Gas emissions and crustal deformation from the Krýsuvík high temperature geothermal system, Iceland

The Krýsuvík volcanic system is located on the oblique spreading Reykjanes Peninsula, SW Iceland. Since early 2009 the region has been undergoing episodes of localized ground uplift and subsidence. From April–November 2013, we operated near-real time monitoring of gas emissions in Krýsuvík, using a Multi-component Gas Analyzer System (Multi-GAS), collecting data on gas composition from a fumarole (H₂O, CO₂, SO₂, H₂S). The dataset in this study, comprises a near-continuous gas composition time series, the quantification of diffuse CO₂ gas flux, analytical results for direct samples of dry gas, seismic records, and GPS data. Gas emissions from the Krýsuvík geothermal system were examined and compared with crustal deformation and seismicity. The gas emissions from the Krýsuvík system are H₂O-dominated, with CO₂ as the most abundant dry gas species, followed by smaller concentrations of H₂S. The average subsurface equilibrium temperature was calculated as 278 °C. This is consistent with previous observations made through sporadic spot sampling campaigns. In addition, the semi-continuous Multi-GAS dataset reveals higher variations in gas composition than previously reported by spot sampling. The diffuse soil CO₂ flux is found to be variable between the three studied degassing areas in Krýsuvík, ranging from 10.9–70.9 T/day, with the highest flux in Hveradalir where the Multi-GAS station is located. The total flux is estimated as 101 T/day. Comparison between Multi-GAS and geophysical data shows that peaks of H₂O-rich emissions appears to follow crustal movements. Coinciding with the H₂O-rich peaks, SO₂ is detected in minor amounts (~0.6 ppmv), allowing for calculations of H₂O/SO₂, CO₂/SO₂ and H₂S/SO₂ ratios. This is the first time SO₂ has been detected in the Krýsuvík area. The large variations in H₂O/CO₂ and H₂O/H₂S ratios are considered to reflect variable degassing activity in the fumarole. The activity of the fumarole appears less intense during intervals of low or no recorded seismic events. The H2₂O/CO₂ and H₂O/H₂S ratios are lower, presumably due to H₂O condensation affecting the steam jet before reaching the Multi-GAS inlet tube

Autoantibodies in relatives of celiac disease patients: a follow-up of 6-10 years

CONTEXT: Autoimmune diseases are 3 to 10 times more frequently in patients with celiac disease and their relatives than in the general population. OBJECTIVE: To investigate a broad spectrum of autoantibodies in celiac disease relatives from Southern Brazil, in a serological follow-up of 6-10 years, aiming to associate with other autoimmune diseases, degree of parentage, demographic and clinical data. METHODS: Serum samples of 233 relatives were analyzed in two different phases: n = 186 in phase I (1997-2000) and n = 138 (being 91 = follow-up group and 47 = newly tested) in phase II (2006-2007). As controls, 100 unrelated individuals were evaluated. Autoantibodies to smooth muscle, mitochondrial, liver-kidney microssome, parietal cell and thyroid microssome were tested by indirect immunofluorescence. RESULTS: A significant increase of autoantibodies, in both phases, was observed in the relatives when compared to the non-relatives (P = 0.0064), specifically to anti-thyroid microssome and anti-parietal cell. In both phases, the female/male proportion of autoantibodies was of 4:1 to 3:1 (P<0.041). The frequency of autoantibodies amongst 1st and 2nd degree relatives was 11.8% and 9.68% in phase I and 4% and 6.67% in phase II. CONCLUSION: Celiac disease relatives presented other autoantibodies and serological screening is a useful instrument for identifying autoimmune diseases along the years