Biogeochemistry最新文献

{"title":"Low molecular weight organic acids mobilize soil organic phosphorus for enzymatic hydrolysis in a temperate montane peatland","authors":"Yuchen Suo,&nbsp;Tong Li,&nbsp;Christian von Sperber,&nbsp;Leming Ge,&nbsp;Chenhao Cao,&nbsp;Zhifeng Zhai,&nbsp;Zhaojun Bu,&nbsp;Meng Wang","doi":"10.1007/s10533-025-01210-1","DOIUrl":"10.1007/s10533-025-01210-1","url":null,"abstract":"<div><p>The stability of carbon (C) stocks in peatlands is intricately linked to phosphorus (P) bioavailability. Given that organic P compounds (P_o) can make up to 89% of total soil P in these ecosystems, it is vital to understand their role in regulating plant productivity and organic matter decomposition. Despite this significance, the mechanisms controlling P bioavailability remain poorly understood. Plants and soil microorganisms primarily regulate the release of soil P via low-molecular-weight organic acids (LMWOAs) and modulate the hydrolysis of P_o through phosphatase enzymes, particularly phosphomonoesterase, phytase, and phosphodiesterase. This study investigated the role of LMWOAs, derived from root exudates of dominant vascular plants and <i>Sphagnum</i> leachates in a temperate montane peatland, in facilitating the release of P. We also quantified the ability of these plants to hydrolyze P_o from various LMWOA-extracted fractions by adding phosphomonoesterase, phytase, and phosphodiesterase. The results show that peatland plants predominantly exuded muconic, azelaic, 3-hydroxybutyric, and malonic acids. The concentration of enzymatically hydrolyzed P_o in the water-extracted fraction was 8.1 ± 3.4 mg kg⁻¹. Notably, azelaic and malonic acids were effective in releasing over 58% of soil P (330–798 mg kg⁻¹), with more than 88% of this P being in organic form. In the azelaic and malonic acid-extracted fractions, the concentration of enzymatically hydrolyzed P_o concentration was 123.7 ± 32.1 mg kg⁻¹, accounting for 23% of the LMWOA-extracted P_o. Phytase, the most important phosphatase enzyme, accounts for 66% (47–88%) of the enzymatically hydrolyzed P_o (81.9 ± 20.9 mg kg⁻¹). Our study demonstrates that LMWOA-mediated release of P_o is an essential prerequisite for enzymatic hydrolysis of P_o in organic peat soils. However, only a small portion of LMWOA-extracted P_o can be hydrolyzed by phosphatase enzymes. The different composition and efficacy of LMWOAs from species of different plant functional types highlight the necessity to consider changes in vegetation composition, as this could significantly impact P dynamics in peatlands and, consequently, the stability of their C stocks.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01210-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moisture and soil depth govern relationships between soil organic carbon and oxalate-extractable metals at the global scale","authors":"Sophie F. von Fromm,&nbsp;Hermann F. Jungkunst,&nbsp;Bright Amenkhienan,&nbsp;Steven J. Hall,&nbsp;Katerina Georgiou,&nbsp;Caitlin Hicks Pries,&nbsp;Fernando Montaño-López,&nbsp;Carlos Alberto Quesada,&nbsp;Craig Rasmussen,&nbsp;Marion Schrumpf,&nbsp;Balwant Singh,&nbsp;Aaron Thompson,&nbsp;Rota Wagai,&nbsp;Sabine Fiedler","doi":"10.1007/s10533-025-01208-9","DOIUrl":"10.1007/s10533-025-01208-9","url":null,"abstract":"<div><p>An important control on long-term soil organic carbon (SOC) storage is the adsorption of SOC by short-range-ordered (SRO) minerals. SRO are commonly quantified by measuring oxalate-extractable metals (M_ox = Al_ox + ½ Fe_ox), which many studies have shown to be positively correlated with SOC. It remains uncertain if this organo-mineral relationship is robust at the global scale, or if capturing regional differences is needed to maximize model accuracy. We used a global synthesis of Al_ox and Fe_ox data to test their role in controlling SOC abundance across regions. We compiled 37,344 individual soil horizon measurements, with soil depth ranging between 0 and 200 cm, from 11,122 profiles. We used the Holdridge Life Zones, which are characterized by biotemperature, precipitation, and potential evapotranspiration, to group the soil profiles by their climatic conditions that also correlate with other important soil-forming factors. Based on linear mixed-effects models, we found a positive relationship between M_ox and SOC across regions and depths, accounting for 49% of the SOC variation. This relationship is strongest in wetter regions and at depths between 20 and 100 cm. Across all environmental conditions, Al_ox is a stronger predictor of SOC than Fe_ox. Our analysis suggests oxalate-extractable metals are good proxies for mineral-induced SOC protection at the global scale. However, our findings also indicate that the importance of organo-mineral interactions at the global scale varies with climatic conditions and depth. The underlying mechanisms need to be considered when incorporating these relationships as proxies for mineral sorption capacity into soil C models.