Net Loss Research Articles

Mixed-cultivation grasslands enhance runoff generation and reduce soil loss in the restoration of degraded alpine hillsides

Abstract. Vegetation restoration is among the most effective measures for controlling runoff and soil erosion resulting from human activities. Nevertheless, few studies have been undertaken to analyze the effects of grassland restoration on maintaining local runoff, especially on alpine degraded hillsides where mixed-cultivation grasslands predominate. In this research, runoff plots were established to investigate the impact of three mixed-cultivation grasslands, each sowing two grass species per plot on a 20° slope: Deschampsia cespitosa and Elymus nutans (DE), Poa pratensis L. cv. Qinghai and Elymus nutans (PE), and Poa pratensis L. cv. Qinghai and Deschampsia cespitosa (PD). The activation and volume of surface runoff and the magnitude of soil loss on alpine degraded hillsides over 3 years (2019, 2020, and 2022) were assessed. A severely degraded meadow (SDM) plot was used as a control. The findings indicated that mixed-cultivation grasslands can effectively maintain runoff and reduce soil loss as planting age increases. Between 2019 and 2022, the values of the average runoff depth for DE, PE, PD, and SDM were 0.47, 0.55, 0.45, and 0.27 mm, respectively. Despite the increase in runoff, grassland restoration favored soil conservation: the net soil losses per unit area of SDM were 1.4, 1.3, and 1.9 times greater than those in DE, PE, and PD, respectively. The key factors affecting soil loss and runoff were rainfall amount, duration, and intensity (60 min intensity). We conclude that the results of this study can serve as scientific guides to formulate efficient policy decisions for planning the most effective vegetation restoration in severely degraded hillside alpine meadows. To improve the effectiveness of grassland restoration, we suggest that protective measures should be prioritized during the initial planting stage of cultivated grasslands.

Assessing the societal value of health lost to alcohol use in India compared to excise taxes on alcohol sales.

We retrospectively studied the societal value of lost health due to alcohol use and compared it with excise taxes on alcohol sales for India in 2019. We estimated the overall alcohol-attributable disease burden using disability-adjusted life-years (DALY) for India and its 30 states for all causes with alcohol use as a risk factor from the GBD 2019 Study. The societal value of lost health was calculated using value of life-year (VLY) approach by multiplying region-specific factors from 'Global Health 2035', 2019-2020 GDP per capita and DALYs. We acquired the national and state-level (top 10 states) alcohol sales excise taxes from the Reserve Bank of India. Net losses were assessed by subtracting the revenue collected from excise taxes from VLY. All values are in Indian rupees (INR). The societal value of health lost due to alcohol use in India was 6.2 (95% uncertainty interval 4.8, 7.8) trillion INR in 2019. The absolute state-level values varied from 7.3 (4.7, 10.4) billion INR in Mizoram to 1.1 (0.8, 1.4) trillion INR in Maharashtra. The per capita values ranged from 950.2 (642.9, 1285.3) INR for Bihar to 61,332 (39,273.7, 87,288.5) INR for Mizoram. Nationally, excise tax collection from alcohol sales was 1.8 trillion INR depicting a net loss of 4.4 (3.1, 6.0) trillion. Maharashtra had the largest absolute and per capita net loss. These are novel estimates depicting the net losses due to alcohol use in India with direct policy implications to disincentivise sales and adequately raise taxes.

Near-surface ocean temperature and air-sea heat flux observed by a buoy array during summer to autumn in year 2014 in the northern South China Sea

The observational data of the air-sea interface and upper ocean elements from a buoy array deployed in the northern South China Sea from June to November 2014 is analyzed. The COARE 3.0 algorithm was adopted to examine the variability of air-sea heat fluxes and their contributions to near-surface ocean temperature changes. During the observation period, air-sea heat exchange in the northern South China Sea is primarily determined by solar shortwave radiation and latent heat flux, with net heat flux mostly negative, indicating that the ocean predominantly loses heat. In autumn, net heat flux loss significantly increased by an average of 34.4 W/m2, primarily due to enhanced latent heat loss driven by stronger winter monsoon. During typhoon period, net air-sea heat flux was significantly suppressed, mainly due to reduced solar shortwave radiation, with minimal contribution from sensible heat flux. Near-surface ocean temperature exhibited a seasonal cooling trend, averaging 29.7°C in summer and 28.4°C in autumn. The maximum cooling during typhoon reached 3.1°C, with minimal contribution from air-sea heat flux. During the monsoon transition period, weaker winds led to a slight increase in near-surface ocean temperature, with air-sea heat flux contributing 70.2% and 56.3% to this process. During winter monsoon, more uniform water column mixing resulted in a gradual decrease in near-surface ocean temperature, with air-sea heat flux contributing over 60% to this process.

