Global Biogeochemical Cycles最新文献_第3页

Nitrogen and Oxygen Isotopes of Shale Nitrate Recorded Soil Nitrate Biogeochemistry Under Arid Paleoclimates 干旱古气候下页岩硝酸盐氮氧同位素记录土壤硝酸盐生物地球化学

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-14 DOI: 10.1029/2024GB008419

Wei-Guo Fan, Mingzhong Zhou, Wei Song, Xue-Yan Liu

{"title":"Nitrogen and Oxygen Isotopes of Shale Nitrate Recorded Soil Nitrate Biogeochemistry Under Arid Paleoclimates","authors":"Wei-Guo Fan, Mingzhong Zhou, Wei Song, Xue-Yan Liu","doi":"10.1029/2024GB008419","DOIUrl":"https://doi.org/10.1029/2024GB008419","url":null,"abstract":"Arid climates severely influence the biota. Nitrogen (N) cycling is crucial information for understanding responses of biota to arid climates. However, it remains unclear whether and how key N-cycling processes respond to aridity under arid paleoclimates. By investigating the contents and N and oxygen (O) isotopes of trace nitrate (NO3−) remaining in black shale under arid paleoclimates, here we established a steady-state model combining dual N and O isotopes to quantify fluxes of microbial NO3− production (nitrification) and consumption (denitrification, assimilation) under low- and high-aridity climates, respectively. We found that nitrification was 11 times higher than atmospheric inputs (0.29 kg N ha−1 yr−1) under low aridity but declined 16-fold under high aridity. Similarly, denitrification was six times higher than microbial assimilation (0.39 kg N ha−1 yr−1) under low aridity but decreased 37-fold, becoming comparable to assimilation (0.33 kg N ha−1 yr−1) under high aridity. Correlation analyses confirmed that nitrification (slope = 0.692, R2 = 0.928) and denitrification (slope = 0.706, R2 = 0.645) were sensitive to the aridity but microbial NO3− assimilation (slope = 0.101, R2 = 0.037) was not sensitive to arid climates. This study provides new isotopic records and geochemical methods for quantifying N-cycle fluxes of dryland paleoecosystems, which are useful for understanding the mechanisms of biological responses to historical arid events and modeling N cycles in modern dryland ecosystems.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144289219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Present-Day Relation Between Observed Bottom Water Oxygenation and Marine Oxygen Proxies 观测到的海底氧合与海洋氧代用物的现今关系

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-12 DOI: 10.1029/2024GB008334

M. Ferraro, B. Risebrobakken, I. Polovodova Asteman, E. Darelius, A. Tisserand, N. D. Gallo, A. G. V. Salvanes

{"title":"The Present-Day Relation Between Observed Bottom Water Oxygenation and Marine Oxygen Proxies","authors":"M. Ferraro, B. Risebrobakken, I. Polovodova Asteman, E. Darelius, A. Tisserand, N. D. Gallo, A. G. V. Salvanes","doi":"10.1029/2024GB008334","DOIUrl":"https://doi.org/10.1029/2024GB008334","url":null,"abstract":"This study investigates how marine sediment proxies reflect dissolved oxygen levels in fjord basin water to improve our understanding of coastal marine deoxygenation that has been associated with ongoing climate change. We use western Norwegian fjords to test how marine sediment proxies for dissolved oxygen perform. Such knowledge is needed to evaluate if the recent reduced renewal of fjord basin waters is driven by anthropogenic impact or is within the range of natural variability. We have explored the potential and limitations of Mn/Ca, δ13C, benthic foraminiferal diversity, the calcareous and agglutinated foraminifera ratio, and the benthic foraminifera indicator species Stainforthia fusiformis as potential proxies for bottom water oxygen concentrations. Within the fjords investigated in western Norway, seven stations are well-oxygenated, one is close to hypoxic oxygen levels, and one shows nearly anoxic conditions. The relative abundance of S. fusiformis shows the strongest potential as a tool for reconstructing past oxygen concentrations. The Mn/Ca and δ13C measured in the seawater also strongly correlate with dissolved oxygen. The foraminiferal diversity indices follow the oxygenation gradient in the fjords. The calcareous/agglutinated species ratio has limitations under anoxic conditions, where an almost monospecific assemblage dominated by calcareous S. fusiformis was found. The signal of Mn/Ca and δ13C measured in shells of species Hyalinea balthica was difficult to assess due to low species abundance at some fjord sites. Hence, further analyses are necessary to employ the Mn/Ca and δ13C in foraminiferal shells as proxies for reconstructing past oxygen concentrations in fjords.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008334","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Orbital Influences on Deep Ocean Oxygen Concentrations and Respired Carbon Storage 轨道对深海氧浓度和呼吸碳储量的影响

