Limnology and Oceanography: Methods最新文献

{"title":"Evaluation of methods for the analysis of oxygen and carbon dioxide in water, sediment, litter, and soil","authors":"Elizabeth Jakobsson,&nbsp;Konstantinos-Marios Vaziourakis,&nbsp;Lars Tranvik","doi":"10.1002/lom3.70079","DOIUrl":"https://doi.org/10.1002/lom3.70079","url":null,"abstract":"<p>Choosing an appropriate analyzer to measure concentrations of oxygen (O₂) and carbon dioxide (CO₂) during biogeochemical cycling studies can be difficult, considering the range of options available. While several studies examine the abilities of specific analyzers, comparison of multiple analyzers and environmental sample types is lacking. We examined the performance of various analyzers across an extensive range of environments, including lake water, soil, sediment, and leaf litter. Analyzers were chosen based on their widespread use and included O₂ optode sensors, membrane inlet mass spectrometry (MIMS), dissolved inorganic carbon (DIC) analyzer, cavity ringdown spectroscopy (CRDS), and gas chromatography (GC). We also present a new aquatic sample handling technique that enables the simultaneous determination of both O₂ and CO₂. Both MIMS and optode sensors perform comparably for O₂ measurements for water samples in terms of speed and reproducibility. However, for the measurement of O₂ in the headspace of enclosed solid samples, MIMS performs better. For CO₂ analysis, MIMS performed best in terms of reproducibility, having the lowest coefficient of variation across all analyzers. Additionally, the MIMS was the only analyzer capable of measuring both gases from both the headspace of enclosed solid and liquid samples as well as directly in liquid samples for dissolved O₂.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70079","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149083996","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 simplified two-station approach for modeling metabolism in dam tailwaters subject to diel flow variation","authors":"Ian W. Bishop,&nbsp;Bridget R. Deemer,&nbsp;Theodore A. Kennedy,&nbsp;Robert A. Payn,&nbsp;Robert O. Hall Jr.,&nbsp;Charles B. Yackulic","doi":"10.1002/lom3.70066","DOIUrl":"https://doi.org/10.1002/lom3.70066","url":null,"abstract":"<p>Tailwaters are ubiquitous and highly managed ecosystems whose food webs often rely disproportionately on autochthonous energy. In situ continuous dissolved oxygen data are increasingly being used to estimate gross primary productivity and ecosystem respiration in rivers, but this approach is complicated in tailwaters, where upriver discontinuities (i.e., dams) violate commonly employed one-station approaches. In such cases, two-station metabolism models can be applied, although substantial diel variation in flow (a common outcome of hydropower production) requires more complex treatment of water parcel travel times. Here, we present a new two-station metabolism model that allows estimation of reach-scale gross primary productivity and ecosystem respiration in streams and rivers that experience within-day variation in flow. Our approach simplifies two-station variable flow model implementation compared to previous efforts. We apply our model to a 6-yr dissolved oxygen time series and use Bayesian inference to estimate daily gross primary productivity, ecosystem respiration, and gas exchange velocity (<i>k</i>₆₀₀) for a ~12-km reach of the Colorado River downriver of Glen Canyon Dam. We compare our model's performance to a more mechanistically detailed and computationally intensive Eulerian dynamic flow model and also to a widely-used one-station model that uses assumptions of reach uniformity that are often strongly violated in tailwaters. These comparisons show that our metabolism estimates conform with output from the more detailed dynamic flow model and that the one-station approach deviates substantially from both two-station approaches. Our new stream metabolism model can help resolve a fundamental analytical impediment in tailwater ecology.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149083939","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":"Field settlement trap designs for Cassiopea spp. polyp recruitment: A preliminary study","authors":"Natalia B. López-Figueroa,&nbsp;Pamela Hallock,&nbsp;Elizabeth W. Stoner,&nbsp;Cheryl Ames,&nbsp;Juleika Y. Vega Pérez,&nbsp;Wigmali Guzmán Echevarría,&nbsp;Lizmar M. Luna Pirela,&nbsp;Milton Muñoz-Hincapié,&nbsp;Liza M. Roger,&nbsp;Megan Maloney,&nbsp;Katherine M. Buckley,&nbsp;André C. Morandini","doi":"10.1002/lom3.70078","DOIUrl":"https://doi.org/10.1002/lom3.70078","url":null,"abstract":"<p>High densities of upside-down jellyfish (<i>Cassiopea</i> spp.) have been documented in anthropogenically disturbed coastal ecosystems including Jobos Bay, Puerto Rico. However, understanding their field ecology remains limited because most studies are laboratory-based, focusing on life history and symbiotic relationships. To investigate recruitment dynamics in field settings and improve ecological studies of this model system, we developed and preliminarily tested three original settlement trap designs to facilitate <i>Cassiopea</i> polyp collection under field conditions. Trap designs 1 and 2 contained only degraded <i>Rhizophora mangle</i> (red mangrove) leaves; trap design 3 included <i>R. mangle leaves</i>, <i>Sargassum fluitans</i>, and <i>Halophila stipulacea</i>; and a control design was void of substrate. Therefore, substrate type was not