Preprints
Filtering by Subject: Biogeochemistry
Functional organic matter components in mangrove soils revealed by density fractionation
Published: 2023-07-04
Subjects: Biogeochemistry, Geochemistry, Soil Science
The mechanisms underlying stabilization of soil organic matter (SOM) in coastal ecosystems, including mangrove forests, are poorly understood, limiting our ability to predict the consequences of disturbances. Here, we introduce density fractionation to mangrove soils to identify the distribution and properties of the functional components of SOM with regard to degradation state, stability, and [...]
Global 1km Land Surface Parameters for Kilometer-Scale Earth System Modeling
Published: 2023-06-28
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Earth Sciences, Hydrology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology
Earth system models (ESMs) are progressively advancing towards the kilometer scale (k-scale). However, the surface parameters for Land Surface Models (LSMs) within ESMs running at the k-scale are typically derived from coarse resolution and outdated datasets. This study aims to develop a new set of global land surface parameters with a resolution of 1 km for multiple years from 2001 to 2020, [...]
Innovating and networking global geochemical data resources through OneGeochemistry
Published: 2023-06-14
Subjects: Biogeochemistry, Cosmochemistry, Databases and Information Systems, Geochemistry, Geology, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Volcanology
A vision of the not-to-distant future: Imagine yourself as a researcher who is making plans for fieldwork in the Andes Mountains. You are behind your computer and load a three-dimensional visualisation of the Earth and its geology to investigate the research already done in the southern Patagonian regions. You zoom in to the mountain range of interest and select various data layers to show [...]
Assessment of Oceanographic Conditions during the North Atlantic EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) Field Campaign
Published: 2023-06-07
Subjects: Biogeochemistry, Oceanography and Atmospheric Sciences and Meteorology
This manuscript presents an overview of NASA’s EXport Processes in the Ocean from Remote Sensing 2021 Field Campaign in the North Atlantic (EXPORTS NA) and provides quantitative and dynamical descriptions of the physical processes modulating water transformations during the study. A major programmatic goal was to conduct the sampling in a Lagrangian mode so that ocean ecological and [...]
Impacts of Carbonate Buffering on Atmospheric Equilibration of CO2, δ13CDIC, and Δ14CDIC in Rivers and Streams
Published: 2023-05-28
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Hydrology
Rivers and streams play an important role within the global carbon cycle, in part through emissions of CO2 to the atmosphere. However, the sources of this CO2 and their spatiotemporal variability are difficult to constrain. Recent work has highlighted the role of carbonate buffering reactions that may serve as a source of CO2 in high alkalinity systems. In this study, we seek to develop a [...]
Oxidoreductases and metal cofactors in the functioning of Earth
Published: 2023-05-15
Subjects: Biochemistry, Biophysics, and Structural Biology, Biogeochemistry, Biology, Microbiology
Life sustains itself using energy generated by thermodynamic disequilibria, commonly existing as redox disequilibria. Metals are significant players in controlling redox reactions, as they are essential components of the engine that life uses to tap into the thermodynamic disequilibria necessary for metabolism. The number of proteins that evolved to catalyze redox reactions is extraordinary, as [...]
Environmental controls on the brGDGT and brGMGT distributions across the Seine River basin (NW France): Implications for bacterial tetraethers as a proxy for riverine runoff
Published: 2023-05-08
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial lipids that have been largely used as environmental proxies in continental paleorecords. Another group of related lipids, branched glycerol monoalkyl glycerol tetraethers (brGMGTs), has recently been proposed as a potential paleotemperature proxy. Nevertheless, the sources and environmental dependencies of both brGDGTs and [...]
Bioavailable Sr and Pb isotope ratios of archaeological cattle bone from coastal India
Published: 2023-04-29
Subjects: Biogeochemistry, Geochemistry
We present the first measurement of bioavailable strontium (87Sr/86Sr) and lead (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) isotope ratios from five cattle bones and one soil sample from Erenda, a chalcolithic site in coastal east India. Bioavailable 87Sr/86Sr of bones differ from that of the soil. A similar Pb isotope ratio of bones to the soil indicates an insignificant diagenesis and local [...]