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-12 DOI: 10.1029/2025GB008503

A. W. Jacobel, C. T. Pallone, K. M. Costa, R. F. Anderson, J. F. McManus

{"title":"Orbital Influences on Deep Ocean Oxygen Concentrations and Respired Carbon Storage","authors":"A. W. Jacobel, C. T. Pallone, K. M. Costa, R. F. Anderson, J. F. McManus","doi":"10.1029/2025GB008503","DOIUrl":"https://doi.org/10.1029/2025GB008503","url":null,"abstract":"Quantitative records of bottom water oxygen (BWO) are critical for understanding deep ocean change through time. Because of the stoichiometric relationship between oxygen and carbon, BWO records provide insight into the physical and biogeochemical processes that control the air-sea partitioning of both gases with important implications for climate over Quaternary glacial-interglacial cycles. Here, we present new geochemical data sets from Ocean Discovery Program Site 1240 in the eastern equatorial Pacific to constrain paleoproductivity (Baxs flux) and BWO using a multiproxy approach (aU, Mn/Al, Δδ13C, and U/Ba). This combination of approaches allows us to quantitatively identify changes in BWO and to parse local and basin-wide contributions to the signal. We find that upwelling, not dust input, is responsible for driving productivity changes at the site. Changes in local carbon export are not the primary driver of changes in BWO, which instead reflect basin-wide changes driven by processes in the Southern Ocean. Our BWO results provide direct evidence for the role of orbital precession and obliquity in driving deep sea respired carbon and oxygen concentrations. We find variations in BWO on the order of ∼50 μmol/kg that occur with ∼23 kyr periodicity during the substages of Marine Isotope Stage 5, and variations of ∼100 μmol/kg on glacial-interglacial timescales. These findings have important implications for the role of insolation in driving deep ocean respired oxygen and carbon concentrations, and point to physical and biogeochemical changes in the Southern Ocean as key drivers of planetary-scale carbon change.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Effects of Biogeochemistry and Water Mass Mixing on the Distribution of Nitrous Oxide in the Tropical South Pacific 生物地球化学和水团混合对热带南太平洋氧化亚氮分布的影响

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-11 DOI: 10.1029/2024GB008267

Noah Gluschankoff, Hannah J. McGoran, Karen L. Casciotti

{"title":"The Effects of Biogeochemistry and Water Mass Mixing on the Distribution of Nitrous Oxide in the Tropical South Pacific","authors":"Noah Gluschankoff, Hannah J. McGoran, Karen L. Casciotti","doi":"10.1029/2024GB008267","DOIUrl":"https://doi.org/10.1029/2024GB008267","url":null,"abstract":"Understanding the oceanic cycling and transport of the climatically relevant greenhouse gas, nitrous oxide (N2O), is imperative for interpreting how it could change with environmental conditions. We studied the distributions of N2O concentration and stable isotopes under biogeochemically and physically diverse environments along the GEOTRACES GP16 section—from the South Pacific oxygen deficient zone (ODZ) into the oligotrophic South Pacific Gyre—in concert with isotopic measurements of nitrate and nitrite, to investigate the interplay of N2O production, consumption, and water mass mixing. We developed an isotope mixing model to determine the relative contributions of four N2O endmembers along the section. The model showed that N2O derived from the ODZ was rapidly diluted outside the ODZ, but was still detected at 152°W, the westernmost extent of the section. Keeling model results similarly confirmed that N2O can be traced in the thermocline from the ODZ into the Gyre. Outside the ODZ thermocline, water mass mixing (background N2O) and N2O produced by ammonia-oxidizing archaea were largely responsible for its distribution. In this study, a moderate SP (22‰) for N2O production from incomplete denitrification was needed to produce realistic endmember distributions, contrasting the 0‰ value often applied. Further, our newly developed tracer, Δ(SP, 18), which accounts for the isotopic impacts of N2O consumption, was used to study the pathways of N2O production within ODZ waters. This approach illustrated distinct patterns of δ15Nβ observations within ODZ waters, highlighting the potential for nitrate and nitrite to contribute differentially to N2O production in ODZ waters.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transport of Dissolved Black Carbon in Three Estuaries in China: Roles of Flood-Ebb Tides and Submarine Groundwater Discharge 中国三个河口溶解黑碳的输运：涨落潮和海底地下水流量的作用

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-11 DOI: 10.1029/2025GB008532