Chromosome breakage-replication/fusion enables rapid DNA amplification.

DNA rearrangements are thought to arise from two classes of processes. The first class involves DNA breakage and fusion ("cut-and-paste") without net DNA gain or loss. The second class involves aberrant DNA replication ("copy-and-paste") and can produce either net DNA gain or loss. We previously demonstrated that the partitioning of chromosomes into aberrant structures of the nucleus, micronuclei or chromosome bridges, can generate cut-and-paste rearrangements by chromosome fragmentation and ligation. Surprisingly, in the progeny clones of single cells that have undergone chromosome bridge breakage, we identified large segmental duplications and short sequence insertions that are commonly attributed to copy-and-paste processes. Here, we demonstrate that both large duplications and short insertions are inherent outcomes of the replication and fusion of unligated DNA ends, a process we term breakage-replication/fusion (B-R/F). We propose that B-R/F provides a unifying explanation for complex rearrangement patterns including chromothripsis and chromoanasynthesis and enables rapid DNA amplification after chromosome fragmentation.

Replacing Tobacco with Hemp in the Beqaa Is Financially Rewarding for Farmers and Government in Lebanon

Lebanon has been grappling with severe financial and monetary crisis since 2019. In this context, minimizing losses and finding additional revenue sources to sustain state operations have become imperative. One potential solution is to replace subsidized tobacco farming, which has no economic value, with hemp farming for industrial and medicinal purposes. This shift not only ensures economic efficiency but also provides farmers with a moral and profitable crop. However, until now, there has been no scientific study examining the economic impact of hemp cultivation in Lebanon’s Beqaa area. To address this gap, we conducted a Cost-Benefit Analysis within a Business Plan framework to assess the benefits of replacing tobacco with hemp and to provide decision-makers with data-driven strategies. For this analysis, we obtained accurate data on tobacco farming from the state-owned Tobacco Monopoly (Regie), while data on hemp was sourced from existing literature and adapted to Lebanon. Our findings indicate that tobacco farming currently generates USD 828 per dunam for farmers but results in a net loss of USD 317 per dunam to the economy, a shortfall subsidized by the Regie. In contrast, hemp yields a net profit of USD 2405 per dunam, equating to an overall gain of USD 19,240,000 in the Bekaa Valley area. This stark contrast in profitability underscores the potential of hemp as a more lucrative and sustainable alternative to tobacco.

Traditional taboos: informal and invisible protection of remaining patches of forest in Vhembe District in Limpopo, South Africa

IntroductionSince 1990, there has been a global decline in forest areas. Between 2010 and 2020, the greatest annual net loss of forests was on the African continent. Despite South African indigenous forests and trees being protected under the National Forests Act of 1998 (Act No. 84 of 1998), the country has also shown an increased annual net loss of forests. Although the Vhembe District Municipality in South Africa has lost forest owing to human-induced deforestation and other land use activities, sacred forests have not been affected. According to traditional beliefs, exploitation of such indigenous patches of sacred forests is taboo. This study aims to explore the role of taboos in the protection of the remaining patches of sacred forest.MethodsThe study relies on data collected between December 2022 and December 2023. Semi-structured interviews were conducted with key informants (n = 61) and local communities in Tshidzivhe and Duthuni villages (n = 60). Observations were used as a further data collection tool. The interview questions were prepared to assess the role of taboos in the protection and management of sacred forests. Data collected through interviews were analysed using thematic content analysis, while field observations helped to corroborate the results from the interviews. Results and discussionThe study identified two main taboos – one that restricts entry into the sacred forests (i.e. preventing entry into the sacred forests, and harvesting, hunting and hiking in these areas), and another that prohibits noise or activities that disrespect sacred forests. The study found that believers and non-believers alike, for fear of retribution by the spirits, still obey these taboos and their related myths. This has allowed these areas to develop dense stands of closed-canopy evergreen forest that support more diverse flora and fauna than found in surrounding areas. Although sacred forests are not meant for biodiversity conservation, they offer opportunities to be integrated into global conservation targets of “30x30” and “Half-Earth” by 2030. They also offer the opportunity of serving as carbon sinks which is key to climate change mitigation. Recommendations for protecting sacred forests and associated taboos are drawn up based on these results.

