Total Carbon Uptake Research Articles

Planting Structures and Carbon Reduction Effects of Urban Greenspaces in Reclaimed Coastal Areas

Background and objective: In order to enhance the contribution of urban greenspaces to carbon uptake, it is essential to assess the carbon reduction effects of these areas. Accordingly, this study examined the planting structures and carbon reduction effects of urban greenspaces in reclaimed coastal areas (RCAs), which are characterized by unique growth conditions, such as high salinity, that distinguish them from inland areas.Methods: Field surveys were conducted across urban greenspaces in RCAs along the west and south coasts of Korea to document their planting structures and soil characteristics. Based on the obtained data, a quantitative analysis of the carbon reduction effect of trees and soil within these greenspaces was conducted.Results: It was found that the average tree cover in the surveyed greenspaces was 37.2%, while soil salinity and organic matter content were measured at 0.03% and 4.2%, respectively. The carbon storage per unit area of the greenspace, attributable to both trees and soil, reached 59.2 t/ha, with an estimated total annual carbon uptake of approximately 5.7 kt/year. This uptake is equivalent to offsetting the carbon emissions of about 153,000 people based on the energy consumption of residential buildings. Drawing on these results, this study proposed strategies to further enhance carbon reduction in reclaimed coastal greenspaces. The recommended strategies include optimizing soil conditions for plant growth, implementing multi-layered and clustered planting with medium and large trees, and selecting tree species that tolerate high salinity.Conclusion: Overall, this study makes a valuable contribution toward establishing a carbon uptake indicator for trees and soil in reclaimed coastal greenspaces, where relevant data are currently scarce. Future research should aim to include diverse types of greenspaces and larger sample sizes to more accurately capture annual soil carbon fluxes.

Carbon dioxide sequestration through mineralization from seawater: The interplay of alkalinity, pH, and dissolved inorganic carbon

Marine carbon dioxide removal technologies rely on the equilibration of seawater with atmospheric CO2, where a pH increase can facilitate CO2 removal either through increased absorption capacity of CO2, or precipitation of minerals. Here, we focus on explicitly defining the governing factors that influence seawater alkalinity with respect to CaCO3 mineralization and atmospheric CO2 uptake. We utilize an electrochemical setup and different water types, such as near-shore Mediterranean seawater and Red Sea Salt water. The setup allows us to separate mineralization from alkalinity enhancement via an electrochemical membrane cell, with a second compartment that allows evaluation of the interplay of ion concentration, precipitation, pH, DIC concentration, and total alkalinity under a controlled evironment. The effect of sparging additional CO2 before, and after the precipitation of CaCO3 was evaluated while utilizing both a mild pH swing (from, ∼8.3 to ∼9.5), and a larger pH swing (from, ∼8.3 to ∼10.2). A thermodynamic model is presented defining the energy consumptionrequired to increase the pH, and the influence of Mg thereon is explicated. Furthermore, we detail theoretical aquatic chemistry simulations via PHREEQC to rationalize the observed intricate dynamics of the carbonate system in seawater. We end with a discussion of the implications of total alkalinity, pH, salt complexation, and carbon uptake capacity relevant to of all ocean alkalinity enhancement and marine-based CO2 removal systems, concluding that the carbon uptake capacity of water returned to the ocean must be verified in such technologies.

The role of different ratios of biochar in the artificial lightweight cold-bonded aggregates (ALCBAs) containing high volume of red mud (RM)

