Limnology and Oceanography最新文献

{"title":"Turbulent mixing layers and associated diffusive fluxes across the epilimnion and metalimnion in stratified large Lake Biwa","authors":"Hikaru Homma,&nbsp;Eiji Masunaga,&nbsp;Ilia Ostrovsky,&nbsp;Hidekatsu Yamazaki","doi":"10.1002/lno.12769","DOIUrl":"10.1002/lno.12769","url":null,"abstract":"<p>Stratification and turbulent mixing have an immense impact on biogeochemical regimes and ecosystem dynamics in stratified large lakes. This study investigates the physical properties of the epi- and metalimnion of Lake Biwa (Japan), focusing on the persistent vertical diffusive fluxes due to turbulent mixing in the lower metalimnion and their effects on upward nitrate transport. We conducted 24-h observations at an offshore station in the summer for three consecutive years to examine the temporal and vertical variations of stratification and turbulence. A mooring system provided long-term data on stratification and current velocity, while thermal profiles along two offshore transects were collected to investigate lateral changes. Our findings revealed strong stratification in the upper metalimnion, where vertical diffusive fluxes were essentially suppressed. Distinct turbulent mixing layers were identified near the water surface and within the moderately stratified lower metalimnion. Field data and numerical model suggested that the turbulence in the lower metalimnion was driven by shear instability, straining, and/or wave–wave interactions linked with the persistent internal waves that occur even during weak winds. Vertical eddy diffusivity of &gt; 10⁻⁵ m² s⁻¹ in the lower metalimnion was associated with rather strong turbulence, which has not been reported in other large lakes. The elevated turbulence resulted in an upward nitrate flux of 0.2 mmol N m⁻² d⁻¹ across the lower metalimnion, indicating that the upward nutrient transport could support primary productivity and play an important ecological role in deep stratified lakes.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"443-460"},"PeriodicalIF":3.8,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12769","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888789","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":"Issue Information & TOC","authors":"","doi":"10.1002/lno.12778","DOIUrl":"10.1002/lno.12778","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 12","pages":"iii"},"PeriodicalIF":3.8,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12778","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888798","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":"Issue Information & Copyright","authors":"","doi":"10.1002/lno.12777","DOIUrl":"10.1002/lno.12777","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 12","pages":"ii"},"PeriodicalIF":3.8,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12777","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888799","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":"Issue Information & Masthead","authors":"","doi":"10.1002/lno.12776","DOIUrl":"10.1002/lno.12776","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 12","pages":"i"},"PeriodicalIF":3.8,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12776","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888788","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":"Issue Information & Members","authors":"","doi":"10.1002/lno.12779","DOIUrl":"10.1002/lno.12779","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 12","pages":"iv"},"PeriodicalIF":3.8,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888797","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":"Habitat heterogeneity over multiple scales supports dense and diverse megafaunal communities on a northeast Pacific ridge","authors":"Fanny Girard,&nbsp;David W. Caress,&nbsp;Jennifer B. Paduan,&nbsp;Linda A. Kuhnz,&nbsp;Steven Y. Litvin,&nbsp;Emma Flattery,&nbsp;Amanda S. Kahn,&nbsp;Andrew DeVogelaere,&nbsp;Erica J. Burton,&nbsp;Christopher Lovera,&nbsp;Eric J. Martin,&nbsp;James P. Barry","doi":"10.1002/lno.12766","DOIUrl":"10.1002/lno.12766","url":null,"abstract":"<p>Marine environments are highly heterogeneous, varying across scales of a few meters to entire ocean basins. Understanding the relationship between environmental variability and species distribution is essential for area-based management and conservation. However, this requires a precise alignment of seabed mapping with environmental and biological sampling, which is often difficult to achieve in the deep sea. There is thus an urgent need to tackle this challenge to effectively manage high-diversity habitats such as deep-sea coral and sponge aggregations. Relying on multiple subsea platforms, seafloor mapping, and imaging techniques, we mapped the distribution of megafaunal communities at Sur Ridge (780–1525-m depth; off central California) across multiple spatial scales. First, remotely operated vehicle video transects were conducted to characterize community distribution along the ridge in relation to substratum type, environmental conditions, and 1-m resolution bathymetry. Five distinct