Genomic diversity and evolution of the Hawaiian Islands endemic Kokia (Malvaceae).

Island species are highly vulnerable due to habitat destruction and their often small population sizes with reduced genetic diversity. The Hawaiian Islands constitute the most isolated archipelago on the planet, harboring many endemic species. Kokia is an endangered flowering plant genus endemic to these islands, encompassing 3 extant and 1 extinct species. Recent studies provided evidence of unexpected genetic diversity within Kokia. Here, we provide high-quality genome assemblies for all 3 extant Kokia species, including an improved genome for Kokia drynarioides. All 3 Kokia genomes contain 12 chromosomes exhibiting high synteny within and between Kokia and the sister taxon Gossypioides kirkii. Gene content analysis revealed a net loss of genes in K. cookei compared to other species, whereas the gene complement in K. drynarioides remains stable and that of Kokia kauaiensis displays a net gain. A dated phylogeny estimates the divergence time from the last common ancestor for the 3 Kokia species at ∼1.2 million years ago (mya), with the sister taxa (K. cookei + K. drynarioides) diverging ∼0.8 mya. Kokia appears to have followed a stepping-stone pattern of colonization and diversification of the Hawaiian archipelago, likely starting on low or now submerged older islands. The genetic resources provided may benefit conservation efforts of this endangered endemic genus.

A large net carbon loss attributed to anthropogenic and natural disturbances in the Amazon Arc of Deforestation

The Amazon forest contains globally important carbon stocks, but in recent years, atmospheric measurements suggest that it has been releasing more carbon than it has absorbed because of deforestation and forest degradation. Accurately attributing the sources of carbon loss to forest degradation and natural disturbances remains a challenge because of the difficulty of classifying disturbances and simultaneously estimating carbon changes. We used a unique, randomized, repeated, very high-resolution airborne laser scanning survey to provide a direct, detailed, and high-resolution partitioning of aboveground carbon gains and losses in the Brazilian Arc of Deforestation. Our analysis revealed that disturbances directly attributed to human activity impacted 4.2% of the survey area while windthrows and other disturbances affected 2.7% and 14.7%, respectively. Extrapolating the lidar-based statistics to the study area (544,300 km2), we found that 24.1, 24.2, and 14.5 Tg C y-1 were lost through clearing, fires, and logging, respectively. The losses due to large windthrows (21.5 Tg C y-1) and other disturbances (50.3 Tg C y-1) were partially counterbalanced by forest growth (44.1 Tg C y-1). Our high-resolution estimates demonstrated a greater loss of carbon through forest degradation than through deforestation and a net loss of carbon of 90.5 ± 16.6 Tg C y-1 for the study region attributable to both anthropogenic and natural processes. This study highlights the role of forest degradation in the carbon balance for this critical region in the Earth system.

Net evaporation-induced mangrove area loss across low-lying Caribbean islands

Abstract Although mangroves provide many beneficial ecosystem services, such as blue carbon storage and coastal protection, they are currently under threat due to changes in climate conditions, such as prolonged drought exposure. Under drought conditions, evaporation exceeds precipitation and high soil salinities can lead to stunted growth and die-back. To quantify this interplay, we developed a database for low-lying and uninhabited mangrove islands in the Caribbean under various evaporation and precipitation regimes. We extracted physical and biological information from each island using remote sensing techniques and coupled it with a process-based model. We used this database to develop a model that explains both the spatial variability in vegetated area across the Caribbean—as a function of rates of evaporation and precipitation—and porewater salinity concentration and dispersion from island edge towards the interior of mangrove islands. We then used this validated model to predict mangrove area loss associated with increases in evaporation to precipitation rates by 2100 for different Shared Socioeconomic Pathways (SSP). Less wealthy Caribbean regions such as Belize, Puerto Rico, and Venezuela are disproportionally affected, with mangrove area losses ranging from 3%–7% for SSP 2.6 and 13%–21% for SSP 7.0. Furthermore, foregone carbon sequestration in lost biomass under SSP 4.5 and 7.0 scenarios could compromise the ability of low-lying Caribbean mangrove islands to vertically adjust to sea level rise.