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01208-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution, sources, and fate of nitrate in groundwater in agricultural areas of Southern Alberta, Canada","authors":"Isabel Plata,&nbsp;Pauline Humez,&nbsp;Leah Wilson,&nbsp;Michael Nightingale,&nbsp;Cynthia McClain,&nbsp;Bernhard Mayer","doi":"10.1007/s10533-025-01209-8","DOIUrl":"10.1007/s10533-025-01209-8","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Nitrate pollution frequently impacts groundwater quality, particularly in agricultural regions across the world, but identifying the sources of nitrate (NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;) pollution remains challenging. The extensive use of nitrogen-containing fertilizers, surpassing crop requirements, and livestock management practices associated with the spreading of manure can lead to the accumulation and transport of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; into groundwater, potentially affecting drinking water sources. We investigated the occurrence and distribution of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; in groundwater in Southern Alberta, Canada, a region characterized by intensive crop cultivation and livestock industry. Over 3500 samples from a provincial-scale groundwater quality database, collated from multiple projects and sources, involving domestic wells, monitoring wells, and springs, coupled with newly obtained samples from monitoring wells provided comprehensive geochemical insights into groundwater quality. While stable isotope compositions of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; (δ&lt;sup&gt;15&lt;/sup&gt;N and δ&lt;sup&gt;18&lt;/sup&gt;O) were exclusively available for groundwater samples obtained from monitoring wells, the stable isotope data were instrumental in constraining NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; sources and transformation processes within the aquifers of the study region. Among all samples, 49% (n = 1746) were associated with NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; concentrations below the detection limits. Ten percent (n = 369) of all groundwater samples, including samples with concentrations below detection limits, exceed the Canadian drinking water maximum acceptable concentration of 10 mg/L for nitrate as nitrogen (NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;–N). Elevated NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; concentrations (&gt; 10 mg/L as NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;–N) in groundwater were mainly detected at shallow depths (&lt; 30 m) predominantly in aquifers in surficial sediments and less frequently in bedrock aquifers. Statistical correlations between aqueous geochemical parameters showed positive associations between concentrations of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;–N and both potassium (K&lt;sup&gt;+&lt;/sup&gt;) and chloride (Cl&lt;sup&gt;−&lt;/sup&gt;), indicating the influence of synthetic fertilizers on groundwater quality. In addition, isotope analyses of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; (δ&lt;sup&gt;15&lt;/sup&gt;N and δ&lt;sup&gt;18&lt;/sup&gt;O) revealed three NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; sources in groundwater, including mineralization of soil organic nitrogen followed by nitrification in soils, nitrification of ammonium or urea-based synthetic fertilizers in soils, and manure. However, manure was identified as the dominant source of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; exceeding the maximum acceptable concentration in groundwater within agriculturally dominated areas. Additionally, this multifaceted approach helped identify denitrification in some groundwater samples, a process that plays a key role in reducing NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; concentrations under favorabl","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-025-01209-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace metals and Mo isotopic fractionation in Skagerrak sediments–effects of different oxygen conditions","authors":"Anna Siems,&nbsp;Tristan Zimmermann,&nbsp;Tina Sanders,&nbsp;Michael E. Wieser,&nbsp;Daniel