Preprints
Filtering by Subject: Biogeochemistry
Influence of macrophytes on stratification and dissolved oxygen dynamics in ponds
Published: 2022-09-23
Subjects: Biogeochemistry, Hydrology, Terrestrial and Aquatic Ecology
1. Small waterbodies are sensitive to stressors such as nutrient enrichment and heatwaves. However, when present, macrophytes may mediate these compounding stressors through their influence on water column thermal structure. Canopy-forming macrophyte beds can induce thermal stratification, which may limit the depth and degree of water column warming during heatwaves. 2. We leveraged an ecosystem [...]
Much of Zero Emissions Commitment Occurs Before Reaching Net Zero Emissions
Published: 2022-08-25
Subjects: Biogeochemistry, Climate, Earth Sciences, Environmental Sciences
We explore the response of the Earth’s climate and carbon system to an idealized sequential addition and removal of CO2 to the atmosphere, following a symmetric and continuous emissions pathway, in contrast to the discontinuous emissions pathways that have largely informed our understanding of the climate response to net-zero and net-negative emissions to date. We find, using both an Earth [...]
Improved estimation of phytoplankton abundance and fine-scale water quality features via simultaneous discrete and semi-continuous surveys
Published: 2022-08-06
Subjects: Biogeochemistry, Environmental Monitoring, Fresh Water Studies, Oceanography, Water Resource Management
The abundance and distribution of phytoplankton is driven by light and nutrient availability which in turn is controlled by larger-scale regional processes such as climatic variability and global teleconnections. However, such estimates are largely built on evidence gathered from coarse (on the order of kilometers), discrete grab sampling networks where the overall set of measured parameters is [...]
MacroSheds: a synthesis of long-term biogeochemical, hydroclimatic, and geospatial data from small watershed ecosystem studies
Published: 2022-08-04
Subjects: Biogeochemistry, Hydrology, Water Resource Management
The U.S. Federal Government supports hundreds of watershed ecosystem monitoring efforts from which solute fluxes can be calculated. While details of instrumentation and sampling methods vary across these studies, the types of data collected and the questions that motivate their analysis are remarkably similar. Nevertheless, little effort toward the compilation of these datasets has previously [...]
Sampling across large-scale geological gradients to study geosphere-biosphere interactions
Published: 2022-07-25
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Life Sciences, Microbiology
Despite being one of the largest microbial ecosystems on Earth, with >1029 microbial cells, many basic open questions remain about how life exists and thrives in the deep subsurface biosphere, inside Earth’s crust. Much of this ambiguity is due to the fact that it is exceedingly difficult and (often prohibitively expensive) to directly sample the deep subsurface, requiring elaborate drilling [...]
Evaluation of preservation protocols for oxygen-sensitive minerals within laminated aquatic sediments
Published: 2022-07-25
Subjects: Biogeochemistry, Environmental Sciences, Geochemistry, Sedimentology
Laminated sediments can record seasonal changes in sedimentation of material from anoxic waters, including minerals of the redox-sensitive elements Fe, Mn, and S that form under varying oxygen levels, mineral saturation conditions, and from microbial metabolism. However, preserving both the oxygen-sensitive minerals for identification is challenging when preservation of the spatial arrangement of [...]
Unraveling the role of polysaccharide-goethite associations on glyphosate’ adsorption-desorption dynamics and binding mechanisms
Published: 2022-07-22
Subjects: Agriculture, Analytical Chemistry, Biogeochemistry, Environmental Chemistry, Environmental Sciences, Organic Chemistry, Physical Chemistry, Soil Science
Hypothesis Glyphosate retention at environmental interfaces is strongly governed by adsorption and desorption processes. In particular, glyphosate can react with organo-mineral associations (OMAs) in soils, sediments, and aquatic environments. We hypothesize mineral-adsorbed biomacromolecules modulate the extent and rate of glyphosate adsorption and desorption where electrostatic and noncovalent [...]
Freshwater Suspended Particulate Matter – Key Components and Processes in Floc Formation and Dynamics.
