Limnology and Oceanography: Methods最新文献_第2页

Methodological constraints for the stable isotope analysis of different tissues: A comparison between muscle and whole-body samples in freshwater gammarids 不同组织稳定同位素分析的方法学约束：淡水伽玛鱼肌肉和全身样本的比较

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-09-03 Epub Date: 2026-06-24 DOI: 10.1002/lom3.70071

Alan Fritsch, Pavel Karel Bystřický, Lukáš Veselý, Paride Balzani

{"title":"Methodological constraints for the stable isotope analysis of different tissues: A comparison between muscle and whole-body samples in freshwater gammarids","authors":"Alan Fritsch, Pavel Karel Bystřický, Lukáš Veselý, Paride Balzani","doi":"10.1002/lom3.70071","DOIUrl":"https://doi.org/10.1002/lom3.70071","url":null,"abstract":"Carbon (δ13C) and nitrogen (δ15N) stable isotope ratios allow the reconstruction of food webs, provided that all trophic levels are properly characterized. In freshwater ecosystems, small-bodied invertebrates often occupy central positions in food webs, with whole-body samples commonly used for their stable isotope analysis, due to insufficient sampling material for single-tissue analysis. However, whole-body samples include multiple tissues, each with its own metabolic routing and turnover rate, thus potentially having different isotopic values. Using two genetic lineages of the Gammarus fossarum complex (Crustacea: Amphipoda) as models, we compared the δ13C and δ15N stable isotope values of muscle and whole-body samples using isotopic niche analysis and diet reconstruction via mixing models. When tested, decarbonation of whole-body samples through acidification had a significant effect on the δ13C values due to the inorganic carbonate in crustaceans' exoskeleton. Thus, decarbonated δ13C values were used for whole-body samples in the analyses. Whole-body samples had significantly higher δ15N and a narrower niche than muscle samples. The interspecific niche overlap did not vary among tissues for one of the lineages, but was twice as high using whole-body samples compared to muscle samples for the other lineage. Mixing models for whole-body samples performed better than those for muscle samples, due to the absence of muscle tissue-specific trophic discrimination factors (TDFs) in the literature, highlighting the need for tissue-specific TDFs in macroinvertebrates. Our results reinforce the pre-established caution around the use of whole-body samples and underline biases that can arise from comparing different tissues.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of preservatives and poisons on the elemental and isotopic composition of freshwater particulate organic matter 防腐剂和毒物对淡水颗粒有机物元素和同位素组成的影响

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-09-03 Epub Date: 2026-06-15 DOI: 10.1002/lom3.70069

Diana Velazquez, Nathan D. Sheldon, Jenan J. Kharbush

{"title":"Effects of preservatives and poisons on the elemental and isotopic composition of freshwater particulate organic matter","authors":"Diana Velazquez, Nathan D. Sheldon, Jenan J. Kharbush","doi":"10.1002/lom3.70069","DOIUrl":"https://doi.org/10.1002/lom3.70069","url":null,"abstract":"Sediment traps, often used in tandem with preservatives or poisons, are widely used for the collection of particulate organic matter (POM), providing insight into the source to sink mechanisms that shape major biogeochemical cycles and sedimentary carbon sequestration. The effectiveness of these treatments has been studied for marine POM, but is poorly constrained for freshwater POM, whose molecular composition differs due to greater terrigenous input. We tested four treatments commonly used in marine sediment traps, along with untreated controls, over a 1-yr period to assess their ability to retain original elemental and isotopic compositions of organic carbon (%TOC and δ13Corg) and nitrogen (%TN and δ15N) in POM collected from a freshwater pond (Willow Pond, Michigan, USA). Consistent with marine studies, 0.005% (w/v) mercuric chloride was the most effective in preserving both C and N geochemical signatures across the 1-yr incubation period. Untreated samples also maintained original POM geochemical signals but only for approximately 6 months, providing an inexpensive, nontoxic alternative that can be used for shorter deployment or storage periods.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

From the sea to DNA barcode: Optimized preservation method for gelatinous zooplankton integrative taxonomy 从海洋到DNA条形码：胶状浮游动物综合分类的优化保存方法

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-09-03 Epub Date: 2026-06-16 DOI: 10.1002/lom3.70068

