Pub Date : 2023-09-14DOI: 10.1007/s10533-023-01082-3
Arne Verstraeten, Nicolas Bruffaerts, Fabiana Cristofolini, Elena Vanguelova, Johan Neirynck, Gerrit Genouw, Bruno De Vos, Peter Waldner, Anne Thimonier, Anita Nussbaumer, Mathias Neumann, Sue Benham, Pasi Rautio, Liisa Ukonmaanaho, Päivi Merilä, Antti-Jussi Lindroos, Annika Saarto, Jukka Reiniharju, Nicholas Clarke, Volkmar Timmermann, Manuel Nicolas, Maria Schmitt, Katrin Meusburger, Anna Kowalska, Idalia Kasprzyk, Katarzyna Kluska, Łukasz Grewling, Małgorzata Malkiewicz, Lars Vesterdal, Morten Ingerslev, Miklós Manninger, Donát Magyar, Hugues Titeux, Gunilla Pihl Karlsson, Regula Gehrig, Sandy Adriaenssens, Agneta Ekebom, Åslög Dahl, Marco Ferretti, Elena Gottardini
The effects of tree pollen on precipitation chemistry are not fully understood and this can lead to misinterpretations of element deposition in European forests. We investigated the relationship between forest throughfall (TF) element fluxes and the Seasonal Pollen Integral (SPIn) using linear mixed-effects modelling (LME). TF was measured in 1990–2018 during the main pollen season (MPS, arbitrary two months) in 61 managed, mostly pure, even-aged Fagus, Quercus, Pinus, and Picea stands which are part of the ICP Forests Level II network. The SPIn for the dominant tree genus was observed at 56 aerobiological monitoring stations in nearby cities. The net contribution of pollen was estimated as the TF flux in the MPS minus the fluxes in the preceding and succeeding months. In stands of Fagus and Picea, two genera that do not form large amounts of flowers every year, TF fluxes of potassium (K+), ammonium-nitrogen (NH4+-N), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) showed a positive relationship with SPIn. However- for Fagus- a negative relationship was found between TF nitrate-nitrogen (NO3−-N) fluxes and SPIn. For Quercus and Pinus, two genera producing many flowers each year, SPIn displayed limited variability and no clear association with TF element fluxes. Overall, pollen contributed on average 4.1–10.6% of the annual TF fluxes of K+ > DOC > DON > NH4+-N with the highest contribution in Quercus > Fagus > Pinus > Picea stands. Tree pollen appears to affect TF inorganic nitrogen fluxes both qualitatively and quantitatively, acting as a source of NH4+-N and a sink of NO3−-N. Pollen appears to play a more complex role in nutrient cycling than previously thought.
{"title":"Effects of tree pollen on throughfall element fluxes in European forests","authors":"Arne Verstraeten, Nicolas Bruffaerts, Fabiana Cristofolini, Elena Vanguelova, Johan Neirynck, Gerrit Genouw, Bruno De Vos, Peter Waldner, Anne Thimonier, Anita Nussbaumer, Mathias Neumann, Sue Benham, Pasi Rautio, Liisa Ukonmaanaho, Päivi Merilä, Antti-Jussi Lindroos, Annika Saarto, Jukka Reiniharju, Nicholas Clarke, Volkmar Timmermann, Manuel Nicolas, Maria Schmitt, Katrin Meusburger, Anna Kowalska, Idalia Kasprzyk, Katarzyna Kluska, Łukasz Grewling, Małgorzata Malkiewicz, Lars Vesterdal, Morten Ingerslev, Miklós Manninger, Donát Magyar, Hugues Titeux, Gunilla Pihl Karlsson, Regula Gehrig, Sandy Adriaenssens, Agneta Ekebom, Åslög Dahl, Marco Ferretti, Elena Gottardini","doi":"10.1007/s10533-023-01082-3","DOIUrl":"10.1007/s10533-023-01082-3","url":null,"abstract":"<div><p>The effects of tree pollen on precipitation chemistry are not fully understood and this can lead to misinterpretations of element deposition in European forests. We investigated the relationship between forest throughfall (TF) element fluxes and the Seasonal Pollen Integral (SPIn) using linear mixed-effects modelling (LME). TF was measured in 1990–2018 during the main pollen season (MPS, arbitrary two months) in 61 managed, mostly pure, even-aged <i>Fagus</i>, <i>Quercus</i>, <i>Pinus</i>, and <i>Picea</i> stands which are part of the ICP Forests Level II network. The SPIn for the dominant tree genus was observed at 56 aerobiological monitoring stations in nearby cities. The net contribution of pollen was