To explore new channels for the effective recycling of red mud (RM) in the field of construction-related materials, and study the feasibility of applying biochar (BC) and RM into capturing CO2, this study developed the artificial lightweight cold-bonded aggregates mixed with high volume of RM (RM-ALCBAs). Different amount of BC (0%, 5%, 10% and 15%) was also added to the RM-ALCBAs, and a set of quantitative devices for assessing carbon absorption of RM-ALCBAs was innovatively developed. Meanwhile, its compressive strength, water absorption rate and apparent density were tested, and then the microscopic properties of RM-ALCBAs were also investigated by using TGA, XRD, SEM-EDS, MIP. Finally, the sustainability and heavy metal leaning behavior of RM-ALCBAs were assessed. It was found that the total carbon uptake of RM-ALCBAs was about 30.58–33.06 kg/tons, indicating that RM-ALCBAs show the obvious carbon-capturing potential, and when the biochar dosage was increased from 0% to 15%, its compressive strength was 1.28 MPa-1.98 MPa, and the water absorption rate and apparent density of RM-ALCBAs before carbonation were 17.96%-20.46% and 1.85 g/cm3-1.98 g/cm3, while the water absorption rate and apparent density of RM-ALCBAs after carbonation were 16.71%-17.04% and 2.02 g/cm3-1.83 g/cm3, respectively, which is in accordance with the specification of LWAs in China. With the increase of BC doping, the porosity in RM-ALCBAs gradually increased, the proportion of micropores gradually decreased, and the proportion of macropores gradually increased. More importantly, converting RM into RM-ALCBAs can effectively lower the toxic leaching and the concentration of heavy metals is also meet the Chinese requirements. RM-ALCBAs mixed with 5% BC has the lowest energy consumption per-unit compressive strength, carbon emission per-unit compressive strength with about 26.0–29.1 kg/t, and cost per-unit compressive strength with much lower than that of FA-ALCBAs and GGBFS-ALCBAs. Overall, the RM-ALCBAs have obvious eco-friendly potentials and belong to the carbon-negative construction materials that can effectively recycle solid waste of RM, which can provide some new insights and useful data for the development path of low-carbon ALCBAs.

Protecting an artificial savanna as a nature‐based solution to restore carbon and biodiversity in the Democratic Republic of the Congo

AbstractA large share of the global forest restoration potential is situated in artificial ‘unstable’ mesic African savannas, which could be restored to higher carbon and biodiversity states if protected from human‐induced burning. However, uncertainty on recovery rates in protected unstable savannas impedes science‐informed forest restoration initiatives. Here, we quantify the forest restoration success of anthropogenic fire exclusion within an 88‐ha mesic artificial savanna patch in the Kongo Central province of the Democratic Republic of the Congo (DR Congo). We found that aboveground carbon recovery after 17 years was on average 11.40 ± 0.85 Mg C ha−1. Using a statistical model, we found that aboveground carbon stocks take 112 ± 3 years to recover to 90% of aboveground carbon stocks in old‐growth forests. Assuming that this recovery trajectory would be representative for all unstable savannas, we estimate that they could have a total carbon uptake potential of 12.13 ± 2.25 Gt C by 2100 across DR Congo, Congo and Angola. Species richness recovered to 33.17% after 17 years, and we predicted a 90% recovery at 54 ± 2 years. In contrast, we predicted that species composition would recover to 90% of old‐growth forest composition only after 124 ± 3 years. We conclude that the relatively simple and cost‐efficient measure of fire exclusion in artificial savannas is an effective nature‐based solution to climate change and biodiversity loss. However, more long‐term and in situ monitoring efforts are needed to quantify variation in long‐term carbon and diversity recovery pathways. Particular uncertainties are spatial variability in socio‐economics and growing conditions as well as the effects of projected climate change.

CO2 emissions in the Amazon: are bottom-up estimates from land use and cover datasets consistent with top-down estimates based on atmospheric measurements?

