Journal of Geophysical Research: Biogeosciences最新文献_第9页

Decline of CO2 Release During the Evolution of the Thaw Slump on the Northern Qinghai-Tibet Plateau 青藏高原北部解冻坍塌演化过程中二氧化碳释放量的减少

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-30 DOI: 10.1029/2024JG008162

Mei Mu, Cuicui Mu, Hebin Liu, Chunling Zhang, Yunjie Jia, Pengsi Lei, Xiaoqing Peng

{"title":"Decline of CO2 Release During the Evolution of the Thaw Slump on the Northern Qinghai-Tibet Plateau","authors":"Mei Mu, Cuicui Mu, Hebin Liu, Chunling Zhang, Yunjie Jia, Pengsi Lei, Xiaoqing Peng","doi":"10.1029/2024JG008162","DOIUrl":"https://doi.org/10.1029/2024JG008162","url":null,"abstract":"Abrupt permafrost thaw accelerates the decomposition of soil organic carbon and might double the warming caused by the carbon release. However, the influence of thaw slump evolution on carbon dioxide (CO2) emission rates and its drives remains unclear, which induces large uncertainties in the prediction of permafrost carbon-climate feedback. Here we collected soil samples in the thaw slump landscapes that happened 1–23 years ago on the northern Qinghai-Tibet Plateau (QTP) and measured the CO2 release rates using a 189-day aerobic laboratory incubation in the dark. The incubation results showed that thaw slump occurred 23 years ago reduced soil CO2–C release by 57 ± 19% compared with the undisturbed area. The relative contribution of O-alkyl C and microbial abundance decreases with the thaw slump initiation time lengthens. We illustrate that soil carbon quality and microbial communities uniquely explained 41% and 13% of the variation in CO2–C release, respectively. We preliminary estimate that the carbon release for thaw slump landscapes on the QTP may be overestimated by approximately 50% if the declining soil CO2–C release is without consideration. Our study highlights the CO2–C release would decrease with the stability of thaw slumps on the warming and wetting QTP, which may weaken the mountain permafrost carbon-climate feedback.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 9","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100390","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}

引用次数: 0

The Validity of Optical Properties as Tracers of Terrigenous Dissolved Organic Carbon During Extensive Remineralization in Coastal Waters 沿海水域大范围再矿化过程中作为土著溶解有机碳示踪剂的光学特性的有效性

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-28 DOI: 10.1029/2024JG008147

Yuan Chen, Yongli Zhou, Patrick Martin

{"title":"The Validity of Optical Properties as Tracers of Terrigenous Dissolved Organic Carbon During Extensive Remineralization in Coastal Waters","authors":"Yuan Chen, Yongli Zhou, Patrick Martin","doi":"10.1029/2024JG008147","DOIUrl":"https://doi.org/10.1029/2024JG008147","url":null,"abstract":"Terrestrial dissolved organic carbon (tDOC) is significant for coastal carbon cycling, and spectroscopy of chromophoric and fluorescent dissolved organic matter (CDOM, FDOM) is widely used to study tDOC cycling. However, CDOM and FDOM are often amongst the more labile components of tDOC. Because few studies have compared spectroscopy to measurements of both bulk tDOC concentration and tDOC remineralization, it remains unclear how accurately CDOM and FDOM actually trace tDOC in coastal waters when tDOC undergoes extensive remineralization. We collected a 4-year coastal timeseries in Southeast Asia, where tropical peatlands provide a large tDOC input. A carbon stable isotope mass balance shows that on average 53% of tDOC was remineralized upstream of our site, while 74% of CDOM was bleached. Despite this extensive tDOC remineralization and preferential CDOM loss, optical properties could still reliably quantify tDOC. CDOM spectral slope properties, such as S275–295, are exponentially related to tDOC; these are highly sensitive tDOC tracers at low, but not at high, tDOC concentrations. Other properties are linearly related to tDOC, and both specific ultraviolet absorbance (SUVA254) and DOC-normalized fluorescence intensity may be suitable to quantify tDOC over a wider range of concentrations. However, the optical properties did not show consistent changes with the extent of tDOC remineralization. Our data support the validity of CDOM and FDOM spectroscopy to trace tDOC across coastal gradients even after the majority of tDOC has been remineralized, but they also show that these measurements may not provide direct information about the degree of natural tDOC processing.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 9","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142089904","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}

引用次数: 0

Hyperspectral Imaging Predicts Differences in Carbon and Nitrogen Status Among Representative Biocrust Functional Groups of the Colorado Plateau 高光谱成像预测科罗拉多高原具有代表性的生物群落功能组碳氮状况的差异