estimated as the TF flux in the MPS minus the fluxes in the preceding and succeeding months. In stands of <i>Fagus</i> and <i>Picea</i>, two genera that do not form large amounts of flowers every year, TF fluxes of potassium (K<sup>+</sup>), ammonium-nitrogen (NH<sub>4</sub><sup>+</sup>-N), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) showed a positive relationship with SPIn. However- for <i>Fagus</i>- a negative relationship was found between TF nitrate-nitrogen (NO<sub>3</sub><sup>−</sup>-N) fluxes and SPIn. For <i>Quercus</i> and <i>Pinus</i>, two genera producing many flowers each year, SPIn displayed limited variability and no clear association with TF element fluxes. Overall, pollen contributed on average 4.1–10.6% of the annual TF fluxes of K<sup>+</sup> > DOC > DON > NH<sub>4</sub><sup>+</sup>-N with the highest contribution in <i>Quercus</i> > <i>Fagus</i> > <i>Pinus</i> > <i>Picea</i> stands. Tree pollen appears to affect TF inorganic nitrogen fluxes both qualitatively and quantitatively, acting as a source of NH<sub>4</sub><sup>+</sup>-N and a sink of NO<sub>3</sub><sup>−</sup>-N. Pollen appears to play a more complex role in nutrient cycling than previously thought.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50482746","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}
Pub Date : 2023-09-14DOI: 10.1007/s10533-023-01080-5
H. Maurice Valett, Rafael Feijó de Lima, Marc Peipoch, Royce C. Engstrom
Abstract The Upper Clark Fork River (UCFR), Montana, a mid-order well-lit system with contemporary anthropogenic nitrogen (N) enrichment and natural geogenic sources of phosphorus (P), experiences annual algal blooms that influence ecosystem structure and function. This study was designed to assess the occurrence of riverine algal blooms (RABs) in the UCFR by characterizing the succession of periphyton and biogeochemical conditions following annual snowmelt runoff through autumnal baseflow conditions, and to provide a framework for assessing RAB progression in montane mid-order rivers more broadly. Using a 21-year database (2000–2020) collected over the growing season at three sites, historical assessment of the persistent and recurrent character of RABs in the UCFR showed that the magnitude of the summer bloom was, in part, moderated by snowmelt disturbance. Abundance and growth forms of benthic algae, along with river physicochemistry (e.g., temperature) and water chemistry (N and P concentration), were measured over the course of snowmelt recession for three years (2018–2020) at the same three sites. Results documented the onset of major blooms of the filamentous green algae Cladophora across all sites, commensurate with declines in dissolved inorganic N. Atomic N:P ratios of river water suggest successional transitions from P- to N-limitation associated with mid-season senescence of Cladophora and development of a secondary bloom of N-fixing cyanobacteria, dominated by Nostoc cf. pruniforme . Rates of N-fixation, addressed at one of the sites during the 2020 snowmelt recession, increased upon Cladophora senescence to a maximal value among the highest reported for lotic systems (5.80 mg N/m 2 /h) before decreasing again to background levels at the end of the growing season. Based on these data, a heuristic model for mid-order rivers responding to snowmelt disturbance suggests progression from phases of physical stress (snowmelt) to optimal growth conditions, to conditions of biotic stress later in the growing season. Optimal growth is observed as green algal blooms that form shortly after peak snowmelt, then transition to stages dominated by cyanobacteria and autochthonous N production later in the growing season. Accordingly, interactions among algal composition, reactive N abundance, and autochthonous N production, suggest successional progression from reliance on external nutrient sources to increased importance of autochthony, including N-fixation that sustains riverine productivity during late stages of snowmelt recession.
