Net Source Research Articles

Study of the erosion and redeposition of W considering the kinetic energy distribution of incident ions through a semi-analytical model

In today’s nuclear fusion devices, erosion of high-Z metallic plasma-facing materials (PFMs) is mainly caused by physical sputtering. That is, by the exchange of energy between plasma ions and the atoms in the walls. In most of the numerical codes currently in use impinging plasma is approximated as a fluid. By averaging the incident particles’ energy distribution the high-energy population of the eroded material is underestimated. For heavy materials such as W, high-energy eroded particles tend to ionize far from the wall and they are less affected by the sheath electric field hence, not being attracted back to the wall, they have a higher chance to contaminate the core plasma. This could in turn result in an underestimation of the net erosion sources. In this work, a semi-analytical model was developed to include the energy distribution of the incident particles. Then, by Monte Carlo method, the net erosion of tungsten from a smooth PFM was calculated. The results show that the kinetic description in energy is important only for incident particles ionized once. For instance, it is particularly important for plasma ions such as Deuterium. It is seen that Deuterium contribution to the W net sources is not always negligible if compared to light impurities or to tungsten self-sputtering in the range of plasma parameters tested. Finally, results show that the difference between the fluid and kinetic models becomes more pronounced for high-screening plasma conditions.

CO2 and CH4 fluxes from inundated floodplain ponds: role of diel variability and duration of inundation

Small waterbodies like floodplain ponds are considered to be an important component of the global carbon budget. Although they are found in large numbers worldwide and their numbers are increasing every year due to the creation of new ponds, we do not have sufficient data on direct estimates of emission fluxes from these waterbodies yet. Herein, we present results from a set of 24 ponds located in the Morava River floodplain, Czech Republic. The ponds varied in their origin (man-made vs. natural), size, depth, sediment organic matter content, and macrophyte growth. Water chemistry parameters, concentrations, and exchange of CO2 and CH4 with the atmosphere were directly measured during the day and night from spring to summer 2020. The ponds emitted more CO2 and CH4 during nighttime, and both CO2 and, in particular, CH4 emissions tend to increase with the duration of pond inundation. Total diffusive fluxes of CO2 and CH4 into the atmosphere ranged from −37072.9 to 432683.3 μmol m−2 d−1, and −11485.3 to 95,889.6 μmol m−2 day−1, respectively. Generally, all ponds were found to be a net source of CO2 and CH4 to the atmosphere. In average, ponds emitted 7.64 g CO2-equivalent m−2 d−1. Thus, our results indicate that floodplain ponds are an important source of both CO2 and CH4 to the atmosphere and they should not be omitted in a regional carbon budget.

Seaweed forests are carbon sinks that may help mitigate CO2 emissions: a comment on Gallagher et al. (2022)

Abstract Recently, Gallagher et al. (2022) suggested that seaweed ecosystems are net heterotrophic carbon sources due to CO2 released from the consumption of external subsidies. Here we outline several flaws in their argument, which we believe confuse research on the blue carbon potential of seaweed ecosystems, and unjustifiably generate doubt around initiatives to protect and restore seaweed forests. Gallagher et al.’s evidence relies on 18 studies with highly variable measures of net ecosystem production, which do not statistically support their conclusion that most seaweed ecosystems are heterotrophic. This dataset is also inappropriate as it is incomplete and misrepresents seaweed ecosystems globally, particularly seaweed forests, which contribute disproportionately to global seaweed productivity. We maintain that the climate change mitigation value of an ecosystem depends on the net difference in CO2 uptake between the original ecosystem and its replacement ecosystem. We provide evidence that most seaweed ecosystems, which drawdown the largest carbon flux of any vegetated coastal habitat, are indeed net autotrophic ecosystems. We recognize that substantial uncertainties remain concerning the magnitude of CO2 drawdown by seaweed ecosystems and recommend that carbon fluxes around seaweed ecosystems should be considered more broadly and taken into account in estimates of their CO2 mitigation potential.