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-25 DOI: 10.1029/2024JG008089

Dong Yan, Sasha C. Reed, William A. Rutherford, Mostafa Javadian, Robin H. Reibold, Miguel Villarreal, Benjamin Poulter, Shujun Song, William K. Smith

{"title":"Hyperspectral Imaging Predicts Differences in Carbon and Nitrogen Status Among Representative Biocrust Functional Groups of the Colorado Plateau","authors":"Dong Yan, Sasha C. Reed, William A. Rutherford, Mostafa Javadian, Robin H. Reibold, Miguel Villarreal, Benjamin Poulter, Shujun Song, William K. Smith","doi":"10.1029/2024JG008089","DOIUrl":"https://doi.org/10.1029/2024JG008089","url":null,"abstract":"Biological soil crusts (biocrusts) are widespread soil photosynthetic communities covering about 12% of Earth's land surface, and play crucial roles in terrestrial carbon (C) and nitrogen (N) cycles, yet scalable quantifications of biocrusts and their biogeochemical contributions are notably lacking. While remote sensing has enormous potential to assess, scale, and contextualize biocrusts and their functions, the applicability of hyperspectral data in predicting C- and N-related biocrust traits remains largely unexplored. We address this issue by evaluating the potential of in situ hyperspectral data to predict C and N across a range of biocrust species and different environmental conditions. We found that in situ hyperspectral reflectance measurements can be used to predict biocrust tissue C/N ratios and N concentrations with relatively high accuracy but to a lesser extent for potential biocrust N2 fixation rates. Critical wavelength domains included the visible region of the spectrum from roughly 490–600 nm, which most effectively captured variations in biocrust tissue C, and the shortwave infrared region from 1,150 to 1,350 nm and 1,550–1,650 nm, which most effectively captured biocrust tissue N and N2 fixation potential. Finally, we provide evidence that multi- and hyperspectral missions with targeted band placement, such as the proposed 26-band Landsat Next, could be effective in predicting biocrust traits. This work provides a critical step in understanding how to apply data from new and upcoming satellite missions to the monitoring of biocrusts.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077954","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}

引用次数: 0

Phylogenetic Effect on Tree Radial Growth Depends on Drought and Tree Sizes 系统发育对树木径向生长的影响取决于干旱和树木大小

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-25 DOI: 10.1029/2023JG007607

Ewuketu Linger, James A. Lutz, Min Cao, Wen-Fu Zhang, Xiao-Fei Yang, Xiao-Bao Deng, Yong Tang, Yue-Hua Hu

{"title":"Phylogenetic Effect on Tree Radial Growth Depends on Drought and Tree Sizes","authors":"Ewuketu Linger, James A. Lutz, Min Cao, Wen-Fu Zhang, Xiao-Fei Yang, Xiao-Bao Deng, Yong Tang, Yue-Hua Hu","doi":"10.1029/2023JG007607","DOIUrl":"https://doi.org/10.1029/2023JG007607","url":null,"abstract":"Tree radial growth is one of the most direct measures of tree performance and is also sensitive to climate. Growth performance is the consequence of the interplay between ecological and evolutionary processes. However, the effect of the evolutionary relatedness among species (i.e., phylogeny) on tree radial growth, especially under stressful conditions, remains largely unknown. Furthermore, there is still no ecological evidence for the influence of phylogeny on tree growth across different tree attributes (i.e., tree diameter variation and tree canopy height) and topographic habitat types. We used Blomberg's K to quantify the tree growth phylogenetic signal (TGPS) using two long-term dendrometer data sets: one a continuous census of 225 tree species at 3-month intervals in a tropical forest in southwest China from 2009 to 2017; the other, 12 tree species measured at 6-month intervals in a temperate forest in Washington State, USA from 2013 to 2019. We found that TGPS values were higher in the temperate forest than in the tropical forest. Precipitation, tree diameter, canopy strata, and habitat types all influenced TGPS values. TGPS values were significantly (p < 0.05) and negatively related to precipitation in Xishuangbanna, and the three of four tree diameter classes in the temperate forest, respectively. Stressful growing conditions arose from either based on low precipitation or among large-diameter trees competing with each other in the upper canopy led to phylogenetic conservatism in trees' radial growth performance. We conclude that phylogeny is pivotal to understanding the growth response differences among species and their responses to climate variability.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077953","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}

