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• The 57.00% of the Yangtze River Economic Belt area exhibited a significant increase in annual NPP. • The response of NPP on climate factors was nonlinear, with greater sensitivity to temperature. • The impact of topographic factors on NPP changes had a threshold effect. Net primary productivity (NPP) of terrestrial ecosystems serves as a crucial carbon sink, playing a significant role in mitigating climate change. This study, focusing on the Yangtze River Economic Belt (YREB), a key area for both economic development and ecological conservation in China, evaluates the temporal and spatial changes in regional NPP and its responses to climatic factors against the backdrop of global change. Utilizing long-term NPP and meteorological grid data from 1981 to 2017, we analyzed the annual change patterns of NPP and its linear and nonlinear responses to climatic factors using copula functions. Our findings indicate that 57.00 % of the YREB has experienced a significant increase in NPP, with the most substantial decreases observed in Shanghai and its surrounding areas (P < 0.05). Temperature emerged as the primary climatic driver, positively correlating with NPP changes in over half of the study area (P < 0.05). Moreover, the nonlinear response of NPP to temperature and precipitation underscores the complex interactions between these factors, revealing a sensitivity to temperature variations that surpasses that to precipitation. The study also highlights the influence of solar radiation and topographic factors, with a significant positive correlation between NPP and solar radiation observed in 15.85 % of the area (P < 0.05). The practical significance of these findings lies in their implications for regional ecological management and climate resilience strategies. The positive correlation between temperature and NPP underscores the potential for targeted temperature management to optimize carbon sequestration across the YREB. Furthermore, the identified nonlinear responses and the role of solar radiation and topography in influencing NPP offer valuable insights for the formulation of adaptive strategies that enhance ecosystem productivity and contribute to achieving carbon neutrality goals. By elucidating the dynamics of NPP in response to a range of environmental factors, this study provides a foundation for informed decision-making in ecological conservation and climate change mitigation efforts within the YREB and similar regions globally. [ABSTRACT FROM AUTHOR]

The cultivation of deep-rooted vegetation greatly alters the tradeoffs between water and carbon dynamics, yet their impact on microbial carbon sequestration (MCS) remains inadequately documented, particularly in thick vadose zones. This information is crucial for global climate mitigation and ecosystem service enhancement. As such, we collected triplicate samples for each land use type, exploring the abundance and structure of cbbL -harboring microbial communities within 10-m deep profiles under cultivated farmland and two apple orchards of varying ages (n = 72). Our findings indicated a shift from water-dominated (improved water retention at the expense of reduced carbon sequestration) to carbon-dominated benefits (enhanced carbon sequestration at the expense of decreased water retention) in deep soil layers (2–10 m) after the transformation from farmland to apple orchards. Despite the lack of significant differences among the three land use types, the gene abundances and microbial diversity indices reduced with soil depths because of variations in substrates, resources, and microenvironments. The cbbL -harboring microorganisms consisted of 5 phyla, 7 classes, 19 orders, 30 families, and 55 genera, with Proteobacteria as the predominant bacterial phylum. The relative contributions of different genera varied with soil depths, reflecting their distinct survival strategies. The microbial network was positively connected in various soil layers under farmland and apple orchards. Furthermore, the results of correlation, redundancy analysis, and structural equation modeling jointly indicated that plant roots and soil properties, including total nitrogen and organic carbon, governed MCS processes in deep unsaturated zones. Specifically, the low microbial variation between farmland and apple orchards can be attributed to the predominant effects of climatic and pedogenic factors on soil properties, the restricted contribution of plant roots to soil nutrient levels per unit depth, and the adverse effects of plant-induced ecohydrological consequences on root systems and microbial populations. This study offers new insights within thick vadose zones containing deep-rooted plants, thereby contributing to a better understanding of global terrestrial carbon cycle processes. [Display omitted] • Microbial carbon sequestration processes were explored in 10-m deep profiles. • The farmland-to-apple orchards conversion led to water-carbon tradeoffs. • Microbial carbon sequestration differed with depths rather than land use types. • Depth-dependent plant roots and soil nutrients affects carbon sequestration. [ABSTRACT FROM AUTHOR]