蒙大拿州上克拉克福克河(UCFR)是一个中等光照系统,具有当代人为氮(N)富集和天然地源磷(P),每年都会发生藻华,影响生态系统的结构和功能。本研究旨在通过表征秋季基流条件下每年融雪径流的周边植物和生物地球化学条件的演替来评估UCFR河流藻华(RABs)的发生,并为更广泛地评估山地中阶河流的RAB进展提供框架。利用在三个地点收集的21年(2000-2020年)生长季节的数据库,对UCFR中RABs的持续和复发性特征进行了历史评估,结果表明,夏季开花的程度在一定程度上受到融雪干扰的缓和。在三年(2018-2020年)融雪衰退期间,在相同的三个地点测量了底栖藻类的丰度和生长形式,以及河流物理化学(如温度)和水化学(N和P浓度)。结果表明,丝状绿藻Cladophora在所有地点的主要华的开始与溶解无机氮的下降相一致。河水的原子N:P比率表明,从P-限制到N-限制的连续转变与Cladophora的季节中期衰老和固氮蓝藻的二次华的发展有关,主要是Nostoc c . pruniforme。在2020年融雪衰退期间,其中一个地点的固氮率在Cladophora衰老时增加到最高值(5.80 mg N/ m2 /h),然后在生长季节结束时再次下降到背景水平。基于这些数据,一个中级河流对融雪干扰响应的启发式模型表明,从物理应激(融雪)阶段到最佳生长条件阶段,再到生长季节后期的生物应激条件。最佳生长是在融雪高峰后不久形成绿藻华,然后在生长季节后期过渡到以蓝藻和原生氮生产为主的阶段。因此,藻类组成、活性氮丰度和原生氮产量之间的相互作用表明,从依赖外部营养源到增加原生氮的重要性,包括在融雪衰退后期维持河流生产力的固氮作用的演替过程。
{"title":"Bloom succession and nitrogen dynamics during snowmelt in a mid-order montane river","authors":"H. Maurice Valett, Rafael Feijó de Lima, Marc Peipoch, Royce C. Engstrom","doi":"10.1007/s10533-023-01080-5","DOIUrl":"https://doi.org/10.1007/s10533-023-01080-5","url":null,"abstract":"Abstract The Upper Clark Fork River (UCFR), Montana, a mid-order well-lit system with contemporary anthropogenic nitrogen (N) enrichment and natural geogenic sources of phosphorus (P), experiences annual algal blooms that influence ecosystem structure and function. This study was designed to assess the occurrence of riverine algal blooms (RABs) in the UCFR by characterizing the succession of periphyton and biogeochemical conditions following annual snowmelt runoff through autumnal baseflow conditions, and to provide a framework for assessing RAB progression in montane mid-order rivers more broadly. Using a 21-year database (2000–2020) collected over the growing season at three sites, historical assessment of the persistent and recurrent character of RABs in the UCFR showed that the magnitude of the summer bloom was, in part, moderated by snowmelt disturbance. Abundance and growth forms of benthic algae, along with river physicochemistry (e.g., temperature) and water chemistry (N and P concentration), were measured over the course of snowmelt recession for three years (2018–2020) at the same three sites. Results documented the onset of major blooms of the filamentous green algae Cladophora across all sites, commensurate with declines in dissolved inorganic N. Atomic N:P ratios of river water suggest successional transitions from P- to N-limitation associated with mid-season senescence of Cladophora and development of a secondary bloom of N-fixing cyanobacteria, dominated by Nostoc cf. pruniforme . Rates of N-fixation, addressed at one of the sites during the 2020 snowmelt recession, increased upon Cladophora senescence to a maximal value among the highest reported for lotic systems (5.80 mg N/m 2 /h) before decreasing again to background levels at the end of the growing season. Based on these data, a heuristic model for mid-order rivers responding to snowmelt disturbance suggests progression from phases of physical stress (snowmelt) to optimal growth conditions, to conditions of biotic stress later in the growing season. Optimal growth is observed as green algal blooms that form shortly after peak snowmelt, then transition to stages dominated by cyanobacteria and autochthonous N production later in the growing season. Accordingly, interactions among algal composition, reactive N abundance, and autochthonous N production, suggest successional progression from reliance on external nutrient sources to increased importance of autochthony, including N-fixation that sustains riverine productivity during late stages of snowmelt recession.","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134913050","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}
Pub Date : 2023-09-10DOI: 10.1007/s10533-023-01072-5
Elizah Z. Stephens, Peter M. Homyak
Wildfires may increase soil emissions of trace nitrogen (N) gases like nitric oxide (NO) and nitrous oxide (N2O) by changing soil physicochemical conditions and altering microbial processes like nitrification and denitrification. When 34 studies were synthesized, we found a significant increase in both NO and N2O emissions up to 1 year post-fire across studies spanning ecosystems globally. However, when fluxes were separated by ecosystem type, we found that individual ecosystem types responded uniquely to fire. Forest soils tended to emit more N2O after fire, but there was no significant effect on NO. Shrubland soils showed significant increases in both NO and N2O emissions after fires; often with extremely large but short-lived NO pulses occurring immediately after fire. Grassland NO emissions increased after fire, but the size of this effect was small relative to shrublands. N2O emissions from burned grasslands were highly variable with no significant effect. To better understand the variation in responses to fire across global ecosystems, more consistent measurements of variables recognized as important controls on soil fluxes of NO and N2O (e.g., N cycling rates, soil water content, pH, and substrate availability) are needed across studies. We also suggest that fire-specific elements like burn severity, microbial community succession, and the presence of char be considered by future studies. Our synthesis suggests that fires can exacerbate ecosystem N loss long after they burn, increasing soil emissions of NO and N2O with implications for ecosystem N loss, climate, and regional air quality as wildfires increase globally.
