Browse
Submit Data
Databases
API
Help

Dataset Information

29 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Water- and plant-mediated responses of ecosystem carbon fluxes to warming and nitrogen addition on the Songnen grassland in northeast China.

ABSTRACT:

Background

Understanding how grasslands are affected by a long-term increase in temperature is crucial to predict the future impact of global climate change on terrestrial ecosystems. Additionally, it is not clear how the effects of global warming on grassland productivity are going to be altered by increased N deposition and N addition.

Methodology/principal findings

In-situ canopy CO(2) exchange rates were measured in a meadow steppe subjected to 4-year warming and nitrogen addition treatments. Warming treatment reduced net ecosystem CO(2) exchange (NEE) and increased ecosystem respiration (ER); but had no significant impacts on gross ecosystem productivity (GEP). N addition increased NEE, ER and GEP. However, there were no significant interactions between N addition and warming. The variation of NEE during the four experimental years was correlated with soil water content, particularly during early spring, suggesting that water availability is a primary driver of carbon fluxes in the studied semi-arid grassland.

Conclusion/significance

Ecosystem carbon fluxes in grassland ecosystems are sensitive to warming and N addition. In the studied water-limited grassland, both warming and N addition influence ecosystem carbon fluxes by affecting water availability, which is the primary driver in many arid and semiarid ecosystems. It remains unknown to what extent the long-term N addition would affect the turn-over of soil organic matter and the C sink size of this grassland.

SUBMITTER: Jiang L

PROVIDER: S-EPMC3446953 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Individual and interactive effects of warming and nitrogen supply on CO<sub>2</sub> fluxes and carbon allocation in subarctic grassland.

Project description:Climate warming has been suggested to impact high latitude grasslands severely, potentially causing considerable carbon (C) losses from soil. Warming can also stimulate nitrogen (N) turnover, but it is largely unclear whether and how altered N availability impacts belowground C dynamics. Even less is known about the individual and interactive effects of warming and N availability on the fate of recently photosynthesized C in soil. On a 10-year geothermal warming gradient in Iceland, we studied the effects of soil warming and N addition on CO2 fluxes and the fate of recently photosynthesized C through CO2 flux measurements and a 13 CO2 pulse-labeling experiment. Under warming, ecosystem respiration exceeded maximum gross primary productivity, causing increased net CO2 emissions. N addition treatments revealed that, surprisingly, the plants in the warmed soil were N limited, which constrained primary productivity and decreased recently assimilated C in shoots and roots. In soil, microbes were increasingly C limited under warming and increased microbial uptake of recent C. Soil respiration was increased by warming and was fueled by increased belowground inputs and turnover of recently photosynthesized C. Our findings suggest that a decade of warming seemed to have induced a N limitation in plants and a C limitation by soil microbes. This caused a decrease in net ecosystem CO2 uptake and accelerated the respiratory release of photosynthesized C, which decreased the C sequestration potential of the grassland. Our study highlights the importance of belowground C allocation and C-N interactions in the C dynamics of subarctic ecosystems in a warmer world.

| S-EPMC10962691 | biostudies-literature

Water scaling of ecosystem carbon cycle feedback to climate warming.

Project description:It has been well established by field experiments that warming stimulates either net ecosystem carbon uptake or release, leading to negative or positive carbon cycle-climate change feedback, respectively. This variation in carbon-climate feedback has been partially attributed to water availability. However, it remains unclear under what conditions water availability enhances or weakens carbon-climate feedback or even changes its direction. Combining a field experiment with a global synthesis, we show that warming stimulates net carbon uptake (negative feedback) under wet conditions, but depresses it (positive feedback) under very dry conditions. This switch in carbon-climate feedback direction arises mainly from scaling effects of warming-induced decreases in soil water content on net ecosystem productivity. This water scaling of warming effects offers generalizable mechanisms not only to help explain varying magnitudes and directions of observed carbon-climate feedback but also to improve model prediction of ecosystem carbon dynamics in response to climate change.

| S-EPMC6703863 | biostudies-other

Plant nitrogen uptake drives responses of productivity to nitrogen and water addition in a grassland.

Project description:Increased atmospheric nitrogen (N) deposition and altered precipitation regimes have profound impacts on ecosystem functioning in semiarid grasslands. The interactions between those two factors remain largely unknown. A field experiment with N and water additions was conducted in a semiarid grassland in northern China. We examined the responses of aboveground net primary production (ANPP) and plant N use during two contrasting hydrological growing seasons. Nitrogen addition had no impact on ANPP, which may be accounted for by the offset between enhanced plant N uptake and decreased plant nitrogen use efficiency (NUE). Water addition significantly enhanced ANPP, which was largely due to enhanced plant aboveground N uptake. Nitrogen and water additions significantly interacted to affect ANPP, plant N uptake and N concentrations at the community level. Our observations highlight the important role of plant N uptake and use in mediating the effects of N and water addition on ANPP.

| S-EPMC4001094 | biostudies-literature

Effects of soil warming and nitrogen addition on soil respiration in a New Zealand tussock grassland.

