Limnology and Oceanography最新文献

{"title":"Radiocarbon analysis reveals the contribution of aged terrestrial carbon to sedimentary methane cycling","authors":"Sigrid van Grinsven, Benedict V. A. Mittelbach, Fatemeh Ajallooeian, Thomas Laemmel, Martin Wessels, Negar Haghipour, Sönke Szidat, Timothy I. Eglinton, Zongguang Liu, Xiaojuan Feng, Carsten J. Schubert","doi":"10.1002/lno.70376","DOIUrl":"https://doi.org/10.1002/lno.70376","url":null,"abstract":"Methane (CH <jats:sub>4</jats:sub> ) production in lacustrine sediments is known to be spatially heterogeneous, varying both horizontally and vertically. Porewater methane concentrations often differ between locations within a lake and with depth within the sediment profile. The drivers of this heterogeneity are often not well understood. Here, we explore methane cycling in the sediments of Lake Constance, the 2 <jats:sup>nd</jats:sup> largest perialpine lake in Europe, with well‐documented sedimentary methane production. We use a novel radiocarbon ( <jats:sup>14</jats:sup> C) based approach to determine the origin and age of buried carbon pools, as well as that of CO <jats:sub>2</jats:sub> and CH <jats:sub>4</jats:sub> in sediment porewaters at two locations with contrasting sediment supply, dominated by either allochthonous or autochthonous inputs. We show that porewater CO <jats:sub>2</jats:sub> is predominantly derived from inorganic carbon inputs, whereas CH <jats:sub>4</jats:sub> is produced from a mixture of CO <jats:sub>2</jats:sub> ‐derived and organic carbon‐derived substrates. At the allochthonous‐dominated location, a larger fraction of the CH <jats:sub>4</jats:sub> seemed to be produced from organic substrates than in the autochthonous location, where the <jats:sup>14</jats:sup> C signals of CO <jats:sub>2</jats:sub> and CH <jats:sub>4</jats:sub> were more comparable to one another. Furthermore, <jats:sup>14</jats:sup> C contents of lignin‐derived phenols and fatty acids, as proxies for mineral‐associated and free organic matter respectively, suggest that the “recalcitrant” carbon pool contributes to the methane production in centennial‐aged sediments. Microbial community data further suggest active methane production in these old sediments, challenging concepts of permanent organic carbon burial in deeper sediment layers and on the recalcitrance of the buried material.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"99 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recirculated submarine groundwater discharge dominates nutrient inputs and enhances eutrophication risk in a coastal lagoon","authors":"Júlia Rodriguez‐Puig, Clara Ruiz‐González, Marc Diego‐Feliu, Irene Alorda‐Montiel, Aaron Alorda‐Kleinglass, Daniel Romano‐Gude, Andrea G. Bravo, Júlia Dordal‐Soriano, Javier Gilabert, Sophia Bergeler, Céline Lavergne, Gemma Casas, Marisol Manzano, Jordi Garcia‐Orellana, Valentí Rodellas","doi":"10.1002/lno.70371","DOIUrl":"https://doi.org/10.1002/lno.70371","url":null,"abstract":"Submarine groundwater discharge (SGD) is a widely recognized pathway for nutrient transport to coastal systems. Prior studies overlook the unique biogeochemical signatures of different SGD pathways, neglecting their differences in biogeochemical transformations and spatiotemporal factors. Here, we present an integrated assessment of nutrient delivery through three SGD pathways (fresh SGD, long‐scale recirculated SGD, and short‐scale porewater exchange), alongside surface water inputs, to evaluate their seasonality and impact on nutrient dynamics in a coastal lagoon. We conducted five field surveys in March, July, and November 2021, July 2024, and March 2025 in the Mar Menor lagoon, an ecosystem facing severe ecological degradation, to analyze nutrient concentrations in stream water, groundwater, and lagoon water. Concentrations in discharging waters were shaped by watershed‐scale land use and local redox‐driven biogeochemical processes. Recirculated SGD (long‐scale and short‐scale), often overlooked, emerged as the dominant source of ammonium (; 100–160 kmol d <jats:sup>−1</jats:sup> ), dissolved organic nitrogen (DON; 270–900 kmol d <jats:sup>−1</jats:sup> ), dissolved inorganic phosphorus (DIP; 4–30 kmol d <jats:sup>−1</jats:sup> ), and dissolved silica (DSi; 200–270 kmol d <jats:sup>−1</jats:sup> ) across seasons, while continental discharge (streams and fresh SGD) was the main source of nitrate and nitrite (NO <jats:sub> <jats:italic>x</jats:italic> </jats:sub> ; 30–210 kmol d <jats:sup>−1</jats:sup> ). Short‐scale recirculation flows controlled seasonal nutrient limitation by delivering additional DIP inputs (24 kmol d <jats:sup>−1</jats:sup> ) in summer, increasing eutrophication risk. Identifying preferential transport pathways for each nutrient into coastal systems is crucial for predicting and managing ecosystem vulnerability.