Subsurface drip irrigation reduces CH4 emissions and ecosystem respiration compared to surface drip irrigation

Sustainable irrigation expansion is pivotal to guarantee global food security. Fertigation techniques with surface or subsurface drip lines are among the most promising irrigation practices. Yet, the effect of surface versus subsurface drip fertigation on ecosystem respiration (CO2) fluxes remains largely unknown while there is not available information regarding CH4 emissions, even though this knowledge is essential to obtain a comprehensive overview of the carbon (C) footprint of these practices. To address this knowledge gap, a field experiment was set up in a maize (Zea mays L.) crop comparing surface and subsurface drip (buried at 30 cm depth) in combination with four fertilization treatments (unfertilized control, calcium nitrate and ammonium sulphate with or without the nitrification inhibitor DMPP). Our results showed that all fertilized treatments (except the unfertilized control) were net CH4 sources (135–208 g C ha−1). Subsurface irrigation reduced cumulative CH4 emissions compared to surface irrigation by 80% (P < 0.05). Moreover, subsurface irrigation also abated ecosystem respiration fluxes (by 41%, P < 0.05) relative to surface irrigation. Emission peaks of both C fluxes were observed after fertigation events. Our results demonstrate that subsurface irrigation is a water-saving strategy that can contribute to decreasing the net greenhouse gas emissions of irrigated croplands through the abatement of CH4 and respiration fluxes.

An Observational Study on Graphical Presentation of Data - A Review

The most effective means of disseminating scientific knowledge, influencing choices on the acceptance or rejection of a paper, and drawing the attention of the scientific community to study findings are figures and charts. Second, a low ink-to-data ratio (the avoidance of unnecessary shading, three dimensionality, gridlines, and what is commonly referred to as "chartjunk"), and third, clear and unambiguous axes labelling, are also important criteria. Histograms, bar charts (always with measurements of error), box-and-whiskers plots, scatter plots, and forest plots should all be included in the researcher's indispensable graphic toolkit. Methodology: The material of graphical presentation of data has been collected from different, articles, authentic literatures, manuscripts, and authentic net sources, like NCBI, PubMed etc. Conclusion: discovered the significance, practicality, and benefits of graphs. Finally, using examples, we covered the various graph kinds. The answer to the more difficult first question will be determined by your data. Do not let the sort of visual that will be utilized be determined by programme restrictions. If your programme is unable to create the sort of visual you want, alter the software, not the graphic.

A Critical Interpretation of Ethics in Research

The moral standards that direct a person's behavior are known as ethics. Doing what is morally and legally correct in research is sometimes referred to as practicing research ethics. They are standards of behavior that set boundaries between what is morally correct and inappropriate. The article discusses the value of ethics in relation to organizing, carrying out, and disseminating research. Good Clinical Practice and several recommendations have been explored. The legal concerns that are pertinent to research procedures have been discussed in the essay. Researchers, ethics committees, and journal editors are just a few of the stakeholders who are very concerned about research misconduct and its consequences. The importance of research ethical awareness has been emphasized. Methodology: The material of research ethics has been collected from different, articles, authentic literatures, manuscripts, and authentic net sources, like NCBI, PubMed etc. Conclusion: For the researchers, a diligent mindset is crucial. To safeguard research participants from damage, it is crucial to uphold protocol compliance, informed consent processes, openness and integrity, confidentiality, and other standards.

Seasonal variations of nitrous oxide in a populous urban estuary and its adjacent sea

The first investigations of seasonal N2O variations and water-to-air fluxes in the Tamsui River estuary and its adjacent sea were carried out in this study. In the Tamsui River estuary, the concentration of N2O decreased with increasing salinity. The seasonal variations of N2O concentrations in the estuary were 46.8–148.5 nM in autumn, 15.9–82.5 nM in spring, 11.0–42.0 nM in summer and 13.1–120.6 nM in winter. When salinity regressed to zero, N2O concentration was highest in autumn, followed by winter, spring, and summer, which might be influenced by the DO and NO3− concentrations as well as temperature. Because of mountains occlusion, the seasonal variations in wind speed were not large in the Tamsui River estuary. Seasonal variations of N2O fluxes in the estuary were 10.9–35.6 μmol m−2 d−1 in autumn, 2.8–15.1 μmol m−2 d−1 in spring, 2.4–9.5 μmol m−2 d−1 in summer and 2.7–26.8 μmol m−2 d−1 in winter. In the adjacent sea of Tamsui River estuary, seasonal average N2O concentrations in the surface seawater were 10.3 ± 0.2 nM in autumn, 11.6 ± 1.2 nM in spring, 11.4 ± 0.7 nM in summer and 13.8 ± 0.9 nM in winter, with no significantly seasonal changes while wind speed varied greatly seasonally. Seasonal variations of average N2O fluxes in Tamsui River estuary’s adjacent sea were 40.3 ± 0.7 μmol m−2 d−1 in autumn, 19.7 ± 2.1 μmol m−2 d−1 in spring, 20.9 ± 1.3 μmol m−2 d−1 in summer and 49.0 ± 3.3 μmol m−2 d−1 in winter. As a result, seasonal variations in N2O fluxes in the estuary were dominated by N2O concentrations in the water, whereas in the sea, it was dominated by wind speed. Overall, the Tamsui River estuary and its adjacent sea were net sources of atmospheric N2O with annual average fluxes 10.6 ± 6.7 and 32.5 ± 14.5 μmol m−2 d−1, respectively.