Claudia Traboni, Rade Garić, Rita Marino, Paolo Sordino, Priscilla Licandro

{"title":"From the sea to DNA barcode: Optimized preservation method for gelatinous zooplankton integrative taxonomy","authors":"Claudia Traboni, Rade Garić, Rita Marino, Paolo Sordino, Priscilla Licandro","doi":"10.1002/lom3.70068","DOIUrl":"https://doi.org/10.1002/lom3.70068","url":null,"abstract":"Assigning taxonomic identity and thus assessing taxonomic diversity in gelatinous zooplankton is challenging due to their fragility and difficult preservation. Formalin fixation compromises DNA integrity, while flash-freezing, ethanol, and acetone preservation affect morphological features. In this study, we developed a methodological protocol to optimize morphological and molecular identification of pelagic cnidarians and tunicates from the Gulf of Naples (Mediterranean Sea). Specimens were identified while fresh and preserved using four methods: liquid nitrogen (N), ethanol (EtOH), ethanol replaced with acetone (EA), and formalin followed by ethanol and acetone (FEA). Genomic DNA was extracted and PCR-amplified targeting the 18S rRNA gene, being subsequently assessed for concentration, integrity, and sequence quality. FEA specimens retained better morphology compared to N, EtOH, or EA samples, while sequencing performance was comparable between methods. DNA concentrations did not significantly differ among treatments (range: 139–1645 ng ind−1) and smaller taxa showed higher values per unit size compared to larger ones. DNA integrity was lower in N and FEA samples, and often undetectable in EA and FEA when assessed by gel electrophoresis. Although 18S : gDNA ratio decreased in some FEA samples, this method still produced high-quality reads (> 500 nucleotides). Our findings show that formalin fixation followed by ethanol and acetone does not compromise molecular analysis, even for species with low DNA content. Unlike other methods, this optimized protocol preserves essential morphological features for accurate taxonomic identification of gelatinous zooplankton while substantially reducing molecular processing time. Overall, the adoption of the proposed protocol could significantly enhance biodiversity assessments of gelatinous taxa.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bed-level tools for monitoring erosion and accretion patterns: Flume validation and field testing 监测侵蚀和增积模式的床级工具：水槽验证和现场测试

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-09-03 Epub Date: 2026-06-20 DOI: 10.1002/lom3.70070

Lucía Rodríguez-Arias, Inés Mazarrasa, Beatriz Marin-Diaz, Teresa Alcoverro, Barbara Ondiviela, Jordi F. Pagès, Eduardo Infantes

{"title":"Bed-level tools for monitoring erosion and accretion patterns: Flume validation and field testing","authors":"Lucía Rodríguez-Arias, Inés Mazarrasa, Beatriz Marin-Diaz, Teresa Alcoverro, Barbara Ondiviela, Jordi F. Pagès, Eduardo Infantes","doi":"10.1002/lom3.70070","DOIUrl":"https://doi.org/10.1002/lom3.70070","url":null,"abstract":"Monitoring short-term changes in surface sediment elevation is fundamental to understanding erosion, transport, and deposition dynamics in shallow coastal environments. However, commonly used field approaches, such as horizontal markers, sediment erosion tables, subsurface sediment plates, or erosion pins, are not always cross-validated under both controlled and field conditions, limiting confidence in their comparative performance. This study experimentally evaluates the performance and potential biases of two widely used and cost-effective bed-level monitoring tools: (1) subsurface sedimentation plates (without string, with string, and with string and buoy) and (2) sedimentation bars. Methods were evaluated under controlled conditions in a hydraulic flume using non-cohesive sandy sediment. Plates and bars were subjected to unidirectional and oscillatory flow regimes at two velocity levels (11 and 23 cm s−1) to compare their erosion responses and assess the hydrodynamic interference generated by their structural components, quantified through Reynolds numbers. A complementary field deployment was conducted over 1 year in a Zostera marina meadow in the Bay of Santander estuary (Spain). Across flume flow regimes and field habitats, bed-level change estimates were comparable among methods, with no detectable differences within the resolution of the experimental design (minimum detectable difference ≈ 1.9 mm for current-driven and 2.5 mm for wave-driven conditions). Although the buoy produced localized turbulence, the resulting shear stress was likely below critical erosion thresholds. Together, the results support the use of sedimentation plates (with or without string or buoy) and bars as practical cost-effective tools for monitoring short-term bed-level change in shallow, non-cohesive sandy and vegetated environments.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 9","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70070","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Acidification-driven molecular fractionation of dissolved organic matter during direct analysis of freshwater using UPLC-Orbitrap MS UPLC-Orbitrap质谱法直接分析淡水中溶解有机物的酸化驱动分子分馏