引用次数: 0

The Effect of Drying Boreal Lakes on Plants, Soils, and Microbial Communities in Lake Margin Habitats 北方湖泊干涸对湖泊边缘栖息地植物、土壤和微生物群落的影响

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-22 DOI: 10.1029/2023JG007819

Vijay P. Patil, Jack W. McFarland, Kimberly P. Wickland, Kristen Manies, Mark Winterstein, Teresa N. Hollingsworth, Eugénie S. Euskirchen, Mark P. Waldrop

{"title":"The Effect of Drying Boreal Lakes on Plants, Soils, and Microbial Communities in Lake Margin Habitats","authors":"Vijay P. Patil, Jack W. McFarland, Kimberly P. Wickland, Kristen Manies, Mark Winterstein, Teresa N. Hollingsworth, Eugénie S. Euskirchen, Mark P. Waldrop","doi":"10.1029/2023JG007819","DOIUrl":"https://doi.org/10.1029/2023JG007819","url":null,"abstract":"Decadal scale lake drying in interior Alaska results in lake margin colonization by willow shrub and graminoid vegetation, but the effects of these changes on plant production, biodiversity, soil properties, and soil microbial communities are not well known. We studied changes in soil organic carbon (SOC) and nitrogen (N) storage, plant and microbial community composition, and soil microbial activities in drying and non-drying lakes in the Yukon Flats National Wildlife Refuge. Historic changes in lake area were determined using Landsat imagery. Results showed that SOC storage in drying lake margins declined by 0.13 kg C m−2 yr−1 over 30 years of exposure of lake sediments, with no significant change in soil N. Lake drying resulted in an increase in graminoid and shrub aboveground net primary production (ANPP, +3% yr−1) with little change in plant functional composition. Increases in ANPP were similar in magnitude (but opposite in sign) to losses in SOC over a 30-year drying trend. Potential decomposition rates and soil enzyme activities were lower in drying lake margins compared to stable lake margins, possibly due to high salinities in drying lake margin soils. Microbial communities shifted in response to changing plant communities, although they still retained a legacy of the previous plant community. Understanding how changing lake hydrology impacts the ecology and biogeochemistry of lake margin terrestrial ecosystems is an underexamined phenomenon with large impacts to landscape processes.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007819","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142045286","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}

引用次数: 0

Seasonal Carbon Budget Succession in Lake Erie's Western Basin 伊利湖西部盆地的季节性碳预算演替

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-21 DOI: 10.1029/2024JG008107

Rachel Eveleth, Rachel S. Gabor, Katherine M. Gaffney, Justin D. Chaffin, Abigail Goda, Orion Pendley, Keara Stanislawczyk

{"title":"Seasonal Carbon Budget Succession in Lake Erie's Western Basin","authors":"Rachel Eveleth, Rachel S. Gabor, Katherine M. Gaffney, Justin D. Chaffin, Abigail Goda, Orion Pendley, Keara Stanislawczyk","doi":"10.1029/2024JG008107","DOIUrl":"https://doi.org/10.1029/2024JG008107","url":null,"abstract":"Lake Erie's Western Basin is a eutrophic region and likely hotspot for carbon transformation. While this basin has received much attention for its high nutrient loads from the Maumee River and recurring harmful algal blooms, carbon has gone understudied. To investigate the seasonal and spatial variability in inorganic and organic carbon budgets, we completed three surveys in spring, summer, and fall on a transect from the Maumee River to South Bass Island. In each survey, we observed higher spatial variability of all carbon species within 11 km of the Maumee River mouth relative to sites outside of Maumee Bay. This variability was driven by pulses of direct river water carbon, steep nutrient gradients, and patchy bloom conditions. Seasonal variability was also greater in Maumee Bay, with the highest river discharge in June adding large amounts of dissolved inorganic and organic carbon and pCO2 flux out of the water when productivity from the diatom bloom was smaller. In August, when and where we observed a Microcystis bloom, particulate organic carbon increased in concentration, and pCO2 flux switched directions into the water. In October, Chl-a concentrations and oxygen saturations were lowest, indicating a seasonal slowdown in productivity, and river discharge was the lowest, resulting in the lowest total carbon observed and dissolved organic matter chemistry indicating less contribution from the terrestrial watershed. In the open water outside of Maumee Bay seasonal and spatial carbon budget dynamics were more stable, highlighting the importance of riverine inputs on lake carbon cycling.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041565","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}