tested across all trap designs, and comparisons among designs are interpreted primarily in relation to trap structure rather than substrate identity. After 5 weeks, 25 polyps were found in Trap 3, exclusively upon <i>R. mangle</i> leaves; no polyps were observed on substrates in Traps 1 or 2, or the control. These preliminary results suggest that Trap 3 is most suitable for recruiting <i>Cassiopea</i> polyps and the preference for degraded <i>R. mangle</i> leaves is consistent with laboratory studies that show favorable conditions for polyp settlement. Biofilm was observed post hoc on the decomposed leaf in Trap 3 bearing 96% of the recruited polyps which warrants further investigation. The unique <i>Cassiopea</i> polyp settlement traps tested herein offer the potential to investigate recruitment rates in situ amidst changing climate conditions, thereby improving our understanding of <i>Cassiopea</i> spp. population explosion and collapse.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149083998","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":"Estimating macrozoobenthos abundance and biomass in river rapids: Accuracy analysis via randomization","authors":"Igor A. Baryshev","doi":"10.1002/lom3.70077","DOIUrl":"https://doi.org/10.1002/lom3.70077","url":null,"abstract":"<p>The accuracy of biomonitoring in river ecosystems depends critically on sampling methods. This is particularly relevant at the mesohabitat level—discrete morphological units such as rapids—which are characteristic of the near-pristine rivers of Eastern Fennoscandia and exhibit high spatial heterogeneity. This study examined how the total number of samples affects the accuracy of regional macrozoobenthos abundance and biomass estimates in such habitats. Based on 535 samples from Eastern Fennoscandia, randomization techniques and regression analysis were employed to relate sample size to estimate accuracy. The required number of samples was determined for confidence levels of 70%, 90%, and 95% and confidence interval widths ranging from 20% to 60% of the mean. At a 70% confidence level, achieving a 60% confidence interval width required at least 16 samples for abundance and 35 for biomass; for a 40% width, 35 samples were needed for abundance and 79 for biomass. The percentile-based method underestimated required sample sizes compared to the more reliable Cox method. Regression models (<i>R</i>² &gt; 0.99) enabled the determination of optimal sample sizes for any desired confidence level (70–95%) and precision (20–60%). Biomass estimation consistently required 2–3 times more samples than abundance to achieve equivalent precision. These findings offer practical sample size guidelines for heterogeneous lotic habitats, where researchers must balance statistical reliability against logistical constraints. These findings offer practical sample size guidelines for heterogeneous lotic habitats, where researchers must balance statistical reliability against logistical constraints.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084047","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":"VIBRASSAY: A standardized protocol to study the ecophysiological responses of benthic invertebrates to substrate vibrations for underwater noise risk assessment","authors":"Viviane David,&nbsp;Elie Retailleau,&nbsp;Gaëtan Richard,&nbsp;Andréaz Dupoué,&nbsp;Aurélie Jolivet,&nbsp;Delphine Mathias","doi":"10.1002/lom3.70072","DOIUrl":"https://doi.org/10.1002/lom3.70072","url":null,"abstract":"<p>Anthropogenic noise has increased over the last decades in marine ecosystems, due to diverse human activities (e.g., ships, pile driving, drilling, dredging, underwater explosions, and seismic testing). Nevertheless, there is currently a knowledge gap regarding the effects of noise pollution, especially substrate vibrations, on benthic species. Within this context, we developed a standardized experimental method to study the ecophysiological responses of benthic invertebrates exposed to substrate vibrations, following a dose–response approach. Our protocol enables the exposure of individuals to different treatments of substrate vibrations (three acceleration levels and a control) with several aquariums (i.e., replicates) exposed simultaneously for each treatment. Four independent vibrating structures were built, allowing for the aquarium replicates to be exposed to the different treatments simultaneously without vibration propagation between structures. The objective of the study was therefore to fully characterize the vibrating structures, for frequencies ranging from 5 to 50 Hz, to ensure precise knowledge of the vibration exposure levels inside the aquariums. Especially, intra-aquarium variability of the vibration signal in function of the frequency was estimated as well as long-term signal stability on 48 h. Finally, we presented an example of application of our protocol on great scallops, suggesting that our system can be used to generate dose–response relationships between substrate vibration levels and biological responses.