Preprints
Filtering by Subject: Biogeochemistry
Matters Arising: Critical Methodological Flaws in Qin et al. (2025) "Mangrove sediment carbon burial offset by methane emissions from mangrove tree stems"
Published: 2025-11-29
Subjects: Biogeochemistry, Earth Sciences
The authors report global mangrove stem CH₄ emissions of 730.60 Gg yr⁻¹, offsetting 16.9% of carbon burial. However, their analysis suffers from critical methodological flaws involving the failure to remove extreme statistical outliers, with 14.2% of chamber measurements and 15.5% of site observations identified as outliers by standard criteria. The analysis demonstrates inappropriate handling of [...]
Nernstian stability of the Eh–O2 relationship reveals redox structural shifts
Published: 2025-11-23
Subjects: Biogeochemistry
Oxidation-reduction potential (Eh) offers a compact descriptor of aquatic redox status, yet its interpretation is obscured by the many co-occurring electron-transfer reactions that determine it. We tested the hypothesis that the persistence of a linear, Nernstian relationship between Eh and ln[O2] reflects the robustness of the underlying redox structure. Using 18 months of depth profiles and [...]
Legacy of peatland erosion shapes microbial communities during recovery
Published: 2025-11-15
Subjects: Biogeochemistry, Environmental Microbiology and Microbial Ecology Life Sciences
Human degradation of peatlands worldwide has turned them into net carbon sources. In upland blanket peatlands, erosion disrupts new plant-derived carbon input and exposes deep peat, putting old carbon at risk of oxidation. The efficacy of restoration in preventing carbon loss and recovering ecosystem function depends on microbial responses to both water table manipulation and renewed litter [...]
Pressure-driven microbial and viral dynamics on individual sinking particles: implications for carbon cycling
Published: 2025-11-13
Subjects: Biogeochemistry, Marine Biology, Oceanography
The ocean’s biological carbon pump (BCP) regulates atmospheric CO2 by exporting organic carbon from the surface to the deep ocean. This process mainly depends on microbial communities associated with sinking particles which produce, degrade and transform organic matter. While many factors impact the efficiency of the BCP, here, we focus on particle heterogeneity and hydrostatic pressure, i.e. the [...]
Hidden in plain sight? Some challenges and needs for practical planetary biosignature exploration, both home and away-A Mini-Review.
Published: 2025-11-02
Subjects: Biogeochemistry, Other Earth Sciences, Other Planetary Sciences, Paleobiology, Planetary Biogeochemistry, Planetary Geochemistry
Identifying organic molecular biosignatures for life is challenging. Most current analytical methods were developed on Earth sediments rich in total organic carbon (TOC), and these methods struggle when dilute organic matter is situated within reactive, mineralogically complex astrobiological samples. Diverse geological alteration processes degrade biomarker signals, often concealing some [...]
Global Biosphere Productivity Response to Atlantic Meridional Overturning Circulation Collapse During Heinrich Stadial 4
Published: 2025-10-11
Subjects: Biogeochemistry, Climate
The slowdown of the Atlantic Meridional Overturning Circulation (AMOC) due to ongoing climate change raises concerns about its impact on the global carbon cycle. Understanding how global biosphere productivity may respond to such changes is essential for predicting the future carbon cycle, yet quantifying past global biosphere productivity remains challenging. We use triple isotope composition of [...]
Formation and fluxes of natural hydrogen in the crust and upper mantle
Published: 2025-10-10
Subjects: Biogeochemistry, Earth Sciences, Geochemistry
Molecular hydrogen (H2) is a fundamental component of planetary evolution and an important energy source for microbial life. It is now understood that natural mechanisms, spanning geological and biological processes, can produce high concentrations of hydrogen in natural fluids. Quantifying the processes that modulate natural hydrogen concentrations is necessary not only for conceptualising the [...]
Peatland Mid-Infrared Database 1.0.0
Published: 2025-10-06
Subjects: Biogeochemistry, Soil Science, Terrestrial and Aquatic Ecology
Systematic collections of peat mid-infrared spectra and other peat properties are scarce, but useful to understand peat chemistry and develop spectral prediction models. The Peatland Mid-Infrared Database ('pmird') stores 3877 mid-infrared spectra of peat, peat-forming vegetation, and dissolved organic matter, together with measurements of other peat properties that were collated from previous [...]