引用次数: 0

Methane in Two Stream Networks: Similar Contributions From Groundwater and Local Sediments While Oxidation Was a Large Sink Controlling Atmospheric Emissions 两个溪流网络中的甲烷：地下水和当地沉积物对甲烷的贡献相似，而氧化作用是控制大气排放的一大吸收池

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-21 DOI: 10.1029/2023JG007836

S. Balathandayuthabani, B. Panneer Selvam, M. Gålfalk, P. Saetre, S. Peura, U. Kautsky, L. Klemedtsson, L. Arunachalam, G. Vellingiri, D. Bastviken

{"title":"Methane in Two Stream Networks: Similar Contributions From Groundwater and Local Sediments While Oxidation Was a Large Sink Controlling Atmospheric Emissions","authors":"S. Balathandayuthabani, B. Panneer Selvam, M. Gålfalk, P. Saetre, S. Peura, U. Kautsky, L. Klemedtsson, L. Arunachalam, G. Vellingiri, D. Bastviken","doi":"10.1029/2023JG007836","DOIUrl":"https://doi.org/10.1029/2023JG007836","url":null,"abstract":"Streams are important sources of methane (CH4) to the atmosphere but magnitudes and regulation of stream CH4 fluxes remain uncertain. Stream CH4 can come from groundwater and/or produced in anoxic sediments. A fraction can be microbially oxidized to carbon dioxide (CO2) when passing redox gradients in soil, sediment, or water, while the fraction escaping oxidation is emitted to the atmosphere. The relative importance of the CH4 sources (groundwater inputs vs. sediment production) and the fraction oxidized is typically unknown, yet key for the regulation and magnitude of stream emissions. In this study, we followed the transport of CH4 from below-stream soils to the stream water surface and to the atmosphere using a combination of CH4 concentration and stable carbon isotope gradient measurements, high resolution stream flux and discharge assessments, and inverse mass-balance modeling. Sampling was done in multiple locations in the stream network of two independent catchments in Sweden to consider spatial variability. We show that the surface water, sub-surface, and groundwater CH4 concentration, CH4 oxidation, and emission were highly variable in space. Our results indicate that the variability could be related to stream morphology and soil characteristics. Of the total CH4 input into the streams, roughly half of it was estimated to come from groundwater CH4 in both catchments (39% and 57%; the rest from sediment production), and most of the CH4 was oxidized (97%–99%) before emission to the atmosphere. Our results indicate that CH4 oxidation is a major sink for CH4 in the studied streams.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007836","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041564","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}

引用次数: 0

Diagnosing Spring Onset Across the North American Arctic-Boreal Region Using Complementary Satellite Environmental Data Records 利用互补卫星环境数据记录诊断整个北美北极-北方地区的春季开始时间

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-18 DOI: 10.1029/2023JG007977

Youngwook Kim, John S. Kimball, Nicholas Parazoo, Xiaolan Xu, Andreas Colliander, Rolf Reichle, Jingfeng Xiao, Xing Li

{"title":"Diagnosing Spring Onset Across the North American Arctic-Boreal Region Using Complementary Satellite Environmental Data Records","authors":"Youngwook Kim, John S. Kimball, Nicholas Parazoo, Xiaolan Xu, Andreas Colliander, Rolf Reichle, Jingfeng Xiao, Xing Li","doi":"10.1029/2023JG007977","DOIUrl":"https://doi.org/10.1029/2023JG007977","url":null,"abstract":"The timing and progression of the spring thaw transition in high northern latitudes (HNL) coincides with warmer temperatures and landscape thawing, promoting increased soil moisture and growing season onset of gross primary productivity (GPP), heterotrophic respiration (HR), and evapotranspiration (ET). However, the relative order and spatial pattern of these events is uncertain due to vast size and remoteness of the HNL. We utilized satellite environmental data records (EDRs) derived from complementary passive microwave and optical sensors to assess the progression of spring transition events across Alaska and Northern Canada from 2016 to 2020. Selected EDRs included land surface and soil freeze-thaw status, solar-induced chlorophyll fluorescence (SIF) signifying canopy photosynthesis, root zone soil moisture (RZSM), and GPP, HR, and ET as indicators of ecosystem carbon and water-energy fluxes. The EDR spring transition maps showed thawing as a precursor to rising RZSM and growing season onset. Thaw timing was closely associated with ecosystem activation from winter dormancy, including seasonal increases in SIF, GPP, and ET. The HR onset occurred closer to soil thawing and prior to GPP activation, reducing spring carbon (CO2) sink potential. The mean duration of the spring transition spanned ∼6 ± 1.5 weeks between initial and final onset events. Spring thaw timing and maximum RZSM were closely related to active layer thickness in HNL permafrost zones, with deeper active layers showing generally earlier thawing and greater RZSM. Our results confirm the utility of combined satellite EDRs for regional monitoring and better understanding of the complexity of the spring transition.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007977","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007248","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}