Enhanced daytime atmospheric mercury in the marine boundary layer in the South Oceans

Understanding the spatial and temporal variations of atmospheric mercury (Hg) in the marine boundary layer could advance our knowledge on ocean evasion of Hg. Here, we conducted continuous measurements of total gaseous mercury (TGM) in the marine boundary layer during a round-the-world cruise from August 2017 to May 2018. We observed the highest and lowest TGM concentrations in Southern Indian Ocean (1.29 ± 0.22 ng m−3) and Southern Atlantic Ocean (0.61 ± 0.28 ng m−3), respectively. During the daytime, enhanced TGM was observed with the diurnal amplitude difference reaching its maximum in the range of 0.30–0.37 ng m−3 in Southern Indian Ocean and Southern Ocean. The positive correlation between TGM (R2 = 0.68–0.92) and hourly solar radiation in each ocean suggested that the daytime enhanced TGM was likely driven by Hg photoreduction in seawater, after excluding the influence of other meteorological factors. The diurnal amplitude of TGM in the marine boundary layer might be impacted by the microbial productivity and the ratio of ultraviolet radiation. Our study highlights that ocean acts as a net TGM source during the daytime in the Southern Hemisphere and aqueous photoreduction process may play an important role in the biogeochemical cycling of Hg.

Characteristics of net ecosystem exchange and source distribution of Xilinhot grassland, China.

To understand carbon sequestration capacity of grasslands, the changes of CO2 flux in Xilinhot grasslands and the influence of environmental factors were analyzed by using the eddy data of Xilinhot National Climate Observatory in 2018-2021, and the distribution of flux source areas was analyzed. The results showed that the southwest wind prevailed in the study area throughout the year, the source area in the growing season was larger than that in the non-growing season, and the source area under stable atmospheric conditions was larger than that under unstable conditions. The maximum length of source region with a contribution rate of 90% was close to 400 m, which was consistent with the length estimated by the classical law. The net ecosystem exchange (NEE) of Xilinhot grasslands had obvious diurnal and seasonal dynamics, which was manifested as a carbon sink in the daytime and a carbon source at night during the growing season and weak carbon source in the non-growing season. From 2018 to 2021, the annual total NEE were -15.59, -46.28, -41.94, and -78.14 g C·m-2·a-1, respectively, with an average value of -45.49 g C·m-2·a-1, indicating that Xilinhot grassland had strong carbon sequestration capacity. Vapor pressure deficit and photosynthetically active radiation helped grasslands absorb atmospheric CO2. At night, when temperature was above 0 ℃, the increases in air and soil temperature promoted vegetation respiration to release CO2.

Significant monthly and diel variations of CH4 emission from a shallow eutrophic lake with submerged aquatic vegetation

Shallow eutrophic lakes with submerged aquatic vegetation (SAV) are a large source of atmospheric methane (CH4) emissions. However, current estimates of CH4 emissions from lakes are uncertain owing to the lack of data on the diel and monthly variability of CH4 emissions. In this study, we conducted monthly diel measurements in Ulansuhai Lake, China during the ice-free period (April to October, 2019) to determine the diel and monthly variability of CH4 emissions. The diffusive CH4 emission flux (FCH4d) from June to September was significantly higher (∼5- to 10-fold) than that from April, May, and October, accounting for > 92% of the total emissions. Daytime measurements would overestimate emissions if extrapolated to the whole day because FCH4d during daytime was higher than that during nighttime. Mean daily FCH4d emission estimates are overestimated by 25%, ranging from 11% in summer to 46% in spring based solely on daytime measurement. The sampling sites were net sources of CH4 emissions, with total FCH4 of 9.74 ± 9.06 mmol m−2 d−1. FCH4d increased sharply when the water temperature was above 20 °C. FCH4 (CO2 eq) accounted for over 90% of the total greenhouse gas emissions (CH4 plus CO2), with the majority occurring from June to September. Our findings indicate that diel and monthly variations should be considered for more accurate estimation of CH4 emissions from the lakes with SAV.