Weiqiang Zhao, Hongyan Bao, Lejin Peng, Moge Du, Keyuan Li, Xiaoqian Zhan, Shuwen Li, Li Tian, Dekun Huang, Wenbin Zou, Jin-Yu Terence Yang, Shuh-Ji Kao

{"title":"Transport of Dissolved Black Carbon in Three Estuaries in China: Roles of Flood-Ebb Tides and Submarine Groundwater Discharge","authors":"Weiqiang Zhao, Hongyan Bao, Lejin Peng, Moge Du, Keyuan Li, Xiaoqian Zhan, Shuwen Li, Li Tian, Dekun Huang, Wenbin Zou, Jin-Yu Terence Yang, Shuh-Ji Kao","doi":"10.1029/2025GB008532","DOIUrl":"https://doi.org/10.1029/2025GB008532","url":null,"abstract":"Estuaries are essential for the ocean's mass balance of terrestrial dissolved organic matter (DOM). Dissolved black carbon (DBC) constitutes the largest known persistent fraction of DOM in marine environments. However, the alterations of DBC during its transport through estuaries remain largely unknown. In this study, we conducted six sampling cruises across three estuaries in China, which varied in size, tidal patterns, and hydrological conditions. We measured DBC concentrations in both the overlying water and sediment porewater. Our results indicated that DBC input occurred during flood tides, whereas DBC removal was observed during ebb tides. Modeling results and laboratory experiments suggest that photodegradation and photo-dissolution were not the primary mechanisms influencing these patterns; instead, variations in submarine groundwater discharge (SGD) of DBC may account for the observed flood-ebb-related fluctuations. Additionally, we found a higher internal accumulation of DBC during the lower runoff period in the three estuaries, which could be related to the longer flushing time. We estimated that SGD-derived DBC flux accounted for ∼12% of DBC discharged from the Jiulong River to the estuary, and represented ∼16–23% of riverine DBC discharge on a global scale. Our study provides new insights into the flood-ebb-tides-related DBC transport in estuaries, which should be considered in future studies of other DOM components in the estuarine region. Furthermore, our study underscores the significance of SGD flux in the transport of terrestrial DOM to the ocean, highlighting the need for its incorporation into the global budget of terrestrial organic matter.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Permafrost, Peatland, and Cropland Regions Are Key to Reconciling North American Carbon Sink Estimates 永久冻土、泥炭地和耕地区域是协调北美碳汇估算的关键

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-11 DOI: 10.1029/2024GB008460

Kelsey T. Foster, Wu Sun, Julian Merder, Oleksandra Hararuk, Werner A. Kurz, Avni Malhotra, Juha Metsaranta, Andrea Nesdoly, Eva Sinha, Ben Bond-Lamberty, Deborah Huntzinger, Susan M. Natali, Christopher Schwalm, Anna M. Michalak

{"title":"Permafrost, Peatland, and Cropland Regions Are Key to Reconciling North American Carbon Sink Estimates","authors":"Kelsey T. Foster, Wu Sun, Julian Merder, Oleksandra Hararuk, Werner A. Kurz, Avni Malhotra, Juha Metsaranta, Andrea Nesdoly, Eva Sinha, Ben Bond-Lamberty, Deborah Huntzinger, Susan M. Natali, Christopher Schwalm, Anna M. Michalak","doi":"10.1029/2024GB008460","DOIUrl":"https://doi.org/10.1029/2024GB008460","url":null,"abstract":"Persistent discrepancies between bottom-up, terrestrial biosphere models (TBMs), and top-down, atmospheric inversions, have made it difficult to quantify the magnitude of the North American terrestrial carbon sink. Previous studies have compared aggregated continent-scale estimates of carbon fluxes from TBMs and inversions for all of North America, but this provides limited insights into finer-scale mismatches that contribute to the overall discrepancies. Here we evaluate agreement between TBM and inversion carbon flux estimates at 1° × 1° resolution to provide more direct insights into where models disagree and what underlying factors drive discrepancies. We find that the additional carbon uptake estimated by inversions, in just 16% of the area of North America, is large enough to account for the discrepancy between TBMs and inversions across the whole continent. The majority of these differences occur in permafrost, peatland, and cropland regions. In these regions, we find a higher likelihood of potential biases in the weaker sink estimates from TBMs, suggesting that the stronger sink implied by inversions is more likely to be realistic. However, the current observational coverage is insufficient for fully assessing the causes of discrepancies or the magnitude of biases in either approach. Encouragingly, improved representation of agricultural processes in a TBM led to better agreement with inversions in croplands. Efforts to accurately model cropland dynamics will help improve agreement between TBMs and inversions. Overall, this work presents a clear path for reconciling the discrepancies between inversion and TBM estimates of the North American carbon sink that have persisted for two decades.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Natural Nanoparticles and Colloids in Forested Streams Across Europe: Seasonal Patterns and Impact of Soil Groups 欧洲森林河流中的天然纳米颗粒和胶体：季节模式和土壤组的影响

