Ecosystem Feedbacks Research Articles

Effects of increased allochthonous dissolved organic carbon on the growth of planktonic biota in freshwater ecosystems: A meta‐analysis

AbstractWater browning, induced by allochthonous dissolved organic carbon (DOC) input, has become a widespread phenomenon in boreal lakes over the past decades. Directly quantifying aquatic organisms' responses to increased DOC concentrations is essential for projecting carbon cycle processes in freshwater ecosystems. In this study, we assessed the impacts of DOC addition on the growth of three freshwater planktonic groups: phytoplankton, zooplankton, and bacteria, and explored potential drivers behind variations in effect size. Background DOC concentrations vary between 0.5 and 25 mg L−1, while total phosphorus concentrations span from 0.0003 to 1.55 mg L−1. Based on a meta‐analysis of 804 observations from 47 publications, we found that DOC addition had a significant positive effect on bacteria, while it had a small but negative impact on both phytoplankton and zooplankton. In different climate zones, DOC addition often stimulated bacterial growth, but it exerted either positive or negative effects on phytoplankton and zooplankton. Additionally, the effect sizes of both phytoplankton and zooplankton showed a significant negative relationship with the magnitude of DOC enrichment, while bacteria exhibited positive responses. Furthermore, the effect sizes of these three taxa correlated negatively with background total phosphorus concentrations and positively with the DOC : total phosphorus ratio. A significant negative correlation between effect size and experimental duration was observed for bacteria. In summary, this synthesis indicates that excessive DOC loading can inevitably inhibit phytoplankton and zooplankton growth. Future studies should focus on the interactions between DOC addition and global change factors to improve forecasts of carbon‐climate feedback in aquatic ecosystems.

Heating up the roof of the world: tracing the impacts of in-situ warming on carbon cycle in alpine grasslands on the tibetan plateau

Abstract Climate warming may induce substantial changes in ecosystem carbon cycle, particularly for those climate-sensitive regions, such as alpine grasslands on the Tibetan Plateau. By synthesizing findings from in-situ warming experiments, this review elucidates the mechanisms underlying the impacts of experimental warming on carbon cycle dynamics within these ecosystems. Generally, alterations in vegetation structure and prolonged growing season favor strategies for enhanced ecosystem carbon sequestration under warming conditions. Whilst warming modifies soil microbial communities and their carbon-related functions, its effects on soil carbon release fall behind the increased vegetation carbon uptake. Despite no significant accumulation of soil carbon stock has been detected upon warming, notable changes in its fractions indicate potential shifts in carbon stability. Future studies should prioritize deep soil carbon dynamics, the interactions of carbon, nitrogen, and phosphorus cycles under warming scenarios, and the underlying biological mechanisms behind these responses. Furthermore, the integration of long-term warming experiments with Earth system models is essential for reducing the uncertainties of model predictions regarding future carbon-climate feedback in these climate-sensitive ecosystems.

Global Distributions of Reactive Iron and Aluminum Influence the Spatial Variation of Soil Organic Carbon.

Organic carbon persistence in soils is predominantly controlled by physical accessibility rather than by its biochemical recalcitrance. Understanding the regulation of soil iron (Fe) and aluminum (Al) (hydr)oxides, playing a dominant role in mineral protection, on soil organic carbon (SOC) would increase the reliable projections of the feedback of terrestrial ecosystems to global warming. Here, we conducted a continental-scale survey in China (341 sites) and a global synthesis (6786 observations) to reveal the global distributions of Fe/Al (hydr)oxides and their effects on SOC storage in terrestrial ecosystems. We generated the first global maps of soil Fe/Al (hydr)oxides with high accuracy (with R2 more than 0.74). The variance decomposition analysis showed that Fe/Al (hydr)oxides explained the most proportion of variance for topsoil (0-30 cm) and subsoil (30-100 cm) SOC. Therefore, soil Fe/Al (hydr)oxides play a stronger role in explaining the spatial variation of SOC than well-studied climate, edaphic, vegetated, and soil depth factors in both topsoil and subsoil. Collectively, the planetary-scale significance of soil Fe/Al (hydr)oxides for SOC highlights that soil Fe/Al (hydr)oxides should be incorporated into Earth System Models to reduce the uncertainty in predicting SOC dynamics.

