What is NanoGeoBio?
NanoGeoBio represents a wide range of natural scenarios where minerals (Geo) and microorganisms (Bio) meet to leave behind nanoscale products or result in microscopic, precisely-controlled processes. Examining these products and processes provides us an alternative and insightful way to understand biogeochemical cycles as well as the co-evolution of the geosphere and the biosphere. The major goal of the NanoGeoBio Laboratory is to leverage the characterization of the smallest components and the illumination of the microscopic processes in various Earth (sub)surface settings to obtain a bigger picture regarding the biogeochemical cycling of elements and relevant implications.
Paper of the Month
Proposed mechanisms of Mo removal along with associated isotopic fractionations in a continental margin setting with euxinic bottom waters and sediment pore water.
The observed difference in molybdenum (Mo) mobility and isotopic fractionation under oxic versus euxinic (i.e., anoxic and sulfidic) aqueous conditions provides a sound operational basis for the use of Mo geochemical signatures in ancient sedimentary records to infer palaeoceanographic redox conditions. While Mo is known to exist predominantly as molybdate (MoO42-) in oxic waters and convert into thiomolybdate species (MoOxS4-x2-) under euxinic conditions, the pathways that lead to Mo sequestration are highly debated. As mechanistic understanding of Mo sequestration is crucial for accurately reconstructing the chemistry of ancient oceans and constraining the timing and intensity of oxygenation events through Earth’s history using Mo paleoproxies, we have closely examined the current proposed mechanisms for Mo sequestration across a wide range of euxinic conditions. Through compilation and comparison of such information, we aim to provide an integrated view of Mo sequestration processes, to identify the current controversies as well as the roots of such controversies, and importantly, to propose avenues for future research.