引用次数: 0

Nitrate Uptake and Primary Production Along the Amazon River Plume Continuum 亚马逊河羽流沿岸的硝酸盐吸收和初级生产力

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-13 DOI: 10.1029/2023JG007662

Jacqueline Umbricht, Christian Burmeister, Joachim W. Dippner, Iris Liskow, Joseph P. Montoya, Ajit Subramaniam, Maren Voss

{"title":"Nitrate Uptake and Primary Production Along the Amazon River Plume Continuum","authors":"Jacqueline Umbricht, Christian Burmeister, Joachim W. Dippner, Iris Liskow, Joseph P. Montoya, Ajit Subramaniam, Maren Voss","doi":"10.1029/2023JG007662","DOIUrl":"https://doi.org/10.1029/2023JG007662","url":null,"abstract":"The Amazon River plume (ARP) has been shown to support high rates of nitrogen fixation and primary production. However, nitrogen fixation alone cannot account for total primary production determined in the region, hinting that other nitrogen uptake processes might play a role. For the first time, we measured nitrate uptake rates in the ARP during three cruises in May 2018, June 2019 and April/May 2021, along with primary production rates and an analysis of phytoplankton community composition via high performance liquid chromatography. Based on a classification according to the salt content the region was divided into estuarine (ES), mesohaline (MH) and oceanic (OC) stations. Primary production was light limited near the river mouth at ES stations and was maximal off the coasts of French Guiana and Suriname, where also nitrate uptake was highest with rates of 11.4 mmol m−2 d−1. The role of eddies pinching off a deflecting plume are discussed as possible reason for higher nutrient concentrations at the MH stations. Surprisingly, at most MH stations north of 5°N, nitrate uptake rates were low despite the presence of sufficient substrate concentration (up to 1.44 μM nitrate). Diatoms, dinoflagellates or Synechococcus sp. dominated phytoplankton communities. OC stations showed lowest productivity rates in accordance with oligotrophic conditions. However, rates seem to be sufficient to completely deplete the remaining riverine nitrate, preventing its export to the open ocean.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007662","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141986104","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}

引用次数: 0

Reconstructing and Mapping Annual Net Primary Productivity (NPP) Since 1940 Using Tree Rings in Southern Indiana, U.S. 利用美国印第安纳州南部的树木年轮重建并绘制 1940 年以来的年净初级生产力 (NPP) 图

IF 3.7 3区环境科学与生态学

Journal of Geophysical Research: Biogeosciences Pub Date : 2024-08-12 DOI: 10.1029/2023JG007929

Hang Li, James H. Speer, Ichchha Thapa

{"title":"Reconstructing and Mapping Annual Net Primary Productivity (NPP) Since 1940 Using Tree Rings in Southern Indiana, U.S.","authors":"Hang Li, James H. Speer, Ichchha Thapa","doi":"10.1029/2023JG007929","DOIUrl":"https://doi.org/10.1029/2023JG007929","url":null,"abstract":"Vegetation absorption is one major form of carbon storage. The earliest spatial distribution of the Net Primary Production (NPP), an index to estimate how much carbon is absorbed, could extend back to the 1980s from satellite imagery. Our study reconstructed a time series annual NPP maps in the southern Indiana since 1940 with point-by-point regression models and ring-width index (RWI) from 16 tree-ring chronologies. Our RWI-NPP model had a good performance using Random Forest (RF) regression comprehensively considering both normal and dry years. The RWI-NPP model performance gap between forest and grassland is acceptable. We also found that the tendency (model of the tendency = −0.50) based on the combination of real NPP data and simulated NPP data were opposite to the one (slope = 18.70) only based on real NPP data where the extended data set could correct some bias caused by limited data. There is a huge NPP fluctuation in the recent years (2010–2013) which is highly likely to be caused by the combination of higher frequency of extreme climate events and the intensive land-use and land-cover change. We assume that most of the vegetation pixels had the same growing pattern with the plot in Morgan Monroe Flux Tower whose dominant species is ACSH (35.66%) or the plot in Hoot Woods whose dominant species is FRAM (34.41%). This study is novel in the assessment of the spatial distribution patterns of NPP since 1940. We can witness how the NPP changes within the last 70 years.","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"129 8","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007929","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980397","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}

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