Organic carbon decomposition temperature sensitivity positively correlates with the relative abundance of copiotrophic microbial taxa in cropland soils

Revealing the relationships between the temperature sensitivity of soil organic matter decomposition (Q10) and microbial communities is critical to predict ecosystem feedbacks to global warming. However, the relationships are still far from well understood, especially within the low latitude regions. To address this knowledge gap, soil samples were collected from >100 cropland sites in Southwest China, a region with highly diverse climatic and environmental conditions. The results showed that Q10 values substantially varied across the region, ranging from 1.85 to 6.81, with an average value of 3.27. They were significantly positively correlated with the contents of soil organic carbon, while negatively correlated with the ratios of soil dissolved organic carbon to total organic carbon content. This indicates that soils with high organic carbon contents are more vulnerable to global warming. Further analysis suggested that Q10 values were positively correlated with soil microbial respiration rates, fungal abundance, prokaryotic diversity, and the relative abundance of copiotrophic microbial lineages, but negatively correlated with the proportions of oligotrophic microbes and microbial co-occurrence network degree. The structural equation modeling analysis suggested that soil organic carbon and its quality, as well as microbial attributes were the main factors explaining the variation in Q10 values. The findings in this study highlight the crucial and complex roles of soil microbiome in determining ecosystem feedbacks to global warming.

Root physiological and morphology processes co-regulate the growth of Chinese-fir saplings in response to warming and precipitation reduction in the sub-tropical regions

Subtropical China is projected to experience elevated temperature greater than the mean global temperature increase and is accompanied by reduced precipitation. The plasticity of roots to changing environment strongly influences ecosystem feedbacks to climate change. However, knowledge gaps on the individual and combined effects of warming and precipitation reduction on root systems hinder our ability to accurately predict the growth and adaptability of forests under future climate change. To examine the effects of warming (W) and precipitation reduction (P) on roots physiology and morphology of Chinese-fir saplings, we used a randomized complete block design with factorial soil warming (ambient, ambient + 5℃) and precipitation reduction (ambient, ambient-50 %) treatments. A full excavation method was adopted to obtain roots, then we measured the root physiology (osmoregulatory substances, oxidant substances, protective enzymes, endogenous hormones), morphology (specific root length, SRL; surface root area, SRA; root tissue density, RTD). The content of carbon and nitrogen, isotopes (δ13C and δ15N); soil temperature, soil moisture and sapling growth were also measured. We found that compared with the control, W decreased the abscisic acid (IAA) content; P increased the contents of hydrogen peroxide (H2O2) and proline (Pro), and decreased the contents of IAA and cytokinin (CTK); warming plus precipitation reduction (WP) increased the Pro content, and decreased the contents of IAA and CTK. In addition, the effects of W and P on root morphology varied with soil depth and root diameter class. W, P, and WP all increased fine root SRL and SRA in deep soil. Warming and precipitation reduction could affect physiological traits (e.g. non-enzymatic substances and antioxidant enzymes) and subsequently morphological traits via influencing soil environment and root tissue chemistry. Collectively, the results indicated that Chinese-fir saplings responded to warming and precipitation reduction by comprehensive regulation of the non-enzymatic substances (e.g., osmotic substances and endogenous hormones) of fine roots and changing root morphological characteristics in deep soil.

Annual time-series 1 km maps of crop area and types in the conterminous US (CropAT-US): cropping diversity changes during 1850–2021

Abstract. Agricultural activities have been recognized as an important driver of land cover and land use change (LCLUC) and have significantly impacted the ecosystem feedback to climate by altering land surface properties. A reliable historical cropland distribution dataset is crucial for understanding and quantifying the legacy effects of agriculture-related LCLUC. While several LCLUC datasets have the potential to depict cropland patterns in the conterminous US, there remains a dearth of a relatively high-resolution datasets with crop type details over a long period. To address this gap, we reconstructed historical cropland density and crop type maps from 1850 to 2021 at a resolution of 1 km × 1 km by integrating county-level crop-specific inventory datasets, census data, and gridded LCLUC products. Different from other databases, we tracked the planting area dynamics of all crops in the US, excluding idle and fallow farm land and cropland pasture. The results showed that the crop acreages for nine major crops derived from our map products are highly consistent with the county-level inventory data, with a residual less than 0.2×103 ha (0.2 kha) in most counties (>75 %) during the entire study period. Temporally, the US total crop acreage has increased by 118×106 ha (118 Mha) from 1850 to 2021, primarily driven by corn (30 Mha) and soybean (35 Mha). Spatially, the hot spots of cropland distribution shifted from the Eastern US to the Midwest and the Great Plains, and the dominant crop types (corn and soybean) expanded northwestward. Moreover, we found that the US cropping diversity experienced a significant increase from the 1850s to the 1960s, followed by a dramatic decline in the recent 6 decades under intensified agriculture. Generally, this newly developed dataset could facilitate spatial data development, with respect to delineating crop-specific management practices, and enable the quantification of cropland change impacts on the environment. Annual cropland density and crop type maps are available at https://doi.org/10.6084/m9.figshare.22822838.v2 (Ye et al., 2023).

