Carbon budget

Abiotic CH4 production driven by Fenton-type reactive oxygen species (ROS) has been confirmed to be an indispensable component of the atmospheric CH4 budget. While the chemical reactions independent of Fenton chemistry to ROS are ubiquitous in nature, it remains unknown whether the produced ROS can drive abiotic CH4 production. Here, we first demonstrated the abiotic CH4 production at the soil-water interface under illumination. Leveraging this finding, polymeric carbon nitrides (CNx) as a typical analogue of natural geobattery material and dimethyl sulfoxide (DMSO) as a natural methyl donor were used to unravel the underlying mechanisms...

Ocean acidification (OA) is a global environmental concern, and submarine groundwater discharge (SGD) is a potentially process that enhances OA. This review summarizes the relationship between two types of constituents carried by SGD into China's seawater and OA. 1) Current research predominantly concentrates on constituent fluxes from SGD, neglecting its ecological impacts on carbon and nutrients budgets, as well as the mechanisms between carbon and nutrients. 2) Uncertainties persist in SGD research methods and acidification characterization...

Soil acidification is an ongoing problem in intensively cultivated croplands due to inefficient nitrogen (N) fertilization. We collected high-resolution data comprising 19,969 topsoil (0-20 cm) samples from the Land Use and Coverage Area frame Survey (LUCAS) of the European commission in 2009 to calculate the impact of N fertilization on buffering substances such as carbonates and base cations. We have only considered the impacts of mineral fertilizers from the total added N, and a N use efficiency of 60 %...

Restoration is increasingly seen as a necessary tool to reverse ecological decline across terrestrial and marine ecosystems.1 , 2 Considering the unprecedented loss of coral cover and associated reef ecosystem services, active coral restoration is gaining traction in local management strategies and has recently seen major increases in scale. However, the extent to which coral restoration may restore key reef functions is poorly understood.3 , 4 Carbonate budgets, defined as the balance between calcium carbonate production and erosion, influence a reef's ability to provide important geo-ecological functions including structural complexity, reef framework production, and vertical accretion...

Sulfur hexafluoride (SF6 ) is a potent greenhouse gas. Here we use long-term atmospheric observations to determine SF6 emissions from China between 2011 and 2021, which are used to evaluate the Chinese national SF6 emission inventory and to better understand the global SF6 budget. SF6 emissions in China substantially increased from 2.6 (2.3-2.7, 68% uncertainty) Gg yr-1 in 2011 to 5.1 (4.8-5.4) Gg yr-1 in 2021. The increase from China is larger than the global total emissions rise, implying that it has offset falling emissions from other countries...

The incorporation of straw with decomposing inoculants into soils has been widely recommended to sustain agricultural productivity. However, comprehensive analyses assessing the effects of straw combined with decomposing inoculants on greenhouse gas (GHG) emissions, net primary production (NPP), the net ecosystem carbon budget (NECB), and the carbon footprint (CF) in farmland ecosystems are scant. Here, we carried out a 2-year field study in a wheat cropping system with six treatments: rice straw (S), a straw-decomposing Bacillus subtilis inoculant (K), a straw-decomposing Aspergillus oryzae inoculant (Q), a combination of straw and Bacillus subtilis inoculant (SK), a combination of straw and Aspergillus oryzae inoculant (SQ), and a control with no rice straw or decomposing inoculant (Control)...

Phytoplankton and sea ice algae are traditionally considered to be the main primary producers in the Arctic Ocean. In this Perspective, we explore the importance of benthic primary producers (BPPs) encompassing microalgae, macroalgae, and seagrasses, which represent a poorly quantified source of Arctic marine primary production. Despite scarce observations, models predict that BPPs are widespread, colonizing ~3 million km2 of the extensive Arctic coastal and shelf seas. Using a synthesis of published data and a novel model, we estimate that BPPs currently contribute ~77 Tg C y-1 of primary production to the Arctic, equivalent to ~20 to 35% of annual phytoplankton production...

Earth System Models (ESMs) continue to diagnose a wide range of carbon budgets for each level of global warming. Here, we present emergent constraints on the carbon budget as a function of global warming, which combine the available ESM historical simulations and future projections for a range of scenarios, with observational estimates of global warming and anthropogenic CO2 emissions to the present day. We estimate mean and likely ranges for cumulative carbon budgets for the Paris targets of 1.5 °C and 2 °C of global warming of 812 [691, 933] PgC and 1048 [881, 1216] PgC, which are more than 10% larger than the ensemble mean values from the CMIP6 models...

Revealing the magnitude, dynamics, and influencing factors of CO2 emissions across the water-air interface in karst water with high resolution is crucial for accurately assessing the carbon budget in a karst environment. Due to the limitations of observation methods, the current research is still very insufficient. To solve the above problems and clarify the main influencing factors of CO2 emission in karst water, this study selected Dalongdong (DLD) Reservoir, located in the typical karst peak and valley area in southwest China, to carry out a multi-parameter high-frequency monitoring study from January to December 2021, and used the thin boundary model method to estimate the CO2 flux across the water-air interface (CF)...

PREMISE: Mast flowering/seeding is often more extreme in lower-resource environments, such as alpine compared to lowland habitats. We studied a masting herb that had less extreme masting at higher elevations, and tested if this difference could be explained by higher photosynthetic productivity and/or lower reproductive investment at the higher-elevation sites. METHODS: We examined the relationship between flowering intervals and carbon budget (i.e., the balance between reproductive investment and annual carbon fixation) in a masting herb, Veratrum album subsp...

