Limnology and Oceanography最新文献

{"title":"Model predicts coastal paralytic shellfish toxicity in mussels from in situ phytoplankton concentrations","authors":"Sylvain Gaillard,&nbsp;David K. Ralston,&nbsp;V. Monica Bricelj,&nbsp;Roman Marin III,&nbsp;Bruce Keafer,&nbsp;Dennis J. McGillicuddy Jr.,&nbsp;Donald M. Anderson","doi":"10.1002/lno.70502","DOIUrl":"10.1002/lno.70502","url":null,"abstract":"<p>Harmful algal blooms (HABs) of <i>Alexandrium catenella</i> occur annually in the Gulf of Maine, leading to accumulation of paralytic shellfish toxins (PSTs) in bivalve mollusks and closure of harvesting areas. State monitoring programs in the region rely on weekly shellfish sampling and toxin analysis, requiring extensive effort with limited temporal resolution. With the development of autonomous in situ detection devices such as the Environmental Sample Processor (ESP), this study aimed to model shellfish toxicity using ESP-derived <i>A</i>. <i>catenella</i> counts to complement traditional monitoring programs using mussels (<i>Mytilus edulis</i>). We developed a one-compartment model of PST accumulation using <i>A. catenella</i> concentrations from nearshore ESP deployments. Multi-year and multi-site data were used to test four approaches for estimating mussel toxin uptake and depuration parameters, that is, local, global, or fixed literature values. When compared with direct PST measurements in nearby shellfish, the models achieved high correlations (<i>R</i>² = 0.69–0.90), with no false negatives. Model fit varied mainly with toxin uptake parameters and was influenced by <i>Alexandrium</i> concentrations. The impact of other environmental and biological factors on uptake and depuration parameters remained elusive, likely due to the mussels' physiological plasticity, spatial or hydrographic separation between ESP and toxicity measurements, and microhabitat conditions. This ESP-based model offers a simple, effective tool for translating offshore, automated cell counts into daily shellfish toxicity estimates and is promising for improvement of monitoring capacity in remote or under-sampled areas. Incorporation of this approach into physical–biological models and application in early warning systems with other biosensors remain to be tested.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70502","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148979657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conserved carbon density in marine picocyanobacteria improves phytoplankton biomass estimates","authors":"Huan Wang,&nbsp;Mingjing Tian,&nbsp;Xinya Xu,&nbsp;Haizheng Hong,&nbsp;Dalin Shi","doi":"10.1002/lno.70500","DOIUrl":"10.1002/lno.70500","url":null,"abstract":"<p>The picocyanobacteria <i>Synechococcus</i> and <i>Prochlorococcus</i> dominate oligotrophic oceans, where nitrogen (N) limitation is pervasive, and contribute substantially to marine primary production. However, their carbon biomass remains poorly constrained due to their extremely small cell size and the scarcity of direct measurements. Existing estimates largely rely on cellular carbon quota (<i>Q</i>_C) or carbon density derived from nutrient-replete laboratory cultures, which may not reflect the sustained N-limited conditions typical of oligotrophic oceans. Here, we established N-limited chemostat systems to investigate how <i>Q</i>_C and cell size respond to different degrees of N limitation in <i>Synechococcus</i> and <i>Prochlorococcus</i>. <i>Synechococcus</i> exhibited gradual declines in both cell volume and <i>Q</i>_C with increasing N limitation. In contrast, <i>Prochlorococcus</i> showed an initial sharp reduction followed by stabilization, suggesting that it may have approached physiological lower limits in cell volume and <i>Q</i>_C. These results indicate a close coupling between cell size and <i>Q</i>_C in both genera under N limitation. Compilation of data from this and previous studies further showed that both genera maintained a nearly constant organic carbon density of ~ 246 fg C <i>μ</i>m⁻³ across strains and environmental conditions, including variations in nutrient supply, light intensity, and temperature. This conserved carbon density provides a simple and reliable conversion factor for estimating picocyanobacterial carbon biomass. By integrating datasets from picocyanobacteria and eukaryotic phytoplankton, we also developed a universal C : vol model spanning a broad cell size spectrum (10⁻¹–10⁷ <i>μ</i>m³). Together, these findings improve estimates of marine phytoplankton carbon biomass and provide improved constraints for marine biogeochemical models.