Project description:Soil respiration (RS) represents a large terrestrial source of CO2 to the atmosphere. Global change drivers such as climate warming and nitrogen deposition are expected to alter the terrestrial carbon cycle with likely consequences for RS and its components, autotrophic (RA) and heterotrophic respiration (RH). Here we investigate the impacts of a 3°C soil warming treatment and a 50 kg ha(-1) y(-1) nitrogen addition treatment on RS, RH and their respective seasonal temperature responses in an experimental tussock grassland. Average respiration in untreated soils was 0.96±0.09 ?mol m(-2) s(-1) over the course of the experiment. Soil warming and nitrogen addition increased RS by 41% and 12% respectively. These treatment effects were additive under combined warming and nitrogen addition. Warming increased RH by 37% while nitrogen addition had no effect. Warming and nitrogen addition affected the seasonal temperature response of RS by increasing the basal rate of respiration (R10) by 14% and 20% respectively. There was no significant interaction between treatments for R10. The treatments had no impact on activation energy (E0). The seasonal temperature response of RH was not affected by either warming or nitrogen addition. These results suggest that the additional CO2 emissions from New Zealand tussock grassland soils as a result of warming-enhanced RS constitute a potential positive feedback to rising atmospheric CO2 concentration.

| S-EPMC3951317 | biostudies-literature

Grassland ecosystem responses to elevated CO2 are contingent on nitrogen conditions

Project description:To study whether and how soil nitrogen conditions affect the ecological effects of long-term elevated CO2 on microbial community and soil ecoprocess, here we investigated soil microbial community in a grassland ecosystem subjected to ambient CO2 (aCO2, 368 ppm), elevated CO2 (eCO2, 560 ppm), ambient nitrogen deposition (aN) or elevated nitrogen deposition (eN) treatments for a decade. Under the aN condition, a majority of microbial function genes, as measured by GeoChip 4.0, were increased in relative abundance or remained unchanged by eCO2. Under the eN condition, most of functional genes associated with carbon, nitrogen and sulfur cycling, energy processes, organic remediation and stress responses were decreased or remained unchanged by eCO2, while genes associated with antibiotics and metal resistance were increased. The eCO2 effects on fungi and archaea were largely similar under both nitrogen conditions, but differed substantially for bacteria. Coupling of microbial carbon or nitrogen cycling genes, represented by positive percentage and density of gene interaction in association networks, was higher under the aN condition. In accordance, changes of soil CO2 flux, net N mineralization, ammonification and nitrification was higher under the aN condition. Collectively, these results demonstrated that eCO2 effects are contingent on nitrogen conditions, underscoring the difficulty toward predictive modeling of soil ecosystem and ecoprocesses under future climate scenarios and necessitating more detailed studies.

2015-04-03 | GSE67531 | GEO

Warming and Nitrogen Addition Alter Photosynthetic Pigments, Sugars and Nutrients in a Temperate Meadow Ecosystem.

Project description:Global warming and nitrogen (N) deposition have an important influence on terrestrial ecosystems; however, the influence of warming and N deposition on plant photosynthetic products and nutrient cycling in plants is not well understood. We examined the effects of 3 years of warming and N addition on the plant photosynthetic products, foliar chemistry and stoichiometric ratios of two dominant species, i.e., Leymus chinensis and Phragmites communis, in a temperate meadow in northeastern China. Warming significantly increased the chlorophyll content and soluble sugars in L. chinensis but had no impact on the carotenoid and fructose contents. N addition caused a significant increase in the carotenoid and fructose contents. Warming and N addition had little impact on the photosynthetic products of P. communis. Warming caused significant decreases in the N and phosphorus (P) concentrations and significantly increased the carbon (C):P and N:P ratios of L. chinensis, but not the C concentration or the C:N ratio. N addition significantly increased the N concentration, C:P and N:P ratios, but significantly reduced the C:N ratio of L. chinensis. Warming significantly increased P. communis C and P concentrations, and the C:N and C:P ratios, whereas N addition increased the C, N and P concentrations but had no impact on the stoichiometric variables. This study suggests that both warming and N addition have direct impacts on plant photosynthates and elemental stoichiometry, which may play a vital role in plant-mediated biogeochemical cycling in temperate meadow ecosystems.

| S-EPMC4865211 | biostudies-literature

Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

Project description:Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

| S-EPMC4728605 | biostudies-literature

Effects of Land Use on the Soil Microbial Community in the Songnen Grassland of Northeast China.

