Hydrothermal and Cold Spring Water and Primary Productivity Effects on Magnesium Isotopes: Lake Myvatn, Iceland
| Autor: | Philip A. E. Pogge von Strandmann, Kevin W. Burton, Sophie Opfergelt, Eydís S. Eiríksdóttir, Melissa J. Murphy, Arni Einarsson, Sigurdur R. Gislason |
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| Přispěvatelé: | UCL - SST/ELI/ELIE - Environmental Sciences, Jarðvísindastofnun (HÍ), Institute of Earth Sciences (UI), Líf- og umhverfisvísindastofnun (HÍ), Institute of Life and Environmental Sciences (UI), Náttúrurannsóknastöðin við Mývatn (HÍ), Mývatn Research Station (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
hydrothermal spring
010504 meteorology & atmospheric sciences Weathering Geochemistry 010502 geochemistry & geophysics 01 natural sciences Hydrothermal circulation Sink (geography) Phytoplankton Ferskvatn D3/D5/D6) [weathering (IGC] groundwater (G.W.) lcsh:Science Groundwater Isotopes of magnesium 0105 earth and related environmental sciences Basalt geography geography.geographical_feature_category Veðrun carbonate chemistry 6. Clean water Jarðeðlisfræði es weathering (IGC: D3/D5/D6) 13. Climate action Isotope geochemistry isotope geochemistry phytoplankton General Earth and Planetary Sciences Environmental science Seawater lcsh:Q Jarðhitasvæði |
| Zdroj: | Frontiers in Earth Science, Vol. 8, p. article 109 (2020) Frontiers in Earth Science, Vol 8 (2020) Frontiers in Earth Science |
| ISSN: | 2296-6463 |
| Popis: | Publisher's version (útgefin grein) Lake Myvatn, Iceland, is one of the most biologically productive lakes in the northern hemisphere, despite seasonal ice cover. Hydrothermal and groundwater springs make up the dominant source to this lake, and we investigate their Mg isotope ratio to assess the effect of mid-ocean ridge hydrothermal springs, which are the primary modern sink of seawater magnesium. We also examine a time series in the only outflow from this lake, the Laxa River, to assess the effects of seasonal primary productivity on Mg isotopes. In the hydrothermal waters, there is a clear distinction between cold waters (largely unfractionated from primary basalt) and relatively hot waters, which exhibit over 1‰ fractionation, with consequences for the oceanic mass balance if the hydrothermal removal of Mg is not fully quantitative. The outflow Mg isotopes are similar to basalts (δ26Mg = −0.2 to −0.3) during winter but reach a peak of ∼0‰ in August. This fractionation corresponds to calcite precipitation during summer in Lake Myvatn, preferentially taking up light Mg isotopes and driving the residual waters isotopically heavy as observed, meaning that overall the lake is a CO2 sink. PP and the analyses were funded by NERC grant NE/I020571/2, and PP and MM are also supported by ERC Consolidator grant 682760 CONTROLPASTCO2. |
| Databáze: | OpenAIRE |
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