Limnology and Oceanography: Methods最新文献

{"title":"A video monitoring and computational system for estimating migratory juvenile fish abundance in river systems","authors":"Meghna N. Marjadi,&nbsp;Sidney Batchelder,&nbsp;Ryan Govostes,&nbsp;Allison H. Roy,&nbsp;John J. Sheppard,&nbsp;Meghan-Grace Slocombe,&nbsp;Joel K. Llopiz","doi":"10.1002/lom3.10607","DOIUrl":"10.1002/lom3.10607","url":null,"abstract":"<p>Diadromous fishes migrate between marine and fresh waters for reproduction. For anadromous species, which spawn in freshwater, improved access to freshwater spawning and nursery habitats and ability of juveniles to emigrate to the ocean may support population recovery. Despite the potentially enormous influence of early life stage survival on adult population size, managers and scientists have limited capacity to assess numbers of juvenile anadromous fishes leaving freshwater ecosystems. Such data are critical for evaluating reproductive success and habitat suitability and have been identified as a top priority in anadromous fish research and management. We developed a state-of-the-art underwater video and computational system to collect videos to estimate abundances and migration timing for juvenile river herring (<i>Alosa pseudoharengus</i>; <i>Alosa aestivalis</i>). We collected continuous video in the Monument River (Bourne, Massachusetts, USA) from June to November 2017. We trained three types of neural network models to detect and count fish in video frames and evaluated model performance by comparing human counts to model outputs. Our top model assessed presence and absence (<i>F</i>1 = 87%) and counted fish (counting error 9.4%) with an accuracy comparable to human counters (<i>F</i>1 = 88%). Our system's capability to collect accurate counts of emigrating juveniles will provide critical information that could be related to the numbers of spawning adults, system-specific productivity, and spawning and nursery habitat suitability. Both the video collection system and computational model may be transferrable to other sites and for other species where tracking juvenile emigration may inform management efforts.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 5","pages":"295-310"},"PeriodicalIF":2.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140128647","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}

{"title":"A new framework for estimating abundance of animals using a network of cameras","authors":"Camille Magneville,&nbsp;Capucine Brissaud,&nbsp;Valentine Fleuré,&nbsp;Nicolas Loiseau,&nbsp;Thomas Claverie,&nbsp;Sébastien Villéger","doi":"10.1002/lom3.10606","DOIUrl":"10.1002/lom3.10606","url":null,"abstract":"<p>While many ecology studies require estimations of species abundance, doing so for mobile animals in an accurate, non-invasive manner remains a challenge. One popular stopgap method involves the use of remote video-based surveys using several cameras, but abundance estimates derived from this method are computed with conservative metrics (e.g., <i>maxN</i> computed as the maximum number of individuals seen simultaneously on a single video). We propose a novel methodological framework based on a remote-camera network characterized by known positions and non-overlapping field-of-views. This approach involves a temporal synchronization of videos and a maximal speed estimate for studied species. Such a design allows computing a new abundance metric called <i>Synchronized maxN</i> (<i>SmaxN</i>). We provide a proof-of-concept of this approach with a network of nine remote underwater cameras that recorded fish for three periods of 1 h on a fringing reef in Mayotte (Western Indian Ocean). We found that abundance estimation with <i>SmaxN</i> yielded up to four times higher values than <i>maxN</i> among the six fish species studied. <i>SmaxN</i> performed better with an increasing number of cameras or longer recordings. We also found that using a network of synchronized cameras for a short time period performed better than using a few cameras for a long duration. The <i>SmaxN</i> algorithm can be applied to many video-based approaches. We built an open-sourced R package to encourage its use by ecologists and managers using video-based censuses, as well as to allow for replicability with <i>SmaxN</i> metric.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"268-280"},"PeriodicalIF":2.7,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140010982","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}