The presentation of income and other comprehensive income in the IAS Conceptual Framework

Introduction. The articulation of profit or loss and other comprehensive income increases the usefulness and faithfully represent information in financial statements. The IAS Conceptual Framework assigns primacy to the reflecting changes measurement assets and liabilities, expressed in terms of rights or requirements with respect to profit or loss. The result of this balance-sheet approach is that net income is determined as a by-product of the recognition and measurement of net assets in the balance sheet. At the same time recognized other comprehensive income. However, other comprehensive income, due to its lack of firm theoretical underpinnings, removes only the incoherencies related to capital- maintenance adjustments, is a debated question that remains unresolved what determines the relevance of the research and enables the formation of its purpose. The purpose of the article is to identify the advantages and disadvantages of applying the balance-sheet approach in determining net income or loss and to study their impact on the accounting practice of non-financial companies. Methods. The methodological basis of the study is the application of a systematic approach to improving the application of the balance-sheet model when determining net profit with the recognition of total income, comparative analysis, scientific generalization – for the study of the approaches proposed by scientists to the calculation of net profit and the use of the principle of matching between revenues and expenses, structural-logical and semantic analysis – to determine the shortcomings of the application of the balance-sheet model for non-financial companies, induction and deduction, abstract-logical – to improve the methodology of using the balance-sheet model taking into account the principles of accrual and compliance, tabular – to determine the list of transactions, as a result of which other aggregate income is recognized and establish the advantages of using the model balance. Results. The determined that the number of operations that require adjustment of assets and liabilities according to requirements IAS increases. As a consequence, profit conventional (realised) and other comprehensive income (unrealised) are recognized, which is not sufficiently represented by the Conceptual Framework. Taking the first step in the above, considered the merits of the concept of the balance-sheet approach: separate presentation of realized and unrealized income or losses (other comprehensive income), accounting for changes in the value of assets and liabilities in the longterm, control over adjustments of previously unrealized income and losses, separate presentation of revaluation results of assets and of articles that are to be reclassified, true presentation of the amount of net assets in the balance-sheet for each reporting date, separation of taxable and of nontaxable income, reduction of uncertainty. Conclusions and prospects. Installed, that the balance-sheet approach in the Framework is a good starting point for evaluating issues of recognition and measurement net assets, profit or loss. However, taking into the implications of а common practice, the of a pure balance-sheet approach cannot be used satisfactorily in non-financial companies without taking into account principles for accrual and matching in the part of the main operating activity. The informative income statement should convey a measure of profit from sales and that requires some form of matching. Mixed approach is more comprehensive, allowing for complementary roles for balance-sheet of an income statement. Common using in practice matching when determining income from operating activities and the balance-sheet method requires more detailed research in subsequent scientific work.

Nitrogen Loss from Pluto’s Birth to the Present Day via Atmospheric Escape, Photochemical Destruction, and Impact Erosion

We estimate the loss of nitrogen from Pluto over its lifetime, including the giant planet instability period, which we term the “Wild Years.” We analyze the orbital migration of 53 simulated Plutinos, which are Kuiper Belt Objects (KBOs) captured into 3:2 mean-motion resonance with Neptune during the instability. This orbital migration brought the Plutinos from 20 to 30 au to their present-day orbits near 40 au along a nonlinear path that includes orbits with semimajor axes from 10 to 100 au. We model the thermal history that results from this migration and estimate the volatile loss rates due to the ever-changing thermal environment. Due to the early Sun’s enhanced ultraviolet radiation, the photochemical destruction rate during the Wild Years was a factor of 100 higher than the present-day rate, but this only results in a loss of ∼10 m global equivalent layer (GEL). The enhanced Jeans escape rate varies wildly with time, and a net loss of ∼100 cm GEL is predicted. Additionally, we model the impact history during the migration and find that impacts are a net source, not loss, of N2, contributing ∼100 cm GEL. The 100 cm GEL is 0.1% of the amount of N2 in Sputnik Planitia. We therefore conclude that Pluto did not lose an excessive amount of volatiles during the Wild Years, and its primordial volatile inventory can be approximated as its present-day inventory. However, significant fractions of this small total loss of N2 occurred during the Wild Years, so estimates made using present-day rates will be underestimates.