Carbon Sequestration Potential of Biomass-Based Products: A System Dynamics Modeling Approach for Grassland Management

It is known that forests are significant carbon storage, as well as harvested wood products. Both sectors are included in the national greenhouse gas inventories. When wood or other types of biomass grow, it absorbs carbon dioxide through photosynthesis. If biomass is used in the production of new products, the carbon stored in them is effectively removed from the atmosphere and held in the product. Carbon stored in products is considered temporary because the products eventually will burn or decompose and release carbon dioxide back into the atmosphere. However, when products are used for long-lasting applications, the carbon stored in them can remain sequestered for many decades, which can significantly contribute to climate change mitigation. If it is possible to store carbon in wood products, the question arises as to whether it is also possible to promote carbon sequestration in products with other types of biomass. In this work perennial biomass was analyzed. It is a product of semi-natural grasslands, where grass cutting is necessary, which produces grass biomass that is often not fully used. A literature analysis was performed to select suitable products with different carbon storage periods and minimal production emissions, such as those made from biorefining, boards for packaging or building materials, and biochar for soil carbon sequestration. A system dynamics model was developed to estimate carbon stocks and flows between atmosphere, living biomass and products. The base scenario is modeled according to carbon flows in grasslands according to IPCC guidelines – grasslands are net carbon sources and the carbon concentration in the atmosphere only increases. The addition of a product-manufacturing scenario decreases the carbon concentration in the atmosphere.

Maize/Peanut Intercropping Reduces Carbon Footprint Size and Improves Net Ecosystem Economic Benefits in the Huang-Huai-Hai Region: A Four-Year Study

The dual challenges of global climate change and reductions in the amount of arable land represent growing threats to the stability of global human populations. Efforts to further optimize cropping systems to maximize yields while minimizing greenhouse gas emissions in limited land areas have thus emerged as a focus in modern agriculture. Cereal-intercropping management strategies may represent a promising approach to simultaneously addressing both of these challenges in China. We aimed at comprehensively assessing changes in yield, carbon footprint, and net ecosystem economic benefit when transitioning from maize/peanut monoculture to intercropping in a field-scale study in an effort to aid in the development of low-carbon intercropping systems that do not have an adverse impact on Chinese grain yields. Beginning in June of 2018, a randomized complete block design with three treatments was used to initiate this study: (1) peanut monoculture (P), (2) maize monoculture (M), and (3) maize/peanut intercropping (MP). We compared yield, greenhouse gas emissions, carbon footprint and net ecosystem economic benefit. Results over four years showed that the land equivalent ratio associated with MP was greater than 1. All three of these cropping systems were net CO2 and N2O sources as well as net CH4 sinks, with MP generating significantly (p &lt; 0.05) lower N2O and CO2 flux as well as smaller seasonal N2O and CO2 emissions relative to M. MP additionally reduced the carbon footprint associated with this cropping system by 11.11–31.65% and 30.37–43.62% relative to M and P, respectively. Consistently, MP treatment resulted in respective 70.69% and 26.25% net ecosystem economic benefit (NEEB) increases relative to the M and P conditions while simultaneously enhancing energy use efficiency. In summary, MP systems have potential economic benefit with lower environmental risk alternative to traditional peanut or maize monocropping systems. Converting from peanut or maize monocropping systems to MP systems practices contributed to improved farmland use efficiency, clean production and increased farmers’ income in an agricultural system.

Nutrient and stoichiometry dynamics of decomposing litter in stream ecosystems: A global synthesis.

