Preprints
Filtering by Subject: Biogeochemistry
Fluctuation Analysis of Redox Potential to Distinguish Microbial Fe(II) Oxidation
Published: 2017-10-30
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
We developed a novel method for distinguishing abiotic and biological iron oxidation in liquid media using oxidation-reduction (redox) potential time series data. The instrument and processing algorithm were tested by immersing the tip of a Pt electrode with an Ag-AgCl reference electrode, into an active iron-oxidizing biofilm in a groundwater discharge zone, as well as in two abiotic systems: a [...]
Bacterial Fe(II)-oxidation Distinguished by Long-Range Correlation in Redox Potential
Published: 2017-10-30
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
The kinetics of bacterial Fe(II) oxidation was investigated 297m underground at the Äspö Hard Rock Laboratory (near Oskarshamn, Sweden) under steady state groundwater flow conditions in a flow-through cell containing well-developed flocculent mats of bacteriogenic iron oxides (BIOS). Pseudo first-order rate constants of 0.004 min^-1 and 0.009 min^-1 were obtained for chemical and bacterial [...]
The role of microbes in snowmelt and radiative forcing on an Alaskan icefield
Published: 2017-10-26
Subjects: Biogeochemistry, Earth Sciences, Glaciology, Physical Sciences and Mathematics
A lack of liquid water limits life on glaciers worldwide but specialized microbes still colonize these environments. These microbes reduce surface albedo, which, in turn, could lead to warming and enhanced glacier melt. Here we present results from a replicated, controlled field experiment to quantify the impact of microbes on snowmelt in red-snow communities. Addition of [...]
Modelling silicon supply during the Last Interglacial (MIS 5e) at Lake Baikal
Published: 2017-10-24
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Life Sciences, Physical Sciences and Mathematics
Throughout the Quaternary, lake productivity has been shown to be sensitive to drivers such as climate change, landscape evolution and lake ontogeny. In particular, sediments from Lake Baikal, Siberia, provide a valuable uninterrupted and continuous sequence of palaeoproductivity, which document orbital and sub-orbital frequencies of regional climate change. Here we augment these records through [...]