Amazon forests are the largest forests in the tropics and play a fundamental role for regional and global ecosystem service provision. However, they are under threat primarily from deforestation. Amazonia's carbon balance trend reflects the condition of its forests. There are different approaches to estimate large-scale carbon balances, including top-down (e.g., CO2 atmospheric measurements combined with atmospheric transport information) and bottom-up (e.g., land use and cover change (LUCC) data based on remote sensing methods). It is important to understand their similarities and differences. Here we provide bottom-up LUCC estimates and determine to what extent they are consistent with recent top-down flux estimates during 2010 to 2018 for the Brazilian Amazon. We combine LUCC datasets resulting in annual LUCC maps from 2010 to 2018 with emissions and removals for each LUCC, and compare the resulting CO2 estimates with top-down estimates based on atmospheric measurements. We take into account forest carbon stock maps for estimating loss processes, and carbon uptake of regenerating and mature forests. In the bottom-up approach total CO2 emissions (2010 to 2018), deforestation and degradation are the largest contributing processes accounting for 58% (4.3 PgCO2) and 37% (2.7 PgCO2) respectively. Looking at the total carbon uptake, primary forests play a dominant role accounting for 79% (−5.9 PgCO2) and secondary forest growth for 17% (−1.2 PgCO2). Overall, according to our bottom-up estimates the Brazilian Amazon is a carbon sink until 2014 and a source from 2015 to 2018. In contrast according to the top-down approach the Brazilian Amazon is a source during the entire period. Both approaches estimate largest emissions in 2016. During the period where flux signs are the same (2015–2018) top-down estimates are approximately 3 times larger in 2015–2016 than bottom-up estimates while in 2017–2018 there is closer agreement. There is some agreement between the approaches–notably that the Brazilian Amazon has been a source during 2015–2018 however there are also disagreements. Generally, emissions estimated by the bottom-up approach tend to be lower. Understanding the differences will help improve both approaches and our understanding of the Amazon carbon cycle under human pressure and climate change.

Contribution of land use and cover change (LUCC) to the global terrestrial carbon uptake

Terrestrial carbon uptake is critical to the removal of greenhouse gases and mitigation of global warming, which are closely related to land use and cover change (LUCC). However, understanding terrestrial carbon uptake and the LUCC contribution remains unclear because of complex interactions with other drivers (particularly climate change). By proposing an innovative approach of “trajectory analysis”, this study aimed to isolate the LUCC contribution to terrestrial carbon uptake over different scales. Methodologically, global land was first divided into sub-regions of land transformations and stable land trajectories. Then, the carbon uptake change in the stable land trajectory was taken as a synthetic influence of climate change, which was used as a reference to isolate the carbon uptake alternation generated from the LUCC contribution in the land transformation trajectories. Finally, future LUCC and the terrestrial carbon uptake response were predicted under different development pathways. The results showed the global mean net ecosystem production (NEP) was 27.44 ± 36.51 g C m−2 yr−1 in the past two decades (2001–2019), generating 3.15 ± 0.88 Pg C yr−1 of the total terrestrial carbon uptake. Both the NEP and total carbon uptake showed significant increasing trends. Specifically, the mean NEP increased from 17.96 g C m−2 yr−1 in 2001 to 37.37 g C m−2 yr−1 in 2019, with the trend written as y = 1.20× + 15.20 (R2 = 0.62, p < 0.01). Meanwhile, the total carbon uptake increased from 2.35 Pg C yr−1 in 2001 to 4.13 Pg C yr−1 in 2019, which could be written as y = 0.12× + 1.93 (R2 = 0.56, p < 0.01). Climate change acted as the dominant factor for the trends at the global scale, which contributed 21.26 g C m−2 yr−1 and 1.59 Pg C yr−1 of the mean NEP and total carbon uptake changes in the stable land trajectories (94.30 million km2 that covered 63.29 % of the global land area), and the historical LUCC contributed −6.30 g C m−2 yr−1 (−40.85 %) and − 0.046 Pg C yr−1 (−57.50 %) of the mean NEP and the total carbon uptake change in the land transformation trajectories (6.64 million km2 that covered 4.46 % of the global land area), respectively. The maximum LUCC contribution (−61.85 g C m−2 yr−1) to the mean NEP occurred in the land transformations from evergreen needleleaf forests to woody savannas, while the maximum contribution (−0.034 Pg C y−1) to total carbon uptake was in the deforested regions from evergreen broadleaf forests to woody savannas. Eight SSP–RCP scenarios predictions demonstrated that future terrestrial carbon uptake would increase by an average of 0.015 Pg C yr−1 in 2100 due to global afforestation. SSP4–3.4 and SSP5–3.4 had the greatest potential for increasing carbon uptake, which is expected to reach a maximum increase (0.045 Pg C yr−1) in 2100. In contrast, the minimum terrestrial carbon uptake would occur in SSP5–8.5, which had the highest CO2 emissions. In conclusion, although relatively limited at the global scale, LUCC (particularly forest change) exerted an unneglectable role on terrestrial carbon uptake in land transformation regions. The results of this study will help to clarify terrestrial carbon uptake dynamics and provide a basis for carbon neutral and climatic adaptation.

Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed

Abstract. The Amazon River plume plays a critical role in shaping the carbonate chemistry over a vast area in the western tropical North Atlantic. We conduct a sensitivity analysis of hypothetical ocean alkalinity enhancement (OAE) via quicklime addition in the Amazon River watershed, examining the response of carbonate chemistry and air–sea carbon dioxide flux to the alkalinity addition. Through a series of sensitivity tests, we show that the detectability of the OAE-induced alkalinity increment depends on the perturbation strength (or size of the alkalinity addition, ΔTA) and the number of samples: there is a 90 % chance to meet a minimum detectability requirement with ΔTA&gt;15 µmol kg−1 and sample size &gt;40, given background variability of 15–30 µmol kg−1. OAE-induced pCO2 reduction at the Amazon plume surface would range between 0–25 µatm when ΔTA=20 µmol kg−1, decreasing with increasing salinity (S). Adding 20 µmol kg−1 of alkalinity at the river mouth could elevate the total carbon uptake in the Amazon River plume (15&lt;S&lt;35) by at least 0.07–0.1 Mt CO2 per month, and a major portion of the uptake would occur in the saltiest region (S&gt;32) due to its large size, comprising approximately 80 % of the S&gt;15 plume area. However, the lowest-salinity region (S&lt;15) has a greater drop in surface ocean partial pressure of CO2 (pCO2sw) due to its low buffer capacity, potentially allowing for observational detectability of pCO2sw reduction in this region. Reduced outgassing in this part of the plume, while more uncertain, may also be important for total additional CO2 uptake. Such sensitivity tests are useful in designing minimalistic field trials and setting achievable goals for monitoring, reporting, and verification purposes.

Carbon cycle extremes accelerate weakening of the land carbon sink in the late 21st century

Abstract. Increasing surface temperature could lead to enhanced evaporation, reduced soil moisture availability, and more frequent droughts and heat waves. The spatiotemporal co-occurrence of such effects further drives extreme anomalies in vegetation productivity and net land carbon storage. However, the impacts of climate change on extremes in net biospheric production (NBP) over longer time periods are unknown. Using the percentile threshold on the probability distribution curve of NBP anomalies, we computed negative and positive extremes in NBP. Here we show that due to climate warming, about 88 % of global regions will experience a larger magnitude of negative NBP extremes than positive NBP extremes toward the end of 2100, which accelerate the weakening of the land carbon sink. Our analysis indicates the frequency of negative extremes associated with declines in biospheric productivity was larger than positive extremes, especially in the tropics. While the overall impact of warming at high latitudes is expected to increase plant productivity and carbon uptake, high-temperature anomalies increasingly induce negative NBP extremes toward the end of the 21st century. Using regression analysis, we found soil moisture anomalies to be the most dominant individual driver of NBP extremes. The compound effect of hotness, dryness, and fire caused extremes at more than 50 % of the total grid cells. The larger proportion of negative NBP extremes raises a concern about whether the Earth is capable of increasing vegetation production with a growing human population and rising demand for plant material for food, fiber, fuel, and building materials. The increasing proportion of negative NBP extremes highlights the consequences not only of reduction in total carbon uptake capacity but also of conversion of land to a carbon source.