Non-native species are expanding globally and can alter ecosystem functions, including food web dynamics, community structure and carbon storage. Seagrass are foundation species that contribute a variety of ecosystem services in near-shore coastal ecosystems, including a significant sink of carbon. In the Caribbean, the rapidly expanding non-native Halophila stipulacea has unknown impacts on carbon storage. To investigate the impacts on carbon storage, we quantified organic carbon (C org) content in sediment and seagrass tissues from monotypic H. stipulacea beds, mixed native seagrass beds dominated by Thalassia testudinum and Syringodium filiforme, and unvegetated substrate in St. John, USVI. We found native seagrass-vegetated sediment contained 1.3 times more C org than sediment covered by H. stipulacea , and 1.6 times more C org than unvegetated areas on average. Whereas, H. stipulacea -dominated substrate stored 1.2 times more C org than unvegetated substrate. Likewise, native species contained 2.2 times more aboveground biomass and 6.0 times more belowground biomass than H. stipulacea. Since seagrasses are critical sources of carbon sequestration, our results suggest that invading H. stipulacea is associated with lower carbon stocks which has potential implications for conservation activities and climate change mitigation. [Display omitted] • Non-native species are expanding globally and can alter ecosystem functions. • Our results suggest that invading H. stipulacea is associated with lower carbon stocks. • In the Caribbean, rapidly expanding Halophila stipulacea may reduce carbon storage. [ABSTRACT FROM AUTHOR]

Abstract Assessing the status of important carbon sinks such as seagrass meadows is of primary importance when dealing with potential climate change mitigation strategies. This study examined plant and sediment properties in seagrass meadows (Cymodocea nodosa (Ucria) Asch.) from two high p CO 2 –low pH Mediterranean vent systems, located at Milos (Greece) and Vulcano (Italy) Islands, providing insights on carbon storage potential in future acidified oceans. Contrary to what has been suggested, carbon content (both inorganic and organic) and its surficial accumulation decreased at high p CO 2 –low pH in comparison with controls. The decrease in inorganic carbon may result from the higher solubility of carbonates due to the more acidic conditions. At Vulcano, the seagrass properties (e.g. , leaf area, biomass) appeared negatively affected by environmental conditions at high p CO 2 –low pH conditions and this may have had a detrimental effect on the organic carbon content and accumulation. At Milos, organic carbon decreased at high p CO 2 –low pH conditions, despite the increase in seagrass aboveground biomass, leaf length and area, probably as a consequence of site-specific features, which need further investigation and may include both biotic and abiotic factors (e.g., oligotrophic conditions, decreased sedimentation rate and input of allochthonous material). Results suggest that, in contrast to previous predictions based exclusively on the expected positive response of seagrasses to ocean acidification, carbon storage capacity of the seagrass C. nodosa may not increase at high p CO 2 -low pH conditions. This study emphasizes the need to investigate further the potential alteration in the climate mitigation service delivered by seagrass meadows in acidified oceans. Highlights • Seagrass features differed between control and low pH stations inconsistently in the two vents. • Carbon content and its surficial accumulation decreased at high p CO 2 –low pH conditions. • Carbon storage capacity of the seagrass may not increase at high p CO 2 -low pH conditions. [ABSTRACT FROM AUTHOR]