Summer Monsoon Drying Accelerates India's Groundwater Depletion Under Climate Change

AbstractGroundwater in north India remains a vital food and water security resource for more than one billion people. Both summer monsoon drying, and winter warming pose considerable challenges for rapidly declining groundwater. However, their impacts on irrigation water demands and groundwater storage under the observed and projected future climate remain unexplored. Using in situ observations, satellite data, and a hydrological model that considers the role of irrigation and groundwater pumping, we show that summer monsoon drying and winter warming accelerate groundwater depletion in north India during the observed climate, which will continue in the projected future climate. Summer monsoon precipitation has significantly (P‐value = 0.04) declined (∼8%) while winters have become warmer in north India during 1951–2021. Both satellite (GRACE/GRACE‐FO) and hydrological model‐based estimates show a rapid groundwater depletion (∼1.5 cm/year) in north India with a net loss of 450 km3 of groundwater during 2002–2021. The summer monsoon drying followed by winter warming cause a substantial reduction in groundwater storage due to reduced groundwater recharge and enhanced pumping to meet irrigation demands. Summer monsoon drying and winter warming will continue to affect groundwater storage in north India in the future. For instance, summer monsoon drying (10%–15% deficit for near‐far periods) followed by substantial winter warming (1–4°C) in the future will further accelerate groundwater depletion by increasing (6%–20%) irrigation water demands and reducing groundwater recharge (6%–12%). Groundwater sustainability measures including reducing groundwater abstraction and enhancing the groundwater recharge during the summer monsoon seasons are needed to ensure future agricultural production.

How adoption of new pharmaceuticals can impact US health system reimbursement under alternative payment models: An economic model measuring the impact of sotagliflozin among patients with heart failure and diabetes.

Heart failure (HF) is among the leading causes of death in the United States. Further, patients hospitalized because of HF with comorbid diabetes mellitus (DM) are at a significantly increased risk of death and rehospitalization. Results from the SOLOIST-WHF trial show that sotagliflozin lowered rates of readmission among hospitalized patients with HF and comorbid DM. However, it is unclear what the economic impact of the use of sotagliflozin would be on hospitals and health systems, particularly in an age where provider reimbursement is increasingly tied to value. To quantify the 1-year financial impact on US provider health systems of adopting sotagliflozin relative to standard of care (SoC) across different alternative payment models. This study created a 3-part decision tree model to quantify the financial impact of using sotagliflozin to treat patients hospitalized with HF in a US hospital setting. The model first estimated the clinical and economic outcomes of health systems with current SoC (no sotagliflozin) to treat US patients hospitalized for HF with comorbid DM. Then, using the results from the SOLOIST trial, the changes in clinical and economic outcomes with sotagliflozin adoption were modeled. Finally, the differences in health care utilization between sotagliflozin and SoC arms were translated to differences in health system reimbursement in the context of 3 common alternative payment models (APMs) in addition to the baseline fee-for-service (FFS) model: FFS with the Hospital Readmissions Reduction Program, the Bundled Payments for Care Improvement-Advanced program, and Accountable Care Organizations. A typical community hospital would have 83.4 patients per year on average with an index HF hospitalization with comorbid DM. The model predicted that sotagliflozin would reduce the probability of hospitalization, emergency department visits, and deaths by 29.3%, 38.5%, and 17.8%, respectively, compared with SoC. For hospitals not participating in APM programs, sotagliflozin resulted in a net loss of $92.94 per person ($7,754 per health system). Conversely, when accounting for provider health system participation in APMs, sotagliflozin adoption increased financial returns by $4,720 per person ($305,604 per health system) under the Hospital Readmissions Reduction Program, $1,200 per person ($100,106 per health system) for the Bundled Payments for Care Improvement-Advanced program, and $1,078 per person ($31,029 per health system) for Accountable Care Organizations. Based on the national average composition of APM reimbursement, sotagliflozin adoption resulted in a $1,576 increase in margin per patient with HF ($105,454 per health system). Although sotagliflozin adoption reduced health system revenue in an FFS payment model, it led to a net positive financial impact after accounting for APM bonus payments.

In-corporating Crisis: Time to Shift the UK Paradigm away from Shareholder Primacy

Shareholder primacy has reigned supreme for over a century and is considered one of the bedrock principles upon which the modern UK corporation is built. This article explores this complex evolution and argues in favour of an alternative theory for the corporation. This alternative theory is advanced because shareholder primacy is flawed in its modern-day adoption. This article deconstructs the foundations for the leading shareholder primacy model. It argues that shareholder primacy fails to recognise the corporation as an entity where wealth maximisation for shareholders is the primary goal. Moreover, the externalities that this model has resulted in are a net loss to economic and environmental welfare generally. Furthermore, shareholder primacy is based upon the ideology that shareholders are an easily identifiable ‘unit’ with one voice. This article deconstructs this as a basis to justify shareholder primacy and identifies that the wide dispersion of shareholders undermines this argument. It proposes a progressive method, the pluralist approach, to advance the ‘new’ modern corporation to affirm the corporation’s position in the market and to reduce negative externalities.