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-05-02 DOI: 10.1002/lom3.70061

Qingfeng Zhao, Yuguo Li, Chen He, Dinggui Wu, Jinglu Wu, Helong Jiang, Quan Shi, Yongge Sun

{"title":"Acidification-driven molecular fractionation of dissolved organic matter during direct analysis of freshwater using UPLC-Orbitrap MS","authors":"Qingfeng Zhao, Yuguo Li, Chen He, Dinggui Wu, Jinglu Wu, Helong Jiang, Quan Shi, Yongge Sun","doi":"10.1002/lom3.70061","DOIUrl":"https://doi.org/10.1002/lom3.70061","url":null,"abstract":"While acidification is widely recognized as a critical step influencing the molecular formula distribution of dissolved organic matter (DOM), pH-dependent molecular fractionation remains largely unexplored. Here, we conducted a comprehensive molecular characterization of DOM by direct analysis of original water samples across a pH gradient (non-acidified, 5, 3, 2, and 1) using online ultrahigh-performance liquid chromatography coupled with Orbitrap mass spectrometry. The results demonstrate that acidification-induced molecules experience a compositional shift from saturated compounds to more oxidized polyphenolic and condensed aromatic species as pH decreases from 5 to 2. However, molecules with higher double-bond equivalents and nitrogen-containing compounds are largely detected when the pH is lowered to 1. This is primarily attributed to the enhanced protonation of DOM molecules under strongly acidic conditions, which reduce their ionization, further improves their retention in reversed-phase systems and facilitates their effective separation from inorganic salts, indicating pH-dependent fractionation of ionizable species. Compared with direct analysis of original water under optimized acidification (pH 1), terrestrially derived and microbial-altered components are largely underestimated in DOM from solid-phase extraction. Given that DOM sources and secondary alterations are key processes governing the fate of DOM, the method developed in this study provides new insights into the composition and transformation of DOM in the original water and offers a novel perspective for exploring its biogeochemical implications in aquatic systems. Future studies should systematically analyze samples from diverse environments to constrain the driving factors of DOM compositional heterogeneity and its environmental implications.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Automated phytoplankton single-cell counting from digital images with transfer learning for harmful algal bloom monitoring in the English Channel and North Sea 基于数字图像的浮游植物单细胞自动计数与迁移学习，用于英吉利海峡和北海的有害藻华监测

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-04-19 DOI: 10.1002/lom3.70058

Guillaume Wacquet, Paul Zanoncelli, Christophe Liet, Alain Lefebvre

{"title":"Automated phytoplankton single-cell counting from digital images with transfer learning for harmful algal bloom monitoring in the English Channel and North Sea","authors":"Guillaume Wacquet, Paul Zanoncelli, Christophe Liet, Alain Lefebvre","doi":"10.1002/lom3.70058","DOIUrl":"https://doi.org/10.1002/lom3.70058","url":null,"abstract":"Monitoring phytoplankton abundance is essential for understanding ecosystem dynamics and detecting harmful algal blooms (HABs). Traditional microscopy-based single-cell counting, while accurate, is time-consuming and poorly suited to high temporal and spatial resolution monitoring. Automated imaging approaches have therefore been developed to assist cell detection and counting, but they face challenges when dealing with colonial forms. In this study, we investigate transfer learning for automated cell counting in digital images of phytoplankton colonies acquired with a FlowCam system. Several Convolutional Neural Network (CNN) architectures pre-trained on the ImageNet database were fine-tuned using annotated datasets of two ecologically relevant colonial taxa commonly observed in the English Channel and the North Sea: Pseudo-nitzschia and Phaeocystis globosa. Model performance and robustness were evaluated using mean absolute error (MAE) and species-specific accuracy metrics. Across both taxa, DenseNet121 architecture achieved the best performance, with a Top 2 accuracy up to 99% for P.-nitzschia and a Top 20% accuracy exceeding 87% for P. globosa. Data augmentation improved model robustness and generalization, particularly for colonies with higher cell numbers. These results demonstrate the ability of deep learning to capture complex spatial patterns and improve counting accuracy across taxa with different morphologies. Beyond methodological performance, this study raises questions about the adequacy of current HAB alert thresholds based on microscopic counts when transitioning to automated imaging systems. Transfer learning provides a robust, fast, and scalable approach that complements traditional monitoring and supports the development of improved environmental assessment strategies.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A simple index for assessing cumulative human impacts on mountain lakes 评估人类对高山湖泊累积影响的简单指数

