Limnology and Oceanography最新文献

{"title":"Long-range transport of terrestrial particulate organic carbon to the open ocean by sediment resuspension","authors":"Hyekyung Park,&nbsp;Hanbyul Lee,&nbsp;Nahyeon Kwon,&nbsp;Sojin Park,&nbsp;Jihyun Park,&nbsp;Weol Ae Lim,&nbsp;Guebuem Kim","doi":"10.1002/lno.70059","DOIUrl":"10.1002/lno.70059","url":null,"abstract":"<p>The transport of particulate organic carbon (POC) from land to deep-sea sediments is a critical component of the global carbon cycle. However, the transport processes of terrestrial POC across continental shelves remain poorly understood due to the complexity of these systems. In this study, we investigated the vertical fluxes and fates of terrestrial vs. marine POC using stable carbon isotope ratios (δ¹³C) and ²³⁴Th tracers along two transects in the southern coastal region of Korea. The POC concentrations were highest in the surface layer and decreased with depth, with a slight increase near the seafloor. The δ¹³C values revealed that terrestrial POC contributed 29% ± 24% of the total POC, with higher contributions at the innermost stations and in the bottom layer. Based on ²³⁴Th–²³⁸U disequilibria, the residence times of particulate ²³⁴Th (8.1 ± 3.6 d) were significantly longer than those of dissolved ²³⁴Th (3.7 ± 2.2 d). The much higher vertical fluxes of terrestrial POC in the deeper layer relative to the upper layer suggest that terrestrial POC undergoes multiple turnover cycles through sediment resuspension before burial, while marine POC degrades preferentially in the course of settling. These findings highlight that effective sediment resuspension and the refractory nature of terrestrial POC allow for its long-range transport (&gt; 200 km) to the deep Ulleung Basin in the East Sea (Japan Sea). This study sheds new light on the mechanisms driving the transport of terrestrial POC from coastal regions to the deep ocean.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 6","pages":"1551-1560"},"PeriodicalIF":3.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832518","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":"Nutrient inversion but not warming drive changes in periphyton biomass and composition in shallow lake mesocosms","authors":"Olivera Stamenković, Juan Pablo Pacheco, Eti E. Levi, Erik Jeppesen, Thomas Alexander Davidson","doi":"10.1002/lno.70053","DOIUrl":"https://doi.org/10.1002/lno.70053","url":null,"abstract":"Periphyton plays an important functional role in shallow lakes and is sensitive to variation in nutrient availability and global warming. Understanding the responses of periphyton to changes in nutrient availability in contrasting warming scenarios can contribute to the development of more efficient techniques for the restoration of lakes in a future warmer world. We analyzed the periphyton response to early eutrophication and oligotrophication under three different warming scenarios and explored the associated environmental drivers of periphyton in 24 shallow lake mesocosms. These were initially set up in 2003 with two nutrient treatments (with or without nutrient addition) and three temperatures (ambient, A2 IPCC scenario and A2 increased by 50%) following a full factorial design. In 2023, the nutrient treatment was inverted, starting nutrient addition in low nutrient mesocosms (nutrient increase) and stopping nutrient addition (nutrient decrease) in the remaining. Artificial plants were placed in each mesocosm to allow periphyton to develop for 21 d, both before and after the inversion of the nutrient treatments. We found marked changes in periphyton biomass and composition to the nutrient inversion, but no response to warming. Nutrient decrease induced lower periphyton biomass and compositional changes at species and group levels. Nutrient increase had no effect on biomass accrual or species composition but altered the group composition. Our results suggest that lower nitrate availability was a crucial factor driving biomass and compositional changes with the cessation of nutrient addition, while a combination of environmental variables explained the altered periphyton group composition in the nutrient increase treatment.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"27 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832520","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 virus-mediated lysis in spatiotemporal dynamics of prokaryotic communities in river–estuary–coastal ecosystems","authors":"Lu Liu,&nbsp;Qi Chen,&nbsp;Jiaxin Chen,&nbsp;Nengwang Chen,&nbsp;Kevin Xu Zhong,&nbsp;Qiang Zheng","doi":"10.1002/lno.70051","DOIUrl":"10.1002/lno.70051","url":null,"abstract":"<p>Viral lysis accounts for approximately 50% of prokaryotic mortality, significantly influencing the diversity, composition, and succession of prokaryotic communities. Despite its importance, the specific influence of viral lysis on seasonal dynamics within aquatic ecosystems remains poorly understood. In this study, we investigated the seasonal dynamics of prokaryotes in the river–estuary–coastal ecosystem surrounding Xiamen Island and explored the environmental factors and virus-mediated cell lysis driving microbial seasonal successions across spatiotemporal scales. A taxon-specific cell lysis was applied to evaluate the contribution of viral lysis to seasonal variations in prokaryotes. Our