Pröfrock","doi":"10.1007/s10533-024-01206-3","DOIUrl":"10.1007/s10533-024-01206-3","url":null,"abstract":"<div><p>The Skagerrak is the main depot center for organic matter and anthropogenic pollutants from the entire North Sea. Changes in ocean circulation or suspended matter supply might impact the sediment redox conditions. Indeed, little is known about the response of Skagerrak sediment and associated pollutants to different oxygen levels. We investigated sediments from three stations within the Skagerrak and incubated them for up to twelve months under aerobic and anaerobic conditions. Furthermore, we present the first <i>δ</i>^98/95Mo data for Skagerrak sediment profiles and the incubations to be utilized as a redox tracer. The sediment profiles of metals reflected anthropogenic pollution (Cu, Ni, Pb) but differed regionally with redox conditions. We differentiated redox conditions mainly by sediment and porewater Fe, Mn, Mo and <i>δ</i>^98/95Mo. In aerobic incubations, no Mn or Fe reduction was detected, while under anaerobic conditions, initial Mn and Fe reduction decreased after approximately three months. Under anaerobic conditions, a strong isotopic fractionation of Mo in the dissolved phase was found, reaching up to 5.03 ± 0.10‰, probably caused by incomplete thiolation of molybdate under low hydrogen sulfide levels. During the incubations, Cd, Cu, Ni, Pb were mobilized. While Cu and Cd were mobilized under aerobic conditions, Ni and Pb mobilization depended mainly on remineralization and redox conditions. Our results show that changes in oxygen conditions in the Skagerrak can have significant effects on the (legacy) metals stored in the sediment over the past decades.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01206-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143056667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Rewet without regret? Nutrient dynamics in fen peat exposed to different rewetting degrees","authors":"Annick van der Laan,&nbsp;Jerry van Dijk,&nbsp;Karin T. Rebel,&nbsp;Martin J. Wassen","doi":"10.1007/s10533-024-01202-7","DOIUrl":"10.1007/s10533-024-01202-7","url":null,"abstract":"","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01202-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do coastal salt mudflats (sabkhas) contribute to the blue carbon sequestration?","authors":"Hadil Elsayed,&nbsp;Zulfa Ali Al Disi,&nbsp;Khaled Naja,&nbsp;Ivan Strakhov,&nbsp;Scott O. C. Mundle,&nbsp;Hamad Al Saad Al-Kuwari,&nbsp;Fadhil Sadooni,&nbsp;Zach Diloreto,&nbsp;Jassim Abdulla A. Al-Khayat,&nbsp;Maria Dittrich","doi":"10.1007/s10533-024-01204-5","DOIUrl":"10.1007/s10533-024-01204-5","url":null,"abstract":"<div><p>Blue carbon represents the organic carbon retained in marine coastal ecosystems. <i>Sabkhas</i> (an Arabic for “mudflats”), formed in tidal environments under arid conditions, have been proposed to be capable of carbon sequestrating. Despite the growing understanding of the critical role of blue carbon ecosystems, there is a current dispute about whether sabkhas around the Persian Gulf can contribute to carbon retention as a blue carbon ecosystem. The arguments often lack data on a critical contributor, inorganic carbon in the form of carbonates, which can drive the net carbon exchange with the atmosphere. In this study we inventory organic and inorganic carbon retention capacity in two contrasting sabkhas of the Qatar Peninsula: carbonaceous Dohat Faishakh and siliciclastic Khor Al-Adaid. Despite the differences in organic carbon stock between the two sabkhas, the Dohat Faishakh sabkha has higher (37.17 ± 0.81 Mg C_org ha⁻¹) than it is in the Khor Al-Adaid sabkha (13.75 ± 0.38 Mg C_org ha⁻¹) for 0. 44 m sediment depth, the organic carbon retained in sabkhas is similar to those reported for mangroves and salt marshes. Notably, calculated CO₂ net sequestration indicated that both sabkhas evade CO₂ into the atmosphere. Thus, carbonate formation negated organic carbon accumulation in carbonaceous sabkha. Consequently, for proper evaluation of sabkhas as a blue carbon ecosystem, an inorganic carbon analysis, especially of carbonate formation, is inevitable. Considering only organic carbon stock may ay overestimate carbon sequestration capacity.