{"title":"Post-fire soil emissions of nitric oxide (NO) and nitrous oxide (N2O) across global ecosystems: a review","authors":"Elizah Z. Stephens, Peter M. Homyak","doi":"10.1007/s10533-023-01072-5","DOIUrl":"10.1007/s10533-023-01072-5","url":null,"abstract":"<div><p>Wildfires may increase soil emissions of trace nitrogen (N) gases like nitric oxide (NO) and nitrous oxide (N<sub>2</sub>O) by changing soil physicochemical conditions and altering microbial processes like nitrification and denitrification. When 34 studies were synthesized, we found a significant increase in both NO and N<sub>2</sub>O emissions up to 1 year post-fire across studies spanning ecosystems globally. However, when fluxes were separated by ecosystem type, we found that individual ecosystem types responded uniquely to fire. Forest soils tended to emit more N<sub>2</sub>O after fire, but there was no significant effect on NO. Shrubland soils showed significant increases in both NO and N<sub>2</sub>O emissions after fires; often with extremely large but short-lived NO pulses occurring immediately after fire. Grassland NO emissions increased after fire, but the size of this effect was small relative to shrublands. N<sub>2</sub>O emissions from burned grasslands were highly variable with no significant effect. To better understand the variation in responses to fire across global ecosystems, more consistent measurements of variables recognized as important controls on soil fluxes of NO and N<sub>2</sub>O (e.g., N cycling rates, soil water content, pH, and substrate availability) are needed across studies. We also suggest that fire-specific elements like burn severity, microbial community succession, and the presence of char be considered by future studies. Our synthesis suggests that fires can exacerbate ecosystem N loss long after they burn, increasing soil emissions of NO and N<sub>2</sub>O with implications for ecosystem N loss, climate, and regional air quality as wildfires increase globally.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-023-01072-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50470477","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}
Pub Date : 2023-09-02DOI: 10.1007/s10533-023-01081-4
Linbin Zhou, Fengjie Liu, Yehui Tan, Claude Fortin, Liangmin Huang, Peter G. C. Campbell
Recent studies suggest aluminum (Al) likely plays a role in the ocean carbon cycle by altering the biological carbon fixation and carbon decomposition of marine diatoms. However, it remains speculative whether Al has similar effects on other ecologically important phytoplankton groups such as the globally important nitrogen-fixing cyanobacterium, Trichodesmium. Here we report the influence of Al on carbon fixation and decomposition in non-axenic cultures of Trichodesmium erythraeum IMS101 (CCMP 1985). By using radiocarbon, and adding oceanic relevant amounts of dissolved Al (yielding concentrations of 40 and 200 nM) along with non-Al-amended controls, we investigated the changes in particulate organic carbon (POC) of Trichodesmium (> 2 μm, Trichodesmium POC), and free-living bacteria (0.2–2 μm, bacterial POC), and dissolved organic carbon (< 0.2 μm, DOC) over a 116-day growth period. The results showed that the rates of increase of POC in the declining growth phase of T. erythraeum were significantly higher (by 11–14%) in the Al-enriched treatments than in the control, and this Al-enhanced carbon fixation is consistent with previous observations on marine diatoms. On the other hand, unlike diatoms, the POC from T. erythraeum decomposed faster in the Al-enriched treatments during the first decay phase when bacterial POC and DOC increased along with the decomposition of Trichodesmium POC. Further addition of the same amounts of Al (again calculated to increase the Al concentration by 40 and 200 nM) was performed on day 71. This treatment was designed to mimic Al supply from sediment after the settling of Trichodesmium colonies to the ocean bottom. Following this second addition, the decomposition rate of both Trichodesmium POC and DOC slowed down by 20–27% and 31–62%, respectively, during the second decay phase, when DOC and bacterial POC decreased. The study suggests that Al fertilization in the surface ocean via dust deposition may increase the net carbon fixation and associated nitrogen fixation by Trichodesmium, and thus the supply of new nitrogen to the euphotic zone, whereas Al from sediment may decrease the decomposition rate of decaying Trichodesmium settled to the ocean bottom.