findings revealed distinct spatiotemporal successions within the prokaryotic community structure, where temporal-related factors, spatial-related factors, and virus-mediated cell lysis contribute comparably to the seasonal variation of prokaryotes. The viral lysis controls on prokaryotic structures were determined by a significant negative correlation between the total microbial community and the cell lysis index (CLI) from amplicon sequence variant (ASV) to order levels. Viral lytic shaping on prokaryotic communities was more pronounced in the estuary–coastal compared to the river region, with similar seasonal variations noted. Specific ASVs, such as ASV3 (<i>Nitrosopumilales</i>), ASV2 (<i>Synechococcales</i>), ASV16 (<i>Nitrosopumilales</i>), and ASV17 (<i>Oceanospirillales</i>) were significantly correlated with CLI, highlighting the pivotal role of viral lysis in their seasonal succession. This study highlights the intricate interplay between microbial populations and viral lysis across spatiotemporal scales, enhancing our understanding of how top-down (virus-mediated cell lysis) and bottom-up (environmental factors) controls drive the seasonal variations in prokaryotic communities.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 6","pages":"1518-1534"},"PeriodicalIF":3.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832521","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 stability of tropical lakes and their sensitivity to climate","authors":"Tongyao Pu,&nbsp;G. Douglas Haffner,&nbsp;Sean A. Crowe,&nbsp;Sergei Katsev","doi":"10.1002/lno.70055","DOIUrl":"10.1002/lno.70055","url":null,"abstract":"<p>Tropical lakes experience less thermal convection than temperate lakes and can be stably stratified by temperature gradients alone. Deep tropical lakes are often presumed meromictic, but conditions for sustained meromixis are poorly constrained. Here, we investigate the stratification stability of a deep (200 m) tropical Lake Towuti (Indonesia) and analyze its sensitivity to meteorological and climatic parameters using exploratory hydrodynamic simulations. The inferred effects on water chemistry are further evaluated with a reactive-transport biogeochemical model. In contrast to the previous assumption of meromixis, our results suggest that in 2008 Lake Towuti experienced mixing over most of its water column, with the attendant weak oxygenation of the previously anoxic lower strata. The lake likely remained stratified afterwards, but the chemical distributions measured after the episode, particularly during the International Continental Scientific Drilling Program in 2015, were out of steady state, and may be still evolving in time. We find the thermal stratification to be most sensitive to average air temperatures and wind speeds and predict further stabilization of the lake by climate change. We also describe a negative feedback mechanism that can stabilize oligomictic tropical lakes for a number of years after the episodes of mixing and cooling, and infer that such episodes should be significantly less frequent in deeper lakes.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 6","pages":"1535-1550"},"PeriodicalIF":3.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832517","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":"Temperature-dependent growth and activity in a globally distributed nitrogen-fixing haptophyte","authors":"Esther Wing Kwan Mak,&nbsp;Kendra A. Turk-Kubo,&nbsp;Anna V. Voznyuk,&nbsp;Mary R. Gradoville,&nbsp;Tyler Coale,&nbsp;Kyoko Hagino,&nbsp;Jonathan P. Zehr","doi":"10.1002/lno.70050","DOIUrl":"10.1002/lno.70050","url":null,"abstract":"<p>Dinitrogen (N₂)-fixing microorganisms play a crucial role in supplying nitrogen (N) to the oceans by converting atmospheric N₂ into bioavailable N. N₂ fixation was thought to be limited to warm oligotrophic ocean waters, but the association between the N₂-fixing UCYN-A cyanobacterium and specific haptophytes, including <i>Braarudosphaera bigelowii</i> and relatives, has been found in diverse ocean environments, including warm subtropical gyres, temperate coastal systems, and cold polar waters. UCYN-A2, previously known as the symbiont of <i>B. bigelowii</i>, and now considered an early-stage organelle that exchanges fixed nitrogen for fixed carbon, has only recently been cultured. This study investigated the growth and activity of <i>B. bigelowii</i> in response to a range of temperatures to better understand its global distribution and ecology. Incubation experiments were conducted with <i>B. bigelowii</i> to determine growth rates, carbon (C) and N₂ fixation rates, and cell sizes across a temperature range of 6–26°C. Growth rates were highest between 10°C and 22°C and lowest at 6°C and 26°C. Significant positive correlations were found between cell count-based growth rates, C-specific and N-specific growth rates. <i>Braarudosphaera bigelowii</i> cell size increased at low temperatures. The growth and metabolic activity detected across a wide range of temperatures help to explain the wide geographic distribution of <i>B. bigelowii</i>. This study presents the first growth and activity measurements under a range of temperatures from <i>B. bigelowii</i>, providing vital information needed to understand the unique ecology of this organism and to parameterize its activity in ecosystem models.