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"21 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Behaviors that come out of a copepod's mind","authors":"Jarl Giske, Tom J. Langbehn, Pawel Burkhardt, Johanna M. Aarflot","doi":"10.1002/lno.70380","DOIUrl":"https://doi.org/10.1002/lno.70380","url":null,"abstract":"Many aquatic environments are changing much faster than the gene pools of animals inhabiting them. To better predict how a copepod will behave, it is helpful to try to fathom the world from its sensory and cognitive system. Studies of genes, hormones, neuropeptides, and neural circuits can reveal underlying mechanisms while behavioral studies may capture their integrated outcomes. From the literature, which is richest for the calanoids <jats:italic>Acartia</jats:italic> and <jats:italic>Calanus</jats:italic> and the harpacticoid <jats:italic>Tigriopus</jats:italic> , we find that copepod decision‐making is centralized in the central nervous system. Copepod decision‐making and behavior can be described and modeled as (i) a dialogue between competing survival circuits that link sensing and behavior via (ii) subjective internal models and (iii) an ontogeny‐ and state‐dependent value system, the latter modulated by clock genes and hormones. Thereafter, (iv) competing neurobiological states can lead to (v) a global organismic state with (vi) narrowed attention. Then, (vii) the copepod's predictive models of near‐future expectations, based on (viii) its memory and (ix) learning from (x) previous prediction errors, will find the expectedly most attractive decision. From this follows our definition of the copepod mind as the integrated cognitive mechanisms underlying decision‐making: (i) awareness of itself, of some past experiences, and of its surroundings; (ii) capacity for competing emotions; and (iii) expectations to the effects of its actions. Copepod behavior and development can be understood and modeled from the decisions that come out of such minds.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"29 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Couples in the deep: Dissolved organic matter–microbial linkages in the oxygenated hypolimnion of a deep freshwater lake","authors":"Morimaru Kida, Ayuri Ohira, Yusuke Okazaki, Yasuhiko T. Yamaguchi, Akiko S. Goto, Kazuhide Hayakawa, Hiroshi Nishimura","doi":"10.1002/lno.70374","DOIUrl":"https://doi.org/10.1002/lno.70374","url":null,"abstract":"The interaction between dissolved organic matter (DOM) and microbial communities is a critical yet understudied driver of biogeochemical cycling in aquatic ecosystems. Understanding these interactions is essential to elucidating chemical and microbial dynamics that sustain ecosystem functioning. Here, we combined non‐targeted ultrahigh‐resolution mass spectrometry (FT‐ICR MS)‐based environmental metabolome analysis with microbiome analysis to conduct the first comprehensive investigation of DOM–microbe linkages in both the epilimnion (5 m and thermocline) and oxygenated hypolimnion (60 and 85 m) of a deep freshwater lake throughout the stratification period, with Lake Biwa (Japan) as a model system. To facilitate the interpretation of DOM–microbe networks, we developed an integrated compound category classification (IC3) framework for assigning molecular formulae (MFs) to putative compound categories. Using a compositional data analysis framework with proportionality‐based association, we identified covarying MFs and bacterial taxa in the hypolimnion, which exhibited substantially more complex networks than the epilimnion. These networks encompassed 1704 MFs and 14 bacterial ASVs, representing the majority of total FT‐ICR MS peak intensity and 22% of the total ASV abundance, underscoring stronger DOM–microbe coupling in deep waters. Several hypolimnion specialist lineages exhibited cluster‐specific associations with N‐rich and oxidized MFs, consistent with niche differentiation within deep‐water heterotrophy. Although network edges do not resolve causality, these patterns provide testable hypotheses about substrate preferences and metabolic pathways shaping hypolimnetic DOM. Our study offers the first high‐resolution insights into DOM–microbe associations in the hypolimnion of a deep freshwater lake and establishes a framework for more efficient and robust analyses of such interactions.