Forearc carbon sink reduces long-term volatile recycling into the mantle.

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

The low power effect on holmium laser enucleation of prostate (HoLEP); A comparison between 20W and 37,5W energy regarding apical enucleation efficacy and patient safety.

INTRODUCTION: The Holmium laser has proven to be an invaluable tool for endoscopic prostate enucleation. The proper energy selection, during the different steps of the procedure, has always been a matter of debate. In this work we compare the effectiveness of the Holmium laser, using two different low-power energy settings, during enucleation and hemostasis (20W and 37.5W). METHODS: One hundred and sixty patients underwent a HoLEP procedure with a 50Hz and 2J (100W) setting. During enuleation and hemostasis, two different low-power settings were applied (20W vs. 37.5W). In both groups, only the prostatic tissue in the bladder neck and enucleated tissue far away from the apex, were cut with a setting of 50Hz and 2J (100W). RESULTS: The mean enucleation efficiency (0.78 vs. 1.2g/min-p:001) was significantly higher by utilizing 37.5W energy (group 2). Additionally, the mean enucleation rate (0.64 vs. 0.88%-P:0.001) and laser efficiency (2.07 vs. 2.12 joule/g-P:0.003) were significantly higher in group 2. The enucleation time was significantly shorter (54 vs. 75.5 mins-P:0.002), while the mean catheter removal time (27 vs. 42 hrs-P:0.008) and Hb decrease (0.5 vs. 0.6g/dl--P:0.019) were significantly lower in group 2. CONCLUSIONS: HoLEP can be performed efficiently with 100 W-37.5W settings. Enucleation and hemostasis can be performed successfully with 37.5W, while the use of 100W during bladder neck dissection shortens the duration of the procedure. LEVEL OF EVIDENCE: 3.