• Large uncertainties are associated with the future magnitude and stability of the forest carbon sink. • Business-as-usual management practices might already be close-to-optimum for supporting forest carbon uptake and storage. • Increases in management intensity have the potential to lower forest carbon sequestration and stocking capacity. • Forest management practices are as important as climate change to regulatethe carbon sink and stock size. Forest management practices might act as nature-based methods to remove CO 2 from the atmosphere and slow anthropogenic climate change and thus support an EU forest-based climate change mitigation strategy. However, the extent to which diversified management actions could lead to quantitatively important changes in carbon sequestration and stocking capacity at the tree level remains to be thoroughly assessed. To that end, we used a state-of-the-science bio-geochemically based forest growth model to simulate effects of multiple forest management scenarios on net primary productivity (NPP) and potential carbon woody stocks (pCWS) under twenty scenarios of climate change in a suite of observed and virtual forest stands in temperate and boreal European forests. Previous modelling experiments indicated that the capacity of forests to assimilate and store atmospheric CO 2 in woody biomass is already being attained under business-as-usual forest management practices across a range of climate change scenarios. Nevertheless, we find that on the long-term, with increasing atmospheric CO 2 concentration and warming, managed forests show both higher productivity capacity and a larger potential pool size of stored carbon than unmanaged forests as long as thinning and tree harvesting are of moderate intensity. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A 500 MW e oxy-coal power plant (PP) with CO 2 capture and storage (CCS) was considered. • 5% CO 2 emitted from the PP can be methanized using surplus electricity from renewables. • 80 % replacement by the PP with CCS contributed to lower 0.09 °C of global temperature. • Realistic implementation of coal PPs with CCS using renewable energy was provided. CO 2 -free power plants (PPs) with renewable electricity have promising sustainability implications, but the impact of their widespread use is yet to be determined. Here, the effect of an oxy-coal PP equipped with CO 2 capture, water electrolysis, and CO 2 methanation on electricity efficiency, CO 2 emission rate, CO 2 capture cost, and global surface temperatures (T g) was investigated. By exploiting surplus electricity from renewable sources for electrolysis, we estimated that 5 % of the CO 2 emitted from the coal PP was methanized. The process flow diagram of a 500 MW e decarbonized oxy-coal PP was constructed and its impact on energetic, economic, and environmental values was evaluated. The results were applied to a model of the global carbon cycle to predict T g considering the prospective global population and carbon emission rate (r ff) of fossil fuels by 2050. An 80 % replacement of conventional coal PPs worldwide by decarbonized oxy-coal PPs contributed to reducing r ff by 6.1 Gt CO2 /y in 2050 and lowering T g by 0.09 °C. The additional capital cost to replace 80 % of conventional coal PPs with decarbonized oxy-coal PPs, including associated geological storage costs, was estimated to be $43/t CO2. This study elucidates the promise and limitations of coal PPs designed for CO 2 capture, utilization, and storage (CCUS). Combining CCUS technologies with global warming estimates can be extended to examine the economic and climatic impact of CCUS under various CO 2 emission sources. [ABSTRACT FROM AUTHOR]

The Sloping Land Conversion Program (SLCP), preferentially initiated to reduce water loss and soil erosion in the Loess Plateau of China in 1999, is the largest eco-restoration project in the world in recent decades. This massive effort improved the vegetation conditions markedly and was expected to have a great potential to enhance terrestrial carbon (C) sequestration. However, the spatially-explicit C consequences of the SLCP remain largely unknown at the regional scale. Using Ansai County in the Loess Plateau as a case study, we assessed the impacts of the SLCP on ecosystem C dynamics based on the General Ensemble Biogeochemical Modeling System (GEMS). The results showed that ecosystem C stock (including C stored in biomass and soil) decreased slightly in the first five years after the implementation of the SLCP (i.e., 1999-2003) due to the low production of the newly forested land, and increased evidently (mostly in biomass) thereafter thanks primarily to the growth of young plantations. Overall, the study area functioned as a net C sink in the past three decades, yet the magnitude was greatly amplified by the SLCP, indicated by a C sink in 2004-2010 nearly twelve times that in 1978-1998 (41.5 vs. 3.5 g C m-2 yr-1). These results highlight the importance of the SLCP in promoting terrestrial C sequestration which may help mitigate climate change. Nevertheless, there were time-lags between the impact of the SLCP and the associated C dynamics in the eco-restored areas, particularly in the soil, calling for future efforts toward addressing long-term C consequences of the SLCP. [ABSTRACT FROM AUTHOR]