{"title":"Aluminum-induced changes in the net carbon fixation and carbon decomposition of a nitrogen-fixing cyanobacterium Trichodesmium erythraeum","authors":"Linbin Zhou, Fengjie Liu, Yehui Tan, Claude Fortin, Liangmin Huang, Peter G. C. Campbell","doi":"10.1007/s10533-023-01081-4","DOIUrl":"10.1007/s10533-023-01081-4","url":null,"abstract":"<div><p>Recent studies suggest aluminum (Al) likely plays a role in the ocean carbon cycle by altering the biological carbon fixation and carbon decomposition of marine diatoms. However, it remains speculative whether Al has similar effects on other ecologically important phytoplankton groups such as the globally important nitrogen-fixing cyanobacterium, <i>Trichodesmium</i>. Here we report the influence of Al on carbon fixation and decomposition in non-axenic cultures of <i>Trichodesmium erythraeum</i> IMS101 (CCMP 1985). By using radiocarbon, and adding oceanic relevant amounts of dissolved Al (yielding concentrations of 40 and 200 nM) along with non-Al-amended controls, we investigated the changes in particulate organic carbon (POC) of <i>Trichodesmium</i> (> 2 μm, <i>Trichodesmium</i> POC), and free-living bacteria (0.2–2 μm, bacterial POC), and dissolved organic carbon (< 0.2 μm, DOC) over a 116-day growth period. The results showed that the rates of increase of POC in the declining growth phase of <i>T. erythraeum</i> were significantly higher (by 11–14%) in the Al-enriched treatments than in the control, and this Al-enhanced carbon fixation is consistent with previous observations on marine diatoms. On the other hand, unlike diatoms, the POC from <i>T. erythraeum</i> decomposed faster in the Al-enriched treatments during the first decay phase when bacterial POC and DOC increased along with the decomposition of <i>Trichodesmium</i> POC. Further addition of the same amounts of Al (again calculated to increase the Al concentration by 40 and 200 nM) was performed on day 71. This treatment was designed to mimic Al supply from sediment after the settling of <i>Trichodesmium</i> colonies to the ocean bottom. Following this second addition, the decomposition rate of both <i>Trichodesmium</i> POC and DOC slowed down by 20–27% and 31–62%, respectively, during the second decay phase, when DOC and bacterial POC decreased. The study suggests that Al fertilization in the surface ocean via dust deposition may increase the net carbon fixation and associated nitrogen fixation by <i>Trichodesmium</i>, and thus the supply of new nitrogen to the euphotic zone, whereas Al from sediment may decrease the decomposition rate of decaying <i>Trichodesmium</i> settled to the ocean bottom.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44431576","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}
Pub Date : 2023-08-27DOI: 10.1007/s10533-023-01079-y
Kevin Jones, Martin Berggren, Johanna Sjöstedt
Transport of terrestrial carbon through riverine systems to coastal water has a negative impact on oxygen concentration in coastal areas. However, information on seasonal variation and the impact of catchment composition on the bioavailability of allochthonous carbon is lacking. In this project we address this knowledge gap by investigating the reactivity of dissolved organic carbon (DOC) at river mouths which originate from agricultural or forested dominated catchments over a year. Using a high-capacity oxygen sensing system biological oxygen demand (BOD) was measured and converted to carbon utilization rate. This allowed a spatial and temporal resolution necessary to understand how concentrations of total nitrogen, total phosphorus, DOC, as well as carbon composition influence carbon bioavailability. Seasonality and the differing catchment compositions yielded variable results about which factors were significantly contributing to reactivity. In addition, we found that carbon utilization rate was highest during April, June, and October for most rivers. The bioavailable fraction (BFc) was significantly higher in rivers with agricultural compared to forest dominated catchments during January, April, June, and October. However, rivers with agricultural dominated catchment had a significantly higher carbon utilization rate in August. This indicate that rivers dominated by forest transport larger and more refractory pools of carbon, while rivers with agricultural dominated catchments have a higher percentage of BFc. Based on these results we suggest that management efforts, to reduce the transport of bioavailable carbon, would be most efficient during spring and autumn with equal importance on rivers with catchment areas dominated by agriculture and forest.
