{"title":"Issue Information & Copyright","authors":"","doi":"10.1002/lno.12790","DOIUrl":"https://doi.org/10.1002/lno.12790","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"317 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142904890","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}
Hikaru Homma, Eiji Masunaga, Ilia Ostrovsky, Hidekatsu Yamazaki
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 > 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.
分层和湍流混合对分层大型湖泊的生物地球化学制度和生态系统动力学有着巨大的影响。本文研究了琵琵湖（日本）表层金属离子和表层金属离子的物理性质，重点研究了表层金属离子湍流混合引起的持续垂直扩散通量及其对硝酸盐向上运移的影响。我们在夏季连续三年在一个海上观测站进行了24小时观测，以研究分层和湍流的时间和垂直变化。一个系泊系统提供了关于分层和流速的长期数据，同时收集了沿两个海上样带的热剖面，以研究横向变化。我们的研究结果显示，在金属离子上部有很强的分层，在那里垂直扩散通量基本上被抑制。在靠近水面和中等分层的下层金属离子内发现了明显的湍流混合层。现场数据和数值模型表明，低金属离子的湍流是由剪切不稳定、应变和/或与持续内波相关的波-波相互作用驱动的，即使在弱风期间也会发生。垂直涡旋扩散系数>；低金属离子的10−5 m2 s−1与较强的湍流有关，这在其他大型湖泊中尚未见报道。湍流度升高导致下层金属离子的硝酸盐通量上升0.2 mmol N m−2 d−1，表明向上的养分运输可以支持初级生产力，并在深层分层湖泊中发挥重要的生态作用。
{"title":"Turbulent mixing layers and associated diffusive fluxes across the epilimnion and metalimnion in stratified large Lake Biwa","authors":"Hikaru Homma, Eiji Masunaga, Ilia Ostrovsky, Hidekatsu Yamazaki","doi":"10.1002/lno.12769","DOIUrl":"https://doi.org/10.1002/lno.12769","url":null,"abstract":"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 > 10<jats:sup>−5</jats:sup> m<jats:sup>2</jats:sup> s<jats:sup>−1</jats:sup> 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<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> across the lower metalimnion, indicating that the upward nutrient transport could support primary productivity and play an important ecological role in deep stratified lakes.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"91 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information & TOC","authors":"","doi":"10.1002/lno.12778","DOIUrl":"https://doi.org/10.1002/lno.12778","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"63 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information & Copyright","authors":"","doi":"10.1002/lno.12777","DOIUrl":"https://doi.org/10.1002/lno.12777","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"33 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information & Masthead","authors":"","doi":"10.1002/lno.12776","DOIUrl":"https://doi.org/10.1002/lno.12776","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"30 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information & Members","authors":"","doi":"10.1002/lno.12779","DOIUrl":"https://doi.org/10.1002/lno.12779","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"3 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fanny Girard, David W. Caress, Jennifer B. Paduan, Linda A. Kuhnz, Steven Y. Litvin, Emma Flattery, Amanda S. Kahn, Andrew DeVogelaere, Erica J. Burton, Christopher Lovera, Eric J. Martin, James P. Barry
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.
{"title":"Habitat heterogeneity over multiple scales supports dense and diverse megafaunal communities on a northeast Pacific ridge","authors":"Fanny Girard, David W. Caress, Jennifer B. Paduan, Linda A. Kuhnz, Steven Y. Litvin, Emma Flattery, Amanda S. Kahn, Andrew DeVogelaere, Erica J. Burton, Christopher Lovera, Eric J. Martin, James P. Barry","doi":"10.1002/lno.12766","DOIUrl":"https://doi.org/10.1002/lno.12766","url":null,"abstract":"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.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"148 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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 > 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.
{"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, Shoji D. Thottathil, Yves T. Prairie","doi":"10.1002/lno.12767","DOIUrl":"https://doi.org/10.1002/lno.12767","url":null,"abstract":"Aquatic sediments represent a key component for understanding CH<jats:sub>4</jats:sub> dynamics and emission to the atmosphere. Once produced in the sediments, CH<jats:sub>4</jats:sub> 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 CH<jats:sub>4</jats:sub> production. Although bubbling is one of the dominant CH<jats:sub>4</jats:sub> 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 CH<jats:sub>4</jats:sub> 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 > 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 CH<jats:sub>4</jats:sub> ebullitive flux during summer. Our results show that lake sediments produced CH<jats:sub>4</jats:sub> at a median rate of 3.3 mmol m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> (ranged from 0.2 to 11.8 mmol m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>), 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 CH<jats:sub>4</jats:sub> production released as bubbles.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"10 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Markel Gómez‐Letona, Javier Arístegui, Ulf Riebesell, Marta Sebastián
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.
{"title":"Consistent prokaryotic successional dynamics across contrasting phytoplankton blooms","authors":"Markel Gómez‐Letona, Javier Arístegui, Ulf Riebesell, Marta Sebastián","doi":"10.1002/lno.12773","DOIUrl":"https://doi.org/10.1002/lno.12773","url":null,"abstract":"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.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"96 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland
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.
切萨皮克湾下游的潮汐支流经历了季节性的有害藻华，而海底地下水排放（SGD）作为营养载体的意义在很大程度上是未知的。在这里，我们确定了两条具有不同水动力条件的支流的季节性SGD养分负荷，河流供给（约克河）和潮汐支配（拉斐特河）。在2021年春季和秋季，对每条河流进行了氡调查，以量化海湾规模的SGD。总SGD由222Rn质量平衡和蒙特卡罗模拟确定。在春季，海底地下水流量的差异为2倍(Lafayette = 11±17 cm d - 1；约克= 6±10 cm d - 1)，秋季为6倍(拉法叶= 19±27 cm d - 1；约克= 3±7cm d−1)。约克郡地下水氮浓度和通量随季节变化（4-7 mmol N m - 2 d - 1）。在拉斐特河，季节氮通量（22-37 mmol N m−2 d−1）是由季节水交换率驱动的，可能是由于周期性的盐水入侵。在每个系统中，海底地下水排放产生的养分通量比河流输入和径流大几个数量级。此外，通过反硝化和厌氧氨氧化去除沉积物氮只能去除SGD提供的溶解无机氮的~ 1-11%。在海湾的潮汐支流中，有害藻华的持续复发可能表明海底地下水携带的营养来源被低估了。这项研究强调了将SGD纳入水质模型的重要性，该模型用于为切萨皮克湾地区及其他地区的恢复工作提供建议。
{"title":"Submarine groundwater discharge as a major nutrient source in river‐fed vs. tidally dominated estuaries","authors":"Stephanie J. Wilson, Joseph J. Tamborski, Bongkeun Song, Peter Bernhardt, Margaret R. Mulholland","doi":"10.1002/lno.12772","DOIUrl":"https://doi.org/10.1002/lno.12772","url":null,"abstract":"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 <jats:sup>222</jats:sup>Rn mass balance and Monte Carlo simulations. Submarine groundwater discharge rates differed by a factor of two during spring (Lafayette = 11 ± 17 cm d<jats:sup>−1</jats:sup>; York = 6 ± 10 cm d<jats:sup>−1</jats:sup>) and a factor of six during fall (Lafayette = 19 ± 27 cm d<jats:sup>−1</jats:sup>; York = 3 ± 7 cm d<jats:sup>−1</jats:sup>). Groundwater N concentrations and fluxes varied seasonally in the York (4–7 mmol N m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>). In the Lafayette River, seasonal N fluxes (22–37 mmol N m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup>) 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.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"24 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","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":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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