Low-cost autonomous chambers enable high spatial and temporal resolution monitoring of soil CO₂ exchange across landscapes
Published: 2025-08-16
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Environmental Engineering, Environmental Indicators and Impact Assessment, Meteorology, Natural Resources and Conservation, Soil Science, Sustainability, Terrestrial and Aquatic Ecology
1. Soil CO₂ flux is a critical component of ecosystem carbon cycling, but due to high cost and mechanistic constraints, existing measurement systems are often limited by trade-offs between resolution (temporal and spatial), and spatial coverage. These constraints hinder efforts to monitor soil fluxes across diverse, heterogeneous landscapes and environmental gradients. 2. We developed Fluxbot [...]
Dual and divergent formation pathways govern the composition and origins of mineral-associated organic carbon
Published: 2025-08-13
Subjects: Biogeochemistry, Terrestrial and Aquatic Ecology
Mineral-associated organic matter (MAOM) is the largest and most stable soil carbon reservoir, playing a central role in soil health and climate mitigation. Yet, quantitative understanding is lacking for the two fundamental processes forming MAOM— adsorption of dissolved organic matter and aggregation of insoluble organic particles—and how each pathway incorporates plant- versus microbial-derived [...]
The Global Woody Surface: A Planetary Interface for Biodiversity, Ecosystem Function, and Climate
Published: 2025-08-08
Subjects: Biogeochemistry, Ecology and Evolutionary Biology, Forest Sciences, Natural Resources and Conservation
Global woody surfaces span an area nearly equivalent to Earth’s terrestrial land surface and mediate CO2 fluxes three times larger than global fossil fuel emissions and methane uptake comparable to the global soil sink, yet remain absent from ecological research and Earth system models despite their critical roles in biodiversity and ecosystem services.
Simulated Soil Respiration is Sensitive to Soil Hydraulic Properties from Intact vs. Repacked Cores
Published: 2025-07-06
Subjects: Biogeochemistry, Hydrology, Soil Science
Soil hydraulic properties, such as water retention and hydrodynamics, play a pivotal role in regulating belowground carbon (C) storage by influencing microbial activity and nutrient availability. However, empirical measurements of these properties are labor-intensive and often fail to replicate field conditions in laboratory settings. Standardizing and increasing the throughput of hydraulic [...]
Continental-Scale Carbonate Sedimentation and Environmental Correlates of the Shuram-Wonoka Excursion
Published: 2025-07-01
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Paleontology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
Strata of the Ediacaran Period record many Earth-Life features that distinguish the Neoproterozoic-Phanerozoic transition. However, it is difficult to determine cause and effect relationships between Ediacaran events. Continental-scale patterns of sedimentation have been used as proxies to investigate controls on Phanerozoic macroevolution, including sea level drivers and potential carbon cycling [...]
Combined thermodynamic-kinetic-competitive controls on anaerobic respiration pathways and the chemistry of natural waters
Published: 2025-06-13
Subjects: Biogeochemistry, Earth Sciences
Microbial metabolisms underpin geochemical cycling in nearly all of the Earth's biosphere. Anaerobic pathways of carbon mineralization by iron and sulfate reduction and methanogenesis, in particular, have existed over most of Earth history and have been central in shaping the chemistry of the oceans and atmosphere. The governing principles by which microbial metabolisms contribute to water-column [...]
Phytoplankton variable stoichiometry modifies key biogeochemical fluxes and the functioning of the ocean biological pump
Published: 2025-05-27
Subjects: Biogeochemistry, Oceanography
Ocean biota absorb carbon at the surface and export some to the ocean interior via the biological pump, affecting surface carbon, air-sea CO₂ exchange, and climate. Marine phytoplankton growth is often limited by nutrients (nitrogen, phosphorus, iron, silicon). The efficiency of carbon export is therefore constrained by nutrient availability and the nutrient/carbon ratios in the biota [...]