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148932929","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":"Role of methanotrophy in a high-methane emitting thermokarst lake","authors":"Teresa Aguirrezabala-Cámpano,&nbsp;Katey Walter Anthony,&nbsp;Frederic Thalasso,&nbsp;Pablo Inchausti,&nbsp;Natalie Tyler","doi":"10.1002/lno.70494","DOIUrl":"10.1002/lno.70494","url":null,"abstract":"<p>Thermokarst (thaw) lakes are projected to be an increasing source of atmospheric methane (CH₄), a potent greenhouse gas, as climate warms and permafrost thaws. However, the magnitude of CH₄ cycling, particularly the role of aerobic CH₄ oxidation (methanotrophy), among thermokarst lakes, is not well constrained. This study assesses year-round methanotrophic CH₄ oxidation in relation to total CH₄ emissions at Big Trail Lake, a young Interior Alaska thermokarst lake which formed in icy, Pleistocene-aged Yedoma permafrost and which is characterized by large CH₄ emissions. By integrating field measurements, incubations, and modeling, we demonstrate that methanotrophy reduced dissolved gas emissions (i.e., diffusive fluxes) by 57–100% during the open water period. However, its impact on total annual lake emissions was much lower (12–19%) due to a paucity of oxygen in the ice-covered water column during winter and high rates of ebullition that bypass methanotrophy in summer. Methanotrophy was most active during short shoulder seasons when snowmelt and autumnal turnover supplied oxygen to CH₄-rich water columns, yet these periods were insufficient to significantly offset the annual CH₄ budget dominated by ebullition emissions. Model predictions for scenarios of shortened ice-cover periods due to future warming suggest marginal increases in CH₄ emissions. This study highlights the limited role of methanotrophy against the backdrop of vast permafrost-derived CH₄ lake emissions in a warming Arctic.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70494","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148932931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulated heatwave reduces resilience to subsequent combined high-temperature and high-carbon-dioxide stress in a diatom","authors":"Xu Zhang,&nbsp;Thomas Mock,&nbsp;Ya-Wei Luo,&nbsp;Leïla Tirichine,&nbsp;Guang Gao,&nbsp;Lin Gao,&nbsp;Xin Zhao,&nbsp;Tianze Zheng,&nbsp;Xin Lin","doi":"10.1002/lno.70495","DOIUrl":"10.1002/lno.70495","url":null,"abstract":"<p>Marine heatwaves pose a significant threat to marine ecosystems, yet the underlying biological mechanisms remain largely elusive. Here, we integrated physiological, transcriptomic, and DNA methylation (5-methylcytosine and N6-methyladenine, 5mC and 6mA) analyses to investigate the response of the model diatom <i>Phaeodactylum tricornutum</i> to a simulated heatwave and subsequent combined high-temperature and high-CO₂ stress. <i>Phaeodactylum tricornutum</i> initially tolerated the simulated heatwave with only minor physiological impacts. However, completing the 16-d simulated heatwave followed by an 11-d recovery significantly compromised its resilience to the subsequent combined stress. This decline was associated with transcriptional signatures of photosynthetic impairment and DNA damage. Moreover, we found that the transcriptional patterns of transposable elements from simulated heatwave to final stress challenge were closely associated with their genomic features and 5mC methylation prior to the simulated heatwave. Throughout the experiment, CG-context methylation within the 5mC landscape remained stable, whereas non-CG context methylation increased progressively. These 5mC dynamics were decoupled from transposable elements transcriptional changes, suggesting that 5mC-mediated regulation was not the primary driver of their expression. In contrast, 6mA acted as a highly labile, stress-responsive mark. We observed a severe global loss of 6mA under the subsequent combined high-temperature and high-CO₂ conditions, which coincided with transposable elements associated genome rearrangement. Collectively, these results suggest that 6mA, rather than 5mC, acts as a dynamic regulator in safeguarding genomic integrity in <i>P. tricornutum</i>. Our findings reveal that a prior simulated heatwave diminishes resilience to subsequent severe stresses, offering critical insights into how climate change impacts marine primary producers.