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01204-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental drivers of seasonal and hourly fluxes of methane and carbon dioxide across a lowland stream network with mixed catchment","authors":"Benedichte Wiemann Olsen,&nbsp;Theis Kragh,&nbsp;Jonas Stage Sø,&nbsp;Emma Polauke,&nbsp;Kaj Sand-Jensen","doi":"10.1007/s10533-024-01205-4","DOIUrl":"10.1007/s10533-024-01205-4","url":null,"abstract":"<div><p>Streams serve as open windows for carbon emissions to the atmosphere due to the frequent supersaturation of carbon dioxide (CO₂) and methane (CH₄) that originates from large carbon input during runoff and associated in-stream processes. Due to the high spatial and temporal variability of the underlying environmental drivers (e.g., concentrations of dissolved CO₂ and CH₄, turbulence, and temperature), it has remained difficult to address the importance and upscale the emissions to annual whole-system and regional values. In this study, we measured concentrations and calculated emissions of CO₂ and CH₄ at diel and seasonal scales at 15 stations in a 1.4 km² stream network that drains a mixed lowland catchment consisting of agriculture (210 km²), forest (56 km²), and lakes, ponds, and wetlands (22 km²) in the upper River Odense, Denmark to evaluate environmental drivers behind the spatiotemporal variability. We used automatically venting floating chambers to calculate hourly diffusive fluxes of CO₂ and CH₄ and CH₄ ebullition. We found: 1) highly supersaturated CO₂ and CH₄ concentrations (median: 175 and 0.33 µmol L⁻¹, respectively) and high diffusive fluxes of CO₂ and CH₄ (median: 3,608 and 19 µmol m⁻² h⁻¹, respectively); 2) lower daytime than nighttime diffusive emissions of CO₂ in spring and summer, but no diel variability of CH₄; 3) higher concentrations and emissions of CH₄ at higher temperatures; and 4) higher emissions of CH₄ at stations located in sub-catchments with higher agricultural coverage. Ebullition of CH₄ peaked at two stations with soft organic sediment and low summer flow, and their ebullition alone constituted 30% of total annual CH₄ emissions from the stream network. Mean annual CO₂ emissions from the hydrological network (37.15 mol CO₂ m⁻² y⁻¹) exceeded CH₄ emissions 100-fold (0.43 mol CH₄ m⁻² y⁻¹), and their combined warming potential was 1.83 kg CO₂e m⁻² y⁻¹. Overall, agricultural sub-catchments had higher CH₄ emissions from streams, while lakes and ponds likely reduced downstream CH₄ and CO₂ emissions. Our findings demonstrate that CO₂ and CH₄ emissions data at high spatial and temporal resolution are essential to frame the heterogeneous stream conditions, understand gas emissions regulation, and upscale to annual values for hydrological networks and larger regions.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01205-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142941127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal patterns in sediment nitrification rates and their linkages to ammonium cycling in three agricultural streams","authors":"Anna E. S. Vincent,&nbsp;Jennifer L. Tank,&nbsp;Ursula H. Mahl","doi":"10.1007/s10533-024-01196-2","DOIUrl":"10.1007/s10533-024-01196-2","url":null,"abstract":"<div><p>Nitrification, or the microbial transformation of ammonium (NH₄⁺–N) to nitrate, is influenced by NH₄⁺–N and dissolved oxygen availability, water temperature, and carbon-to-nitrogen ratios. Open-canopy agricultural streams receive excess inorganic nitrogen (N) from the surrounding landscape and the mineralization of organic-rich sediments, and the form and timing of these N inputs varies throughout the year. Compared to forested streams, the seasonality of nitrification rates in agricultural streams are not well documented. We conducted nitrification assays on stream sediments to estimate seasonal rates in three agricultural streams from summer 2020 to spring 2021. We documented seasonal variation in nitrification rates and identified changes in environmental controls [e.g., stream temperature, NH₄⁺–N and dissolved organic carbon (DOC) availability, chlorophyll-<i>a</i>]. Nitrification rates were highest in spring (54.4 ± 12.7 mg N m⁻² d⁻¹; p = 0.02), coinciding with elevated NH₄⁺–N and higher stream temperatures relative to winter (p &lt; 0.001). Rates were lowest in autumn (19.9 ± 3.5 mg N m⁻² d⁻¹) when organic carbon concentrations peaked (17.2 ± 10.3 mg C L⁻¹; p = 0.01). Algal senescence in autumn may allow heterotrophs to outcompete nitrifiers for NH₄⁺–N. However, partial least square regression analyses indicated that sediment organic matter (as %OM) is an important positive predictor of nitrification, suggesting carbon can be an indirect positive control on nitrification. In the context of previous studies, agricultural streams had elevated NH₄⁺–N concentrations, but nitrification rates were comparable to those in less impacted systems. Although complex interactions exist among rates and drivers, rates from this study help expand documentation of nitrification in agricultural streams, and provide insight into temporal variation and dominant controls.