Additive effects of N addition and changing precipitation on soil respiration in a climate transitional forest

Global carbon (C) cycling can be greatly affected by the increasing nitrogen (N) deposition and changing precipitation regimes in terrestrial ecosystems. Nevertheless, whether N enrichment and precipitation variability interactively or additively influence soil C release during a long-term period remain largely elusive. Here, a seven-year (2016–2022) field experiment was conducted to explore the responses of soil respiration to N addition, decreased and increased precipitation in a subtropical-warm temperate forest in Central China. The results showed soil respiration was elevated by 11.0%, 12.2%, and 12.3% under N addition, decreased precipitation, and increased precipitation, respectively, primarily originating from the enhancements in plant root respiration. Increased precipitation led to a temporal increase in soil respiration over the experimental period, mostly due to the elevating understory richness and reducing soil C/N ratio. There were additive effects between N addition and changing precipitation on soil respiration observed in our study, suggesting that the impacts of concurrent global change drivers can be predicted from their respective influences. These findings indicated that global change may intensify soil C release from climate transition forests, thus helping to accurately assess the climate change–C feedback in natural ecosystems.

Nitrogen input modulates the effects of coastal acidification on nitrification and associated N2O emission

Acidification of coastal waters, synergistically driven by increasing atmospheric carbon dioxide (CO2) and intensive land-derived nutrient inputs, exerts significant stresses on the biogeochemical cycles of coastal ecosystem. However, the combined effects of anthropogenic nitrogen (N) inputs and aquatic acidification on nitrification, a critical process of N cycling, remains unclear in estuarine and coastal ecosystems. Here, we showed that increased loading of ammonium (NH4+) in estuarine and coastal waters alleviated the inhibitory effect of acidification on nitrification rates but intensified the production of the potent greenhouse gas nitrous oxide (N2O), thus accelerating global climate change. Metatranscriptomes and natural N2O isotopic signatures further suggested that the enhanced emission of N2O may mainly source from hydroxylamine (NH2OH) oxidation rather than from nitrite (NO2−) reduction pathway of nitrifying microbes. This study elucidates how anthropogenic N inputs regulate the effects of coastal acidification on nitrification and associated N2O emissions, thereby enhancing our ability to predict the feedbacks of estuarine and coastal ecosystems to climate change and human perturbations.

Estimating the global root exudate carbon flux

Root exudation, the export of low-molecular weight organic carbon (C) from living plant roots to soil, influences microbial activity, nutrient availability, and ecosystem feedbacks to climate change, but the magnitude of this C flux at ecosystem and global scales is largely unknown. Here, we synthesize in situ measurements of root exudation rates and couple those to estimates of fine root biomass to estimate global and biome-level root exudate C fluxes. We estimate a global root exudate flux of 13.4 (10.1–20.2) Pg C y−1, or about 9% (7–14%) of global annual gross primary productivity. We did not find differences in root mass-specific exudation rates among biomes, though total exudate fluxes are estimated to be greatest in grasslands owing to their high density of absorptive root biomass. Our synthesis highlights the global importance of root exudates in the terrestrial C cycle and identifies regions where more in situ measurements are needed to improve future estimates of root exudate C fluxes.

Plant functional traits modulate the effects of soil acidification on above- and belowground biomass

Abstract. Atmospheric sulfur (S) deposition has been increasingly recognized as a major driver of soil acidification. However, little is known about how soil acidification influences above- and belowground biomass by altering leaf and root traits. We conducted a 3-year S-addition experiment to simulate soil acidification in a meadow. Grass (Leymus chinensis (Trin.) Tzvelev) and sedge (Carex duriuscula C.A.Mey) species were chosen to evaluate the linkage between plant traits and biomass. Sulfur addition led to soil acidification and nutrient imbalances. Soil acidification decreased specific leaf area (SLA) but increased leaf dry-matter content (LDMC) in L. chinensis, showing a conservative strategy and thus suppressing aboveground instead of belowground biomass. However, in C. duriuscula, soil acidification increased plant height and root nutrients (N, P, S, and Mn), favoring competition for natural resources through enhanced above- and belowground biomass, i.e., adoption of an acquisitive strategy. Increased soil acidity resulted in an overall reduction in aboveground community biomass by 3 %–33 %, but it led to an increase in community root biomass by 11 %–22 % due to upregulation as a result of higher soil nutrient availability. Our results demonstrate that both above- and belowground plant biomass is affected by S-induced acidification. Understanding the linkage between plant biomass and functional traits contributes to a better understanding of plant–soil feedback in grassland ecosystems.