{"title":"Automated monitoring of early life-stage development in Atlantic cod (Gadus morhua) embryos exposed to a reference toxicant","authors":"David R. Williamson,&nbsp;Ron R. Togunov,&nbsp;Emlyn J. Davies,&nbsp;Martin Ludvigsen,&nbsp;Bjørn Henrik Hansen","doi":"10.1002/lom3.10599","DOIUrl":"10.1002/lom3.10599","url":null,"abstract":"<p>Early life stages of fish are widely used for regulatory toxicity testing, and marine fish display high sensitivity to pollutant exposure. Exposure to pollutants during embryogenesis causes acute effects on embryonic development and survival, but also sub-lethal impacts manifested as maldeveloped larvae. Acquiring time- and exposure-dependent responses to pollutant exposure and other stressors in small organisms is labor intensive and often subjective. This leads to studies obtaining small sample sizes, with measurements often made infrequently during development. Automated monitoring methods can maintain consistency between measurements and allow many more measurements to be made, improving the quantity and quality of such data. We exposed Atlantic cod embryos to 3,4-dichloroaniline, a reference chemical widely used as a positive control agent in regulatory fish embryo toxicity testing. We monitored their growth through daily imaging with an automated flow-through imaging system. Biologically relevant sublethal endpoints were estimated from these images with a neural network and traditional machine vision methods. We demonstrate the automated capture and analysis of tens of thousands of images, producing detailed morphometric data from hundreds of fish over a 10-d study period, and assess the effectiveness of the automated system. The automated method presented allows measurements to be made frequently without sacrificing the sampled organisms, making detailed time series of development obtainable. We show dose-dependent effects of the toxicant on development and capture nonlinear responses that would not be attainable under a conventional manual sampling regime.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 3","pages":"170-189"},"PeriodicalIF":2.7,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10599","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003869","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}

{"title":"Investigating the impacts of solid phase extraction on dissolved organic matter optical signatures and the pairing with high-resolution mass spectrometry data across a freshwater stream network","authors":"J. Alan Roebuck Jr,&nbsp;Allison N. Myers-Pigg,&nbsp;Vanessa Garayburu-Caruso,&nbsp;James Stegen","doi":"10.1002/lom3.10603","DOIUrl":"10.1002/lom3.10603","url":null,"abstract":"<p>Advancing our understanding of dissolved organic matter (DOM) chemistry in aquatic systems necessitates the integration of data streams from multiple analytical platforms. Some measurements require pretreatment with solid phase extraction (SPE), while others are performed directly on whole water samples. Evidence has suggested that SPE will be biased against select DOM fractions, leading to concerns over the ability to establish data linkages across platforms with variable needs for SPE pretreatment, such as those from optical measurements and those that provide high-resolution molecular information. Here, we directly addressed this concern by assessing the impact of SPE on DOM optical properties through excitation–emission matrices with parallel factor analysis (PARAFAC) for 47 samples across a stream network within a single watershed reflective of variable DOM sources. PARAFAC data was further paired with molecular information obtained by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). A comparison of PARAFAC models first revealed no systematic qualitative differences in major components between whole water DOM and DOM isolated by SPE (SPE-DOM); however, quantitative biases against select components were observed. Further linkages with FTICR-MS data revealed that the molecular fingerprint associated with each PARAFAC component was consistent between the whole water DOM and SPE-DOM. Our results suggest that bulk scale linkages across these analytical platforms could be inferred irrespective of the observed quantitative biases resulting from SPE for samples within this example watershed. This work represents a key step toward the systematic evaluation of linkages between optical and high-resolution mass spectrometry datasets in freshwater lotic environments.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"241-253"},"PeriodicalIF":2.7,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10603","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003865","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}

