Journal of Geophysical Research: Biogeosciences最新文献

{"title":"The 2020 Heatwave Led to a Larger Enhancement in Annual Gross Primary Production in West Siberia Than in East Siberia","authors":"Sung-Bin Park,&nbsp;Chang-Eui Park,&nbsp;Jin-Soo Kim,&nbsp;Jingfeng Xiao,&nbsp;Eun-Ji Song,&nbsp;Damwon Seo,&nbsp;Sang Seo Park","doi":"10.1029/2024JG008487","DOIUrl":"https://doi.org/10.1029/2024JG008487","url":null,"abstract":"<p>Spring and summer vegetation productivity in Siberia shows opposing responses to warmer spring. Spring warming causes excessive vegetation growth and earlier start of photosynthesis, enhancing productivity in spring. However, this leads to reduced productivity in the following season (i.e., summer) through soil moisture depletion. To understand how an exceptional spring heatwave (HW) affected ecosystem carbon uptake, we investigated the spatiotemporal cascade of gross primary production (GPP) and multiple climate variables over Siberia in 2020, using a satellite-retrieved GPP product (GOSIF-GPP) and the ERA5-Land reanalysis data set for 2001–2020. Results showed a positive impact of anomalous spring warming on annual GPP (GPP_ann). GPP_ann from GOSIF-GPP in West Siberia (55°–70°N, 50°–90°E) was enhanced by up to 10% above the 2001–2019 average despite continued dry conditions from May to August. In East Siberia (55–70°N, 90–130°E), the GPP increases for May and June were sufficient to compensate for marked reduction of GPP in July due to negative anomaly in radiation. In addition, the higher sensitivity of GPP_ann to spring temperature in West Siberia than in East Siberia suggests that GPP increase coupled with strong warming and respective excessive vegetation growth might be more pronounced in the western region, as observed in 2020. Our results indicate that the warming trend in spring, combined with possible extreme heat events, could elevate annual carbon uptake in Siberia, particularly in West Siberia. Further, this case study for the extreme HW event that occurred in 2020 can provide useful insight for understanding future change in carbon uptake over Siberia.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity of Chlorophyll Vertical Structure to Model Parameters in the Biogeochemical Southern Ocean State Estimate (B-SOSE)","authors":"Angela M. Kuhn,&nbsp;Matthew R. Mazloff,&nbsp;Sarah T. Gille,&nbsp;Ariane Verdy","doi":"10.1029/2024JG008300","DOIUrl":"https://doi.org/10.1029/2024JG008300","url":null,"abstract":"<p>The Southern Ocean is a region of intense air–sea exchange that plays a critical role for ocean circulation, global carbon cycling, and climate. Subsurface chlorophyll-a maxima, annually recurrent features throughout the Southern Ocean, may increase the energy flux to higher trophic levels and facilitate downward carbon export. It is important that model parameterizations appropriately represent the chlorophyll vertical structure in the Southern Ocean. Using BGC-Argo chlorophyll profiles and the Biogeochemical Southern Ocean State Estimate (B-SOSE), we investigate the sensitivity of chlorophyll vertical structure to model parameters. Based on the sensitivity analysis results, we estimate optimized parameters, which efficiently improve the model consistency with observations. We characterize chlorophyll vertical structure in terms of Empirical Orthogonal Functions and define metrics to compare model results and observations in a series of parameter perturbation experiments. We show that chlorophyll magnitudes are likely to respond quasi-symmetrically to perturbations in the analyzed parameters, while depth and thickness of the subsurface chlorophyll maximum show an asymmetric response. Perturbing the phytoplankton growth tends to generate more symmetric responses than perturbations in the grazing rate. We identify parameters that affect chlorophyll magnitude, subsurface chlorophyll or both and discuss insights into the processes that determine chlorophyll vertical structure in B-SOSE. We highlight turbulence, differences in phytoplankton traits, and grazing parameterizations as key areas for improvement in models of the Southern Ocean.