Lake ecosystem tipping points and climate feedbacks

Abstract. Lakes and ponds experience anthropogenically forced changes that may be non-linear and sometimes initiate ecosystem feedbacks leading to tipping points beyond which impacts become hard to reverse. In many cases climate change is a key driver, sometimes in concert with other stressors. Lakes are also important players in the global climate by ventilating a large share of terrestrial carbon (C) back to the atmosphere as greenhouse gases and will likely provide substantial feedbacks to climate change. In this paper we address various major changes in lake ecosystems and discuss if tipping points can be identified, predicted, or prevented, as well as the drivers and feedbacks associated with climate change. We focus on potential large-scale effects with regional or widespread impacts, such as eutrophication-driven anoxia and internal phosphorus (P) loading, increased loading of organic matter from terrestrial to lake ecosystems (lake “browning”), lake formation or disappearance in response to cryosphere shifts or changes in precipitation to evaporation ratios, switching from nitrogen to phosphorus limitation, salinization, and the spread of invasive species where threshold-type shifts occur. We identify systems and drivers that could lead to self-sustaining feedbacks, abrupt changes, and some degree of resilience, as opposed to binary states not subject to self-propelling changes or resilience. Changes driven by warming, browning, and eutrophication can cause increased lake stratification, heterotrophy (browning), and phytoplankton or macrophyte mass (eutrophication), which separately or collectively drive benthic oxygen depletion and internal phosphorus loading and in turn increase greenhouse gas (GHG) emissions. Several of these processes can feature potential tipping point thresholds, which further warming will likely make easier to surpass. We argue that the full importance of the vulnerability of lakes to climate and other anthropogenic impacts, as well as their feedback to climate, is not yet fully acknowledged, so there is a need both for science and communication in this regard.

Opinion: New directions in atmospheric research offered by research infrastructures combined with open and data-intensive science

Abstract. The acquisition and dissemination of essential information for understanding global biogeochemical interactions between the atmosphere and ecosystems and how climate–ecosystem feedback loops may change atmospheric composition in the future comprise a fundamental prerequisite for societal resilience in the face of climate change. In particular, the detection of trends and seasonality in the abundance of greenhouse gases and short-lived climate-active atmospheric constituents is an important aspect of climate science. Therefore, easy and fast access to reliable, long-term, and high-quality observational environmental data is recognised as fundamental to research and the development of environmental forecasting and assessment services. In our opinion article, we discuss the potential role that environmental research infrastructures in Europe (ENVRI RIs) can play in the context of an integrated global observation system. In particular, we focus on the role of the atmosphere-centred research infrastructures ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure), IAGOS (In-service Aircraft for a Global Observing System), and ICOS (Integrated Carbon Observation System), also referred to as ATMO-RIs, with their capabilities for standardised collection and provision of long-term and high-quality observational data, complemented by rich metadata. The ATMO-RIs provide data through open access and offer data interoperability across different research fields including all fields of environmental sciences and beyond. As a result of these capabilities in data collection and provision, we elaborate on the novel research opportunities in atmospheric sciences which arise from the combination of open-access and interoperable observational data, tools, and technologies offered by data-intensive science and the emerging collaboration platform ENVRI-Hub, hosted by the European Open Science Cloud (EOSC).

Immersive virtual reality for learning about ecosystems: effect of two signaling levels and feedback on action decisions.