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084005","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":"Sodium sulfite can reliably induce chemical hypoxia without toxic effects in the model sea anemone species, Exaiptasia diaphana","authors":"Zhen Qin,&nbsp;Lorenzo Vassura,&nbsp;Bianca A. Parodi,&nbsp;Elise M. J. Laetz","doi":"10.1002/lom3.70075","DOIUrl":"https://doi.org/10.1002/lom3.70075","url":null,"abstract":"<p>Climate change is accelerating the deoxygenation of aquatic ecosystems, so understanding its effects on biological processes is increasingly critical. An emerging method for inducing hypoxia during experimentation utilizes sodium sulfite (SSI) to scavenge oxygen; however, it remains unclear if hypoxia-inducing concentrations of SSI are toxic to aquatic species. We decoupled SSI's potential toxicity from its hypoxia-inducing effects by rapidly replacing the oxygen it removes via vigorous aeration. We examined the model species <i>Exaiptasia diaphana</i> (a sea anemone) and its endosymbiotic dinoflagellates by exposing them to a dosage that mimics the diel oxygen cycle for 2 weeks. We examined common stress indicators, including the anemone's metabolic rates and thermal tolerance, the algae's photosynthetic efficiency, cell density, and reproduction in treated and untreated specimens, finding no effects of SSI exposure. A second trial assessed acute toxicity, finding that anemones lacked observable stress responses after 21.2 times the concentration needed to induce anoxia. We therefore conclude that SSI is a viable, cost-effective, and nontoxic way to induce hypoxia in this species and that this method shows broad potential for hypoxia studies on other aquatic organisms.</p>","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084074","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 novel approach to estimate non-algal particle absorption for improved retrieval of pigment concentrations in coastal waters","authors":"Margherita Costanzo,&nbsp;Vittorio E. Brando,&nbsp;Emmanuel Boss,&nbsp;Alison Chase,&nbsp;David Doxaran","doi":"10.1002/lom3.70073","DOIUrl":"https://doi.org/10.1002/lom3.70073","url":null,"abstract":"&lt;p&gt;Phytoplankton play a central role in ocean biogeochemistry and understanding their composition and variability is critical for monitoring marine ecosystem dynamics. Continuous spectrophotometric measurements (using a Seabird Sci. AC-S) along ship tracks enable high-resolution measurements of particle spectral absorption (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mi&gt;λ&lt;/mi&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;), and beam attenuation spectra (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mi&gt;λ&lt;/mi&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;), across large spatial and temporal scales. Here, we present a new method to estimate non-algal particle absorption (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;NAP&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mi&gt;λ&lt;/mi&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;) from AC-S data, using &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mn&gt;660&lt;/mn&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; to derive both &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;NAP&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mn&gt;400&lt;/mn&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; and the spectral slope of non-algal particles (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mi&gt;NAP&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;). This method allows the estimation of the total spectra of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;NAP&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mi&gt;λ&lt;/mi&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt; directly from &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;c&lt;/mi&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mn&gt;660&lt;/mn&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;&lt;/math&gt;, and consequently the derivation of phytoplankton absorption (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;ph&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 ","PeriodicalId":18145,"journal":{"name":"Limnology and Oceanography: Methods","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lom3.70073","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149084131","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":"Refining techniques for high-frequency monitoring of chlorophyll a fluorescence in estuarine systems","authors":"Nicole Dix,&nbsp;Hannah Nicklay,&nbsp;Jacob Cianci-Gaskill,&nbsp;Shannon Dunnigan Kimmel,&nbsp;J. Silas Tanner,&nbsp;Kim Cressman,&nbsp;Steven E. McMurray,&nbsp;Yoshimi M. Rii,&nbsp;Rikke Jeppesen,&nbsp;Rachel Guy,&nbsp;Erik Smith","doi":"10.1002/lom3.70065","DOIUrl":"https://doi.org/10.1002/lom3.70065","url":null,"abstract":"<p>Concentrations of the photosynthetic pigment chlorophyll <i>a</i> are commonly used as a proxy for phytoplankton biomass in aquatic systems. Traditional methods for extracting chlorophyll <i>a</i> in discrete samples limit measurement frequency, while in situ sensor technology provides high frequency chlorophyll <i>a</i> fluorescence measurements at a more appropriate time scale to study processes related to phytoplankton turnover and a more rapid response to harmful algal blooms. Caveats to in situ measurements include that temperature, fluorescent dissolved organic matter, and turbidity can affect accuracy and that chlorophyll <i>a</i> fluorescence does not always correlate well to extracted chlorophyll <i>a</i>. Therefore, practitioners need guidance to interpret fluorescence data considering potential errors and relationships to extracted chlorophyll <i>a</i> to inform management decisions. Before this project, the nature of those relationships had not been tested across a wide gradient in water properties. To address