[Display omitted] • We compared two valuation approaches to assess carbon sequestration ecosystem service. • The retired lands in the "Grain for Green" project was used as an illustration. • The dynamic method obtained high economic value from carbon sequestration. • The dynamic method decreased the possibility of biomass harvesting. Carbon sequestration plays an essential role in climate regulation, and its monetary value is critical for decision-making. To encourage carbon sequestration and avoid expensing the ecosystem services for future generations, a dynamic monetary valuation perspective was developed by integrating a carbon dynamics model of ecosystems and an atmospheric carbon cycle model. A case study of biomass utilization in Northern Shaanxi was conducted to illustrative the performance of this approach by comparing with the conventional approach. The carbon dynamics in the available lands were simulated by the CENTURY model under the RCP4.5 climate change scenario. The results suggested that the carbon storage was doubled without biomass utilization in the projected 25 years. When biomass was harvested, carbon storage decreased slightly. The monetary value without biomass harvesting in the dynamic approach was higher than that in the conventional approach. After analogizing the monetary values of carbon sequestration and biomass utilization, there was a lower likelihood of biomass harvesting in the dynamic approach than in the conventional approach. [ABSTRACT FROM AUTHOR]

The African Sahel-Sudano-Guinean region is one of the largest water limited environments in the world, thus making it highly vulnerable to climate change. Recent studies have shown vegetation greening in the region, but few have investigated the impact of this greening on carbon and water cycles. We used a combination of earth observation (EO) data and a diagnostic model to evaluate the extent of the vegetation greening and its impacts on carbon sequestration potential (i.e., Gross Primary Productivity-GPP) and the water cycle (i.e., Evapotranspiration-ET and Water Use Efficiency-WUE) from 1982 to 2015. Additionally, we evaluated the influence of key climatic variables (i.e., precipitation, temperature, and solar radiation) on vegetation greening, carbon sequestration potential and the water cycle. Our results showed widespread vegetation greening during the first half of the study period (1982–2000), driven mainly by increase in precipitation. However, the rate of greening reduced or became stagnant during the latter half of the study (2000–2015), but did not revert to pre-greening levels of 1980s, implying a persistent ecosystem change. The vegetation greening and increased precipitation resulted in a ~ 17.95% increase in GPP (from ~3.9 PgC/year in 1982 to ~4.6 PgC/year in 2000) and a ~ 21.28% increase in ET (from ~47 mm/year in 1982 to ~57 mm/year in 2015). The WUE showed an overall reduction, mainly attributed to large increases in ET not matched by similar magnitude of increases in GPP. Currently, there is lack of consensus on the magnitude of the contribution of drylands to the global carbon and water cycle. This study shows that drylands undergoing ecosystem change, coupled with climate change, may in future become important contributors to the global carbon and water cycle. Therefore, they could play a key role in future global warming and climate change mitigation strategies. • Widespread vegetation greening from 1982 to 2000, which stagnates from 2000 to 2015 • Precipitation dynamics was the key driver to vegetation greening. • Greening led to increases in gross primary productivity and evapotranspiration. • Overall reduction in water use efficiency was observed in the region. • Potential changes in future role of drylands in the global carbon and water cycle. [ABSTRACT FROM AUTHOR]

Coastal marine vegetation has been recently highlighted for its highly efficient carbon storage capacity. Among the sixty-four species of seagrass, Posidonia oceanica , a Mediterranean endemic species, appears to be the most effective in carbon fixation and storage. Based on new data from the study of one of the largest P. oceanica meadows in the Mediterranean Sea (100 km of coastline, 20 425 ha), and a synthesis of available data from the whole of the Mediterranean basin, the aim of this work is to evaluate the amount of carbon fixed each year by P. oceanica and sequestered in the matte, in relation with the mitigation of the impact of climate change (carbon sink). The mean total carbon fixation (blades, sheaths and rhizomes) per year varies between 33.5 and 426.6 g C.m−2 and the mean carbon sequestration (long-term sink in the matte), corresponding to the sheath and rhizome tissues, varies between 7.7 and 84.4 g C.m−2, with a clear decreasing trend according to depth because of the meadow density decrease. The synthesis of a hundred measurements made throughout the Mediterranean Sea and at depths between 0.5 and 32.0 m provides a basis for estimating the average annual carbon fixation and sequestration rate throughout the Mediterranean basin. The fixation of the blades is estimated at 1 024 t C.ha−1.yr−1, that of the sheaths at 220 t C ha−1.yr−1 and that of the rhizomes at 58 t C ha−1.yr−1; i.e. a total fixation rate of 1 302 t C ha−1.yr−1 and sequestration rate (dead sheaths and rhizomes) of 278 t C ha−1.yr−1. This annual carbon fixation represents only 0.61% on average of CO 2 emissions/releases for all Mediterranean countries but in the large Mediterranean islands this fixation is on average 3.1% and can reach almost 14.4% for Corsica. Moreover, the major advantage of the P. oceanica meadow lies in its capacity to store carbon from annual carbon sequestration for centuries to millennia and can be compared to several terrestrial ecosystems considered to be efficient in carbon storage (peatlands). • First assessment of carbon fixation and sequestration by Mediterranean seagrass. • 5 681 206 tons of CO 2 emissions, are fixed annually by Posidonia oceanica. • 21% of this carbon is sequestered, annually, by the Posidonia oceanica soil (matte). • For Mediterranean islands, carbon fixation can reach up to 14.5% of carbon emissions. [ABSTRACT FROM AUTHOR]