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-11 DOI: 10.1029/2024GB008467

Heike Schimmel, Wulf Amelung, Nina Gottselig, Maria-Teresa Sebastiá, Jan Jacob Keizer, Martinho A. S. Martins, Annalea Lohila, Christin Müller, Hjalmar Laudon, Erwin Klumpp, Melanie Braun

{"title":"Natural Nanoparticles and Colloids in Forested Streams Across Europe: Seasonal Patterns and Impact of Soil Groups","authors":"Heike Schimmel, Wulf Amelung, Nina Gottselig, Maria-Teresa Sebastiá, Jan Jacob Keizer, Martinho A. S. Martins, Annalea Lohila, Christin Müller, Hjalmar Laudon, Erwin Klumpp, Melanie Braun","doi":"10.1029/2024GB008467","DOIUrl":"https://doi.org/10.1029/2024GB008467","url":null,"abstract":"The element loss from forested ecosystems is largely reflected by the so-called dissolved phase (<450 nm) in stream waters. However, natural colloids (1 nm–1 μm), including natural nanoparticles (NNP, 1–100 nm), constitute a major but largely unexplored part of this dissolved phase. We hypothesized (a) that there is a systematic seasonal variation in colloidal concentrations across European catchments, and (b) that the colloidal concentrations are mainly controlled by site conditions, that is, prevalent reference soil groups. To test these hypotheses, the base flow of seven stream waters was sampled from a transect across Europe from Northern Finland to Portugal at monthly intervals for 1 year. Three colloidal size fractions (1–20 nm, >20–60 nm, and >60 nm) were identified using field flow fractionation coupled with inductively coupled plasma mass spectrometry and an organic carbon detector for the size-resolved detection of Al, Si, P, Ca, Mg, Mn, Fe, Zn, and organic C. Colloids accounted for up to 90%–100% of total element concentrations, emphasizing the importance of colloids for element cycling. Element concentrations showed seasonal patterns in stream waters. However, these patterns differed between the catchments with distinct soil groups: the catchments with dystrophic terrestrial soils exhibited peak flows in colloidal element concentrations during spring, whereas those with eutrophic terrestrial soils did during summer. By contrast, catchments with Gleysols showed season-unrelated single peaks of high element export. Peak concentrations were also influenced by the climatic regime, which in turn impacted colloid abundance.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008467","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantifying Lithogenic Inputs to the Ocean From the GEOTRACES Thorium Transects in a Data-Assimilation Model 在数据同化模型中量化GEOTRACES钍样条对海洋的岩石成因输入

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-09 DOI: 10.1029/2024GB008485

Hairong Xu, Thomas Weber

{"title":"Quantifying Lithogenic Inputs to the Ocean From the GEOTRACES Thorium Transects in a Data-Assimilation Model","authors":"Hairong Xu, Thomas Weber","doi":"10.1029/2024GB008485","DOIUrl":"https://doi.org/10.1029/2024GB008485","url":null,"abstract":"The primordial thorium (Th) isotope 232Th is delivered to global ocean waters by lithogenic material dissolution, originating from dust deposition on the ocean surface and seafloor sediments around continental margins. Radiogenic 230Th shares the same particle-scavenging removal processes as 232Th but has a simpler source from uniform 234U decay. The 232Th–230Th isotope system is therefore widely used to jointly constrain source and sink processes and infer lithogenic trace element inputs but has not been leveraged systematically at the global scale. This study utilizes data-assimilation models of the 230Th and 232Th cycles to draw global insights from GEOTRACES section data. Optimization of 230Th model reveals that scavenging onto biogenic particles is the largest Th removal mechanism globally, but regional-scale losses are dominated by scavenging onto metal oxides near hydrothermal vents, nepheloid layer particles along deep margins, and lithogenic particles beneath dust plumes. Together with large-scale ocean circulation, these processes shape the global distribution of 230Th. A subsequent ensemble of 232Th model optimizations reveals that the observed 232Th distribution is consistent with a global source of 2.8 ± 0.54 Mmol/yr from dust dissolution, and implies a higher and more homogeneous solubility of 232Th relative to other lithogenic trace elements. An additional source of 5.25 ± 0.86 Mmol/yr from lithogenic sediment dissolution is required to match observed 232Th, with a distribution controlled by sediment lithology and accumulation rate. This translates to an oceanic Fe source of 5–50 Gmol/yr, highlighting the need to resolve this process in Fe cycle models that often only consider a reductive sedimentary source.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144244953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Oligotrophic Ocean New Production Supported by Lateral Transport of Dissolved Organic Nutrients 溶解有机营养物横向运输支持的寡营养海洋新生产