these gaps, a one-year study was conducted across 12 biogeochemically diverse sites to quantify possible fluorescence interferences and test the predictability of extracted chlorophyll <i>a</i> using uncorrected in situ chlorophyll <i>a</i> (in relative fluorescence units) combined with routinely measured water quality parameters. Overall, sensor fluorescence was positively correlated with extracted chlorophyll <i>a</i>, but the strength and drivers of the relationship varied by site. Temperature, turbidity, and fluorescent dissolved organic matter influenced sensor readings independently of phytoplankton biomass. Hence, considerations for in situ sensor implementation depend on monitoring goals and resources. Where feasible, we recommend the simultaneous use of in situ and extractive approaches to track short-term variability and long-term change in chlorophyll <i>a</i>.</p>","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/lom3.70065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878249","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 novel approach for in situ benthic habitat characterization","authors":"Ryan J. W. Mathews,&nbsp;David K. A. Barnes,&nbsp;Simon A. Morley,&nbsp;Gareth Flint,&nbsp;Lloyd S. Peck","doi":"10.1002/lom3.70064","DOIUrl":"https://doi.org/10.1002/lom3.70064","url":null,"abstract":"<p>Habitat heterogeneity is a key driver of temporal and spatial variability of subtidal marine benthic biodiversity. However, this makes it a challenging environment in which to measure and quantify the factors driving biodiversity in a consistent manner. Current methodologies are either expensive, logistically challenging, require extensive technical knowledge, or are limited to shallow water environments. To overcome some of these limitations, a novel “SeaPen” device was designed as a cost-effective, safe, easily deployable instrument that can provide repeatable and comparable survey results over the small spatial scales required to describe heterogeneous environments. The device, which comprises a tripod frame holding a steel weighted bar in the center, allows gravity to force a graduated metal spindle into the substratum when it is dropped. A video camera fixed to a tripod leg allows the recording of the nature of the seabed and the depth of penetration of the spindle, from which seabed properties can be described. The device does not need to be recovered to the surface between measurements, which allows it to be repeatedly dropped for multiple replicates in a single deployment. The combination of a penetrating spindle and a camera allows for rapid repeat measures and, most importantly, can be used to measure heterogeneity on finer scales (within a site; m) than other more traditional techniques. The SeaPen was used in a shallow water (&lt;50 m) coastal habitat on the West Antarctic Peninsula. The survey area comprised heterogeneous substrata composed of sediments interspersed between boulders, cobbles, and pebbles, which allowed for proof of concept that the SeaPen could discriminate a wide range of seabed habitat types.</p>","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/lom3.70064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878531","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":"Statistical filtering to aid in the sorting of phytoplankton: The effects of image library size and phytoplankton shape","authors":"Christopher R. Farrow,&nbsp;Josef D. Ackerman","doi":"10.1002/lom3.70062","DOIUrl":"https://doi.org/10.1002/lom3.70062","url":null,"abstract":"<p>The demand for efficient image sorting methods has increased due to technological advancements that enable more intensive phytoplankton monitoring. Both statistical and machine learning algorithms can misidentify algal taxa in taxonomically diverse samples, in which phytoplankton morphology and image traits can vary. We evaluated the statistical filtering performance of the image processing software of an imaging flow cytometer (FlowCam) for two approaches to image library development; these were applied independently to seven commonly occurring algal shapes in mixed natural samples. The “intrinsic method” used a small selection of images (5–15 images of a target taxon) from the same sample being filtered (i.e., intrinsic), whereas the “compiled method” used a larger selection of images (30–80 images of a target taxon) compiled from multiple samples. Filter performance varied with the type of image library, image library size, and target taxon. The largest image libraries offered the highest recall (&gt; 86% for intrinsic, &gt; 94% for compiled) but lower precision (3–85% for intrinsic, &lt; 1–8% for compiled). Precision was highest for the smallest image libraries, and was higher for the intrinsic method (&gt; 75% for most taxa) than the compiled method (&lt; 20% for most taxa). Statistical filtering performance was higher for larger, solitary-celled taxa with relatively uniform features (e.g., <i>Gyrosigma</i>) compared to small-celled colonial species with more complex or variable shapes (e.g., mucilaginous colonial cyanobacteria, and <i>Scenedesmus</i>). Iteratively using the intrinsic statistical filtering method with manual correction between each iteration can be used to augment manual sample classification and reduce processing time.</p>","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/lom3.70062","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148878532","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}