Phagocytosis of aggrecan-positive perineuronal nets surrounding motor neurons by reactive microglia expressing MMP-9 in TDP-43Q331K ALS model mice

Perineuronal nets (PNNs) are extracellular matrix structures that surround excitable neurons and their proximal dendrites. PNNs play an important role in neuroprotection against oxidative stress. Oxidative stress within motor neurons can act as a trigger for neuronal death, and this has been implicated in motor neuron degeneration in amyotrophic lateral sclerosis (ALS). We therefore characterised PNNs around alpha motor neurons and the possible contributing cellular factors in the mutant TDP-43Q331K transgenic mouse, a slow onset ALS mouse model. PNNs around alpha motor neurons showed significant loss at mid-stage disease in TDP-43Q331K mice compared to wild type strain control mice. PNN loss coincided with an increased expression of matrix metallopeptidase-9 (MMP-9), an endopeptidase known to cleave PNNs, within the ventral horn. During mid-stage disease, increased numbers of microglia and astrocytes expressing MMP-9 were present in the ventral horn of TDP-43Q331K mice. In addition, TDP-43Q331K mice showed increased levels of aggrecan, a PNN component, in the ventral horn by microglia and astrocytes during this period. Elevated aggrecan levels within glia were accompanied by an increase in fractalkine expression, a chemotaxic protein responsible for the recruitment of microglia, in alpha motor neurons of onset and mid-stage TDP-43Q331K mice. Following PNN loss, alpha motor neurons in mid-stage TDP-43Q331K mice showed increased 3-nitrotyrosine expression, an indicator of protein oxidation. Together, our observations along with previous PNN research provide suggests a possible model whereby microglia and astrocytes expressing MMP-9 degrade PNNs surrounding alpha motor neurons in the TDP-43Q331K mouse. This loss of nets may expose alpha-motor neurons to oxidative damage leading to degeneration of the alpha motor neurons in the TDP-43Q331K ALS mouse model.

Reduced accrual of mineral-associated organic matter after two years of enhanced rock weathering in cropland soils, though no net losses of soil organic carbon

Enhanced rock weathering (ERW), the application of crushed silicate rock to soil, can remove atmospheric carbon dioxide by converting it to (bi) carbonate ions or solid carbonate minerals. However, few studies have empirically evaluated ERW in field settings. A critical question remains as to whether additions of crushed rock might positively or negatively affect soil organic matter (SOM)—Earth’s largest terrestrial organic carbon (C) pool and a massive reservoir of organic nitrogen (N). Here, in three irrigated cropland field trials in California, USA, we investigated the effect of crushed meta-basalt rock additions on different pools of soil organic carbon and nitrogen (i.e., mineral-associated organic matter, MAOM, and particulate organic matter, POM), active microbial biomass, and microbial community composition. After 2 years of crushed rock additions, MAOM stocks were lower in the upper surface soil (0–10 cm) of plots with crushed rock compared to unamended control plots. At the 2 sites where baseline pre-treatment data were available, neither total SOC nor SON decreased over the 2 years of study in plots with crushed rock or unamended control plots. However, the accrual rate of MAOM-C and MAOM-N at 0–10 cm was lower in plots with crushed rock vs. unamended controls. Before ERW is deployed at large scales, our results suggest that field trials should assess the effects of crushed rock on SOM pools, especially over multi-year time scales and in different environmental contexts, to accurately assess changes in net C and understand the mechanisms driving interactions between ERW and SOM cycling.