{"title":"Lotic-SIPCO2: Adaptation of an open-source CO2 sensor system and examination of associated emission uncertainties across a range of stream sizes and land uses","authors":"Andrew L. Robison,&nbsp;Lauren E. Koenig,&nbsp;Jody D. Potter,&nbsp;Lisle E. Snyder,&nbsp;Christopher W. Hunt,&nbsp;William H. McDowell,&nbsp;Wilfred M. Wollheim","doi":"10.1002/lom3.10600","DOIUrl":"10.1002/lom3.10600","url":null,"abstract":"<p>River networks play a crucial role in the global carbon cycle, as relevant sources of carbon dioxide (CO₂) to the atmosphere. Advancements in high-frequency monitoring in aquatic environments have enabled measurement of dissolved CO₂ concentration at temporal resolutions essential for studying carbon variability and evasion from these dynamic ecosystems. Here, we describe the adaptation, deployment, and validation of an open-source and relatively low-cost in situ <i>p</i>CO₂ sensor system for lotic ecosystems, the lotic-SIPCO2. We tested the lotic-SIPCO2 in 10 streams that spanned a range of land cover and basin size. Key system adaptations for lotic environments included prevention of biofouling, configuration for variable stage height, and reduction of headspace equilibration time. We then examined which input parameters contribute the most to uncertainty in estimating CO₂ emission rates and found scaling factors related to the gas exchange velocity were the most influential when CO₂ concentration was significantly above saturation. Near saturation, sensor measurement of <i>p</i>CO₂ contributed most to uncertainty in estimating CO₂ emissions. We also found high-frequency measurements of <i>p</i>CO₂ were not necessary to accurately estimate median emission rates given the CO₂ regimes of our streams, but daily to weekly sampling was sufficient. High-frequency measurements of <i>p</i>CO₂ remain valuable for exploring in-stream metabolic variability, source partitioning, and storm event dynamics. Our adaptations to the SIPCO2 offer a relatively affordable and robust means of monitoring dissolved CO₂ in lotic ecosystems. Our findings demonstrate priorities and related considerations in the design of monitoring projects of dissolved CO₂ and CO₂ evasion dynamics more broadly.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"191-207"},"PeriodicalIF":2.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10600","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968681","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}

{"title":"A temperature-controlled, circular maintenance system for studying growth and development of pelagic tunicates (salps)","authors":"Svenja J. Müller,&nbsp;Wiebke Wessels,&nbsp;Sara Driscoll,&nbsp;Evgeny A. Pakhomov,&nbsp;Lutz Auerswald,&nbsp;Katharina Michael,&nbsp;Bettina Meyer","doi":"10.1002/lom3.10605","DOIUrl":"10.1002/lom3.10605","url":null,"abstract":"<p>Salps have attracted attention as zooplankton organisms that may be able to expand their habitat range and increase their ecological importance in the face of ongoing global warming. Due to their gelatinous nature, unique feeding strategy, and reproductive ecology such changes could have profound impacts on regional marine ecosystems. While their role in the regional carbon cycle is receiving attention, our knowledge of their physiology and life cycle is still limited. This knowledge gap is mainly due to their fragile gelatinous nature, which makes it difficult to capture and maintain intact specimen in the laboratory. We present here a modified kreisel tank system that has been tested onboard a research vessel with the Southern Ocean salp <i>Salpa thompsoni</i> and at a research station with <i>Salpa fusiformis</i> and <i>Thalia democratica</i> from the Mediterranean Sea. Successful maintenance over days to weeks allowed us to obtain relative growth and developmental rates comparable to in situ field samples of <i>S. thompsoni</i> and <i>S. fusiformis</i>, and provided insights into previously unknown features of their life cycle (e.g., testes development). Our results show that traditional methods of estimating growth, such as cohort analysis, may lead to a general overestimation of growth rates and neglect individual strategies (e.g., shrinkage), which can affect the results and conclusions drawn from population dynamic models. By providing a starting point for the successful maintenance of different species, comparable experiments on the physiology of salps is made possible. This will contribute to refining model parameters and improving the reliability of the predictions.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 5","pages":"281-294"},"PeriodicalIF":2.7,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139952297","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}