The goal of the present study was to test the effect of signaling associated with feed-back in learning forest ecosystems in the context of realistic living forest simulator, in IVR conditions for students in agriculture. Two signaling modalities, corresponding to two signaling levels, were investigated: visual flashing of forest elements (tree species, plants, flowers, fungi, wet-areas etc.) and marker-stones, both with text in pop-up windows, in a 2x2 experimental plan. Ninety-three pupils of an agricultural technological high school had to explore (including physically), interrogate (search for) and select (using the joysticks) relevant elements of the forest in three living forest areas (visually delimited inside of a broader forest area) in order to choose (and justify) the best area, among the three, in which an equipped public-tourist reception site (picnic, resting, reception site) could be built. The chosen site must have the least possible negative impact on the ecosystem of the forest and its development over time. After their decision (and justification) they were provided a feed-back with a series of VR desktop multimedia slides showing the effect of this choice on the ecosystem of the chosen area. After the feed-back they had to decide and justify again whether they would change or maintain their first decision. Finally, subjective scales were also used in order to investigate presence, cognitive complexity, sickness and overall enjoyment. Results showed significant positive effects of both signaling levels, and of the feed-back on the correct decision answers. Further, the combination, and interaction, between signaling and feedback seemed to enhance, the activation and retrieval from memory, of the task-relevant concepts. In addition, the results indicated a significant positive effect (medium size) of presence on decision performances, a finding which is consistent with the immersion principle.

Deterministic assembly of grassland soil microbial communities driven by climate warming amplifies soil carbon loss

Perturbations in soil microbial communities caused by climate warming are expected to have a strong impact on biodiversity and future climate–carbon (C) feedback, especially in vulnerable habitats that are highly sensitive to environmental change. Here, we investigate the impact of four-year experimental warming on soil microbes and C cycling in the Loess Hilly Region of China. The results showed that warming led to soil C loss, mainly from labile C, and this C loss is associated with microbial response. Warming significantly decreased soil bacterial diversity and altered its community structure, especially increasing the abundance of heat-tolerant microorganisms, but had no effect on fungi. Warming also significantly increased the relative importance of homogeneous selection and decreased “drift” of bacterial and fungal communities. Moreover, warming decreased bacterial network stability but increased fungal network stability. Notably, the magnitude of soil C loss was significantly and positively correlated with differences in bacterial community characteristics under ambient and warming conditions, including diversity, composition, network stability, and community assembly. This result suggests that microbial responses to warming may amplify soil C loss. Combined, these results provide insights into soil microbial responses and C feedback in vulnerable ecosystems under climate warming scenarios.

High preseason temperature variability drives convergence of xylem phenology in the Northern Hemisphere conifers

Wood growth is key to understanding the feedback of forest ecosystems to the ongoing climate warming. An increase in spatial synchrony (i.e., coincident changes in distant populations) of spring phenology is one of the most prominent climate responses of forest trees. However, whether temperature variability contributes to an increase in the spatial synchrony of spring phenology and its underlying mechanisms remains largely unknown. Here, we analyzed an extensive dataset of xylem phenology observations of 20 conifer species from 75 sites over the Northern Hemisphere. Along the gradient of increase in temperature variability in the 75 sites, we observed a convergence in the onset of cell enlargement roughly toward the 5th of June, with a convergence in the onset of cell wall thickening toward the summer solstice. The increase in rainfall since the 5th of June is favorable for cell division and expansion, and as the most hours of sunlight are received around the summer solstice, it allows the optimization of carbon assimilation for cell wall thickening. Hence, the convergences can be considered as the result of matching xylem phenological activities to favorable conditions in regions with high temperature variability. Yet, forest trees relying on such consistent seasonal cues for xylem growth could constrain their ability to respond to climate warming, with consequences for the potential growing season length and, ultimately, forest productivity and survival in the future.

The illusion of balance in the history of the biosphere.

Earth's surface has been irreversibly altered by the activity of organisms, a process that has accelerated as the power of the biosphere (the rate at which life extracts and deploys energy) has increased over time. This trend is incompatible with the expectation that the inputs to Earth's surface of life's materials from the crust and mantle be matched by export from Earth's surface to long-term reservoirs. Here, I suggest that the collective activity of organisms has always violated this balance. The biosphere's ability to extract, retain, recycle, and accumulate materials has allowed living biomass to increase and for exports to decrease over very long timescales. This collective metabolism implies a net transfer of materials from the planet's interior to its surface. The combination of metabolic innovations, competition, adaptive evolution, and the establishment of collaborative economic feedback in ecosystems created dynamic ecological stability despite great spatial and temporal heterogeneity in physical and biological inputs and export of nutrients into and out of the biosphere. Models of geochemical cycling must take the fundamental role of living organisms and the evolutionary changes in these roles into account to explain past and future conditions.