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 5","pages":"1499-1511"},"PeriodicalIF":3.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805828","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":"Trophic strategies of freshwater nanoflagellates under variable run‐off scenarios","authors":"Katerina Symiakaki, Stella A. Berger, Gabriela Ágreda‐López, Bence Buttyán, Bence Gergácz, Silke Langenheder, Jens C. Nejstgaard","doi":"10.1002/lno.70054","DOIUrl":"https://doi.org/10.1002/lno.70054","url":null,"abstract":"Terrestrial run‐off is increasing in temperate lakes due to climate change and can lead to loading of colored dissolved organic matter (cDOM) and nutrients, thus reducing light availability and increasing carbon, nitrogen, and phosphorus. Run‐off events are highly irregular, resulting in temporal resource variability that may determine the energy flow in planktonic communities. To understand the effects of run‐off variability on natural plankton communities, we conducted a mesocosm experiment at SITES AquaNet in Lake Erken, Sweden. Treated mesocosms received equal total amount of cDOM and nutrients but at different frequencies and magnitudes (Daily, Intermittent, Extreme), while keeping an untreated Control. Here, we performed three surrogate prey incubation experiments with fluorescently labeled bacteria in the mesocosms to study the trophic strategies of nanoflagellates under the run‐off scenarios. Our results show that phototrophic nanoflagellates increased under Daily and Intermittent additions of cDOM and nutrients at early stages but declined thereafter, likely due to light limitation and grazing by rotifers. Heterotrophic nanoflagellate biovolume was highest in the beginning, while the grazing rate on bacteria was highest in the middle of the experiment when bacterial abundance was highest. The mixotrophic nanoflagellate abundance was generally low and unaffected by the treatments, despite high bacterial densities and reduced light, while the highest abundance was found in the Control. The overall development of nanoflagellates was modulated by microzooplankton grazing pressure over time. Our study contributes to better understanding the influence of future global change, including variable terrestrial run‐off scenarios, on food‐web interactions considering both bottom‐up and top‐down processes.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"97 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813440","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 “Cascading, interactive, and indirect effects of climate change on aquatic communities, habitats, and ecosystems”","authors":"","doi":"10.1002/lno.70044","DOIUrl":"10.1002/lno.70044","url":null,"abstract":"<p>Menden-Deuer, S., J.C. Mullarney, M. Boersma, H.-P. Grossart, R. Sponseller, and S.A. Woodin. 2023. “Cascading, Interactive, and Indirect Effects of Climate Change on Aquatic Communities, Habitats, And Ecosystems.” <i>Limnology and Oceanography</i> 68: S1–S7. https://doi.org/10.1002/lno.12384</p><p>This article was published on July 12, 2023, with an incorrect article category of “Article.”</p><p>This article has been corrected on April 7, 2025 to article category “Editorial.”</p><p>We apologize for this error.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 5","pages":""},"PeriodicalIF":3.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813430","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":"Co-occurrence and successional patterns among diatoms, dinoflagellates, and potential parasites in a coastal upwelling experiment","authors":"Joseph H. Vineis,&nbsp;Jessica M. Burger,&nbsp;Sarah E. Fawcett,&nbsp;Bess B. Ward","doi":"10.1002/lno.70048","DOIUrl":"10.1002/lno.70048","url":null,"abstract":"<p>Diatom-dominated blooms in coastal upwelling systems contribute disproportionately to global primary production. The fate of carbon captured during a diatom bloom is often influenced by species-specific ecological differences. However, successional patterns that take place during a diatom bloom are often oversimplified, and the diversity of diatom adaptations to different stages of a bloom remains poorly characterized. To improve our understanding of diatom specificity to certain conditions within a bloom, we employed microscopy, 18S rRNA amplicons, and biogeochemical analysis within a simulated upwelling mesocosm experiment. We successfully simulated a diatom bloom and found that diatoms bloomed during early and late phases of the bloom. Surprisingly, the relative abundance of congeneric diatoms with the <i>Thalassiosira</i>, <i>Chaetoceros</i>, and <i>Pseudonitzschia</i> displayed opposing patterns that were consistent among experimental mesocosms. The late stage of the bloom was especially interesting because some diatoms continued to bloom among mixotrophic dinoflagellate genera <i>Akashiwo</i>, <i>Heterocapsa</i>, and <i>Prorocentrum</i>. Additionally, Syndiniales putative parasites were correlated with several diatoms, especially in the initial phase of the bloom. The novel observations of consistent rapid successional changes within our mesocosms reflect the ability of diatom and dinoflagellate genera to occupy bloom conditions that fall outside traditional expectations. Syndiniales parasite co-occurrence with blooming diatoms may be important to successional trends of coastal diatom populations, and this parasitic interaction deserves further study in coastal upwelling systems. This study indicates there are underlying diatom traits and biotic interactions that should be considered when estimating their contribution to productivity and carbon cycling within upwelling systems.