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"9 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Competing biotic interactions between fibrous algae and macrobenthos shape pioneer vegetation establishment in tidal marshes","authors":"Sarah Hautekiet, Jim van Belzen, Gregory S. Fivash, Ken Schoutens, Johan van de Koppel, Oberon Geunens, Wim Mertens, Bart Vandevoorde, Tjeerd J. Bouma, Stijn Temmerman","doi":"10.1002/lno.70379","DOIUrl":"https://doi.org/10.1002/lno.70379","url":null,"abstract":"The conservation and restoration of tidal marshes and their highly valued ecosystem services require in‐depth knowledge of the ecological processes facilitating or hindering marsh vegetation establishment on initially bare mudflats. While abiotic factors such as the impact of hydrodynamics and sediment bed dynamics have been extensively studied, the role of biotic interactions in marsh establishment is less understood. Here, we investigate how interactions among three key organism groups —benthic polychaetes ( <jats:italic>Hediste diversicolor</jats:italic> ), benthic filamentous algae ( <jats:italic>Vaucheria</jats:italic> sp.), and pioneer plant species ( <jats:italic>Aster tripolium</jats:italic> )— control early successional dynamics in brackish tidal marshes in a northwestern European estuary. Combining field monitoring, field transplantation experiments and lab mesocosm experiments, we show that polychaete predation substantially reduces plant seedling survival, thereby constraining vegetation establishment. However, mat‐forming filamentous algae, which preferentially establish adjacent to tidal drainage channels, play a pivotal role in mitigating these negative effects of polychaetes on plant seedlings. Algal mats had significantly lower polychaete densities and higher seedling survival compared to bare mudflats. Further, algae reduced polychaete‐induced seedling mortality, likely by limiting burrowing activity and potentially offering an alternative food source. Our findings highlight the critical role of benthos–algae–plant interactions in the early stages of tidal marsh development. These insights suggest that promoting filamentous algal mat development —for instance, by creating drainage channels or topographic heterogeneity— could enhance tidal marsh restoration success by facilitating pioneer vegetation establishment.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"115 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147739614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probabilistic assessment of algal nutrient limitation across lakes, leveraging trends with temperature and depth","authors":"Brian W. Baird, Smitom S. Borah, James J. Elser, Daniel R. Obenour","doi":"10.1002/lno.70375","DOIUrl":"https://doi.org/10.1002/lno.70375","url":null,"abstract":"Lake eutrophication remains a significant challenge for water‐quality management across the world. Many management strategies focus on reducing nutrient inputs, but other environmental factors can substantially influence the yield of algal biomass for a given level of nutrients. While various large‐scale studies have explored how different lake characteristics impact eutrophication, there remains a need to integrate these factors into a comprehensive model capable of assessing nitrogen vs. phosphorus limitation. In this study, we refine chlorophyll–nutrient relationships across the conterminous United States by considering auxiliary variables (i.e., temperature, lake depth, and nutrient enrichment) within a Bayesian hierarchical framework. We leverage over 4000 sampling events of 2755 different lakes from the National Lakes Assessments (2007–2022) to inform model development. We first consider auxiliary variables independently, exploring how they influence the intercept, slope, and critical nutrient ratio (nitrogen : phosphorus) in a regression to predict chlorophyll based on the limiting nutrient. Next, we integrate significant auxiliary variables into a comprehensive model for chlorophyll prediction. Results indicate that the critical nutrient ratio increases in relation to increased lake depth, and the slope of the nutrient–chlorophyll relationship increases with increasing temperature. We apply the model to map mean summer conditions across US lakes and find that 23% and 16% of lakes are strongly limited by phosphorus and nitrogen, respectively (i.e., at &gt; 90% probability). These proportions, however, vary substantially across different subregions. Overall, the probabilistic modeling approach and results can serve as an effective tool to inform water resources management, especially at large spatial scales.