Decomposing organic matter forms a substantial resource base fueling the biogeochemical function and secondary production of most aquatic ecosystems. However, detrital N (nitrogen) and P (phosphorus) dynamics remain relatively unexplored in aquatic relative to terrestrial ecosystems, despite fundamentally linking microbial processes to ecosystem function across broad spatial scales. We synthesized 217 published time series of detrital carbon (C), N, P, and their stoichiometric ratios (C:N, C:P, N:P) from stream ecosystems to analyze the temporal nutrient dynamics of decomposing litter using generalized additive models. Model results indicated that detritus was a net source of N (irrespective of inorganic or organic form) to the environment regardless of initial N content. In contrast, P sink/source dynamics were more strongly influenced by initial P content, where P-poor litters were sinks of nutrients until shifting to net P mineralization after ~40% mass loss. However, large variation surrounded both N and P predictions, suggesting the importance of non-microbial factors such as fragmentation by invertebrates. Detrital C:N ratios converged and became more similar toward the end of decomposition, suggesting predictable microbial functional effects throughout detrital ontogeny. C:P and N:P ratios also converged to some degree, but these model predictions were less robust than for C:N, due in part to the lower number of published detrital C:P time series. Explorations of environmental covariate effects were frequently limited by few coincident covariate measurements across studies, but temperature, N availability, and P tended to accelerate existing ontogenetic patterns in C:N. Our analysis helps unite organic matter decomposition across aquatic-terrestrial boundaries by describing basic patterns of elemental flows catalyzed by decomposition in streams, and points to a research agenda to continue addressing gaps in our knowledge of detrital nutrient dynamics across ecosystems. This article is protected by copyright. All rights reserved.

Soil profile greenhouse gas concentrations and fluxes from a semiarid grassland and a cropland site in an agro-pastoral ectone of northern China

Despite broad information on greenhouse gas (GHG) emissions from the soil surface, only few studies have examined the depth related GHG concentration and production within the soil. We coupled chamber surface GHG flux measurements with analysis of subsurface GHG concentrations at five depths (0, 10, 30, 50 and 70 cm) using silicon tubes in a grassland and cropland soils in a semi-arid agro-pastoral ecotone over a full year. Grassland and cropland soils behaved as net CO2 and N2O sources, but sinks of CH4. CO2 and N2O concentrations increased but CH4 decreased with soil depth. Subsurface GHG fluxes calculated using Fick’s law decreased with depth. The modeled GHG and measured surface fluxes agreed much better for CO2 than N2O or CH4. Spring-thaw and rainfall events triggered N2O pulses, CH4 uptake peaks and CH4 concentration drops. Annual emissions or uptake based on chamber method were 4820–7580 kg C ha−1 yr−1, 2.4–1.5 kg C ha−1 yr−1, and 0.13–0.14 kg N ha−1 yr−1 for CO2, CH4, and N2O across the grassland and cropland, respectively. Modeled annual accumulation of GHG fluxes dropped with depth, whereas the topsoil (0–20 cm) contributed about 65% for CO2, 68% for N2O and 72% for CH4 of the total profile. The vertical distribution of GHG fluxes reflected those of soil organic carbon and root biomass. The grassland had higher annual CO2 flux but lower CH4 uptake than the cropland. Annual N2O fluxes were similar between the two ecosystems.

Air‐Sea Fluxes of CO2 in the Indian Ocean Between 1985 and 2018: A Synthesis Based on Observation‐Based Surface CO2, Hindcast and Atmospheric Inversion Models

AbstractThe Indian Ocean significantly influences the global carbon cycle but it is one of the undersampled regions with reference to surface ocean pCO2. As a part of the Regional Carbon Cycle Assessment and Processes‐2 (RECCAP2) project, several approaches, such as interpolated observational climatology, hindcast model, observation‐based surface CO2 (empirical models), and atmospheric inversion models have been employed for estimating net sea‐to‐air CO2 fluxes between 1985 and 2018. The seasonal, spatial and long‐term variability in sea‐to‐air fluxes of CO2 were compared with observational climatology. The mean value of CO2 in the Indian Ocean (north of 37.5°S) for the period of 1985–2018 using all models is estimated to be −0.19 ± 0.1 PgC yr−1 and it is consistent with the observational climatology (−0.07 ± 0.14 PgC yr−1). The Indian Ocean north of 18°S is found to be the mean annual source (0.04 ± 0.05 PgC yr−1) whereas a net sink (−0.23 ± 0.11 PgC yr−1) in the south of 18°S. All models captured observed spatial patterns but underestimated the net source of CO2 in the Oman/Somalia upwelling, the Equatorial Indian Ocean and the Bay of Bengal whereas CO2 sink is overestimated in the South Indian Ocean. Overall, all models captured the seasonality in pCO2 levels and CO2 fluxes but overestimated the amplitude of their variability. All models suggested the strengthening of the sink over the period between 1985 and 2018 by 0.02 PgC yr−1 decade−1. A significant increase in the collection of surface ocean pCO2 and atmospheric CO2 measurements improves the model simulations in the Indian Ocean.