The efficiency of mixotrophic microalgae in enhancing the recovery of waste nutrients has been well established; however, the recovery rate is crucial in meeting the needs of field applications. This study evaluated the impact of media characteristics on nutrient recovery under mixotrophic conditions. The mixotrophic N recovery rate with S. acuminatus in modified BG-11 reached 2.59 mg L-1 h-1 . A mixotrophic growth optimization strategy was applied to achieve a high-rate nutrient recovery from municipal wastewater treatment plant effluents...

The world is currently experiencing the environmental challenge of global warming, necessitating careful planning of carbon dioxide (CO2 ) emissions to deal with this problem. This study examines the environmental challenge posed by CO2 emissions from both a long and short-term perspective. In the long term, despite efforts made by countries, our change-point detection analysis shows that there has been no structural change in CO2 emissions since 1950. Without significant efforts, the carbon budget corresponding to the Paris Agreement's target will be exhausted by 2046...

BACKGROUND: Marine microalgae (phytoplankton) mediate almost half of the worldwide photosynthetic carbon dioxide fixation and therefore play a pivotal role in global carbon cycling, most prominently during massive phytoplankton blooms. Phytoplankton biomass consists of considerable proportions of polysaccharides, substantial parts of which are rapidly remineralized by heterotrophic bacteria. We analyzed the diversity, activity, and functional potential of such polysaccharide-degrading bacteria in different size fractions during a diverse spring phytoplankton bloom at Helgoland Roads (southern North Sea) at high temporal resolution using microscopic, physicochemical, biodiversity, metagenome, and metaproteome analyses...

Volatile sulfur compounds, such as dimethyl sulfide (DMS), carbonyl sulfide (OCS), and carbon disulfide (CS2 ), have significant implications for both atmospheric chemistry and climate change. Despite the crucial role of oceans in regulating their atmospheric budgets, our comprehension of their cycles in seawater remains insufficient. To address this gap, a field investigation was conducted in the western North Pacific to clarify the sources, sinks, and biogeochemical controls of these gases in two different marine environments, including relatively eutrophic Kuroshio-Oyashio extension (KOE) and oligotrophic North Pacific subtropical gyre...

Wetlands are the largest natural source of methane (CH4 ) globally. Climate and land use change are expected to alter CH4 emissions but current and future wetland CH4 budgets remain uncertain. One important predictor of wetland CH4 flux, plants, play an important role in providing substrates for CH4 -producing microbes, increasing CH4 consumption by oxygenating the rhizosphere, and transporting CH4 from soils to the atmosphere. Yet, there remain various mechanistic knowledge gaps regarding the extent to which plant root systems and their traits influence wetland CH4 emissions...

Labile carbon (C) continuously delivered from the rhizosphere profoundly affects terrestrial nitrogen (N) cycling. However, nitrous oxide (N2 O) and dinitrogen (N2 ) production in agricultural soils in the presence of continuous root C exudation with applied N remains poorly understood. We conducted an incubation experiment using artificial roots to continuously deliver small-dose labile C combined with 15 N tracers to investigate N2 O and N2 emissions in agricultural soils with pH and organic C (SOC) gradients...

The major ion chemistry of the ocean has been assumed to be controlled by river input, hydrothermal circulation at mid-ocean ridges, carbonate production, and low-temperature alteration of seafloor basalt, but marine chemical budgets remain difficult to balance. Here we propose that large-scale groundwater flow and diagenetic reactions in continental shelf sediments have been overlooked as an important contributor to major ion budgets in the ocean. Based on data synthesized from 17 passive margin basins, continental shelves contribute fluid exchanges comparable to hydrothermal circulation at mid-ocean ridges...

In this study, we present a comprehensive atmospheric 14 C record spanning from 1940 to 2016, derived from 77 single tree rings of Cedrela odorata located in the Eastern Amazon Basin (EAB). This record, comprising 175 high-precision radiocarbon measurements obtained through accelerator mass spectrometry (AMS), offers a detailed chronology of post-1950 CE (Anno Domini) 14 C fluctuations in the Tropical Low-Pressure Belt (TLPB). To ensure accuracy and reliability, we included 14 C-AMS results from intra-annual successive cuts of the tree rings associated to the calendar years 1962 and 1963 and conducted interlaboratory comparisons...

A significant amount of organic carbon is transported in dissolved form from soils to coastal oceans via inland water systems, bridging land and ocean carbon reservoirs. However, it has been discovered that the presence of terrigenous dissolved organic carbon (tDOC) in oceans is relatively limited. Therefore, understanding the fates of tDOC in coastal oceans is essential to account for carbon sequestration through land ecosystems and ensure accurate regional carbon budgeting. In this study, we developed a state-of-the-art modeling approach by coupling a land-to-ocean tDOC flux simulation model and a coastal tDOC tracking model to determine the potential fates of tDOC exported from three primary drainage basins in the Gulf of Maine (GoM)...

Soil microbiomes are highly diverse, and to improve their representation in biogeochemical models, microbial genome data can be leveraged to infer key functional traits. By integrating genome-inferred traits into a theory-based hierarchical framework, emergent behaviour arising from interactions of individual traits can be predicted. Here we combine theory-driven predictions of substrate uptake kinetics with a genome-informed trait-based dynamic energy budget model to predict emergent life-history traits and trade-offs in soil bacteria...