Preprints
Filtering by Subject: Biogeochemistry
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: 2024-12-17
Subjects: Biogeochemistry, Earth Sciences, Other Earth Sciences
The biological carbon pump plays a crucial role in the global carbon cycle, particularly through sinking particles carrying carbon to deep waters. The Underwater Vision Profilers (UVP) is widely used for studying particle properties. UVP-based particulate organic carbon (POC) flux is typically derived from particle size distributions (PSDs) assuming size dependent sinking rates and carbon [...]
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, [...]
Potential effects of coagulation processes on phytoplankton mortality in the Elbe estuary from a Lagrangian point of view
Published: 2024-10-17
Subjects: Biogeochemistry, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Oceanography, Water Resource Management
Within the Elbe estuary, a sudden change in depth occurs when the river enters the shipping channel in the Port of Hamburg. This change in depth correlates with a sharp decline in phytoplankton concentrations. This decline affects the estuarine food web and shifts the ecosystem from autotrophic to heterotrophic during the summer months. Previous studies have hypothesized that this collapse is [...]
Instability in the geological regulation of Earth’s climate
Published: 2024-10-06
Subjects: Biogeochemistry
Negative feedback between climate and atmospheric CO2, as mediated via weathering of silicate minerals, is thought to provide the dominant regulation of Earth’s climate on geological timescales. In contrast, we show here that faster feedbacks involving organic matter are critical and create unexpected instability in the system. Specifically, using an Earth system model, we show how organic carbon [...]
Prioritizing Safety, Advancing Efficiency: Developing a New Total Phosphorous Microwave Digestion Method for Sediment Core Nutrient Analysis
Published: 2024-09-26
Subjects: Biogeochemistry, Environmental Chemistry, Inorganic Chemistry, Soil Science
Long-term datasets are invaluable resources for understanding broad-level temporal patterns in ecosystems. For over two decades, UC Davis and Lake County Water Resources Department have collaborated on a long-term monitoring project of Clear Lake sediment nutrient concentrations, in an effort to better understand nutrient cycling in Clear Lake. When the need for a new total phosphorus digestion [...]
Contributions to the discussion of novel detection of dark oxygen production at the abyssal seafloor
Published: 2024-09-18
Subjects: Biogeochemistry, Earth Sciences
There is an overwhelming consensus between researchers based on a vast body of peer-reviewed literature that deep sea ecosystems constitute an oxygen sink. Specific studies on abyssal seafloor regions that contain polymetallic nodules have also confirmed this result. In contrast to this well-founded and longstanding paradigm, Sweetman et al. claim to provide evidence to support a hypothesis that [...]
Carbon storage in Northern Ireland’s aquatic ecosystems: an evidence synthesis to support policy development.
Published: 2024-09-06
Subjects: Biogeochemistry, Marine Biology, Oceanography
Blue carbon is defined as carbon that is naturally sequestered and stored in the world’s aquatic ecosystems. Governments around the world are currently seeking to develop a range of tools to help meet their commitments to reduce greenhouse gas emissions and potentially reverse anthropogenic climate change. As such, there is growing interest from policy makers in natural processes which may be [...]
Sensitivities of soil respiration and heterotrophic respiration to temperature in a cool-temperate forest with sika deer-induced understory vegetation alteration
Published: 2024-08-05
Subjects: Biogeochemistry, Environmental Health and Protection, Environmental Monitoring, Forest Biology, Forest Management, Soil Science, Terrestrial and Aquatic Ecology
Overpopulated ungulates reduce the biomass of understory vegetation and promote the expansion of unpalatable plants in world forests. These understory degradations possibly influence sensitivities of soil respiration (Rs) and heterotrophic respiration (Rh) to temperature and moisture. Here, we examined this possibility in a cool-temperate forest in southern Kyushu, Japan. At the study site, the [...]
Relating Multi-Scale Plume Detection and Area Estimates of Methane Emissions: A Theoretical and Empirical Analysis
Published: 2024-07-23
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Oil, Gas, and Energy, Physical Sciences and Mathematics
Methodologies for inferring surface emissions of atmospheric trace gases can be categorized into plume detection and area-scale estimation. Plume detections are observations of emissions from either individual or clustered point sources. Area estimates are derived from top-down atmospheric flux inversion models or bottom-up inventories, which infer mean emissions typically over spatial scales [...]
Excitable Dynamics of Neoproterozoic to Early Paleozoic Atmospheric and Ocean Oxygen
Published: 2024-07-05
Subjects: Biogeochemistry
The geochemical carbon isotope and redox proxy record indicates that Earth’s surface oxygenation involved a prolonged period of extreme variability in atmospheric and oceanic oxygen, spanning from the early Neoproterozoic to the early Paleozoic. This variability has been linked to external tectonic and evolutionary forcings, as well as to internal nonlinear feedbacks related to the [...]
Diversity at Goldschmidt conference
Published: 2024-06-19
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Geochemistry, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Sciences
The field of geochemistry has grown significantly over the past seventy years, contributing to our understanding of Earth's processes. However, geochemists often identify with broader fields like geology or oceanography, reflecting an identity crisis within the discipline. The Goldschmidt Conference, established in 1988, serves as a central international meeting for geochemists, promoting their [...]
Taxon-specific hydrogen isotope signals in cultures and mesocosms facilitate ecosystem and hydroclimate reconstruction
Published: 2024-06-07
Subjects: Biogeochemistry
Phytoplankton play a key role in biogeochemical cycles, impacting atmospheric and aquatic chemistry, food webs, and water quality. However, it remains challenging to reconstruct changes in algal community composition throughout the geologic past, as existing proxies are suitable only for a subset of taxa and/or influenced by degradation. Here, we investigate if compound-specific hydrogen [...]