arctic seafloor : the AMORE Expedition headed for the so-called “Gakkel Ridge” where, on the floor of the Arctic Ocean, there is hot work afoot – for this ocean ridge is composed of active volcanoes

Beginning: When Jules Verne made his imaginary journey of exploration to the centre of the earth through the vents in an Icelandic volcano over a hundred years ago, he assumed that all volcanoes are interlinked in a subterranean system. But even his imagination failed to visualise the world-wide system of submarine volcanoes that extends over a distance of over 60,000 kilometres and only breaks the surface of the ocean at Iceland. This mid-oceanic ridge, which spans the entire world ocean, has evolved along the boundaries between the tectonic plates of the Earth’s crust. Gakkel Ridge, in the central eastern Arctic Ocean is the northern most spur of the plate boundary between Eurasia and North America, and at the same time the most slowly opening ridge segment in the world, opening only a few millimetres each year

Auswirkungen zweijähriger Düngung mit NAWARO-Biogasgülle auf chemische und physikalische Bodeneigenschaften

Using biomass from intercrops as feedstock for biogas production makes it possible to produce renewable energy without compromising food production. In order that using intercrops for biogas and fertilizing with liquid digestate is sustainable, it must be secured that this practice does not have adverse effects on soil fertility. Two-year randomised field experiments were conducted on two different soil types near Bruck/Leitha (A). On chernozem soil, soil pH and composition of the cation exchange complex were hardly influenced by liquid digestate. Also on a parachernozem with pH 5.9 short-term effects of liquid digestate were small due to the low salt content and high C/N ratio of the digestate. Nevertheless the distinct increase in soil K content shows that if fertilization with liquid digestate is continued at rates clearly above K offtake by crops, K percentage on the exchange complex will exceed the critical value of 5% soon. Aggregate stability of the parachernozem was increased by the organic matter applied via digestate. Aggregate stability and infiltration rate of the chernozem were not affected. For a long-term sustainable use of intercrops for biogas and recycling of liquid digestate as a fertilizer, it is necessary that the rate of digestate fertilization corresponds to the amount of intercrop biomass harvested, and that digestate fertilization is adjusted to the potassium requirements and potassium uptake of the crops

Carbon storage in soil size-density fractions after 20 years of compost fertilization

Fractionation by particle size provides a rough differentiation between young active, and older intermediate and passive soil organic matter. Soil samples from three treatments of a 20 years` fertilization experiment, C2 which had been fertilized with 10 t ha-1 (wet wt.) compost per year on average, N2 with mineral N fertilizer at 32 kg N ha-1 year-1, and the unfertilized control (O) were subjected to particle size fractionation and to density fractionation. After low-energy sonication the samples were separated into the size fractions coarse sand (200-200 µm), fine sand (200-63 µm) silt (63-2 µm) and clay (2-0,1 µm). Density fractionation using Na-polytungstate with 1.8 g cm-3 density was applied to separate particulate organic matter (POM) from the sand-sized fraction. Compost fertilization resulted in an increase in Corg in all size and density fractions. In total, the Corg content was 10 % higher with compost fertilization than in the unfertilized control. Approximately 40 % of the additional soil carbon was located in the POM, 56 % in the silt-sized fraction and 3 % in the clay-sized fraction. With mineral N fertilization the sum of Corg contents of all fractions was about the same as without fertilization, with an increase of POM-Corg and a decrease of Corg in the silt and clay-sized fraction.Keywords: fractionation, particulate organic matter, POM, soil organic matte

Functional analysis and identification of cis-regulatory elements of human chromosome 21 gene promoters

Given the inherent limitations of in silico studies relying solely on DNA sequence analysis, the functional characterization of mammalian promoters and associated cis-regulatory elements requires experimental support, which demands cloning and analysis of putative promoter regions. Focusing on human chromosome 21, we cloned 182 gene promoters of 2500 bp in length and conducted reporter gene assays on transfected-cell arrays. We found 56 promoters that were active in HEK293 cells, while another 49 promoters could be activated by treatment of cells with Trichostatin A or depletion of serum. We observed high correlations between promoter activities and endogenous transcript levels, RNA polymerase II occupancy, CpG islands and core promoter elements. Truncation of a subset of 62 promoters to ∼500 bp revealed that truncation rarely resulted in loss of activity, but rather in loss of responses to external stimuli, suggesting the presence of cis-regulatory response elements within distal promoter regions. In these regions, we found a strong enrichment of transcription factor binding sites that could potentially activate gene expression in the presence of stimuli. This study illustrates the modular functional architecture of chromosome 21 promoters and helps to reveal the complex mechanisms governing transcriptional regulatio

Functional analysis and identification of cis-regulatory elements of human chromosome 21 gene promoters

Given the inherent limitations of in silico studies relying solely on DNA sequence analysis, the functional characterization of mammalian promoters and associated cis-regulatory elements requires experimental support, which demands cloning and analysis of putative promoter regions. Focusing on human chromosome 21, we cloned 182 gene promoters of 2500 bp in length and conducted reporter gene assays on transfected-cell arrays. We found 56 promoters that were active in HEK293 cells, while another 49 promoters could be activated by treatment of cells with Trichostatin A or depletion of serum. We observed high correlations between promoter activities and endogenous transcript levels, RNA polymerase II occupancy, CpG islands and core promoter elements. Truncation of a subset of 62 promoters to ∼500 bp revealed that truncation rarely resulted in loss of activity, but rather in loss of responses to external stimuli, suggesting the presence of cis-regulatory response elements within distal promoter regions. In these regions, we found a strong enrichment of transcription factor binding sites that could potentially activate gene expression in the presence of stimuli. This study illustrates the modular functional architecture of chromosome 21 promoters and helps to reveal the complex mechanisms governing transcriptional regulation