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulation Mechanisms of CO2 Fluxes in Subtropical Mountain Peatlands Based on Long-Term In Situ Observations at the Dajiuhu Peatland","authors":"Shiyu Yang,&nbsp;Jiwen Ge,&nbsp;Xiangnan Xu,&nbsp;Ziwei Liu,&nbsp;Jiumei Wang,&nbsp;Yuehuan Wang","doi":"10.1029/2024JG008328","DOIUrl":"https://doi.org/10.1029/2024JG008328","url":null,"abstract":"<p>The Dajiuhu peatland in Shennongjia, China, is a highly representative subalpine peatland, emblematic of subtropical mountainous peatlands. Due to the lack of long-term in situ continuous observations and in-depth studies on CO₂ absorption and emission patterns, the regulation mechanisms of CO₂ flux in subtropical peatlands remain unclear. Since July 2015, we have conducted over five years of continuous in situ observations of CO₂ fluxes and major environmental factors in the Dajiuhu peatland ecosystem. We calculated the annual average net ecosystem carbon exchange (NEE) of CO₂ and decomposed NEE into gross primary productivity (GPP) and ecosystem respiration (Reco), thus examining the peatland ecosystem's absorption and emission of CO₂ separately. The results indicate that the annual average NEE from 2016 to 2020 was −283.6 g C m⁻² yr⁻¹, reflecting a strong CO₂ sink. Our study indicates the regulation mechanisms of CO₂ flux in the peatland. Temperature is the most direct factor affecting CO₂ absorption and emission, serving as the most important driver of CO₂ flux on short time scales. Precipitation only affects CO₂ absorption but has a significant impact on NEE, being a key factor in maintaining the peatland's CO₂ sink function. Variations in annual precipitation also led to differences in net CO₂ absorption between years. Our results illustrate an important role of sub-tropical mountain peatlands in mitigating the greenhouse effect and maintaining moisture conditions is crucial for protecting its ecological functions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying Dust Nutrient Mobility Through an Alpine Watershed","authors":"Jeffrey R. Nielson,&nbsp;Janice Brahney","doi":"10.1029/2024JG008175","DOIUrl":"https://doi.org/10.1029/2024JG008175","url":null,"abstract":"<p>Dust has the potential to play a significant role in the nutrient dynamics of alpine watersheds with important ecological implications. However, little is known about how dust nutrients circulate through the environment and which watershed characteristics facilitate dust impacts on water quality. This study explored the contribution of dust-deposited nutrients, focusing on a high-elevation Long Term Ecological Research site, where dust samples have been continuously collected since 2017. We incorporated observed dust nutrient compositions, including fractions of inorganic and organic nitrogen and phosphorus, into a popular hydrological model, the Soil and Water Assessment Tool, and ran simulations for 2019–2021. By comparing simulations with and without dust nutrient inputs, we estimated the impact of dust-deposited nutrients on individual watershed processes. Results revealed a significant contribution of dust-deposited nutrients, particularly soluble reactive phosphorus (SRP), to several nutrient cycling and transport pathways. Notably, dust contributed up to 19.3% of the SRP load in annual streamflow (increasing monthly streamflow concentration by up to 10.9 μg <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>L</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{L}}^{-1}$</annotation>\u0000 </semantics></math> ). Spatial analysis of model estimates demonstrated a relationship between topography, soil type, and the cycling and transport of dust nutrients. The largest dust nutrient contributions were found in catchment areas with lower slope and less hydric soils, where other natural mobilization processes may be limited. This comparative modeling approach stresses the importance of including dust nutrients in watershed models, especially in oligotrophic systems, and has potential to validate these findings elsewhere and identify how watershed characteristics may either mollify or accentuate the impacts of dust deposition on mountain freshwater systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Hot