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148932932","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":"Stratification–ventilation cycling regulates the storage and emission of carbonaceous greenhouse gases in a subtropical reservoir","authors":"Lianghao Ge,&nbsp;Jianzhong Su,&nbsp;Ru Wan,&nbsp;Ehui Tan,&nbsp;Moge Du,&nbsp;Zifu Xu,&nbsp;Bingchen Lv,&nbsp;Wenbin Zou,&nbsp;Huihuang Chen,&nbsp;Jun Yang,&nbsp;Shuh-Ji Kao","doi":"10.1002/lno.70497","DOIUrl":"10.1002/lno.70497","url":null,"abstract":"<p>Lakes and reservoirs are significant sources of methane (CH₄) and carbon dioxide (CO₂), yet the role of the stratification–ventilation cycle in regulating their production, storage, and emissions remains poorly quantified. Using high-resolution vertical profiling in a eutrophic subtropical reservoir, we demonstrate that stratification poses a dual control on CH₄ dynamics. Stratification traps CH₄ produced by methanogenesis in hypolimnetic waters, where it comprises up to 50% of total carbonaceous greenhouse gases (C-GHGs). Simultaneously, stratification could promote the climate effect of oxic CH₄ production probably associated with phytoplankton photosynthesis in surface layers, which became the major contributor to the diffusive CH₄ emission. Seasonal ventilation events (e.g., cooling, typhoons) disrupt this balance. Approximately 16% of CH₄ escaped oxidation was emitted to the atmosphere during the early mixing stage, while ~ 84% of CH₄ was oxidized and converted to CO₂ during mid to late mixing stages. A global synthesis reveals that extended stratification reduced C-GHGs diffusive emissions. With increasing eutrophication and global warming, intensified stratification could amplify the climatic impact of aerobic, rather than anaerobic, CH₄ production in inland water ecosystems, challenging current carbon-climate feedback projections.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148932930","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":"Correction to “Shifts in subsurface oxygen transport and consumption patterns in a restored coastal flood plain over five years”","authors":"","doi":"10.1002/lno.70485","DOIUrl":"10.1002/lno.70485","url":null,"abstract":"<p>\u0000 <span>Grande, E.</span>, <span>R. N. Ghosh</span>, <span>McCIntire, </span>, <span>M. J. Freeman</span>, <span>P. Regier</span>, and <span>N. D. Ward</span>. <span>2026</span>. “ <span>Shifts in Subsurface Oxygen Transport and Consumption Patterns in a Restored Coastal Flood Plain Over Five Years</span>.” <i>Limnology and Oceanography</i> <span>71</span>: e70477. https://doi.org/10.1002/lno.70477.</p><p>This article originally published with two authors' names incorrectly stated.</p><p>McCintire has been corrected to “Charles McIntire” and Mike J. Freeman has been corrected to “Michael J. Freeman” in the original article.</p><p>Additionally, the research funding has been corrected to state “Small Business Innovation Research award number: DE-SC0017132, US Department of Energy, Office of Science, Biological and Environmental Research (DOE-BER)” after this article originally published with research funding incorrectly stated as “Biological and Environmental Research. Grant Number: DE-SC0017132.”</p><p>We apologize for these errors.