communities, located in specific areas of the ridge, were identified. These communities were primarily structured by depth, availability of hard substrata, and terrain complexity (slope and rugosity). Indicator taxa were identified for each community and their distributions were characterized at the centimeter scale from coregistered 5-mm resolution photomosaic and 5-cm lateral resolution bathymetry produced during low altitude remotely operated vehicle surveys. High-resolution mapping allowed the identification of associations between deep-sea coral and sponge and other benthic taxa and showed that, even at these small scales, different taxa associate with distinct microhabitats. These results highlight the importance of accounting for habitat heterogeneity, and its role in supporting biodiversity when designing management and conservation strategies.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"377-392"},"PeriodicalIF":3.8,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12766","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874279","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":"Consistent prokaryotic successional dynamics across contrasting phytoplankton blooms","authors":"Markel Gómez-Letona,&nbsp;Javier Arístegui,&nbsp;Ulf Riebesell,&nbsp;Marta Sebastián","doi":"10.1002/lno.12773","DOIUrl":"10.1002/lno.12773","url":null,"abstract":"<p>Heterotrophic prokaryotes play a vital role in organic matter cycling in the ocean and have been observed to undergo substrate-controlled successions during phytoplankton blooms. However, there is limited understanding of the succession patterns during blooms triggered by upwelling events of different characteristics. Here we simulated eight upwelling scenarios of varying intensity and duration (single vs. recurring pulses) by adding nutrient-rich mesopelagic waters into large-scale mesocosms containing oligotrophic surface waters from the subtropical North Atlantic. Over a monitoring period of nearly 6 weeks, we observed that phytoplankton blooms displayed diverging outcomes depending on the upwelling mode: treatments with single upwelling pulses presented a unique, short-lived bloom, whereas recurring upwelling resulted in blooms that were sustained over time. Prokaryotic abundances were positively related to upwelling intensity and presented three similar abundance cycles in all treatments, whereas heterotrophic activity differed between the two upwelling modes. The successional dynamics of free-living and particle-associated communities were consistent regardless of upwelling intensity and mode, with four or five prokaryotic assemblages sequentially proliferating during the experiment. Yet, some differences were observed in the taxa that formed the assemblages in both upwelling modes. Together, our results suggest that, despite differences in activity, prokaryotes seemed to be more influenced by processes taking place within the community than by phytoplankton bloom patterns, with similar succession dynamics even under widely distinct blooms. These findings can help advance our understanding on prokaryotic ecology and its relation to organic matter cycling across different upwelling scenarios.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"493-508"},"PeriodicalIF":3.8,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12773","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874336","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":"Submarine groundwater discharge as a major nutrient source in river-fed vs. tidally dominated estuaries","authors":"Stephanie J. Wilson,&nbsp;Joseph J. Tamborski,&nbsp;Bongkeun Song,&nbsp;Peter Bernhardt,&nbsp;Margaret R. Mulholland","doi":"10.1002/lno.12772","DOIUrl":"10.1002/lno.12772","url":null,"abstract":"<p>The tidal tributaries of the lower Chesapeake Bay experience seasonally recurring harmful algal blooms and the significance of submarine groundwater discharge (SGD) as a nutrient vector is largely unknown. Here, we determined seasonal SGD nutrient loads in two tributaries with contrasting hydrodynamic conditions, river-fed (York River) vs. tidally dominated (Lafayette River). Radon surveys were performed in each river to quantify SGD at the embayment-scale during spring and fall 2021. Total SGD was determined from a ²²²Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm d⁻¹; York = 6 ± 10 cm d⁻¹) and a factor of six during fall (Lafayette = 19 ± 27 cm d⁻¹; York = 3 ± 7 cm d⁻¹). Groundwater N concentrations and fluxes varied seasonally in the York (4–7 mmol N m⁻² d⁻¹). In the Lafayette River, seasonal N fluxes (22–37 mmol N m⁻² d⁻¹) were driven by seasonal water exchange rates, likely due to recurrent saltwater intrusion. Submarine groundwater discharge–derived nutrient fluxes were orders of magnitude greater than riverine inputs and runoff in each system. Additionally, sediment N removal by denitrification and anaerobic ammonium oxidation would only remove ~ 1–11% of dissolved inorganic nitrogen supplied through SGD. The continued recurrence of harmful algal blooms in the Bay's tidal tributaries may be indicative of an under-accounting of submarine groundwater-borne nutrient sources. This study highlights the importance of including SGD in water quality models used to advise restoration efforts in the Chesapeake Bay region and beyond.