Project description:Land use change obviously changes the plant community composition and soil properties of grasslands and thus affects multiple functions and services of grassland ecosystems. However, the response mechanisms of soil microorganisms, key drivers of the nutrient cycle and other soil functions during changes in grassland use type and associated vegetation are not well understood. In this study, Illumina high-throughput sequencing was used to analyze the changes in the soil microbial community structure of four grassland use types: exclosure (EL), mowed land (ML), grazed land (GL), and farmland (FL) in the Songnen Plain of Northeast China. The results showed that the FL and EL had significantly higher soil total nitrogen (TN) and lower soil electrical conductivity (EC) and pH than GL and ML. In contrast, the GL and ML had higher soil bulk density (BD) and organic matter, respectively, than the other land use types. In addition, the values of the Shannon diversity and Pielou's evenness indexes were highest in the EL of all the land use types. Based on the high-throughput sequencing results, we observed high levels of α diversity in the FL for both bacteria and fungi. A structural equation model (SEM) revealed that pH and EC had a direct and positive effect on the bacterial community structure and composition. In addition, plant taxonomic diversity (according to the Shannon diversity and Pielou's evenness indexes) indirectly affected the bacterial community composition via soil pH and EC. Notably, fungal composition was directly and positively correlated with soil nutrients and the value of Pielou's evenness index changed with land use type. In conclusion, soil properties and/or plant diversity might drive the changes in the soil microbial community structure and composition in different grassland use types.

| S-EPMC9307977 | biostudies-literature

Precipitation overrides warming in mediating soil nitrogen pools in an alpine grassland ecosystem on the Tibetan Plateau.

Project description:Soils in the alpine grassland store a large amount of nitrogen (N) due to slow decomposition. However, the decomposition could be affected by climate change, which has profound impacts on soil N cycling. We investigated the changes of soil total N and five labile N stocks in the topsoil, the subsoil and the entire soil profile in response to three years of experimental warming and altered precipitation in a Tibetan alpine grassland. We found that warming significantly increased soil nitrate N stock and decreased microbial biomass N (MBN) stock. Increased precipitation reduced nitrate N, dissolved organic N and amino acid N stocks, but increased MBN stock in the topsoil. No change in soil total N was detected under warming and altered precipitation regimes. Redundancy analysis further revealed that soil moisture (26.3%) overrode soil temperature (10.4%) in explaining the variations of soil N stocks across the treatments. Our results suggest that precipitation exerted stronger influence than warming on soil N pools in this mesic and high-elevation grassland ecosystem. This indicates that the projected rise in future precipitation may lead to a significant loss of dissolved soil N pools by stimulating the biogeochemical processes in this alpine grassland.

| S-EPMC4985624 | biostudies-literature

The effects of warming and nitrogen addition on ecosystem respiration in a Tibetan alpine meadow: The significance of winter warming.

Project description:In recent decades, global warming has become an indisputable fact on the Tibetan Plateau. Alpine ecosystems are very sensitive to global warming, and the impact may depend on the degree of atmospheric nitrogen (N) deposition. The previous studies have paid more attention to year-round warming, but the effect of winter warming has been unstudied. In this study, a manipulative experiment was conducted, consisting of warming and N addition. It was carried out since 2010 in an alpine meadow, and three types of warming treatments were set up: no warming (NW), year-round (YW), and winter warming (WW). Warming significantly increased air and soil temperature, but decreased soil moisture. Under no N addition, YW showed significantly decreased ecosystem respiration (Reco) in 2012, and WW decreased Reco in 2014. Under N addition, neither YW nor WW had significant effects on Reco, indicating that N addition compensated the negative effect of warming on Reco. Annually, YW and WW decreased ecosystem carbon (C) emissions, and the extent of the reduction was even larger under WW. Under no N addition, both YW and WW significantly decreased aboveground biomass. Moreover, especially under no N, YW and WW significantly decreased soil inorganic N. WW also had negative effects on soil microbial biomass C. Structure equation modeling showed that soil moisture was the most important factors controlling Reco, and soil inorganic N content and microbial biomass C could explain 46.6% and 16.8% of the variation of Reco. The findings indicate that soil property changes under warming had substantial effects on ecosystem C efflux. The inhibitory effects of winter warming on ecosystem C efflux were mainly attributed to the decline of soil N and microbial biomass. Thus, the effects of winter warming on ecosystem C emissions in this semiarid alpine meadow are not as serious as expected and largely depend on N deposition.

| S-EPMC6206223 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data