Microbial carbon fixation and its influencing factors in saline lake water

Microbial carbon fixation in saline lakes constitutes an important part of the global lacustrine carbon budget. However, the microbial inorganic carbon uptake rates in saline lake water and its influencing factors are still not fully understood. Here, we studied in situ microbial carbon uptake rates under light-dependent and dark conditions in the saline water of Qinghai Lake using a carbon isotopic labeling (14C-bicarbonate) technique, followed by geochemical and microbial analyses. The results showed that the light-dependent inorganic carbon uptake rates were 135.17–293.02 μg C L−1 h−1 during the summer cruise, while dark inorganic carbon uptake rates ranged from 4.27 to 14.10 μg C L−1 h−1. Photoautotrophic prokaryotes and algae (e.g. Oxyphotobacteria, Chlorophyta, Cryptophyta and Ochrophyta) may be the major contributors to light-dependent carbon fixation processes. Microbial inorganic carbon uptake rates were mainly influenced by the level of nutrients (e.g., ammonium, dissolved inorganic carbon, dissolved organic carbon, total nitrogen), with dissolved inorganic carbon content being predominant. Environmental and microbial factors jointly regulate the total, light-dependent and dark inorganic carbon uptake rates in the studied saline lake water. In summary, microbial light-dependent and dark carbon fixation processes are active and contribute significantly to carbon sequestration in saline lake water. Therefore, more attention should be given to microbial carbon fixation and its response to climate and environmental changes of the lake carbon cycle in the context of climate change.

Estimated Carbon Stock In The Mangrove Sylvo-Ecotourism Area, Tanjung Piayu Village, Sei Beduk District, Batam Island, Indonesia

The mangrove ecosystem acts as a carbon absorber in the atmosphere with more absorption capacity than other types of forest ecosystems. The mangrove sylvo-ecotourism area in Tanjungpiayu Village, Batam City, is part of the forest and land rehabilitation program carried out by BPDAS Sei Jang Duriangkang in the Riau Islands region. In an effort to provide data and information regarding the potential for carbon absorption in mangrove forest ecosystems resulting from the rehabilitation program, it is necessary to calculate the stored carbon stock as a reference for monitoring in subsequent years. The research was carried out from August to September 2023. The method used was the roaming method without harvesting using an allometric model. Data analysis was carried out by calculating the value of biomass, carbon stock and CO2 absorption. The analysis results show that the average total mangrove biomass at the top surface (ABG) and below the surface (BGB) is 420.50 tons/Ha with a biomass composition of AGB of 265.23 tons/Ha, and BGB of 155.27 tons/Ha. Ha. The average value of total carbon stock is 197.63 tonC/Ha with a carbon stock composition of AGB of 124.66 tonC/Ha and BGB of 72.97 tonC/Ha. Furthermore, the average value of total carbon uptake is 724.65 CO2 e ton /Ha with a carbon uptake composition of ABG of 457.07 CO2 e ton /Ha and BGB of 267.58 CO2 e ton /Ha.

Microbial carbon use efficiency along an altitudinal gradient

Soil microbial carbon-use efficiency (CUE), described as the ratio of growth over total carbon (C) uptake, i.e. the sum of growth and respiration, is a key variable in all soil organic matter (SOM) models and critical to ecosystem C cycling. However, there is still a lack of consensus on microbial CUE when estimated using different methods. Furthermore, the significance of many fundamental drivers of CUE remains largely unknown and inconclusive, especially for tropical ecosystems. For these reasons, we determined CUE and microbial indicators of soil nutrient availability in seven tropical forest soils along an altitudinal gradient (circa 900–2200 m a.s.l) occurring at Taita Hills, Kenya. We used this gradient to study the soil nutrient (N and P) availability and its relation to microbial CUE estimates. For assessing the soil nutrient availability, we determined both the soil bulk stoichiometric nutrient ratios (soil C:N, C:P and N:P), as well as SOM degradation related enzyme activities. We estimated soil microbial CUE using two methods: substrate independent 18O-water tracing and 13C-glucose tracing method. Based on these two approaches, we estimated the microbial uptake efficiency of added glucose versus native SOM, with the latter defined by 18O-water tracing method. Based on the bulk soil C:N stoichiometry, the studied soils did not reveal N limitation. However, soil bulk P limitation increased slightly with elevation. Additionally, based on extracellular enzyme activities, the SOM nutrient availability decreased with elevation. The 13C-CUE did not change with altitude indicating that glucose was efficiently taken up and used by the microbes. On the other hand, 18O-CUE, which reflects the growth efficiency of microbes growing on native SOM, clearly declined with increasing altitude and was associated with SOM nutrient availability indicators. Based on our results, microbes at higher elevations invested more energy to scavenge for nutrients and energy from complex SOM whereas at lower elevations the soil nutrients may have been more readily available.

Housing starts and the associated wood products carbon storage by county by Shared Socioeconomic Pathway in the United States.