Published: 2022-02-18
Subjects: Biogeochemistry, Environmental Chemistry, Environmental Microbiology and Microbial Ecology Life Sciences, Environmental Sciences, Fresh Water Studies, Geochemistry, Hydrology, Sedimentology
Freshwater suspended particulate matter (SPM) plays an important role in many biogeochemical cycles and serves multiple ecosystem functions. Most SPM is present as complex floc-like aggregate structures composed of various minerals and organic matter from the molecular to the organism level. Flocs provide habitat for microbes and feed for larger organisms. They constitute microbial bioreactors, [...]
A one-million-year isotope record from siderites formed in modern ferruginous sediments
Published: 2022-02-16
Subjects: Biogeochemistry, Other Environmental Sciences, Sedimentology, Stratigraphy
Ancient iron formations hold important records of environmental conditions during the Precambrian Eons. Reconstructions of past oceanic systems require investigating modern ferruginous analogs to disentangle water column and diagenetic signals recorded in iron-bearing minerals. We analyzed oxygen, iron, and carbon isotopes in siderite, a ferrous carbonate phase commonly used as an environmental [...]
Biophysical potential and uncertainties of global seaweed farming
Published: 2022-02-11
Subjects: Biogeochemistry, Earth Sciences
International climate goals require over 5 gigatons/year (Gt/year) of CO2 to be removed from the atmosphere by midcentury. Macroalgae mariculture has been proposed as a strategy for such carbon dioxide removal (CDR). However, the global potential for seaweed cultivation has not been assessed in detail. Here, we develop and use a dynamic seaweed growth model, the Global MacroAlgae Cultivation [...]
Two decades of changing anthropogenic mercury emissions in Australia: inventory development, trends, and atmospheric implications
Published: 2022-01-27
Subjects: Atmospheric Sciences, Biogeochemistry, Environmental Health and Protection
Mercury is a toxic environmental pollutant emitted into the atmosphere by both natural and anthropogenic sources. In Australia, previous estimates of anthropogenic mercury emissions differ by up to a factor of three, with existing inventories either outdated or inaccurate and several lacking Australia-specific input data. Here, we develop a twenty-year inventory of Australian anthropogenic [...]
The DIC carbon isotope evolutions during CO2 bubbling: implications for ocean acidification laboratory culture
Published: 2022-01-05
Subjects: Biogeochemistry, Earth Sciences, Geochemistry
Ocean acidification increases pCO2 and decreases pH of seawater and its impact on marine organisms has emerged as a key research focus. In addition to directly measured variables such as growth or calcification rate, stable isotopic tracers such as carbon isotopes have also been used to more completely understand the physiological processes contributing to the response of organisms to ocean [...]
Copper availability governs nitrous oxide accumulation in wetland soils and stream sediments
Published: 2021-12-15
Subjects: Biogeochemistry, Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Geochemistry, Life Sciences
Denitrification is microbially-mediated through enzymes containing metal cofactors. Laboratory studies of pure cultures have highlighted that the availability of Cu, required for the multicopper enzyme nitrous oxide reductase, can limit N2O reduction. However, in natural aquatic systems, such as wetlands and hyporheic zones in stream beds, the role of Cu in controlling denitrification remains [...]
Multi-proxy assessment of surface sediments using APPI-P FTICR-MS reveals a complex biogeochemical record along a salinity gradient in the Pearl River estuary and coastal South China Sea
Published: 2021-12-10
Subjects: Analytical Chemistry, Biogeochemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics
The Pearl River drains the second largest watershed in China, funnelling large amounts of freshwater and organic matter into the northern part of the South China Sea through an estuary characterized by pronounced biogeochemical gradients. In this study we analyzed organic extracts of surface sediments collected along land-sea transect that captures a transition from freshwater environment at the [...]
Continuous cultivation of the lithoautotrophic nitrate-reducing Fe(II)-oxidizing culture KS in a chemostat bioreactor
Published: 2021-12-07
Subjects: Biogeochemistry
Laboratory-based studies on microbial Fe(II) oxidation are commonly performed over just a few weeks in small volumes with high substrate concentrations, resulting in geochemical gradients and volumetric effects caused by sampling. We used a chemostat to enable uninterrupted supply of medium, and investigated autotrophic growth of the nitrate-reducing Fe(II)-oxidizing culture KS for 24 days. We [...]