Seal bypass at the Giant Gjallar Vent (Norwegian Sea): indications for a new phase of fluid venting at a 56-Ma-old fluid migration system

Highlights: • The Giant Gjallar Vent is still active in terms of fluid migration and faulting. • The Base Pleistocene Unconformity acts as a seal to upward fluid migration. • Seal bypass in at least one location leads to a new phase of fluid venting. The Giant Gjallar Vent (GGV), located in the Vøring Basin off mid-Norway, is one of the largest (~ 5 × 3 km) vent systems in the North Atlantic. The vent represents a reactivated former hydrothermal system that formed at about 56 Ma. It is fed by two pipes of 440 m and 480 m diameter that extend from the Lower Eocene section up to the Base Pleistocene Unconformity (BPU). Previous studies based on 3D seismic data differ in their interpretations of the present activity of the GGV, describing the system as buried and as reactivated in the Upper Pliocene. We present a new interpretation of the GGV’s reactivation, using high-resolution 2D seismic and Parasound data. Despite the absence of geochemical and hydroacoustic indications for fluid escape into the water column, the GGV appears to be active because of various seismic anomalies which we interpret to indicate the presence of free gas in the subsurface. The anomalies are confined to the Kai Formation beneath the BPU and the overlying Naust Formation, which are interpreted to act as a seal to upward fluid migration. The seal is breached by focused fluid migration at one location where an up to 100 m wide chimney-like anomaly extends from the BPU up to the seafloor. We propose that further overpressure build-up in response to sediment loading and continued gas ascent beneath the BPU will eventually lead to large-scale seal bypass, starting a new phase of venting at the GGV

Impact of Blueberry Consumption on the Human Fecal Bileacidome: A Pilot Study of Bile Acid Modulation by Freeze-Dried Blueberry

Cholesterol-derived bile acids (BAs) affect numerous physiological functions such as glucose homeostasis, lipid metabolism and absorption, intestinal inflammation and immunity, as well as intestinal microbiota diversity. Diet influences the composition of the BA pool. In the present study, we analyzed the impact of a dietary supplementation with a freeze-dried blueberry powder (BBP) on the fecal BA pool composition. The diet of 11 men and 13 women at risk of metabolic syndrome was supplemented with 50 g/day of BBP for 8 weeks, and feces were harvested before (pre) and after (post) BBP consumption. BAs were profiled using liquid chromatography coupled with tandem mass spectrometry. No significant changes in total BAs were detected when comparing pre- vs. post-BBP consumption samples. However, post-BBP consumption samples exhibited significant accumulations of glycine-conjugated BAs (p = 0.04), glycochenodeoxycholic (p = 0.01), and glycoursodeoxycholic (p = 0.01) acids, as well as a significant reduction (p = 0.03) in the secondary BA levels compared with pre-BBP feces. In conclusion, the fecal bileacidome is significantly altered after the consumption of BBP for 8 weeks. While additional studies are needed to fully understand the underlying mechanisms and physiological implications of these changes, our data suggest that the consumption of blueberries can modulate toxic BA elimination

Relationship between estimates of the number of <i>Phytophthora infestans</i> sporangia deposited on silicon-greased rotating-arm sampler rods based on the <i>P</i>. <i>infestans</i> real-time qPCR assay and estimates based on microscope counts.

<p>Relationship between estimates of the number of <i>Phytophthora infestans</i> sporangia deposited on silicon-greased rotating-arm sampler rods based on the <i>P</i>. <i>infestans</i> real-time qPCR assay and estimates based on microscope counts.</p

The number of lesions per leaf as a function of airborne sporangia concentration for four <i>Phytophthora infestans</i> clonal lineages.

<p>A two-parameter exponential rise to a maximum was fitted to the data. The clonal lineages tested in the study were US-8, US-11, US-23, and US-24.</p

Infection Efficiency of Four <i>Phytophthora infestans</i> Clonal Lineages and DNA-Based Quantification of Sporangia

<div><p>The presence and abundance of pathogen inoculum is with host resistance and environmental conditions a key factor in epidemic development. Therefore, several spore-sampling devices have been proposed to monitor pathogen inoculum above fields. However, to make spore sampling more reliable as a management tool and to facilitate its adoption, information on infection efficiency and molecular tools for estimating airborne sporangia concentration are needed. Experiments were thus undertaken in a growth chamber to study the infection efficiency of four clonal lineages of <i>P</i>. <i>infestans</i> (US-8, US-11, US-23, and US-24) by measuring the airborne sporangia concentration and resulting disease intensity. The relationship between the airborne sporangia concentration and the number of lesions per leaf was exponential. For the same concentration, the sporangia of US-23 caused significantly more lesions than the sporangia of the other clonal lineages did. Under optimal conditions, an airborne sporangia concentration of 10 sporangia m⁻³ for US-23 was sufficient to cause one lesion per leaf, whereas for the other clonal lineages, it took 15 to 25 sporangia m⁻³ to reach the same disease intensity. However, in terms of diseased leaf area, there was no difference between clonal lineages US-8, US-23 and US-24. Also, a sensitive quantitative real-time polymerase chain reaction (qPCR) tool was developed to quantify <i>P</i>. <i>infestans</i> airborne sporangia with detection sensitivity of one sporangium. The specificity of the qPCR assay was rigorously tested for airborne inoculum and was either similar to, or an improvement on, other published PCR assays. This assay allows rapid and reliable detection and quantification of <i>P</i>. <i>infestans</i> airborne sporangia and thereby, facilitates the implementation of spores-sampling network.</p></div

Relationship between the quantification cycle (Cq) value and the log concentration of <i>Phytophthora infestans</i> sporangia and between the Cq value and the log concentration of internal transcribed spacer 2 (ITS2) copies.

<p>Relationship between the quantification cycle (Cq) value and the log concentration of <i>Phytophthora infestans</i> sporangia and between the Cq value and the log concentration of internal transcribed spacer 2 (ITS2) copies.</p

Isolates/DNA of species used in this investigation and evaluation of species specificity of the TaqMan assay.

<p>1 Dr. Bud Platt Agriculture and Agri-Food, Prince Edward Island, Canada</p><p>2 Dr. Bill Fry, Cornell University, Ithaca, NYC, USA</p><p>4 Dr. Fouad Daayf, University of Manitoba, Winnipeg, Manitoba</p><p>5 Dr. Michael Coffey, University of California Riverside, Riverside, California, USA</p><p>6 Dr. Schmale, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA</p><p>Fluorescence is indicated as detected (+) or undetected (−) for <i>Phytophthora</i> species.</p

Primer and probe names and sequences for qPCR reactions.

<p>^a Zen double-quenched fluorescent-labelled probe 5′-6-Fam, 3′-IBHQ1.</p><p>^b Zen double-quenched fluorescent-labelled probe 5′-HEX, 3′-IBHQ1.</p><p>Primer and probe names and sequences for qPCR reactions.</p

Relationship between the percentage of leaf area diseased and <i>Phytophthora infestans</i> airborne sporangia concentration.

<p>A linear function was fitted to the data. The clonal lineages tested in the study were US-8, US-11, US-23, and US-24.</p