Harvested wood products found in the built environment are an important carbon sink, helping to mitigate climate change, and their trends in use are determined by economic and demographic factors, which vary spatially. Spatially detailed projections of construction and stored carbon are needed for industry and public decision making, including for appreciating trends in values at risk from catastrophic disturbances. We specify econometric models of single-family and multifamily housing starts by U.S. Census Region, design a method for their spatial downscaling to the county level, and project their quantities and carbon content according to the five Shared Socioeconomic Pathways (SSPs). Starts are projected to decline across all scenarios and potentially drop to below housing replacement levels under SSP3 by mid-century. Wood products carbon stored nationally in structures in use and in landfills is projected to grow across all scenarios but with significant spatial heterogeneity related to disparate trends in construction across counties, ranging from strong growth in the urban counties of the coastal South and West to stagnation in rural counties of the Great Plains and the northern Rockies. The estimated average annual carbon stored in wood products used in and discarded from US residential housing units between 2015-2070 ranged from 51 million t CO2e in SSP3 to 85 million t CO2e in SSP5, representing 47% to 78% of total carbon uptake relative to uptake by all wood products in the United States in 2019.

The importance of understanding the regulation of bacterial metabolism.

The importance of understanding the regulation of bacterial metabolism.

Remotely sensed carotenoid dynamics improve modelling photosynthetic phenology in conifer and deciduous forests

Detecting the phenology of photosynthesis, which conveys the length of the growing season, is key for terrestrial ecosystem models to constrain total annual carbon uptake and estimate gross primary productivity (GPP). However, some of the vegetation indices that are widely used for modelling GPP lack the ability to represent changes in the magnitude of photosynthesis, leading to errors in detecting phenology and large uncertainties. Crucially, remotely sensed vegetation indices such as the photochemical reflectance index (PRI) and chlorophyll/carotenoid index (CCI) can detect changes in foliar carotenoid composition that represent adjustments in photosynthetic light-use-efficiency (LUE) and changes in phenology. We modeled GPP from remote sensing data using PRI and CCI to represent foliar carotenoid changes as proxies for LUE. GPP values estimated from these PRI and CCI modified LUE models were compared against GPP from eddy covariance flux tower measurements, MODerate Resolution Imaging Spectroradiometer (MODIS) GPP product, conventional meteorological driven LUE-model, and process-based dynamic global vegetation model (ie. JULES) in an evergreen needleleaf and a deciduous broadleaf forest in the Great Lakes region. Overall, and in particular for evergreen needleleaf forests, estimates of start and end of growing season using PRI and CCI LUE-models showed less year-to-year variability than estimates obtained by process-based meteorological models. Although many process-based models provide reasonable estimates of start and end of growing season, our results demonstrate that using regulatory carotenoids and photosynthetic efficiency can improve remote monitoring of the phenology of forest vegetation.

Increasing Functional Diversity in a Global Land Surface Model Illustrates Uncertainties Related to Parameter Simplification

AbstractSimulations of the land surface carbon cycle typically compress functional diversity into a small set of plant functional types (PFT), with parameters defined by the average value of measurements of functional traits. In most earth system models, all wild plant life is represented by between five and 14 PFTs and a typical grid cell (≈100 × 100 km) may contain a single PFT. Model logic applied to this coarse representation of ecological functional diversity provides a reasonable proxy for the carbon cycle, but does not capture the non‐linear influence of functional traits on productivity. Here we show through simulations using the Energy Exascale Land Surface Model in 15 diverse terrestrial landscapes, that better accounting for functional diversity markedly alters predicted total carbon uptake. The shift in carbon uptake is as great as 30% and 10% in boreal and tropical regions, respectively, when compared to a single PFT parameterized with the trait means. The traits that best predict gross primary production vary based on vegetation phenology, which broadly determines where traits fall within the global distribution. Carbon uptake is more closely associated with specific leaf area for evergreen PFTs and the leaf carbon to nitrogen ratio in deciduous PFTs.