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-07 DOI: 10.1029/2024GB008345

Zhou Liang, Robert T. Letscher, Angela N. Knapp

{"title":"Oligotrophic Ocean New Production Supported by Lateral Transport of Dissolved Organic Nutrients","authors":"Zhou Liang, Robert T. Letscher, Angela N. Knapp","doi":"10.1029/2024GB008345","DOIUrl":"https://doi.org/10.1029/2024GB008345","url":null,"abstract":"Dissolved organic nitrogen (DON) and phosphorus (DOP) are potential nutrient sources to sustain productivity in the oligotrophic ocean where inorganic nutrient concentrations are low. Variations in the carbon(C):nitrogen(N):phosphorus(P) stoichiometry of surface ocean dissolved organic matter (DOM) can trace patterns of DON and DOP production and consumption; however, concurrent dissolved organic carbon (DOC), DON, and DOP concentration observations are limited. Using new global ocean DOM concentration data sets, we develop inverse DOC and DON models to obtain global ocean DOC and DON concentration fields and associated biogeochemical fluxes. Including autotrophic DON uptake improves the model fit to observations. Combining our modeled DOC and DON concentration fields with a global ocean DOP concentration field from our previous inverse DOP model, we obtain a modeled global ocean DOM stoichiometry field. We further evaluate the lateral transport of semi-labile DON (SLDON) and semi-labile DOP (SLDOP) to the oligotrophic low latitudes (15° to 40°) and identify the equatorial Pacific and Atlantic as important sources of SLDON and SLDOP. We also quantify the preferential loss of DON and DOP relative to DOC from the surface to 500 m, which, with physical circulation, may retain nutrients in the gyres, further enhancing productivity. Our findings highlight two modes by which DON and DOP serve as organic nutrient sources to sustain productivity in the oligotrophic low latitudes, with lateral transport more important and capable of supporting ∼6–15% of export production in these regions.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GB008345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144232245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Microbial Carbon Accumulation Efficiency in Global Soils Resolved via 13C-Glucose Amendment Experiments 13c -葡萄糖修正实验研究全球土壤微生物碳积累效率

IF 5.4 2区地球科学

Global Biogeochemical Cycles Pub Date : 2025-06-04 DOI: 10.1029/2025GB008553

Wanjia Hu, Yue Cai, Xingqi Li, Cheng Wang, Juan Jia, Xiaojuan Feng

{"title":"Microbial Carbon Accumulation Efficiency in Global Soils Resolved via 13C-Glucose Amendment Experiments","authors":"Wanjia Hu, Yue Cai, Xingqi Li, Cheng Wang, Juan Jia, Xiaojuan Feng","doi":"10.1029/2025GB008553","DOIUrl":"https://doi.org/10.1029/2025GB008553","url":null,"abstract":"Accurately assessing the efficiency of microbial carbon (C) conversion and accumulation associated with soil “microbial C pump” (MCP) is essential for understanding microbial-mediated soil C sequestration. Conventional assessments based on microbial C use efficiency (CUE) hinge on living biomass only and do not include microbial necromass, which may not depict microbial C accumulation. Here we propose a simple and rapid approach based on 13C-glucose amendment experiment to assess microbial C accumulation efficiency (CAE) in a relatively short term. We first validated the approach by showing negligible sorption of glucose to soils with a wide range of edaphic properties. Glucose-derived 13C may hence be considered to represent microbial C (including biomass and residues) after a few days of addition, given the rapid uptake of glucose by microbes. Microbial CAE may thus be assessed as the recovery of glucose-derived 13C in the soil. By further conducting a meta-analysis of literature data involving isotopically labeled glucose amendment experiments, we revealed distinct variation patterns and influencing factors of CAE and CUE across various terrestrial ecosystems. Compared to CUE, which is mainly regulated by factors influencing microbial physiological processes (particularly substrate availability), CAE is jointly regulated by factors that influence microbial growth and residue persistence (e.g., clay content). These findings underscore that CAE is decoupled from CUE. Given the potential divergence in microbial biomass and residue responses to environmental perturbations, CAE provides a more accurate measure of microbial C conversion and accumulation efficiency than CUE, enabling a clearer understanding of MCP dynamics under global changes.","PeriodicalId":12729,"journal":{"name":"Global Biogeochemical Cycles","volume":"39 6","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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