{"title":"Toward a synthesis of phytoplankton community composition methods for global-scale application","authors":"Sasha J. Kramer,&nbsp;Luis M. Bolaños,&nbsp;Dylan Catlett,&nbsp;Alison P. Chase,&nbsp;Michael J. Behrenfeld,&nbsp;Emmanuel S. Boss,&nbsp;E. Taylor Crockford,&nbsp;Stephen J. Giovannoni,&nbsp;Jason R. Graff,&nbsp;Nils Haëntjens,&nbsp;Lee Karp-Boss,&nbsp;Emily E. Peacock,&nbsp;Collin S. Roesler,&nbsp;Heidi M. Sosik,&nbsp;David A. Siegel","doi":"10.1002/lom3.10602","DOIUrl":"10.1002/lom3.10602","url":null,"abstract":"<p>The composition of the marine phytoplankton community has been shown to impact many biogeochemical processes and marine ecosystem services. A variety of methods exist to characterize phytoplankton community composition (PCC), with varying degrees of taxonomic resolution. Accordingly, the resulting PCC determinations are dependent on the method used. Here, we use surface ocean samples collected in the North Atlantic and North Pacific Oceans to compare high-performance liquid chromatography pigment-based PCC to four other methods: quantitative cell imaging, flow cytometry, and 16S and 18S rRNA amplicon sequencing. These methods allow characterization of both prokaryotic and eukaryotic PCC across a wide range of size classes. PCC estimates of many taxa resolved at the class level (e.g., diatoms) show strong positive correlations across methods, while other groups (e.g., dinoflagellates) are not well captured by one or more methods. Since variations in phytoplankton pigment concentrations are related to changes in optical properties, this combined dataset expands the potential scope of ocean color remote sensing by associating PCC at the genus- and species-level with group- or class-level PCC from pigments. Quantifying the strengths and limitations of pigment-based PCC methods compared to PCC assessments from amplicon sequencing, imaging, and cytometry methods is the first step toward the robust validation of remote sensing approaches to quantify PCC from space.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"217-240"},"PeriodicalIF":2.7,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10602","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139952270","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}

{"title":"Hit or miss? Impact of time series resolution on resolving phytoplankton dynamics at hourly, weekly, and satellite remote sensing frequencies","authors":"Virginie Sonnet,&nbsp;Colleen B. Mouw,&nbsp;Audrey B. Ciochetto,&nbsp;Jessica Carney-Almeida","doi":"10.1002/lom3.10604","DOIUrl":"10.1002/lom3.10604","url":null,"abstract":"<p>Characterizing marine phytoplankton community variability is crucial to designing sampling strategies and interpreting time series. Satellite remote sensing, microscopy sampling, and flow through imaging systems have widely different resolutions: from weekly or monthly with microscopy sampling to daily when no cloud cover or glint is present with polar-orbiting satellites, and hourly for autonomous imaging instruments. To improve our understanding of data robustness against sampling resolution at different taxonomic levels, we analyze 2 yr of data from an Imaging FlowCytobot with hourly resolution and resample it to daily, satellite-temporal, and weekly microscopy sampling resolution. We show that weekly and satellite-temporal resolutions are sufficient to resolve general community composition but that the randomness of satellite-temporal resolution can result in overrepresenting or underrepresenting certain categories. While the yearly phytoplankton biomass bloom is detected in late winter by all four resolutions, category-specific yearly blooms are generally consistent in timing but often underestimated or missed by the weekly and satellite-temporal resolutions, introducing a bias in year-to-year comparisons. A minimum of biweekly sampling, particularly during known bloom periods, would lower the bias in such categories. Similarly, sampling time should be considered as daily variations are category-specific. Overall, morning and low tide sampling tended to have higher biomass. We provide tables for categories detected by the IFCB in Narragansett Bay with their major bloom characteristics and recorded daily variability to inform future sampling designs. These results provide tools to interpret past and future time series, including possible detection of specific taxonomic groups with targeted satellite algorithms.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"254-267"},"PeriodicalIF":2.7,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10604","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139952215","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}