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"149 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147739615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinetics of sulfate‐ and iron‐dependent anaerobic methane oxidation in freshwater lake sediment","authors":"Alina Mostovaya, Michael Wind‐Hansen, Bo Thamdrup","doi":"10.1002/lno.70373","DOIUrl":"https://doi.org/10.1002/lno.70373","url":null,"abstract":"Anaerobic oxidation of methane (AOM) is a potentially important sink for methane in freshwater sediments. Assessing the contribution of AOM to methane budgets requires an understanding of AOM process kinetics, yet such information remains scarce. In the present study, we experimentally quantified the kinetics of AOM in the sediments of the Danish Lake Ørn, where sulfate‐ and iron‐dependent AOM occur side by side. The process exhibited saturation kinetics for methane, sulfate, and Fe(III), and the derived half‐saturation constants ( <jats:italic>K</jats:italic> <jats:sub>m</jats:sub> ) implied that these substrates co‐limit in situ AOM rates across concentration ranges typical for the study site and many other freshwater systems. Nevertheless, values of <jats:italic>K</jats:italic> <jats:sub>m</jats:sub> for methane (414 ± 79 <jats:italic>μ</jats:italic> M) and sulfate (31 ± 29 <jats:italic>μ</jats:italic> M) were low relative to marine systems, indicating an adaptation of the microbial community to the limnic environment. Experiments involving a synthetic analog of humic substances, anthraquinone‐2,6‐disulfonate (AQDS), demonstrated that sedimentary organic matter could play a role in alleviating restrictive Fe‐AOM kinetics. Incorporation of the obtained kinetic parameters into predictions of AOM rate profiles based on methane, sulfate, and Fe(III) concentrations revealed similar contributions of sulfate‐ and Fe(III)‐AOM pathways in the sulfate–methane transition zone. Our study expands the limited knowledge on the kinetics of microbial methane oxidation in freshwater systems and highlights the potential importance of AOM in regulating methane emissions from inland waters.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"19 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147739618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flux‐driven evolution: Nitrogen fixation underlies contrasting stoichiometric strategies and genetic lineages in an open‐ocean copepod","authors":"Kazutaka Takahashi, Fuminori Hashihama, Mitsuhide Sato, Takuhei Shiozaki, Sachiko Horii, Junya Hirai","doi":"10.1002/lno.70377","DOIUrl":"https://doi.org/10.1002/lno.70377","url":null,"abstract":"Variability in nutrient supply is a defining feature of oligotrophic oceans, yet how nutrient fluxes shape consumer physiology and population structure remains poorly resolved. Here, we examine how diazotrophic nitrogen fixation relates to stoichiometric metabolism and genetic structure in the widespread pelagic copepod <jats:italic>Pleuromamma xiphias</jats:italic> across the subtropical North Pacific. Using in situ excretion assays, body elemental composition, and genome‐wide single‐nucleotide polymorphism analyses, we show that individuals inhabiting regions of high nitrogen fixation excrete nitrogen and phosphorus in near‐Redfield proportions (N : P ≈ 18) and maintain higher body nitrogen and carbon contents. In contrast, copepods from regions with low nitrogen fixation exhibit strongly nitrogen‐sparing excretion (N : P ≈ 7.5) and reduced body elemental contents. These contrasting stoichiometric phenotypes align closely with two genetically distinct lineages, indicating that spatial variation in nitrogen flux is associated with coordinated physiological and population‐level divergence. Our results demonstrate that diazotrophic nitrogen supply can structure zooplankton‐mediated nutrient regeneration and population differentiation, with implications for nutrient cycling and ecosystem functioning in oligotrophic oceans.