Versus Dry Vapor Pressure Deficit on Ecosystem Carbon and Water Fluxes","authors":"Miriam R. Johnston,&nbsp;Mallory L. Barnes,&nbsp;Yakir Preisler,&nbsp;William K. Smith,&nbsp;Joel A. Biederman,&nbsp;Russell L. Scott,&nbsp;A. Park Williams,&nbsp;Matthew P. Dannenberg","doi":"10.1029/2024JG008146","DOIUrl":"https://doi.org/10.1029/2024JG008146","url":null,"abstract":"<p>Vapor pressure deficit (VPD) has increased and will likely continue increasing, with wide-ranging effects on ecosystems. Future VPD increases will largely be driven by warming, yet most experiments examining VPD effects on plants have done so by changing humidity. Here, we used meteorological data and carbon and water fluxes measured at 26 climatically-diverse eddy covariance sites to quantify the extent to which VPD has been driven by variation in air temperature versus humidity. We fit generalized additive models (GAMs) at each site to quantify effects of hotter (and wetter) and cooler (and drier) versus typical VPD on ecosystem-scale fluxes of carbon and water. We found that VPD has occurred under diverse combinations of temperature and humidity: &gt;50% of a site's daytime growing season temperature range and &gt;35% of its relative humidity range have often combined to define a particular VPD. We found moderate evidence that hotter versus drier VPD of the same magnitude differentially affect gross primary productivity (GPP), net ecosystem productivity (NEP), and latent heat flux (LE): Selected GPP and NEP GAMs at about half of sites and LE GAMs at about a third of sites included a VPD-temperature interaction. The magnitude of the interaction varied, but was generally 29%–57% of the effect attributable solely to VPD. The direction of the interaction also varied, but hot VPD was commonly associated with higher carbon fluxes. These effects were not strongly modified by soil moisture. Overall, results emphasize the relevance of VPD-temperature interactions at a critical time of rapid VPD increase.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008146","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Machine Learning Approach for Filling Long Gaps in Eddy Covariance Time Series Data in a Tropical Dry Forest","authors":"Mohammed Abdaki,&nbsp;Arturo Sanchez-Azofeifa,&nbsp;Hendrik F. Hamann","doi":"10.1029/2024JG008375","DOIUrl":"https://doi.org/10.1029/2024JG008375","url":null,"abstract":"<p>Long-term eddy covariance (EC) data are crucial for understanding the impact of global change on ecosystem functions. However, EC data often contain long gaps, particularly in tropical dry forests (TDF) due to seasonality and El Niño-Southern Oscillation (ENSO) phases. These factors create high variability, complex dependencies, and dynamic flux footprints. No current gap-filling method adequately addresses long gaps in TDFs. This study introduces a novel framework for addressing this issue by (a) defining gap sizes by their relative percentages, (b) training, tuning, and evaluating two machine learning (ML) models: MissForest for short gaps and Prophet for intermediate and long gaps, and (c) predicting half-hourly EC data from 2013 to 2022 for six EC variables, where actual gap data sets ranged from 26.6% to 28.4%, at TDF in Costa Rica. Results indicate that MissForest excelled at filling short gaps (≤5%, <i>R</i>² = 0.76 and Nash-Sutcliffe efficiency (NSE) = 0.71), while Prophet performed exceptionally well for gaps between 5% and 10% (<i>R</i>² = 0.72 and NSE = 0.67). However, both models struggled with gaps between 10% and 13%. Validation showed <i>R</i>² values of 0.79, 0.88, and 0.77 for CO₂ flux, sensible heat flux, and latent heat flux, respectively, with corresponding NSE values of 0.78, 0.86, and 0.72, and normalized root mean squared error (NRMSE) around 2E-4. Additionally, to validate our results, we applied our approach at three EC sites with different ecological conditions, demonstrating robust performance. This study presents a reliable ML approach for imputing long gaps in EC data, which can be applied to sites with strong variability.