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01196-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid response of moss-associated nitrogen fixation to nutrient additions in tropical montane cloud forests with different successional stages","authors":"Lina Avila Clasen,&nbsp;Danillo Oliveira Alvarenga,&nbsp;Yinliu Wang,&nbsp;Rune Fromm Andersen,&nbsp;Kathrin Rousk","doi":"10.1007/s10533-024-01195-3","DOIUrl":"10.1007/s10533-024-01195-3","url":null,"abstract":"<div><p>Nitrogen (N) fixation in association with mosses could be a key source of new N in tropical montane cloud forests since these forests maintain high humidity levels and stable temperatures, both of which are important to N fixation. Here, nutrient availability could be a prominent control of N fixation processes. However, the mechanisms and extent of these controls, particularly in forests at different successional stages, remains unknown to date. To address this knowledge gap, we investigated the impact of N, phosphorus (P) and molybdenum (Mo) additions on moss-associated N fixation in tropical montane cloud forests of two successional stages, an old-growth forest and an early-successional natural regrowth forest. We hypothesized that if N is available, N fixation rates would be rapidly reduced, while P and Mo would promote nitrogenase activity. Our results show that Mo additions did not affect N fixation rates, whereas N and P additions, in different doses and combinations, immediately reduced N fixation in both forests. Nonetheless, rates recovered within 1 year of nutrient additions. Nitrogen fixation rates associated with ground-covering mosses were similar in both forests. Interestingly, one year after the nutrient additions, N fixation rates across all the treatments were higher in the natural regrowth forests than the mature forests, suggesting more nutrient limitation in these regrowing forests, likely as a result of higher demand for growth. Our study highlights how moss-associated N fixation responds to changes in nutrient availability across distinct successional stages, deepening our understanding of processes that contributes to tropical montane cloud forests.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01195-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expanding towards contraction: the alternation of floods and droughts as a fundamental component in river ecology","authors":"S. Bernal,&nbsp;J. L. J. Ledesma,&nbsp;X. Peñarroya,&nbsp;C. Jativa,&nbsp;N. Catalán,&nbsp;E. O. Casamayor,&nbsp;A. Lupon,&nbsp;R. Marcé,&nbsp;E. Martí,&nbsp;X. Triadó-Margarit,&nbsp;G. Rocher-Ros","doi":"10.1007/s10533-024-01197-1","DOIUrl":"10.1007/s10533-024-01197-1","url":null,"abstract":"<div><p>Climate warming is causing more extreme weather conditions, with both larger and more intense precipitation events as well as extended periods of drought in many regions of the world. The consequence is an alteration of the hydrological regime of streams and rivers, with an increase in the probability of extreme hydrological conditions. Mediterranean-climate regions usually experience extreme hydrological events on a seasonal basis and thus, freshwater Mediterranean ecosystems can be used as natural laboratories for better understanding how climate warming will impact ecosystem structure and functioning elsewhere. In this paper, we revisited and contextualized historical and new datasets collected at Fuirosos, a well-studied Mediterranean intermittent stream naturally experiencing extreme hydrological events, to illustrate how the seasonal alternation of floods and droughts influence hydrology, microbial assemblages, water chemistry, and the potential for biogeochemical processing. Moreover, we revised some of the most influential conceptual and quantitative frameworks in river ecology to assess to what extent they incorporate the occurrence of extreme hydrological events. Based on this exercise, we identified knowledge gaps and challenges to guide future research on freshwater ecosystems under intensification of the hydrological cycle. Ultimately, we aimed to share the lessons learned from ecosystems naturally experiencing extreme hydrological events, which can help to better understand warming-induced impacts on hydrological transport and cycling of matter in fluvial ecosystems.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"168 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10533-024-01197-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142924472","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}