Carbon footprint of crop production in Heilongjiang land reclamation area, China

In the context of global warming, agriculture, as the second-largest source of greenhouse gas emissions after industry, had attracted widespread attention from all walks of life to reduce agricultural emissions. The carbon footprint of the planting production system of the Heilongjiang Land Reclamation Area (HLRA), an important commodity grain base in China, was evaluated and analyzed in this paper. On this basis, this paper sought feasible strategies to reduce carbon emissions from two aspects: agronomic practices and cropping structure adjustment, which were particularly crucial to promote the low-carbon and sustainable development of agriculture in HLRA. Therefore, using the accounting methods in IPCC and Low Carbon Development and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories compiled by the Chinese government, relevant data were collected from 2000 to 2017 in HLRA and accounted for the carbon emissions of the planting production system in four aspects: carbon emissions from agricultural inputs, N2O emissions from managed soils, CH4 emissions from rice cultivation and straw burning emissions. Then carbon uptake consisted of seeds and straws. Finally, with farmers' incomes were set as the objective function and carbon emissions per unit of gross production value was set as the constraint, this paper simulated and optimized the cropping structure in HLRA. The results showed that there was a “stable-growing-declining” trend in the total carbon emissions and carbon uptake of the planting production system in HLRA, with total carbon emissions of 2.84×1010 kg and total carbon uptake of 7.49×1010 kg in 2017. In the past 18 years, carbon emissions per unit area and carbon emissions per unit of gross production had both shown a decreasing trend. To achieve further efficiency gains and emission reductions in the planting production system, it was recommended that the local governments strengthen the comprehensive use of straw resources, optimize irrigation and fertilization techniques, and adjust the cropping structure, i.e., increase the planting area of maize and soybeans and reduce the planting area of rice, and increase subsidies to protect the economic returns of planters. Keywords: carbon footprint, carbon emissions, carbon uptake, crop planting structure, Heilongjiang Land Reclamation Area DOI: 10.25165/j.ijabe.20221501.5588 Citation: Chu T S, Yu L, Wang D R, Yang Z L. Carbon footprint of crop production in Heilongjiang land reclamation area, China. Int J Agric & Biol Eng, 2022; 15(1): 182–191.

Potential of carbon stock on red jabon stand (Anthocephalus macrophyllus (Roxb.) Havil) in Tampinna Village, Angkona District, Luwu Timur Regency

In addition to producing wood as a raw material for construction, pulp and firewood, forests also serve as carbon sinks so they have an important role in the global carbon cycle. Red jabon is a fast-growing plant species, so it is suspected to have high carbon absorption. The purpose of this study is to know the potential of carbon content and increased uptake of carbon above the soil surface for species of red jabon (Anthocephalus macrophyllus (Roxb.) Havil) in the forest Tampinna village community. Methods of data collection in the field is done by census, that is data retrieval as a whole. In the sample tree, the diameter measured at breast height (dbh) and tree height (TBC). Furthermore, the resulting data was processed to determine the biomass produced by using allometric equations. Samples of 302 red jabon trees were obtained from six sites with four different age levels, which were three to six years old. Based on the result of paired observation test of red jabon biomass prediction by using volume formula gives bigger result than allometric equation. The average potential of total carbon uptake in red jabon stands is 19.57125 ton/ha. In general, there is a tendency that the older age of the tree stands to produce a large carbon content as well. Equation of relationship between age with carbon content in the form of quadratic.

Land cover change-induced decline in terrestrial gross primary production over the conterminous United States from 2001 to 2016