{"title":"Seasonal variation and importance of catchment area composition for transport of bioavailable carbon to the Baltic Sea","authors":"Kevin Jones, Martin Berggren, Johanna Sjöstedt","doi":"10.1007/s10533-023-01079-y","DOIUrl":"10.1007/s10533-023-01079-y","url":null,"abstract":"<div><p>Transport of terrestrial carbon through riverine systems to coastal water has a negative impact on oxygen concentration in coastal areas. However, information on seasonal variation and the impact of catchment composition on the bioavailability of allochthonous carbon is lacking. In this project we address this knowledge gap by investigating the reactivity of dissolved organic carbon (DOC) at river mouths which originate from agricultural or forested dominated catchments over a year. Using a high-capacity oxygen sensing system biological oxygen demand (BOD) was measured and converted to carbon utilization rate. This allowed a spatial and temporal resolution necessary to understand how concentrations of total nitrogen, total phosphorus, DOC, as well as carbon composition influence carbon bioavailability. Seasonality and the differing catchment compositions yielded variable results about which factors were significantly contributing to reactivity. In addition, we found that carbon utilization rate was highest during April, June, and October for most rivers. The bioavailable fraction (BFc) was significantly higher in rivers with agricultural compared to forest dominated catchments during January, April, June, and October. However, rivers with agricultural dominated catchment had a significantly higher carbon utilization rate in August. This indicate that rivers dominated by forest transport larger and more refractory pools of carbon, while rivers with agricultural dominated catchments have a higher percentage of BFc. Based on these results we suggest that management efforts, to reduce the transport of bioavailable carbon, would be most efficient during spring and autumn with equal importance on rivers with catchment areas dominated by agriculture and forest.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-023-01079-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42755467","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}
Pub Date : 2023-08-26DOI: 10.1007/s10533-023-01077-0
Scott Raulerson, Johnson B. Jeffers, Natalie A. Griffiths, Benjamin M. Rau, Cody Matteson, C. Rhett Jackson
Leaching of excess nitrogen (N) to groundwater in fertilized landscapes can overwhelm natural biogeochemical processes and cause long-term eutrophication of aquatic systems. We investigated N fate and transport from an intensively managed short-rotation woody crop (Pinus taeda) plantation through the riparian zone of an intermittent, low-gradient blackwater stream. Fertilization of the P. taeda plantation on the uplands resulted in contamination of groundwater with nitrate concentrations between 0.9 and 1.9 mg N L−1. No corresponding increase in nitrate was observed in stream water or shallow groundwater in the riparian zone. Groundwater travel-time modeling predicted that N from near-stream, upland plantation areas should have reached streams during the monitoring period. Two years of measuring N species in well water in contrasting landscape positions (within the plantation, swale, riparian edge, forested hillslope, and valley), indicated rapid nitrate transformation and denitrification within the forested wetland valleys. Denitrification in the shallow groundwater system within the toeslopes and the riparian zone was estimated to have removed > 90% of nitrate. These results highlight the importance of riparian zones as pathways for the removal of N and for controlling downstream N loads.