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-05-02 DOI: 10.1002/lom3.70059

Clara Sáez, Ignasi Arranz, Guillermo García-Gómez, Javier Sánchez-Hernández

{"title":"A simple index for assessing cumulative human impacts on mountain lakes","authors":"Clara Sáez, Ignasi Arranz, Guillermo García-Gómez, Javier Sánchez-Hernández","doi":"10.1002/lom3.70059","DOIUrl":"https://doi.org/10.1002/lom3.70059","url":null,"abstract":"Mountain lakes are highly sensitive ecosystems and effective sentinels of environmental change, yet the exposure and magnitude of the human footprint remain poorly quantified. In this study, we develop a simple and non-invasive abiotic index to assess cumulative pressures on mountain lakes. The proposed index integrates eight variables grouped into three categories (potential human impacts, accessibility, and recreational exposure) into a single cumulative score, providing a straightforward but informative measure of human pressure on lakes. We employed a dataset comprising 29 lakes from two Iberian protected areas (Sierra de Gredos and Sanabria region) as a case study for assessing the reliability of the index. We observed strong variability among lakes, highlighting the importance of local pressures that are often overlooked by global indicators such as the Human Footprint Index. Our index provides an accessible first-step diagnostic tool that facilitates the integration of human pressure assessment into site-specific monitoring and conservation actions.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coccolithophore particulate inorganic and organic carbon ratios: An evaluation of acid decalcification methods 球石团颗粒无机碳和有机碳比值：酸脱钙方法的评价

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-04-14 DOI: 10.1002/lom3.70051

Madison B. Cox, Robert F. Whitehead, Alison R. Taylor

{"title":"Coccolithophore particulate inorganic and organic carbon ratios: An evaluation of acid decalcification methods","authors":"Madison B. Cox, Robert F. Whitehead, Alison R. Taylor","doi":"10.1002/lom3.70051","DOIUrl":"https://doi.org/10.1002/lom3.70051","url":null,"abstract":"Accurate direct measurements of coccolithophore particulate inorganic and organic carbon ratios (PIC/POC) are crucial for understanding the physiology and role these microbes play in global ocean carbon flux. Direct measurements of POC are commonly obtained by acid fuming or applying acid directly to filters to dissolve PIC (CaCO3) prior to CN analysis. Review of the literature revealed considerable variation in methods for this decalcification step demonstrating a clear need for a validated standard operating procedure. Importantly, visual verification of complete decalcification after acid treatment was absent. We therefore systematically tested the efficacy of two common acid decalcification methods for several species of coccolithophores. We examined acid fuming wet or dry filters, time spent fuming, and whether there are significant differences in PIC/POC determined using decalcification by acid fuming or direct addition. Scanning electron microscopy was used to visually verify acid fuming completely decalcified filters and there was no statistically significant difference in PIC/POC obtained by fuming for 5 min to 24 h. Direct addition of 0.5 M HCl to wet filters also yielded complete decalcification across all species and cell densities tested with less variation in subsequent CN-analysis. There were no statistically significant differences in PIC/POC obtained from samples treated either by direct acid addition, 30 min acid fuming, or 24 h acid fuming. Moreover, by utilizing the direct acid addition method we were able to reliably resolve PIC/POC for haploid coccolithophores. This study provides important recommendations for obtaining accurate and precise PIC/POC utilizing either acid fuming or direct addition protocols.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantifying temporal dynamics of greenhouse gas emissions in lake mesocosms: Deployment of a low-cost measurement system 湖泊中生态系统温室气体排放的时间动态量化：低成本测量系统的部署