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148902496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coral reef habitat complexity decreases and diversifies local availability of light","authors":"Viviana Brambilla,&nbsp;Joshua S. Madin,&nbsp;Nader Boutros,&nbsp;Luisa Fontoura,&nbsp;Mia Hoogenboom,&nbsp;Oscar Pizarro,&nbsp;Damaris Torres-Pulliza,&nbsp;Stefan Williams,&nbsp;Rachael M. Woods,&nbsp;Kyle J. A. Zawada,&nbsp;Maria Dornelas","doi":"10.1002/lno.70493","DOIUrl":"10.1002/lno.70493","url":null,"abstract":"<p>The spatial distribution of environmental conditions fundamentally determines where organisms can and cannot live. When the distribution of micro-environments within a landscape is mediated by the shape of its surface, structural complexity can indirectly affect environmental niche distributions. This study investigates how light availability patterns, particularly Photosynthetically Active Radiation (PAR), change along a gradient of habitat complexities measured as surface rugosity and height range in tropical shallow reefs. We used 903 high spatial resolution light measurements across different locations (mean minimum pairwise distance within site = 0.49 m) to determine the proportion of incoming light that is available at the reef surface. After accounting for light attenuation due to depth, light availability decreased with increasing surface rugosity: a unit increase in local surface rugosity corresponds to an 11–29% decrease in light availability. Nonetheless, we found that light availability on the reef surface is highly variable even at low complexity sites, with proximate locations experiencing up to 86.7% difference in daily photon input (25.7 mol/m²/d). Local surface complexity affects distributions of light availability, while site-scale metrics do not capture this variability. While decreasing overall light availability and potential photosynthetic activity, structural complexity enhances environmental variability, and so it is essential for understanding ecosystem functioning and its processes.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148902400","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":"Spatial and temporal patterns of bottom water euxinia in shallow areas of the southwestern Baltic Sea","authors":"Timo Spiegel,&nbsp;Matthias Thiele,&nbsp;Mark Schmidt,&nbsp;Ulrike Löptien,&nbsp;Heiner Dietze,&nbsp;René Friedland,&nbsp;Hermann W. Bange,&nbsp;Sarima Vahrenkamp,&nbsp;Mirjam Perner,&nbsp;Florian Scholz","doi":"10.1002/lno.70492","DOIUrl":"10.1002/lno.70492","url":null,"abstract":"<p>Sediments in productive coastal regions are hotspots of hydrogen sulfide (H₂S) production through microbial sulfate reduction. Under anoxic seafloor conditions, H₂S can escape the sediment and accumulate in bottom waters, where elevated concentrations render the benthic environment toxic, posing ecological and economic risks. The central Kiel Bight in the southwestern Baltic Sea shows a strong seasonal water column stratification, with hypoxic to anoxic bottom waters in late summer. Euxinic conditions (H₂S &gt; 1 <i>μ</i>M) have been observed locally, but their extent and underlying controls are not fully understood. This study investigates spatial and temporal patterns of bottom water H₂S in the central Kiel Bight using multi-annual sediment and water column measurements combined with machine learning models. We find that euxinia affects ~ 27% of the 622 km² seafloor in late summer, with recurring H₂S detections over the past decade highlighting its frequent occurrence. Sedimentary H₂S production is enhanced in areas with high organic matter delivery, yet H₂S production alone does not control its accumulation in bottom waters. Instead, the highest H₂S levels are observed in channels and basins where long deep-water residence times deplete oxidants, thereby facilitating H₂S accumulation. Furthermore, our findings demonstrate that effective H₂S monitoring requires sampling directly above the seafloor, such as collecting the supernatant water from sediment cores, because H₂S is often restricted to the lowermost water layer undetected by conventional water column profiling. Adapted monitoring is crucial to predict future development of euxinia in the shallow Baltic Sea and other coastal environments.