在肥沃的景观中,过量的氮(N)浸出到地下水中会压倒自然的生物地球化学过程,并导致水生系统的长期富营养化。研究了集约化管理的短轮作木本作物松林(Pinus taeda)通过间歇低梯度黑水河流带的氮的命运和运输。高原柽柳人工林施肥导致地下水硝酸盐浓度在0.9 ~ 1.9 mg N L−1之间。河岸带的溪水和浅层地下水中硝酸盐含量未见相应的增加。地下水走时模型预测,在监测期间,来自近溪流、旱地种植区的氮应该已经到达溪流。对不同景观位置(人工林、沼泽、河岸边缘、森林山坡和山谷)井水中氮的测定表明,森林湿地山谷中硝酸盐的快速转化和反硝化作用。据估计,坡道和河岸地带浅层地下水系统的反硝化作用已经去除了90%的硝酸盐。这些结果强调了河岸带作为去除氮和控制下游氮负荷的途径的重要性。
{"title":"Rapid denitrification of nitrate-contaminated groundwater in a low-gradient blackwater stream valley","authors":"Scott Raulerson, Johnson B. Jeffers, Natalie A. Griffiths, Benjamin M. Rau, Cody Matteson, C. Rhett Jackson","doi":"10.1007/s10533-023-01077-0","DOIUrl":"10.1007/s10533-023-01077-0","url":null,"abstract":"<div><p>Leaching of excess nitrogen (N) to groundwater in fertilized landscapes can overwhelm natural biogeochemical processes and cause long-term eutrophication of aquatic systems. We investigated N fate and transport from an intensively managed short-rotation woody crop (<i>Pinus taeda</i>) plantation through the riparian zone of an intermittent, low-gradient blackwater stream. Fertilization of the <i>P. taeda</i> plantation on the uplands resulted in contamination of groundwater with nitrate concentrations between 0.9 and 1.9 mg N L<sup>−1</sup>. No corresponding increase in nitrate was observed in stream water or shallow groundwater in the riparian zone. Groundwater travel-time modeling predicted that N from near-stream, upland plantation areas should have reached streams during the monitoring period. Two years of measuring N species in well water in contrasting landscape positions (within the plantation, swale, riparian edge, forested hillslope, and valley), indicated rapid nitrate transformation and denitrification within the forested wetland valleys. Denitrification in the shallow groundwater system within the toeslopes and the riparian zone was estimated to have removed > 90% of nitrate. These results highlight the importance of riparian zones as pathways for the removal of N and for controlling downstream N loads.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47919309","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}
Pub Date : 2023-08-23DOI: 10.1007/s10533-023-01076-1
Ove H. Meisel, Ruud Rijkers, Joshua F. Dean, Michiel H. in ‘t Zandt, Jacobus van Huissteden, Trofim C. Maximov, Sergey V. Karsanaev, Luca Belelli Marchesini, Arne Goovaerts, Lukas Wacker, Gert-Jan Reichart, Steven Bouillon, Cornelia U. Welte, Mike S. M. Jetten, Jorien E. Vonk, Han Dolman
Thermokarst lakes are important conduits for organic carbon sequestration, soil organic matter (soil-OM) decomposition and release of atmospheric greenhouse gases in the Arctic. They can be classified as either floating-ice lakes, which sustain a zone of unfrozen sediment (talik) at the lakebed year-round, or as bedfast-ice lakes, which freeze all the way to the lakebed in winter. Another key characteristic of thermokarst lakes are their eroding shorelines, depending on the surrounding landscape, they can play a major role in supplying the lakebeds with sediment and OM. These differences in winter ice regime and eroding shorelines are key factors which determine the quantity and quality of OM in thermokarst lake sediments. We used an array of physical, geochemical, and microbiological tools to identify the differences in the environmental conditions, sedimentary characteristics, carbon stocks and microbial community compositions in the sediments of a bedfast-ice and a floating-ice lake in Far East Siberia with different eroding shorelines. Our data show strong differences across most of the measured parameters between the two lakes. For example, the floating-ice lake contains considerably lower amounts of sediment organic matter and dissolved organic carbon, both of which also appear to be more degraded in comparison to the bedfast-ice lake, based on their stable carbon isotope composition (δ13C). We also document clear differences in the microbial community composition, for both archaea and bacteria. We identified the lake water depth (bedfast-ice vs. floating-ice) and shoreline erosion to be the two most likely main drivers of the sedimentary, microbial and biogeochemical diversity in thermokarst lakes. With ongoing climate warming, it is likely that an increasing number of lakes will shift from a bedfast- to a floating-ice state, and that increasing levels of shoreline erosion will supply the lakes with sediments. Yet, still little is known about the physical, biogeochemical and microbial differences in the sediments of these lake types and how different eroding shorelines impact these lake systems.