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"426-442"},"PeriodicalIF":3.8,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12772","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874337","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":"A simple approach to quantifying whole-lake methane ebullition and sedimentary methane production, and its application to the Canadian Lake Pulse dataset","authors":"Jihyeon Kim,&nbsp;Shoji D. Thottathil,&nbsp;Yves T. Prairie","doi":"10.1002/lno.12767","DOIUrl":"10.1002/lno.12767","url":null,"abstract":"<p>Aquatic sediments represent a key component for understanding CH₄ dynamics and emission to the atmosphere. Once produced in the sediments, CH₄ is released either by diffusion at the sediment–water interface or by bubbling out to the atmosphere when total gas pressure in the sediment exceeds local ambient pressure due to high CH₄ production. Although bubbling is one of the dominant CH₄ emission pathways in lakes, direct measurements of this flux are hampered by its high spatiotemporal variability and methodological limitations. Here, we develop a conceptual approach to quantify CH₄ production in lake sediments and particularly its release as bubbles based on simple measurements of bubble gas content and depth. Its main assumptions were empirically tested using &gt; 200 long-term bubble trap deployments collected from 4 temperate lakes. We then applied the developed methodology to a suite of 408 Canadian lakes to produce the first standardized large-scale assessment of lakes CH₄ ebullitive flux during summer. Our results show that lake sediments produced CH₄ at a median rate of 3.3 mmol m⁻² d⁻¹ (ranged from 0.2 to 11.8 mmol m⁻² d⁻¹), releasing 33% via ebullition to the atmosphere. These rates are remarkably similar in magnitude to other regional estimates in the literature. Moreover, our approach revealed that catchment slope was an important determinant of both the lake-wide ebullitive fluxes and the fraction of sediment CH₄ production released as bubbles.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"393-410"},"PeriodicalIF":3.8,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12767","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874280","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":"Propagules go with the flow: Near-field particle dispersion in reaches with different hydrodynamic conditions","authors":"Christopher R. Farrow,&nbsp;Loong-Tak Lim,&nbsp;Josef D. Ackerman","doi":"10.1002/lno.12760","DOIUrl":"10.1002/lno.12760","url":null,"abstract":"<p>We examined the effects of riverbed roughness and turbulence (shear velocity, <span></span><math>\u0000 <mrow>\u0000 <msub>\u0000 <mi>u</mi>\u0000 <mo>*</mo>\u0000 </msub>\u0000 </mrow></math>) on propagule dispersion in the near-field region (&lt; 100 m) by releasing microbead models of larval and juvenile unionid mussels in tributaries of the Grand River (Ontario, Canada). The Conestogo River had the roughest bed and highest mean <span></span><math>\u0000 <mrow>\u0000 <msub>\u0000 <mi>u</mi>\u0000 <mo>*</mo>\u0000 </msub>\u0000 </mrow></math>, followed by the Grand and Speed rivers. We predicted more downstream transport with higher velocities and that longitudinal dispersion coefficients (<i>K</i>_<i>x</i>) would match the patterns in roughness and <span></span><math>\u0000 <mrow>\u0000 <msub>\u0000 <mi>u</mi>\u0000 <mo>*</mo>\u0000 </msub>\u0000 </mrow></math>. The Conestogo River had the highest downstream particle flux and <i>K</i>_<i>x</i> as predicted by simple empirical equations. Inconsistent with model predictions, however, the Grand River had the lowest particle flux and <i>K</i>_<i>x</i>. These differences were greater than expected based on the small differences in reach-averaged mean velocities between the Grand and Conestogo rivers. This mismatch between <i>K</i>_<i>x</i> predicted by simple empirical models and those fit to an advection–diffusion model was related to the inertial properties of the flow in the advective zone (i.e., near field) of the reaches. Streamwise, lateral, and especially vertical velocities at drift nets were spatially heterogeneous within and among reaches, demonstrating the influence of the flow direction on particle flux. Although bulk fluid statistics provided a useful indication of how dispersal distances vary among rivers, our results suggest that near-field dynamics can be complex, requiring high-resolution bathymetry and velocity data for the development of improved advection–diffusion models. Care should be exercised in predicting the dispersal of particles at ecologically relevant spatial scales in rivers.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"305-318"},"PeriodicalIF":3.8,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12760","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867412","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}