Accounting for deep soil carbon in tropical forest conservation payments

Secondary tropical forests are at the forefront of deforestation pressures. They store large amounts of carbon, which, if compensated for to avoid net emissions associated with conversion to non-forest uses, may help advance tropical forest conservation. We measured above- and below-ground carbon stocks down to 1 m soil depth across a secondary forest and in oil palm plantations in Malaysia. We calculated net carbon losses when converting secondary forests to oil palm plantations and estimated payments to avoid net emissions arising from land conversion to a 22-year oil palm rotation, based on land opportunity costs per hectare. We explored how estimates would vary between forests by also extracting carbon stock data for primary forest from the literature. When tree and soil carbon was accounted for, payments of US$18–51 tCO2–1 for secondary forests and US$14–40 tCO2–1 for primary forest would equal opportunity costs associated with oil palm plantations per hectare. If detailed assessments of soil carbon were not accounted for, payments to offset opportunity costs would need to be considerably higher for secondary forests (US$28–80 tCO2–1). These results show that assessment of carbon stocks down to 1 m soil depth in tropical forests can substantially influence the estimated value of avoided-emission payments.

A grazing crab drives saltmarsh carbon storage and recovery.

Consumers can directly (e.g., consumption) and indirectly (e.g., trophic cascades) influence carbon cycling in blue carbon ecosystems. Previous work found that large grazers have nuanced effects on carbon stocks, yet, small, bioturbating-grazers, which remove plant biomass and alter sediment properties, remain an understudied driver of carbon cycling. We used field-derived and remote sensing data to quantify how the purple marsh crab, Sesarma reticulatum, influenced carbon stocks, flux, and recovery in salt marshes. Sesarma caused a 40%-70% loss in carbon stocks as fronts propagated inland (i.e., ungrazed to recovered transition), with front migration rates accelerating over time. Despite latitudinal differences, front migration rate had no effect on carbon stocks, flux, or time to replacement. When we included Sesarma disturbance in carbon flux calculations, we found it may take 5-100 years for marshes to replace lost carbon, if at all. Combined, we show that small grazers cause a net loss in carbon stocks as they move through the landscape, and irrespective of migration rate, these grazer-driven impacts persist for decades. This work showcases the significant role of consumers in carbon storage and flux, challenging the classic paradigm of plant-sediment feedbacks as the primary ecogeomorphic driver of carbon cycling in blue carbon ecosystems.

On-site and in-kind: Compensatory mitigation of California Coastal Zone habitat impacts between 2010 and 2018

Planning development while minimizing negative impacts to sensitive habitats poses a challenge for global natural resource management. After impacts from development are avoided and minimized, remaining adverse impacts may be offset using compensatory mitigation. Along the California coast, the California Coastal Commission (CCC) regulates development and subsequent mitigation for allowable impacts. We reviewed publicly available CCC staff reports for approved projects that impacted coastal habitats and required compensatory mitigation from 2010 to 2018. The median project size was approximately 728 square meters and almost all permanent impacts were mitigated at a >1:1 ratio, with regional and habitat-specific planning regulations driving some variation across the state. We found that wetlands were the most frequently impacted and had higher mitigation ratios. Temporary impacts were almost always mitigated at a 1:1 ratio. While most mitigation was on-site and in-kind, mitigation that was required off-site had a median distance of 4.7 km from the site of impact. Restoration was the most frequent mitigation action, over creation, enhancement, or preservation, but proportions of each action varied across habitat types. While our findings suggest no net loss of habitat area within the California Coastal Zone, the net change in ecosystem function is dependent on the performance of the mitigation projects. This review is only the first step in evaluating the success of compensatory mitigation along California's coast.

Evaluating the Impact of CO2 Capture on the Operation of Combined Cycles with Different Configurations

In order to reduce greenhouse gas emissions associated with power generation, the replacement of fossil fuels with renewables must be accompanied by the availability of dispatchable sources needed to balance electricity demand and production. Combined cycle (CC) power plants adopting post-combustion capture (PCC) can serve this purpose, ensuring near-zero CO2 emissions at the stack, as well as high efficiency and load flexibility. In particular, the chemical absorption process is the most established approach for industrial-scale applications, although widespread implementation is lacking. In this study, different natural gas combined cycle (NGCC) configurations were modeled to estimate the burden of retrofitting the capture process to existing power plants on thermodynamic performance. Simulations under steady-state conditions covered the widest possible load range, depending on the gas turbine (GT) model. Attention was paid to the net power loss and net efficiency penalty attributable to PCC. The former can be mitigated by lowering the GT air–fuel ratio to increase the CO2 concentration (XCO2) in the exhaust, thus decreasing the regeneration energy. The latter is reduced when the topping cycle is more efficient than the bottoming cycle for a given GT load. This is likely to be the case in the less-complex heat recovery units.