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 5","pages":"1481-1498"},"PeriodicalIF":3.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805588","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":"Seasonality modulates coral trophic plasticity in an extreme, multi-stressor environment","authors":"Sarah L. Solomon,&nbsp;Jasper M. de Goeij,&nbsp;Emily M. Croasdale,&nbsp;Verena Schoepf","doi":"10.1002/lno.70046","DOIUrl":"10.1002/lno.70046","url":null,"abstract":"<p>Corals with high trophic plasticity, i.e., the ability to change the relative contribution of heterotrophic and autotrophic nutrition to their mixotrophic diet, can have increased tolerance to individual stressors, but it is poorly understood how trophic strategies shift in response to combined global (e.g., warming, acidification) and local stressors (e.g., nutrient input). Furthermore, it remains unclear how season-associated changes in physicochemical conditions modulate trophic strategies and which coral species generally have trophic plasticity. We measured the tissue stable isotopes (δ¹³C and δ¹⁵N) of three coral species (<i>Siderastrea siderea</i>, <i>Siderastrea radians</i>, and branching <i>Porites</i> sp.) from two distinct habitats: extreme, multi-stressor inland bay habitats and nearby fringing reefs with more benign environmental conditions. We further captured trophic plasticity between dry and wet seasons, as well as the effects of in situ heat stress on trophic strategies. Bay corals tended to be more autotrophic than fringing reef corals, which may be driven by higher nutrient input in the bays. All three coral species shifted their trophic strategy between the cool dry and warm wet seasons; however, the direction of trophic shifts varied between δ¹³C and δ¹⁵N. Bay <i>S. siderea</i> had the highest trophic plasticity across seasons, which likely facilitates their success in these multi-stressor habitats. Interestingly, not all species relied equally on heterotrophy, as bay <i>Porites</i> had a primarily autotrophic diet, even during the wet season when conditions were more extreme. This highlights that coral tolerance to more extreme conditions is promoted through dynamic shifts in diet, rather than only increasing heterotrophy.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 5","pages":"1466-1480"},"PeriodicalIF":3.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.70046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143784676","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":"Water column ammonium regeneration supports productivity in two large, eutrophic lakes","authors":"Margot Sepp,&nbsp;Marju Tamm,&nbsp;Silvia E. Newell,&nbsp;Justin A. Myers,&nbsp;Triin Hunt,&nbsp;Kadi Palmik-Das,&nbsp;Lea Tuvikene,&nbsp;Peeter Nõges,&nbsp;Tiina Nõges,&nbsp;Mark J. McCarthy","doi":"10.1002/lno.70047","DOIUrl":"10.1002/lno.70047","url":null,"abstract":"&lt;p&gt;Phytoplankton often rely on the regeneration of ammonium (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;) to produce biomass and, for some cyanobacteria, nitrogen-rich toxins, despite low or unmeasurable &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; concentrations in water. Thus, measuring &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; turnover rates (i.e., uptake and regeneration) is necessary to determine its actual availability. The objectives of this study were to quantify water column &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; turnover rates in two large, shallow, eutrophic, cyanobacteria-dominated lakes in Estonia (Lakes Võrtsjärv and Peipsi), explore which in-lake variables drive these processes, and evaluate the importance of internal nitrogen loading in supporting community &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; uptake. Stable isotope (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mmultiscripts&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;mprescripts&gt;&lt;/mprescripts&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mn&gt;15&lt;/mn&gt;\u0000 &lt;/mmultiscripts&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;) incubations were conducted almost monthly in Võrtsjärv and several times per year in Peipsi (from March 2019 to March 2022). Despite being located at a higher latitude, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; turnover rates in Võrtsjärv and Peipsi were similar to those reported for other large, eutrophic lakes. &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;NH&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; turnover rates were strongly related to seasonally changing water quality variables, including temperature, nutrient concentrations, and chlorophyll &lt;i&gt;a&lt;/i&gt; concentrations, which, combined, explained 68–71% of the variation in measured rates. &lt;span&gt;&lt;/span&gt;&lt;math","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 5","pages":"1449-1465"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757761","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}