As one of the most dynamic aspects of global environmental change, land cover change (LCC) has a profound impact on terrestrial carbon sequestration. However, LCC-induced carbon fluxes are still the most uncertain terms in global and regional carbon budgets. Ecosystem gross primary production (GPP) is the total carbon uptake by vegetation through photosynthesis, serving as a major control on ecosystem function and land carbon balance during and after the modification of the land surface. However, accurately capturing LCC-induced GPP changes requires both high-quality land cover data and controlling for variation driven by other environmental factors such as climate. In this study, we comprehensively examined the effects of LCC on annual GPP trends over the conterminous United States (CONUS) from 2001 to 2016 using the USGS National Land Cover Database, a remote sensing-driven ecosystem model, and the Google Earth Engine cloud computing platform. We designed a series of model experiments to identify LCC effects on GPP by controlling climate effects. During the study period, LCC exerted a strong negative effect on total GPP across the CONUS ([-2.2, -1.8] Tg C yr−2), while climate had smaller positive effects ([0.17, 0. 92] Tg C yr−2). The LCC-induced reduction of GPP was mainly caused by net forest loss ([-1.98, -1.39] Tg C yr−2) and urban expansion ([-2.03, -1.92] Tg C yr−2), but was partially offset by increases in crop area ([+0.66, +0.79] Tg C yr−2). Ensemble simulations from TRENDY did not capture the strong negative LCC influences on GPP, likely due to limitations of the adopted land use/cover data. Our study provides a novel perspective on LCC-induced GPP changes, which could help to improve our understanding of ecosystem function changes and constrain the estimation of land carbon balance in the context of anthropogenic activity and climate change.

Physiological Responses of Mesodinium major to Irradiance, Prey Concentration and Prey Starvation.

Ciliates within the Mesodinium rubrum/Mesodinium major species complex harbor chloroplasts and other cell organelles from specific cryptophyte species. Mesodinium major was recently described, and new studies indicate that blooms of M. major are just as common as blooms of M. rubrum. Despite this, the physiology of M. major has never been studied and compared to M. rubrum. In this study, growth, food uptake, chlorophyll a and photosynthesis were measured at six different irradiances, when fed the cryptophyte, Teleaulax amphioxeia. The results show that the light compensation point for growth of M.major was significantly higher than for M.rubrum. Inorganic carbon uptake via photosynthesis contributed by far most of total carbon uptake at most irradiances, similar to M.rubrum. Mesodinium major cells contain ~four times as many chloroplast as M. rubrum leading to up to ~four times higher rates of photosynthesis. The responses of M. major to prey starvation and refeeding were also studied. Mesodinium major was well adapted to prey starvation, and 51d without prey did not lead to mortality. Mesodinium major quickly recovered from prey starvation when refed, due to high ingestion rates of >150prey/predator/d.

Characteristics of Different Size Phytoplankton for Primary Production and Biochemical Compositions in the Western East/Japan Sea.

The current phytoplankton community structure is expected to change, with small phytoplankton becoming dominant under ongoing warming conditions. To understand and evaluate the ecological roles of small phytoplankton in terms of food quantity and quality, the carbon uptake rates and intracellular biochemical compositions (i.e., carbohydrates, CHO; proteins, PRT; and lipids, LIP) of phytoplankton of different sizes were analyzed and compared in two different regions of the western East/Japan Sea (EJS): the Ulleung Basin (UB) and northwestern East/Japan Sea (NES). The average carbon uptake rate by the whole phytoplankton community in the UB (79.0 ± 12.2 mg C m–2 h–1) was approximately two times higher than that in the NES (40.7 ± 2.2 mg C m–2 h–1), although the average chlorophyll a (chl a) concentration was similar between the UB (31.0 ± 8.4 mg chl a m–2) and NES (28.4 ± 7.9 mg chl a m–2). The main reasons for the large difference in the carbon uptake rates are believed to be water temperature, which affects metabolic activity and growth rate, and the difference in euphotic depths. The contributions of small phytoplankton to the total carbon uptake rate were not significantly different between the regions studied. However, the rate of decrease in the total carbon uptake with increasing contributions from small phytoplankton was substantially higher in the UB than in the NES. This result suggests that compared to other regions in the EJS, the primary production in the UB could decrease rapidly under ongoing climate change. The calorific contents calculated based on biochemical compositions were similar between the small (1.01 ± 0.33 Kcal m–3) and large (1.14 ± 0.36 Kcal m–3) phytoplankton in the UB, whereas the biochemical contents were higher in the large phytoplankton (1.88 ± 0.54 Kcal m–3) than in the small phytoplankton (1.06 ± 0.18 Kcal m–3) in the NES. The calorific values per unit of chl a were higher for the large phytoplankton than for the small phytoplankton in both regions, which suggests that large phytoplankton could provide a more energy efficient food source to organisms in higher trophic levels in the western EJS.