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70492","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148902401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond rhodoliths: Community-level carbon metabolism and calcification in coralline algal beds","authors":"Nadine Schubert,&nbsp;Fernando Tuya,&nbsp;Eduardo O. Bastos,&nbsp;Néstor E. Bosch,&nbsp;Paulo A. Horta,&nbsp;Julia Loring,&nbsp;André F. B. Macedo,&nbsp;Pedro Neves,&nbsp;Francisco Otero-Ferrer,&nbsp;Viviana Peña,&nbsp;Cláudia Ribeiro,&nbsp;Rui Santos,&nbsp;Marina N. Sissini,&nbsp;Enrique Tejero-Caballo,&nbsp;Tainá L. Gaspar,&nbsp;João Silva","doi":"10.1002/lno.70491","DOIUrl":"10.1002/lno.70491","url":null,"abstract":"<p>Coastal ecosystems play a major role in global carbon cycling and storage, yet the contribution of calcifying macroalgal habitats, such as coralline algal beds (CABs; rhodolith and maerl beds), remains poorly understood. Because carbon cycling in CABs is governed by community productivity and calcification, which exert opposing effects on seawater carbonate chemistry, understanding the balance between these processes is essential for determining whether CABs function as net carbon sinks or sources. Yet, community-level measurements remain scarce, and the environmental and biological drivers of CAB carbon balance are largely unknown. Here, we quantified net community productivity (NCP), net community calcification (NCC), and the resulting net carbon balance (NCP : NCC) in shallow warm-temperate and subtropical Atlantic CABs with contrasting rhodolith-associated communities, using in situ benthic chamber incubations. All CABs were net autotrophic, with NCP : NCC ratios ≥ 0.6, indicating that they acted as potentially carbon neutral and net carbon sinks. By combining our measurements with available community-level datasets, we identified light availability as the primary environmental driver of community productivity and calcification, whereas benthic community structure influenced the balance between these processes. Together, our findings demonstrate that CAB carbon balance is governed by the interaction between environmental conditions and community structure, providing the first mechanistic insight into the drivers of ecosystem carbon balance. This pronounced context dependency highlights the need for community-level assessments across broader environmental and biological settings to test the generality of these relationships and determine under which conditions carbon burial in CABs translates into a net contribution to coastal carbon storage.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895194","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":"Marine heatwaves reorganize phytoplankton bloom phenology in the Gulf of Alaska","authors":"Hisatomo Waga,&nbsp;Hiromichi Ueno,&nbsp;Thomas B. Kelly,&nbsp;Curry J. Cunningham,&nbsp;Sarah M. Hendricks","doi":"10.1002/lno.70487","DOIUrl":"10.1002/lno.70487","url":null,"abstract":"<p>Phytoplankton blooms structure primary production and food-web dynamics in the Gulf of Alaska, yet their response to recent warming and marine heatwaves (MHWs) remains poorly described. Using a parametric Gaussian framework applied to 21 years of satellite chlorophyll <i>a</i> (Chl <i>a</i>), this study classified daily Chl <i>a</i> timeseries into double-bloom, single spring-bloom, single fall-bloom, and no-bloom regimes and related these to large-scale oceanographic and atmospheric forcing. Double blooms with distinct spring and fall peaks dominated much of the domain in cold, dynamically active years characterized by negative sea surface temperature anomalies, depressed sea level, strong cross-shelf pressure gradients, and more frequent storms associated with an intensified Aleutian Low. In contrast, warm years with elevated sea level and weaker cross-shelf and atmospheric forcing favored single spring blooms and, in some areas, no-bloom conditions, while single fall blooms occurred under intermediate physical states. Although no significant linear trends in the areal extent occupied by each regime were detected over 2003–2023, years influenced by major MHWs projected strongly onto the warm, weakly forced end of this physical gradient and were associated with reduced double-bloom extent and an increased prevalence of single spring and no-bloom regimes. These shifts imply that contraction and weakening of the seasonal production window, with likely consequences for zooplankton growth, match–mismatch dynamics for fish early life stages, and the balance between pelagic retention and export, highlighting how MHWs and ongoing climate change can suppress and reorganize phytoplankton bloom phenology in the Gulf of Alaska.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"71 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70487","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}