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"54 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147739617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eelgrass‐associated invertebrate biodiversity patterns in a subarctic seascape","authors":"Nicole S. Knight, Mélanie Leblanc, Elliot Dreujou, Fanny Noisette, Kaleigh E. Davis, Felipe Amadeo, Armand LaRocque, Mary I. O'Connor","doi":"10.1002/lno.70378","DOIUrl":"https://doi.org/10.1002/lno.70378","url":null,"abstract":"Abiotic, biotic, and spatial processes shape patterns of biodiversity in coastal ecosystems. In this study, we test how these processes influence eelgrass‐associated invertebrate diversity in a subarctic seascape. We sampled invertebrate assemblages in 12 meadows along 300 km of coastline in James Bay, Canada, and tested the relative contributions of abiotic conditions, spatial arrangement, and meadow attributes in explaining variation in invertebrate community composition, abundance, and diversity within and among meadows. We found that eelgrass meadows in James Bay support diverse invertebrate communities comprising at least 72 taxa. Greater invertebrate abundance was associated with higher epiphyte load and clearer water (lower turbidity). Invertebrate diversity increased with aboveground eelgrass biomass and epiphyte loads, and species richness increased in clearer water. Invertebrate communities in very salty and very fresh waters contributed the most to regional beta diversity. Variation in taxonomic composition across the seascape was notable; no species was observed at every site, and most taxa were observed at 3–5 sites. The most widely distributed taxa were the arctic amphipod <jats:italic>Gammarus setosus</jats:italic> and the bivalves <jats:italic>Mytilus trossulus</jats:italic> and <jats:italic>Macoma balthica</jats:italic> , each observed at 11 of the 12 sites. Variation in taxonomic composition among meadows was partially explained by meadow spatial arrangement and local abiotic conditions (salinity, fetch, temperature, and turbidity) but not meadow attributes such as eelgrass biomass or shoot size. We conclude that both local conditions and regional ecological processes such as spatially structured population dynamics and species interactions may be important for regional‐scale biodiversity patterns on this coastline.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"46 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147739616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal nitrate drawdown transitions lake ecosystems from phosphorus to nitrogen deficiency in annual cycles","authors":"Jasmine K. Stovall, Nicole D. Wagner, Katelyn McKindles, Michelle Neudeck, Matthew Rich, George S. Bullerjahn, J. Thad Scott","doi":"10.1002/lno.70367","DOIUrl":"https://doi.org/10.1002/lno.70367","url":null,"abstract":"Phytoplankton biomass is often limited by nitrogen (N) and/or phosphorus (P). Quantifying the relative availability of N and P in an ecosystem is useful in indicating nutrient limitation status. In subtropical lakes, nitrate availability generally follows a seasonal pattern with maxima in the late winter/early spring and minima in late summer/early autumn, also known as seasonal nitrate drawdown. Phytoplankton nutrient limitation in response to seasonal nitrate drawdown is largely understudied in lakes. We used a long‐term dataset of seasonal nitrate drawdown/accumulation alongside short‐term fertilization bioassay experiments and phytoplankton metatranscriptomes to quantify phytoplankton nutrient limitation and physiological response to seasonally changing nutrient availability in Beaver Lake, Arkansas. We hypothesized a seasonal shift in the phytoplankton community from P to N limitation. We found that the seasonal nitrate drawdown pattern in Beaver Lake has consistently occurred for at least 25 yr and is related to water temperature and season. We also found that Beaver Lake shifts from P limitation in spring to N and P co‐limitation in summer. A transition in phytoplankton physiological response from N assimilation and transport in spring to synthesis and fixation in summer/early autumn suggests that microbial activity and phytoplankton gene expression are responsive to seasonality and nutrient availability. We concluded that while N <jats:sub>2</jats:sub> fixation expression increases in response to N deficiency, it is not sufficient to offset N limitation. This study is the first to formally test the <jats:italic>nitrate drawdown hypothesis</jats:italic> , highlighting nitrate drawdown effects on phytoplankton and its implications for dual nutrient control in lakes.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"16 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147733672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}