title: High Molybdenum availability for evolution in a Mesoproterozoic lacustrine environment.
abstract: Trace metal data for Proterozoic marine euxinic sediments imply that the expansion of nitrogen-fixing cyanobacteria and diversification of eukaryotes were delayed while the availability of bioessential metals such as molybdenum in the ocean was limited. However, there is increasing recognition that the Mesoproterozoic evolution of nitrogen fixation and eukaryotic life may have been promoted in marginal marine and terrestrial environments, including lakes, rather than in the deep ocean. Molybdenum availability is critical to life in lakes, just as it is in the oceans. It is, therefore, important to assess molybdenum availability to the lacustrine environment in the Mesoproterozoic. Here we show that the flux of molybdenum to a Mesoproterozoic lake was 1 to 2 orders of magnitude greater than typical fluxes in the modern and ancient marine environment. Thus, there was no barrier to availability to prevent evolution in the terrestrial environment, in contrast to the nutrient-limited Mesoproterozoic oceans.
authors.affiliation: School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK.
authors.forename: John
authors.initials: J
authors.lastname: Parnell
authors.affiliation: School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK.
authors.forename: Samuel
authors.identifier: http://orcid.org/0000-0002-5794-6361
authors.initials: S
authors.lastname: Spinks
authors.affiliation: School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Andrews
authors.affiliation: School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK.
authors.forename: Wanethon
authors.initials: W
authors.lastname: Thayalan
authors.affiliation: School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bowden
mesh_terms: D001272:Atmosphere; D005075:Biological Evolution; D002244:Carbon / Q000737:chemistry; D000458:Cyanobacteria / Q000378:metabolism; D019015:Geologic Sediments; D060106:Lakes; D008982:Molybdenum / Q000737:chemistry*; D009586:Nitrogen Fixation; D009792:Oceans and Seas; D010100:Oxygen / Q000737:chemistry; D012606:Scotland; D012623:Seawater; D013455:Sulfur / Q000737:chemistry
chemical_list: D013455:Sulfur; D002244:Carbon; D008982:Molybdenum; D010100:Oxygen