{"title":"Combined benthic and stream edge sampling better represent macroinvertebrate assemblages than benthic sampling alone along an aridity gradient","authors":"Brian A. Gill,&nbsp;Daniel C. Allen,&nbsp;Meryl C. Mims,&nbsp;Thomas M. Neeson,&nbsp;Albert Ruhi,&nbsp;Carla L. Atkinson,&nbsp;Arial J. Shogren,&nbsp;Travis M. Apgar,&nbsp;Zacchaeus G. Compson,&nbsp;Stephen Cook,&nbsp;Daryl R. Trumbo,&nbsp;Michelle H. Busch,&nbsp;Kelsey D. Hollien,&nbsp;Kyle Leathers,&nbsp;Megan C. Malish,&nbsp;Grace L. O'Malley,&nbsp;Samuel Silknetter,&nbsp;Chelsea R. Smith,&nbsp;Howard Dunleavy,&nbsp;Michael T. Bogan","doi":"10.1002/lom3.10601","DOIUrl":"10.1002/lom3.10601","url":null,"abstract":"<p>Studies of stream macroinvertebrates traditionally use sampling methods that target benthic habitats. These methods could underestimate biodiversity if important assemblage components exist outside of the benthic zone. To test the efficacy of different sampling methods, we collected paired reach-wide benthic and edge samples from up to 10 study reaches in nine basins spanning an aridity gradient across the United States. Edge sampling targeted riparian-adjacent microhabitats not typically sampled, including submerged vegetation, roots, and overhanging banks. We compared observed richness, asymptotic richness, and assemblage dissimilarity between benthic samples alone and different combinations of benthic and edge samples to determine the magnitude of increased diversity and assemblage dissimilarity values with the addition of edge sampling. We also examined how differences in richness and assemblage composition varied across an aridity gradient. The addition of edge sampling significantly increased observed richness (median increase = 29%) and asymptotic richness (median increase = 173%). Similarly, median Bray–Curtis dissimilarity values increased by as much as 0.178 when benthic and edge samples were combined. Differences in richness metrics were generally higher in arid basins, but assemblage dissimilarity either increased or decreased across the aridity gradient depending on how benthic and edge samples were combined. Our results suggest that studies that do not sample stream edges may significantly underestimate reach diversity and misrepresent assemblage compositions, with effects that can vary across climates. We urge researchers to carefully consider sampling methods in field studies spanning climatic zones and the comparability of existing data sets when conducting data synthesis studies.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 4","pages":"208-216"},"PeriodicalIF":2.7,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139835423","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}

{"title":"The Ellrott grab: A small, lightweight sediment sampler for collecting undisturbed sandy sediments","authors":"Chyrene Moncada,&nbsp;Andreas Ellrott,&nbsp;Dirk de Beer,&nbsp;Rudolf Amann,&nbsp;Katrin Knittel","doi":"10.1002/lom3.10598","DOIUrl":"10.1002/lom3.10598","url":null,"abstract":"<p>Sampling sandy surface sediments is an important first step in understanding biogeochemical processes in these dynamic environments. However, sampling such sediments poses several challenges, especially when undisturbed samples with porewater are required. Several grab samplers are commercially available, but they are either prone to sample loss, too heavy or bulky for use in small vessels, or those with spring-loaded mechanisms present safety issues. Here, we present the Ellrott grab, a lightweight sediment sampler designed for collecting undisturbed surface sediments including porewater and overlying bottom seawater. The sampler consists of a frame and a rotating bowl that can collect 370 cm² of surface sediments up to 10 cm deep (2.5 liters total volume). The instrument is 40 × 60 cm in size, has a basic weight of 10 kg, with up to 20 kg additional weights for stability in sandy sediments. Two persons can operate the grab and it can be used on small boats with a crane and winch system or a hand winch. The grab is now in routine use in the Wadden Sea and in Isfjorden, Svalbard. The samples obtained from the grab were suitable for various geochemical and microbial analyses. Using microelectrodes, we found that in situ oxygen profiles were similar to ex situ profiles in cores subsampled from the grab, confirming that the grab causes minimal disturbance to the sample. Although the grab was designed for collecting sandy sediments, it could also be applied to silty sediments, allowing straightforward and efficient sampling of various sediment types.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"22 3","pages":"159-169"},"PeriodicalIF":2.7,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.10598","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139475501","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}