{"title":"Geochemical, sedimentological and microbial diversity in two thermokarst lakes of far Eastern Siberia","authors":"Ove H. Meisel, Ruud Rijkers, Joshua F. Dean, Michiel H. in ‘t Zandt, Jacobus van Huissteden, Trofim C. Maximov, Sergey V. Karsanaev, Luca Belelli Marchesini, Arne Goovaerts, Lukas Wacker, Gert-Jan Reichart, Steven Bouillon, Cornelia U. Welte, Mike S. M. Jetten, Jorien E. Vonk, Han Dolman","doi":"10.1007/s10533-023-01076-1","DOIUrl":"10.1007/s10533-023-01076-1","url":null,"abstract":"<div><p>Thermokarst lakes are important conduits for organic carbon sequestration, soil organic matter (soil-OM) decomposition and release of atmospheric greenhouse gases in the Arctic. They can be classified as either floating-ice lakes, which sustain a zone of unfrozen sediment (talik) at the lakebed year-round, or as bedfast-ice lakes, which freeze all the way to the lakebed in winter. Another key characteristic of thermokarst lakes are their eroding shorelines, depending on the surrounding landscape, they can play a major role in supplying the lakebeds with sediment and OM. These differences in winter ice regime and eroding shorelines are key factors which determine the quantity and quality of OM in thermokarst lake sediments. We used an array of physical, geochemical, and microbiological tools to identify the differences in the environmental conditions, sedimentary characteristics, carbon stocks and microbial community compositions in the sediments of a bedfast-ice and a floating-ice lake in Far East Siberia with different eroding shorelines. Our data show strong differences across most of the measured parameters between the two lakes. For example, the floating-ice lake contains considerably lower amounts of sediment organic matter and dissolved organic carbon, both of which also appear to be more degraded in comparison to the bedfast-ice lake, based on their stable carbon isotope composition (δ<sup>13</sup>C). We also document clear differences in the microbial community composition, for both archaea and bacteria. We identified the lake water depth (bedfast-ice vs. floating-ice) and shoreline erosion to be the two most likely main drivers of the sedimentary, microbial and biogeochemical diversity in thermokarst lakes. With ongoing climate warming, it is likely that an increasing number of lakes will shift from a bedfast- to a floating-ice state, and that increasing levels of shoreline erosion will supply the lakes with sediments. Yet, still little is known about the physical, biogeochemical and microbial differences in the sediments of these lake types and how different eroding shorelines impact these lake systems.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-023-01076-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47900477","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}
Pub Date : 2023-08-16DOI: 10.1007/s10533-023-01078-z
N. Raczka, C. Walter, J. Carrara, E. Brzostek
{"title":"Divergent responses of belowground carbon investment in Quercus spp. and Acer saccharum to reduced precipitation","authors":"N. Raczka, C. Walter, J. Carrara, E. Brzostek","doi":"10.1007/s10533-023-01078-z","DOIUrl":"https://doi.org/10.1007/s10533-023-01078-z","url":null,"abstract":"","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48536458","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}
Pub Date : 2023-08-08DOI: 10.1007/s10533-023-01075-2
Tingjiu Zhang, Wenming Ma, Yu Tian, S. Bai, Zuoma Dengzheng, Dong-ying Zhang, X. Ma, X. Mu
{"title":"The mitigation of microbial carbon and nitrogen limitations by shrub encroachment: extracellular enzyme stoichiometry of the alpine grassland on the Qinghai-Tibetan Plateau","authors":"Tingjiu Zhang, Wenming Ma, Yu Tian, S. Bai, Zuoma Dengzheng, Dong-ying Zhang, X. Ma, X. Mu","doi":"10.1007/s10533-023-01075-2","DOIUrl":"https://doi.org/10.1007/s10533-023-01075-2","url":null,"abstract":"","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44493567","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}
Pub Date : 2023-08-07DOI: 10.1007/s10533-023-01074-3
Shannon L. Speir, J. Tank, Jason M. Taylor, Amelia L. Grose
{"title":"Temperature and carbon availability interact to enhance nitrous oxide production via denitrification in alluvial plain river sediments","authors":"Shannon L. Speir, J. Tank, Jason M. Taylor, Amelia L. Grose","doi":"10.1007/s10533-023-01074-3","DOIUrl":"https://doi.org/10.1007/s10533-023-01074-3","url":null,"abstract":"","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44579111","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}