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-05-08 DOI: 10.1002/lom3.70060

Tuba Bucak, Eti Ester Levi, Claus Melvad, Jianming Deng, Mikhail Mastepanov, Robert Ladwig, Thomas Alexander Davidson

{"title":"Quantifying temporal dynamics of greenhouse gas emissions in lake mesocosms: Deployment of a low-cost measurement system","authors":"Tuba Bucak, Eti Ester Levi, Claus Melvad, Jianming Deng, Mikhail Mastepanov, Robert Ladwig, Thomas Alexander Davidson","doi":"10.1002/lom3.70060","DOIUrl":"https://doi.org/10.1002/lom3.70060","url":null,"abstract":"Greenhouse gas (GHG) emissions from freshwater ecosystems contribute significantly to global carbon budgets, yet they remain poorly constrained due to limited high-frequency measurements. We tested a low-cost, high-frequency GHG measurement system in a long-term mesocosm experiment in Lemming, Denmark, over a 7-month period, focusing on CO2 and CH4 fluxes. We deployed a methodology for calculating CH4 diffusive fluxes using high-frequency sensor data and tested the effects of sampling intervals on emission upscaling. Our findings reveal substantial temporal variability in GHG emissions, particularly for CH4, with ebullitive fluxes dominating and exhibiting large variation. Pronounced diurnal fluctuations were also observed for CO2 and diffusive CH4 fluxes, whereas ebullitive CH4 emissions showed no significant diurnal pattern. Relying solely on daytime measurements led to a significant overestimation of overall CO2 fluxes and CH4 diffusive fluxes. Resampling data at lower frequency showed that reduced sampling frequency leads to an underestimation of total emissions, especially for CH4 ebullitive fluxes. Increasing the sampling interval from daily to monthly markedly increased uncertainty, while weekly sampling better captured overall GHG flux patterns and reduced the uncertainty compared with more infrequent sampling. These results underscore the value of high-frequency GHG measurements in capturing both diurnal and seasonal variations, improving the accuracy of flux estimates, and reducing uncertainties in upscaling emission. We emphasize the need to optimize sampling intervals and incorporate diurnal cycle measurements to enhance the accuracy and reliability of freshwater GHG assessments.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A machine learning assisted method for rapidly annotating benthic megafauna in large volumes of marine imagery 一种在大量海洋图像中快速标注底栖巨型动物的机器学习辅助方法

IF 2.2 3区地球科学

Limnology and Oceanography: Methods Pub Date : 2026-08-04 Epub Date: 2026-04-19 DOI: 10.1002/lom3.70057

Katharine T. Bigham, Ada Carter

{"title":"A machine learning assisted method for rapidly annotating benthic megafauna in large volumes of marine imagery","authors":"Katharine T. Bigham, Ada Carter","doi":"10.1002/lom3.70057","DOIUrl":"https://doi.org/10.1002/lom3.70057","url":null,"abstract":"Recent technological advancements have rapidly expanded our capacity for collecting image data in the marine environment, but processing images into meaningful ecological metrics remains a manual, time-consuming, and biased process. This is particularly challenging with electro-optical cabled imaging systems which generate images at a rate that makes manual identification impractical. To address this challenge, we have developed a machine learning-assisted method for annotating images. Our approach leverages a pre-trained model based on marine-specific imagery from the FathomNet database (499 classes; some classes to species level). We demonstrated the application of this method on a 1-yr time series of images collected at Southern Hydrate Ridge by a digital still camera on the NSF Ocean Observatories Initiative Regional Cabled Array, which resulted in 92,153 benthic megafaunal (organisms > 2 cm) annotations across 10 morphotaxa classes in 50,840 images. This method annotated the full dataset in 6 weeks, compared to an estimated ~ 5.9 yr required for fully manual annotation, representing approximately a 50-fold increase in efficiency. This process also produced a computer vision model with a precision of 0.75, recall of 0.80, mAP50 of 0.84, and mAP50-95 of 0.65. Our method combines machine learning efficiency with human expertise to create high-quality, verified datasets. The output of this methodology is key to achieving the full potential of sustained ecosystem monitoring via cabled observing systems that can capture both short-term and long-term ecological and environmental dynamics.","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 8","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148667424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0