Preprints
Filtering by Subject: Biogeochemistry
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 [...]
Calcium isotope constraints on Mesoarchean seawater
Published: 2025-04-24
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology
The cause of the Great Oxidation Event ~2.4 billion-years-ago (Ga) is hotly debated. Recent models favor the emergence of continents as driving the event. However, we suggest that extensive shallow-marine carbonate platforms existed in the Mesoarchean. This conclusion is based on Ca isotopes from 2.8 Ga carbonate rocks, that constrains the Ca isotope value of Mesoarchean seawater to -0.5‰ [...]
Tracing mercury from land to river: global sources, retention, and implications for sustainability
Published: 2025-03-14
Subjects: Biogeochemistry, Earth Sciences, Environmental Health and Protection, Environmental Monitoring, Environmental Sciences, Water Resource Management
Mercury (Hg) pollution in river systems is a global sustainability challenge. Yet the transport, transformation, and retention of Hg within global rivers remain poorly quantified, particularly in regions with sparse observations such as Southeast Asia and Africa, hindering effective pollution mitigation and reinforcing geographic inequities in scientific knowledge and environmental governance. [...]
Phytoplankton blooms in the new Southern Ocean sea ice regime
Published: 2025-02-24
Subjects: Biogeochemistry, Geophysics and Seismology, Oceanography
Over the last decade, the Antarctic sea ice extent has recorded record highs and lows. The anomalous low in 2023 suggested a new reduced sea-ice state, with unknown impacts on phytoplankton blooms, including phenology and magnitude. Analysing both Biogeochemical (BGC) and Core Argo floats, we compare annual sea ice extent (SIE) anomalies and sea ice volume (SIV) to physical and biological [...]
Rewetting drained boreal peatland forests does not mitigate climate warming in the 21st century
Published: 2025-02-08
Subjects: Biochemistry, Biophysics, and Structural Biology, Biogeochemistry, Forest Sciences, Natural Resources and Conservation, Natural Resources Management and Policy, Sustainability
Rewetting of drained peatland forests restores ecosystem functions and improves peatland ecological status. It is also considered to mitigate climate change, yet some studies challenge this view Recently, Laine et al. (2024, Restoration Ecology, 32(7), p.e14213) considered feasible restoration outcomes of boreal forestry drained peatlands and proposed that rewetting nutrient-rich peatland forests [...]
Glacially enhanced silicate weathering revealed by Holocene lake records
Published: 2025-02-08
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
How glaciation affects CO2 drawdown by chemical weathering sets the strength of the weathering-climate feedback, which controls the exogenic carbon cycle and planetary habitability (Kump et al., 2000). However, the exact role of glaciers remains elusive as glaciation alters multiple factors controlling weathering, the net effect of which is ambiguous even in directionality. While illustrative, [...]
Challenges in Integrating Dissolved Organic Matter Chemodiversity into Kinetic Models of Soil Respiration
Published: 2025-01-25
Subjects: Biogeochemistry, Soil Science
The chemodiversity of dissolved organic matter (DOM) in soil has been proposed to influence the microbial metabolism and fate of belowground organic carbon (C). However, effectively integrating DOM chemistry into soil C cycle models to improve predictions of C stocks and fluxes—beyond simply considering DOM pool size—remains a challenge. While recent research suggests that incorporating DOM [...]
A bipolar convection seesaw explains Earth system response to Heinrich events
Published: 2025-01-25
Subjects: Biogeochemistry, Climate, Oceanography
GelCam: Visualizing Sinking Particle Flux via a Polyacrylamide Gel-Based Sediment Trap
Published: 2025-01-10
Subjects: Biogeochemistry, Earth Sciences, Oceanography
Sinking particles play a key role in the biological carbon pump. While previous studies have analyzed particulate carbon flux over timescales of days to years, few have been able to resolve flux variability on shorter, hourly scales at multiple depths simultaneously. This study uses an array of upward-facing cameras, built from off-the-shelf components for under $500 each, to visualize particle [...]
Origin and fate of methane in the Central American convergent margin
Published: 2025-01-10
Subjects: Biogeochemistry, Environmental Microbiology and Microbial Ecology Life Sciences, Volcanology
Convergent margins are gateways to Earth’s interior where volatile species are cycled between the planet's surface and interior. At these locations, carbon is recycled from deep reservoirs in two main forms: oxidized carbon, such as carbon dioxide, and reduced carbon, such as methane. While the former is quantitatively more important and its volcanic fluxes have been better constrained, the [...]
Hydrogenotrophic metabolisms in the subsurface and their implications for underground hydrogen storage and natural hydrogen prospecting
Published: 2025-01-08
Subjects: Biogeochemistry, Earth Sciences, Environmental Microbiology and Microbial Ecology Life Sciences, Oil, Gas, and Energy
Hydrogen is a fundamental electron donor in diverse microbial metabolisms and it is considered the energetic currency exchanged within microbial communities in anaerobic environments. Hydrogen is also the major actor in the transition to alternative low-carbon energy sources, primarily due to its dual role as energy source and energy carrier and to the production of water as a byproduct of its [...]
Preliminary Development of Machine Learning Emulators for Long-Term Atmospheric CO2 Evolution
Published: 2024-12-22
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Environmental Chemistry, Physical Sciences and Mathematics
This study evaluates machine learning emulators for modeling long-term atmospheric CO2 evolution by comparing Random Forests (RF) and Multilayer Perceptrons (MLP) in replicating cGENIE Earth System Model outputs over a one-million-year timescale. Using one-year pulse emission experiments spanning 1,000-20,000 PgC with outputs tracked for 106 years, we assessed emulator performance across multiple [...]
On the assessment of sinking particle fluxes from in situ particle size distributions
Published: 2024-12-16
Subjects: Biogeochemistry, Earth Sciences, Other Earth Sciences
The biological carbon pump is a vital component of the global carbon cycle, particularly through sinking of particulate organic carbon (POC) to the ocean interior. Particle size distribution (PSD) observations from the Underwater Vision Profiler (UVP) have been widely used to quantify sinking POC fluxes. This approach assumes that the sinking POC flux is a function of the PSD multiplied by a [...]
Towards statistical modeling of chlorophyll-a concentrations in Balikpapan Bay, Indonesia: Implications for algal bloom detection
Published: 2024-10-26
Subjects: Artificial Intelligence and Robotics, Biogeochemistry, Environmental Monitoring, Marine Biology, Oceanography
This study presents a comprehensive statistical analysis of chlorophyll-a dynamics in Balikpapan Bay, Indonesia, combining time series analysis, extreme value modeling, and machine learning techniques to understand phytoplankton variability near Indonesia's planned new capital city. Analysis of daily chlorophyll-a concentrations (2019-2021) revealed a non-Gaussian distribution (skewness = 2.212, [...]