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of Micrometeorological Memory in Modulating Sub-Daily Scale Variability of Net Ecosystem Exchange","authors":"Akash Verma,&nbsp;Leena Khadke,&nbsp;Elizabeth Eldhose,&nbsp;Subimal Ghosh","doi":"10.1029/2024JG008356","DOIUrl":"https://doi.org/10.1029/2024JG008356","url":null,"abstract":"<p>Net Ecosystem Exchange (NEE) is crucial for understanding the carbon balance in ecosystems, indicating whether they act as carbon sinks or sources. While the impact of hydrometeorological factors on NEE at daily and monthly scales has been well-researched, the significance of sub-daily variability and the influence of memory in micrometeorological variables remain understudied. This study addresses this gap by analyzing the temporal dynamics of NEE using half-hourly data from 29 FLUXNET sites over at least 6 years. We found that sub-daily variability of NEE contributes 10%–55% of 13-day NEE variability, depending on seasonal cycles and biome characteristics. Using an information theory based transfer entropy (TE) approach, we identified the causal drivers of NEE variability at sub-daily scales within a 6-hr memory. Our results show that the memory of micrometeorological variables significantly impacts NEE, surpassing their instantaneous effects. Temperature (TA), vapor pressure deficit (VPD), and soil water content (SWC_Mean) consistently affect NEE within this 6-hr memory, whereas the influence of sensible heat (H) and incoming shortwave radiation (SW_IN) diminishes at higher lags. While the magnitude of average TE from micrometeorological variables to NEE exhibits notable seasonal variations, the temporal structure of how information is transferred does not significantly differ across seasons, as reflected by the shape of TE values over various time lags. SWC_Mean, VPD, and TA impact NEE jointly, while H and SW_IN have overlapping effects. Additionally, precipitation influences NEE indirectly through SWC_Mean. Our findings highlight the importance of accounting for high-frequency NEE variability and its underlying drivers when investigating the ecohydrological interactions, shedding light on the role of memory in carbon-water interactions.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Simulations of Forest Hurricane Disturbance and Recovery in Puerto Rico by ELM-FATES Using Field Measurements","authors":"Mingjie Shi,&nbsp;Michael Keller,&nbsp;Barbara Bomfim,&nbsp;Lara Kueppers,&nbsp;Charlie Koven,&nbsp;Jessica Needham,&nbsp;Tamara Heartsill-Scalley,&nbsp;L. Ruby Leung","doi":"10.1029/2024JG008350","DOIUrl":"https://doi.org/10.1029/2024JG008350","url":null,"abstract":"<p>In the past three decades, Puerto Rico (PR) experienced five hurricanes that met or exceeded category three, and they caused severe forest structural damage and elevated tree mortality. To improve our mechanistic understanding of hurricane impacts on tropical forests and assess hurricane-affected forest dynamics in Earth system models, we use in situ forest measurements at the Bisley Experimental Watersheds in Northeast PR to evaluate the Functionally Assembled Terrestrial Ecosystem Simulator coupled with the Energy Exascale Earth System Model Land Model (ELM-FATES). The observations show that before Hurricane Hugo, 77.3% of the aboveground biomass (AGB) is from the shade-tolerant plant function type (PFT). The Hugo-induced mortality rates are over ∼50%, and they induce a ∼39% AGB reduction, which recovers to a level like the pre-Hugo condition in 2014, following a second, lower intensity hurricane, Georges. We perform numerical experiments that simulate damage from Hugo and Georges on the forests, including defoliation, sapwood and structural biomass damage, and hurricane-induced mortality. ELM-FATES can reasonably represent coexistence between the two PFTs–light-demanding and shade-tolerant–for both the pre-Hugo and post-Hugo conditions. The model represents a reasonable size distribution of mid-and large-sized trees although it underestimates AGB, likely due to the overestimated nonhurricane mortality. ELM-FATES temporarily stimulated leaf biomass and diameter increment after Georges, an effect that should be tested with observations of future hurricane defoliation events. This research indicates that addressing model-data mismatches in tree mortality and understory dynamics are essential to simulation of more extreme hurricane effects under climate change.