Simulating and predicting the development trends of the water–energy–food–ecology system in Henan Province, China

The intricate interplay among water, energy, food, and ecology underscores the paramount importance of investigating water–energy–food–ecology (WEFE) systems to foster regional sustainable development. In this study, a dynamic simulation model for the WEFE system was formulated using system dynamics, probing alterations in resource supply, demand dynamics, and ecosystem responses to resource shifts. Utilizing Henan Province as a case study and factoring in resource scarcity and environmental pollution, five scenarios were crafted to forecast WEFE system developmental trajectories from 2005 to 2035. The findings revealed the following key insights: (1) Within each subsystem, the food supply–demand balance ratio maintained a robust level of approximately 4.0. Conversely, the water and energy supply–demand balance ratio remained below 1.0 throughout the study period, indicating a worsening trend in the annual misalignment between supply and demand. Carbon dioxide (CO2) emissions are projected to surge by 103%, posing challenges for future CO2 emission reduction efforts. (2) Among the various scenarios, the Green Development (GD) scenario emerged as pivotal for fostering a coordinated development of the WEFE system. Implementation of the GD scenario showcased a notable 38.1% improvement in the resource supply–demand ratio and a 26% reduction in CO2 emissions. (3) Addressing ecosystem feedback, the reduction of carbon emissions emerges as a focal point for future ecological environment enhancement initiatives in Henan Province. Strategic emphasis should be placed on adjusting energy consumption and its structure to propel the healthy development of the ecological environment. This study serves as a guide for managing regional WEFE systems effectively.

Opinion: The strength of long-term comprehensive observations to meet multiple grand challenges in different environments and in the atmosphere

Abstract. To be able to meet global grand challenges (climate change; biodiversity loss; environmental pollution; scarcity of water, food and energy supplies; acidification; deforestation; chemicalization; pandemics), which all are closely interlinked with each other, we need comprehensive open data with proper metadata, along with open science. The large data sets from ground-based in situ observations, ground and satellite remote sensing, and multiscale modeling need to be utilized seamlessly. In this opinion paper, we demonstrate the power of the SMEAR (Station for Measuring Earth surface–Atmosphere Relations) concept via several examples, such as detection of new particle formation and the particles' subsequent growth, quantifying atmosphere–ecosystem feedback loops, and combining comprehensive observations with emergency science and services, as well as studying the effect of COVID-19 restrictions on different air quality and climate variables. The future needs and the potential of comprehensive observations of the environment are summarized.

Season shapes the functional diversity of microbial carbon metabolism in mangrove soils of Hainan Island, China

Carbon storage in mangroves is considered a natural solution to mitigate climate change as an essential coastal blue carbon ecosystem service for climate change. The magnitude of carbon storage in soils depends on the carbon metabolic activities of the microbial community, and these dynamics are subject to the influence of climate conditions, including seasonal changes. Despite mangroves being one of the world's highest in soil carbon density and carbon sequestration rates, our understanding of this aspect remains limited. Here, we investigated the seasonal changes in the carbon metabolic profile of microbial communities in mangrove soils along the seashore of the whole Hainan Island (with the highest diversity of mangrove species in China). There was a clear season dependence in the metabolic activity and functional diversity of mangrove soil microbial community on Hainan Island, showing the trend of the rainy season > the dry season. The carbon metabolic activity in the rainy season is three times higher than in the dry season. The season plays a critical role in shaping the carbon functional diversity of microbial communities, which that by changing biotic interactions and soil properties, particularly soil TN, NO2−–N, plant richness and mean DBH. This study provides important insights into comprehend the carbon metabolic functional diversity of microbial communities in mangrove soils and provides basic data support for predicting the blue carbon feedback of mangrove ecosystems to global climate change.

Positive feedback to regional climate enhances African wildfires

Regional climate strongly regulates the occurrence of wildfires partly because drying of fuel load increases fires. The large amounts of aerosols released by wildfires can also strongly affect regional climate. Here we show positive feedback (a seasonal burned area enhancement of 7-17%) due to wildfire aerosol forcing in Africa found in the simulations using the interactive REgion-Specific ecosystem feedback Fire (RESFire) model in the Community Earth System Model (CESM). The positive feedback results partly from the transport of fire aerosols from burning (dry) to wet regions, reducing precipitation and drying fuel load to enhance fires toward the non-burning (wet) region. This internally self-enhanced burning is an important mechanism for the regulation of African ecosystems and for understanding African fire behaviors in a changing climate. A similar mechanism may also help sustain wildfires in other tropical regions.