• C org burial was evaluated in seagrass sediments at the northern Mexican Caribbean. • Thalassia testudinum seagrass meadows showed C org storage within ~ 40 to ~ 100 years. • C org stock increments were related with increasing sediment accumulation rates. • Seagrasses might be gradually impacted by population growth and land use changes. Carbon sequestration in seagrass meadows mitigates the currently rising CO 2 atmospheric levels, as these ecosystems are highly productive and preserve sediment organic carbon over long periods. Five 210Pb dated sediment cores, collected from seagrass meadows dominated by Thalassia testudinum in the northern Mexican Caribbean touristic corridor Cancun-Riviera Maya, were used to establish temporal trends of organic carbon (C org) content, burial rates and stock variation over the past 100 years. C org contents (0.17–1.94%) and burial rates (2.0–252 g m−2 yr−1) were generally within the lower end range reported for seagrass meadow sediments worldwide. C org stock gradually increased over the past decades, associated with increasing sediment accumulation, possibly caused by inland erosion promoted by agricultural and forestry activities and, in the recent decades, by a rapid increase of urban development due to a fast growth of the tourist industry and population, likely causing fertilization of coastal waters. Seagrass meadow sediments in the northern Mexican Caribbean coastline showed long-term C org storage and preservation, since ~ 40 to ~ 100 years depending on the core, which emphasizes the need to protect these ecosystems against impacts of global change, and their incorporation into climate change mitigation strategies should be considered. [ABSTRACT FROM AUTHOR]

Carbon capture and storage sites in Barents Sea shelf are currently in progress as part of climate change mitigation activities. However environmental impacts of a possible CO 2 seepage on bacterial community are lacking knowledge. This work addressed potential consequences on bacterial communities from Snøvit region in Barents Sea sediments. Long-term experiment (92 days) was carried out mimicking realistic conditions of pressure (∼30 bars) using the unique hyperbaric chamber (Karl Erik TiTank). The experiment was divided in three stages: i) 21 days of no CO 2 , ii) 50 days of simulation of carbon dioxide leakage (depletion of pH to 7.0) and iii) 14 days emulating a leakage cessation. Results suggested that bacterial communities can adapt to a CO 2 leakage in short term. However, bacteria showed negative effects in terms of activity, community structure, and number of cells after long term CO 2 exposure. After CO 2 leakage cessation, bacterial communities did not show a significant recovery. These findings highlighted that, even though marine bacteria showed adaptation to the new conditions (acidified environment), in case of a small but continuous CO 2 leakage marine bacteria might not be recovered upon pre-exposure status. • Simulation of real conditions of a CCS site are essentials for environmental risk assessments. • Marine bacteria may adapt to a new situation in case of acidification event for a short time. • Marine bacteria community is altered in case of a CO 2 leakage after 3 weeks in long-term simulation. • Results did not show a potential recovery of marine bacteria when CO 2 was stopped within the monitored period. [ABSTRACT FROM AUTHOR]