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biogeochemistry of Riverine Organic Matter Inputs to the Patagonian Fjords and Implications for Fjord Organic Carbon Budgets","authors":"Sebastien Bertrand","doi":"10.1029/2024JG008531","DOIUrl":"https://doi.org/10.1029/2024JG008531","url":null,"abstract":"<p>Fjords are increasingly recognized as hotspots for organic carbon (OC) burial. The OC buried in fjords is of both marine and terrestrial origin, with a predominance of terrestrial OC in fjords worldwide. The proportions of marine and terrestrial OC in fjords are traditionally calculated using end-member modeling based on <i>δ</i>¹³C and/or N/C. However, characterizing the terrestrial end-member remains a challenge, with authors inconsistently using measurements obtained on land plants, soils, and/or river sediments. Here, we analyzed the TOC, <i>δ</i>¹³C, and N/C composition of soil samples, suspended river sediments, and bulk and grain-size fractions of river sediments from the main rivers discharging into the Patagonian fjords (44–48°S), to identify the processes that affect the biogeochemistry of the terrestrial organic matter reaching fjords via rivers. Radiocarbon measurements indicate that Patagonian rivers contain 0.18% petrogenic OC and variable concentrations of biospheric OC. Despite soil <i>δ</i>¹³C significantly decreasing with precipitation, <i>δ</i>¹³C in river sediments remains relatively stable around −27‰. In contrast, N/C in river sediments is highly variable, mostly due to a high contribution of petrogenic nitrogen in glacier-fed rivers. Furthermore, N/C varies significantly with sediment grain size, making it virtually impossible to define a fixed N/C value to represent the terrestrial end-member. By comparison, grain size has a limited influence on <i>δ</i>¹³C. Overall, our results support the use of riverine <i>δ</i>¹³C to define terrestrial OC in mixing models, regardless of the presence of glaciers in the watershed, and they suggest that the fraction of terrestrial OC buried in fjord sediments may have been underestimated.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008531","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atmospheric Dryness Constrains CO2 Uptake During the Peak Growing Season and at Noontime in an Alpine Wetland Ecosystem","authors":"Liqin Hua,&nbsp;Jing Tao,&nbsp;Yahui Qi,&nbsp;Zhuangzhuang Wang,&nbsp;Da Wei,&nbsp;Xiaodan Wang","doi":"10.1029/2024JG008262","DOIUrl":"https://doi.org/10.1029/2024JG008262","url":null,"abstract":"<p>Increase in atmospheric dryness, characterized as vapor pressure deficit (VPD), might constrain terrestrial productivity. Nevertheless, the precise temporal impacts of VPD on the gross primary productivity (GPP) of alpine wetland ecosystems during the growing season remain elusive. The alpine ecosystems of the Tibetan Plateau (TP), where productivity is highly constrained by the cold climate, have experienced pronounced warming of 0.26°C decade⁻¹ with associated increase in VPD. In this study, by examining eddy covariance observations taken in an alpine wetland on the TP over five consecutive years, we characterized when and how VPD variation causes negative impact on ecosystem productivity. The TP alpine wetland functioned as a net CO₂ sink with magnitude of 164.6 ± 22.0 g C m⁻² yr⁻¹. It was found that VPD played a crucial role in the seasonal variation in GPP especially in the peak growing season, that is, it even suppressed the positive effect of temperature on GPP. As temperatures declined in the latter stages of the growing season, the inhibitory effect of VPD on GPP gradually diminished. We further found that the VPD at midday (13:00–14:30) was crucial for inhibition of photosynthesis and midday depression of GPP. Our results emphasize the role of atmospheric dryness during the middle growing season and at midday on GPP, thereby providing new insights into how VPD affects CO₂ uptake in a warming climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}