Machine Learning Applied to X-Ray Spectra: Separating Stars in Orion Nebula Cluster from Active Galactic Nuclei in CDFS

Modern X-ray telescopes have detected hundreds of thousands of X-ray sources in the universe. However, current methods to classify these sources using the X-ray data themselves suffer problems—detailed X-ray spectroscopy of individual sources is too time consuming, while hardness ratios often lack accuracy, and can be difficult to use effectively. These methods fail to use the power of X-ray CCD detectors to identify X-ray emission lines and distinguish line-dominated spectra (from chromospherically active stars, supernova remnants, etc.) from continuum-dominated ones (e.g., compact objects or active galactic nuclei, AGN). In this paper, we probe the use of artificial neural networks (ANN) in differentiating Chandra spectra of young stars in the Chandra Orion Ultradeep Project (COUP) survey from AGN in the Chandra Deep Field South (CDFS) survey. We use these surveys to generate 100,000 artificial spectra of stars and AGN, and train our ANN models to separate the two kinds of spectra. We find that our methods reach an accuracy of ∼92% in classifying simulated spectra of moderate-brightness objects in typical exposures, but their performance decreases on the observed COUP and CDFS spectra (∼91%), due in large part to the relatively high background of these long-exposure data sets. We also investigate the performance of our methods with changing properties of the spectra such as the net source counts, the relative contribution of background, the absorption column of the sources, etc. We conclude that these methods have substantial promise for application to large X-ray surveys.

Tree stems are a net source of CH4 and N2O in a hemiboreal drained peatland forest during the winter period

Nutrient-rich northern peatlands are often drained to enhance forest productivity, turning peatland soils into sinks of methane (CH4) and sources of nitrous oxide (N2O). However, further attention is needed on CH4 and N2O dynamics during the winter period to fully understand the spatio-temporal variability of fluxes. Besides soil, tree stems can also emit CH4 and N2O. However, stem contribution is not considered in most biogeochemical models. We determined the temporal dynamics of winter-time CH4 and N2O fluxes in a drained peatland forest by simultaneously measuring stem and soil fluxes and exploring the relationships between gas fluxes and soil environmental parameters. During sampling (October 2020–May 2021), gas samples from Downy Birch (Betula pubescens) and Norway Spruce (Picea abies) trees were collected from different tree heights using manual static chambers and analysed using gas chromatography. Soil CH4 and N2O concentrations were measured using an automated dynamic soil chamber system. Tree stems were a net source of CH4 and N2O during the winter period. The origin of stem CH4 emissions was unclear, as stem and soil CH4 fluxes had opposite flux directions, and the irregular vertical stem flux profile did not indicate a connection between stem and soil fluxes. Stem N2O emissions may have originated from the soil, as emissions decreased with increasing stem height and were driven by soil N2O emissions and environmental parameters. Soil was a net sink for CH4, largely determined by changes in soil temperature. Soil N2O dynamics were characterised by hot moments—short periods of high emissions related to changes in soil water content. Tree stem emissions offset the soil CH4 sink by 14% and added 2% to forest floor N2O emissions. Therefore, CH4 and N2O budgets that do not incorporate stem emissions can overestimate the sink strength or underestimate the total emissions of the ecosystem.

Heterotrophic aquatic metabolism and sustained carbon dioxide emissions in a mineral-soil wetland restored with treated effluent

