Preprints
Filtering by Subject: Biogeochemistry
Effective Microbial Kinetics under Pore-Scale Transport Limitation: A Biofilm Effectiveness-Factor Theory
Published: 2026-07-27
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Reactive-transport models of porous media usually evaluate microbial reactions with Monod kinetics and rate constants measured on well-mixed laboratory cultures, in which every cell is exposed to the same substrate concentration. In natural sediments and aquifers this assumption fails at the pore scale, because the cells are not suspended but reside in biofilms and aggregates attached to the [...]
Connectivity effects on fluid age and residence time distributions in two- and three-dimensional pore networks
Published: 2026-07-27
Subjects: Biogeochemistry, Earth Sciences, Hydrology, Physical Sciences and Mathematics
Pore-scale simulations are often run on a single plane cut from a three-dimensional image, because resolving the whole pore space is expensive. This study asks what that shortcut costs. What is at stake is the distribution of fluid ages, and above all its long tail, because that tail is what slow reactions respond to. We computed the distribution directly from the flow field, by labeling the [...]
Reconstructing age and reactivity distributions from the moments carried by central-moment transport models
Published: 2026-07-26
Subjects: Biogeochemistry, Earth Sciences, Hydrology, Physical Sciences and Mathematics
A central-moment transport model follows a property that varies across a population, such as the age of water parcels or the decay rate of organic-matter particles. Instead of storing the whole distribution of that property, it keeps only a few summary numbers, the moments, and moves those through the model. But the distribution itself is usually what a scientist wants, so it has to be rebuilt [...]
Soil acidity governs cropland phosphorus availability under future climate
Published: 2026-07-21
Subjects: Agriculture, Biogeochemistry, Soil Science
Understanding the response of agricultural phosphorus (P) cycling to climate change is fundamental for ensuring global food security and protecting planetary boundaries1–2. Recently, Wang et al.3 reported a drastic reduction in soil P bioavailability (32–34%) under long-term elevated carbon dioxide (eCO2) and warming in rice paddies, attributing it to enhanced geochemical sequestration via [...]
Glycerolipids track sinking particle sources and remineralization in two ocean basins
Published: 2026-07-15
Subjects: Biogeochemistry, Geochemistry, Oceanography
The biological carbon pump is a major control on ocean carbon storage. On long time scales, changes in the biological carbon pump modulate atmospheric CO2 concentrations and climate. Attenuation in sinking carbon fluxes is derived from a combination of remineralization by bacteria, zooplankton, and fragmentation. However, the importance of these attenuation processes varies spatially and [...]
The Rise of Diamond Open Access Journals in Earth Sciences: Past Developments, Present Tensions, and Future Pathways
Published: 2026-07-08
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Library and Information Science, Paleontology, Planetary Sciences, Sedimentology, Tectonics and Structure, Volcanology
Over roughly the last decade, a visible, community-led Diamond Open Access (OA) ecosystem has emerged in the Earth sciences, not as a departure from tradition, but as the latest expression of a long-standing culture of open, society-supported scholarly communication. While free-to-read, fee-free publishing initiatives have deep roots in the field, predating the Diamond terminology by decades and [...]
From linguistic evaluation to mechanistic verification: testing LLM-generated farm recommendations
Published: 2026-07-03
Subjects: Agricultural Science, Agriculture, Agronomy and Crop Sciences Life Sciences, Biochemistry, Biophysics, and Structural Biology, Biogeochemistry, Environmental Indicators and Impact Assessment, Research Methods in Life Sciences, Soil Science, Sustainability
Large language models (LLM) are increasingly used to generate farm-management advice, but their biophysical consequences remain largely unverified. We introduce a process-based verification framework that combines management portfolios generated by ChatGPT and Claude with the process-based model LandscapeDNDC across 11 contrasting agroecosystems. The LLMs produced agronomically plausible [...]
Spectrally structured CNN encoding for interpretable and edge-ready fractional vegetation cover mapping using UAS multispectral and imaging spectroscopy
Published: 2026-06-30
Subjects: Artificial Intelligence and Robotics, Biogeochemistry, Computer Sciences, Earth Sciences, Engineering, Environmental Monitoring, Environmental Sciences, Natural Resources and Conservation, Physical Sciences and Mathematics, Remote Sensing
Fractional vegetation cover (FVC) is a key indicator of semi-arid ecosystem condition, but non-photosynthetic vegetation (NPV) remains difficult to map because dry or senescent vegetation, litter, woody debris, and standing dead material can overlap spectrally with photosynthetic vegetation (PV) and bare ground (BE), especially where shadows, exposed bare earth surfaces, and mixed vegetation-soil [...]