Radiocarbon analysis of soil microbial biomass via direct chloroform extraction
Published: 2023-04-15
Subjects: Biogeochemistry
Microbial processing of soil organic matter is a significant driver of C cycling, yet we lack an understanding of what shapes the turnover of this large terrestrial pool. In part, this is due to limited options for accurately identifying the source of C assimilated by microbial communities. Laboratory incubations are the most common method for this; however, they can introduce artifacts due to [...]
Extrapolation based regionalized re-evaluation of the global estuarine surface area
Published: 2023-02-24
Subjects: Biogeochemistry, Earth Sciences, Geomorphology, Hydrology
At the interface between the continental and oceanic domains, estuaries are essential components of the land-ocean aquatic continuum that play a significant role in biogeochemical cycles, as they transform and export large amounts of carbon and nutrients from rivers to coastal waters. Because of this intense biogeochemical processing, they are significant ecosystems in terms of greenhouse gas [...]
Deforestation as an anthropogenic driver of mercury pollution
Published: 2023-01-25
Subjects: Atmospheric Sciences, Biogeochemistry, Earth Sciences, Environmental Sciences
Deforestation reduces the capacity of the terrestrial biosphere to take up the toxic pollutant mercury (Hg) and enhances the release of secondary Hg from soils. The consequences of deforestation for Hg cycling are not currently considered by anthropogenic emissions inventories or specifically addressed under the global Minamata Convention on Mercury. Using global Hg modeling constrained by field [...]
Are marl-limestone alternations mainly driven by CaCO3 variations at the astronomical timescale? New insights from extraterrestrial 3He
Published: 2023-01-07
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Sedimentology, Stratigraphy
Marl-limestone alternations are rhythmical inter-bedded deposits that commonly occur in many sedimentological environments. It is quite well established that these lithological variations originate from astronomically-driven climatic variations paced by the Milankovitch cycles of main periods 19, 23, 41, 100 and 405 ka. However, the sedimentological mechanisms involved are not clear: some models [...]
Tracing timing of growth in cultured mollusks using strontium spiking
Published: 2022-12-23
Subjects: Aquaculture and Fisheries Life Sciences, Biogeochemistry, Geochemistry, Paleontology
Growth experiments present a powerful tool for determining the effect of environmental parameters on growth and carbonate composition in biogenic calcifiers. For successful proxy calibration and biomineralization studies, it is vital to exactly identify volumes of carbonate precipitated at precise intervals during the experiment. Here, we investigate the use of strontium labelling in mollusk [...]
Oxidation Rates and Redox Stabilization of Ferrous Iron in Trioctahedral Smectites
Published: 2022-12-16
Subjects: Biogeochemistry, Geochemistry, Other Earth Sciences, Planetary Biogeochemistry, Planetary Geochemistry
Iron(II)-bearing trioctahedral smectites (saponites) form during anoxic alteration of basaltic rock. They are predicted to have been widespread on the early Earth and are observed in the oceanic subsurface today. Smectite structures, including the occupancy of sites in the octahedral sheet, affect iron redox behavior but the rates and products of trioctahedral smectite oxidation have been largely [...]
Geosphere and Biosphere coevolution: the role of trace metals availability in the evolution of biogeochemistry
Published: 2022-11-21
Subjects: Biochemistry, Biophysics, and Structural Biology, Biogeochemistry, Earth Sciences, Ecology and Evolutionary Biology, Microbiology, Planetary Sciences
Earth’s geosphere and biosphere have coevolved over time, influencing each other’s stability and keeping our planet habitable for most of its 4.543 billion years of history. Biogeochemical cycles play a key role in controlling this interaction, connecting long-term geological cycles and the much faster evolution of the Earth’s outer biologically dominated envelopes. A small set of [...]