Active methanogenesis during the melting of Marinoan snowball Earth

Abstract

Geological evidence indicates that the deglaciation of Marinoan snowball Earth ice age (~635 Myr ago) was associated with intense continental weathering, recovery of primary productivity, transient marine euxinia, and potentially extensive CH4 emission. It is proposed that the deglacial CH4 emissions may have provided positive feedbacks for ice melting and global warming. However, the origin of CH4 remains unclear. Here we report Ni isotopes (δ60Ni) and Yttrium-rare earth element (YREE) compositions of syndepositional pyrites from the upper most Nantuo Formation (equivalent deposits of the Marinoan glaciation), South China. The Nantuo pyrite displays anti-correlations between Ni concentration and δ60Ni, and between Ni concentration and Sm/Yb ratio, suggesting mixing between Ni in seawater and Ni from methanogens. Our study indicates active methanogenesis during the termination of Marinoan snowball Earth. This suggests that methanogenesis was fueled by methyl sulfides produced in sulfidic seawater during the deglacial recovery of marine primary productivity.

Significance of the high-pressure properties and structural evolution of gas hydrates for inferring the interior of icy bodies

“…As such, MH is a relevant material for contemporary global environmental and energy resource issues. MH reportedly played a role in past environmental changes, such as the recovery from "snowball Earth" in the Neoproterozoic era (e.g., Zhao et al 2021), the warming that led to the mass extinction in the Permian-Triassic boundary (e.g., Burger et al 2019), and glacial-interglacial climate changes (e.g., Deng et al 2021). Based on experiments, theoretical calculations, and spacecraft measurements, MH has been predicted to exist widely in the solar system beyond the Earth (e.g., Mao et al 2007).…”

Sedimentary cycling of zinc and nickel and their isotopes on an upwelling margin: Implications for oceanic budgets and paleoenvironment proxies

“…As outlined in the introduction, sedimentary Zn and Ni isotope records may serve as tracers that enable reconstruction of past nutrient cycling and ocean chemistry (e.g., Liu et al, 2017;John et al, 2017;Sweere et al, 2018Sweere et al, , 2020S.-J. Wang et al, 2019;Yan et al, 2019;Chen et al, 2021;Li et al, 2021;Zhao et al, 2021). It is clear from this study, and that on the Peru margin of Ciscatio et al (2018), that records of authigenic Ni isotopes at upwelling margins have great potential for recording the d 60 Ni of contemporary seawater.…”

Early Earth microbial metallome: Insights from Cd, Ba, and Ni isotopes in stromatolites

“…Hydrogenase, superoxide dismutase, and methyl-coenzyme M reductase use Ni as catalytic metal. While the first two are linked to photosynthesis, the latter is essential in methanogenesis and associated with a significant kinetic Ni isotope fractionation 11,12 . Given the importance of Ni in biological methanogenesis, one might expect Ni isotopic fractionation to be associated with microbial communities that have evolved to incorporate Ni for these purposes.…”

“…The presence of manganese/iron-oxide coatings on microbial mats, along with negative CeSN anomalies and pronounced Cd isotope compositions in stromatolitic carbonates comparable to modern surface oceans, supports the idea of a slightly oxygenated Mesoarchean Pongola depositional environment, which was shaped by some of Earth's earliest oxygenic phototrophs. 39 , 12 23 , 13 20 , 14 52 ; C: Ni isotope compositions and associated isotope fractionation between marine precipitates and ambient fluid 15 12 , 16 11 , 17 16 .…”