Tectonic pump closes the evolutionary loop for long-buried subseafloor microbes
Published: 2026-06-22
Subjects: Biogeochemistry, Geophysics and Seismology, Hydrology, Tectonics and Structure
Deep marine sediments host one of Earth’s largest microbial biospheres, yet most cells in this environment persist in a non-growing state for thousands to millions of years beneath kilometers of sediment. For natural selection to favor such extraordinary long-term survival, a mechanism must exist that is capable of returning buried living populations to near-surface environments, where [...]
Spatial autocorrelation inflates the global leaf-wax d2H-precipitation slope
Published: 2026-06-19
Subjects: Biogeochemistry, Earth Sciences, Geochemistry
Leaf wax hydrogen isotope ratios (δ²Hwax) are used to make inferences about past hydroclimate, but global calibrations between δ²Hwax and precipitation isotopes (δ²Hprecip) ignore spatial autocorrelation and inflate apparent relationships. This study compiled 1,129 surface sediment and soil measurements of δ²Hwax from n-C29 alkanes and developed hierarchical Bayesian spatial models to separate [...]
Reactive soil inputs during high-flow events decouple carbon chemistry and CO2 evasion in a granitic headwater stream
Published: 2026-06-11
Subjects: Biogeochemistry, Hydrology
Quantifying CO2 dynamics in low-alkalinity headwater streams is challenging because thermodynamically based evaluations of pCO2 and CO2 fluxes (FCO2) assume coherent DIC-alkalinity-pH coupling. This study examines how hydrologically driven disturbances violate this assumption in a forested, granitic headwater stream using 15 months of calculated pCO2 and FCO2, alongside measurements of pH, [...]
Subsurface advective flow unveils the architecture of Earth’s crustal biosphere
Published: 2026-06-09
Subjects: Biogeochemistry, Environmental Microbiology and Microbial Ecology Life Sciences, Geology, Microbiology, Other Earth Sciences, Other Environmental Sciences
The subsurface biosphere is one of Earth’s largest microbial reservoirs, yet its spatial extent remains poorly constrained due to limited direct access. Here we propose using the integrated environmental readouts encoded in deep subsurface fluids to shift from simply mapping where life can be detected to constraining where life can exist. Deeply-sourced advective fluids provide an integrated [...]
Mineral stabilization of soil organic sulfur at the continental scale
Published: 2026-06-01
Subjects: Biogeochemistry, Life Sciences, Physical Sciences and Mathematics, Soil Science
Declining atmospheric sulfur (S) deposition makes S an emerging limiting macronutrient to plants, yet the stability and dynamics of soil organic S - the largest terrestrial S pool supplying plant-available sulfate via mineralization - remain unclear. Across North American soils, mineral-associated organic S (MAOS), a stabilized pool by mineral protection, dominates (61 ± 26% of the total soil S) [...]
ATMOSPHERIC DEPOSITION AND SOURCE APPORTIONMENT OF MERCURY AND LEAD OVER THE LAST 150 YEARS IN HIGHLAND PEATLANDS OF SOUTHEASTERN BRAZIL
Published: 2026-05-28
Subjects: Biogeochemistry, Geochemistry
Trace elements like mercury (Hg) and lead (Pb) are major global pollutants subject to long-range atmospheric transport, posing a threat for human and environmental health at a global scale. Both have a great affinity with organic matter and show limited mobility in soils under stable environmental conditions. Therefore, peatlands efficiently trap and act as reliable archives of changes in [...]
Marine Heatwaves Disrupt Phytoplankton Communities Through Trait-dependent Selection
Published: 2026-05-24
Subjects: Biodiversity, Biogeochemistry, Climate, Marine Biology
Phytoplankton communities, key regulators of marine ecosystems and the global carbon cycle, are susceptible to sea surface temperature variability, such as marine heatwaves (MHWs). However, their trait-dependent responses and the resulting compositional shifts during MHWs remain poorly understood. Here, using an advanced global ocean–biogeochemical model that resolves 310 phytoplankton trait [...]