Wetlands are economically valuable ecosystems, in part because they purify wastewater by retaining and processing nutrients, organic matter (OM), and other pollutants. While natural wetlands are highly productive and sequester large pools of carbon (C), it is unclear whether the C cycle of restored treatment wetlands is functionally consistent with natural systems. This knowledge gap limits our appreciation for the role that wetland restoration can play as a natural solution to climate change. Here, we quantified metabolic and C cycling patterns of a restored, multi-basin wetland (Frank Lake, Alberta, Canada) receiving municipal and beef processing plant effluents rich in nutrients and OM. We conducted metabolic measurements in all three basins using dissolved oxygen sensors deployed under ice and in open water. Extreme production and respiration indicated that effluent was largely mineralized and replaced with wetland OM in transit. The heterotrophic status of all basins aligned with a published mass budget demonstrating the aquatic habitat of the wetland was an OM sink under current drought conditions that lengthen effluent processing time. Floating chamber measurements in open water zones confirmed that the wetland was a source of CO2 to the atmosphere. From input to outflow, sustained emissions led to declining pCO2 and a decline in the ratio of dissolved inorganic to organic C. Over 30 years post-restoration, the open water habitats in Frank Lake remain heterotrophic and a net source of CO2, suggesting that the trajectory of aquatic C cycling may be distinct from wetlands restored with non-effluent water sources.

Mapping the unjust global distribution of harmful fisheries subsidies

Harmful fisheries subsidies contribute to overfishing leading to environmental and societal impacts. If only fisheries and ecosystems within the subsidising nations’ jurisdiction were affected, then unilateral actions might be sufficient to help safeguard our ocean and the people reliant upon it. However, just as fish move between jurisdictions, so too do the subsidised fishing fleets that target them. As such, the impacts and solutions to subsidies-induced overfishing are often matters of international concern. Mapping the distribution and flows of harmful subsidies is therefore key to understanding these concerns, informing multilateral reform, and empowering impacted nations to strengthen the terms of access to their waters and resources. Here we quantify the amount of harmful fisheries subsidies that supports fishing in the high seas, domestic and foreign waters. We estimate that between 20% and 37% of all harmful fisheries subsidies support fishing in foreign waters or the high seas, that is outside the jurisdictions of the subsidising nations. We show that harmful subsidies primarily originate from nations with high-Human Development Index (HDI), strong fisheries management capacity and relatively sustainable fish stocks, yet disproportionately impact nations with low or very low-HDI, lower management capacity and more vulnerable fish stocks—40% of the harmful subsidies that support fishing in very low-HDI nations waters originate from high-HDI and very-high HDI nations. We show that Asia, Europe, and North America, are net subsidy sources; they provide more harmful subsidies to their fishing fleets than their respective ecosystems are impacted by; while Africa, South, Central America and Caribbean, and Oceania are net subsidy-sinks. This discrepancy between the source of harmful subsidies and the nations that are ultimately impacted is unsustainable and unjust. Prohibiting all harmful subsidies to distant-water fishing and fishing in the high seas—with narrow exceptions for Small Island Developing States—should be prioritised to support the advancement of sustainable and equitable fisheries worldwide.

Climate change mitigation potential of Louisiana's coastal area: Current estimates and future projections.

Coastal habitats can play an important role in climate change mitigation. As Louisiana implements its climate action plan and the restoration and risk reduction projects outlined in its 2017 Louisiana Coastal Master Plan, it is critical to consider potential greenhouse gas (GHG) fluxes in coastal habitats. This study estimated the potential climate mitigation role of existing, converted, and restored coastal habitats for years 2005, 2020, 2025, 2030, and 2050, which align with the Governor of Louisiana's GHG reduction targets. An analytical framework was developed that considered 1) available scientific data on net ecosystem carbon balance fluxes per habitat and 2) habitat areas projected from modeling efforts used for the 2017 Louisiana Coastal Master Plan to estimate the net GHG flux of coastal area. The coastal area was estimated as net GHG sinks of -38.4 ± 10.6 and - 43.2 ± 12.0 Tg CO2 equivalents (CO2 e) in 2005 and 2020, respectively. The coastal area was projected to remain a net GHG sink in 2025 and 2030, both with and without implementation of Coastal Master Plan projects (means ranged from -25.3 to -34.2 Tg CO2 e). By 2050, with model-projected wetland loss and conversion of coastal habitats to open water due to coastal erosion and relative sea level rise, Louisiana's coastal area was projected to become a net source of greenhouse gas emissions both with and without the Coastal Master Plan projects. However, at year 2050, Louisiana Coastal Master Plan project implementation was projected to avoid the release of +8.8 ± 1.3 Tg CO2 e compared to an alternative with no action. Reduction in current and future stressors to coastal habitats, including impacts from sea level rise, as well as the implementation of restoration projects could help to ensure coastal areas remain a natural climate solution.