Limnology and Oceanography最新文献

{"title":"Colony-forming and single-cell picocyanobacteria nitrogen acquisition strategies and carbon fixation in the brackish Baltic Sea","authors":"Christien P. Laber,&nbsp;Javier Alegria Zufia,&nbsp;Catherine Legrand,&nbsp;Elin Lindehoff,&nbsp;Hanna Farnelid","doi":"10.1002/lno.12636","DOIUrl":"10.1002/lno.12636","url":null,"abstract":"<p>Picocyanobacteria are widespread and globally significant primary producers. In brackish waters, picocyanobacterial populations are composed of diverse species with both single-cell and colony-forming lifestyles. Compared to their marine counterparts, brackish picocyanobacteria are less well characterized and the focus of research has been weighted toward single-cell picocyanobacteria. Here, we investigate the uptake dynamics of single and colony-forming picocyanobacteria using incubations with dual carbon-13 and inorganic (ammonium and nitrate) or organic (urea and amino acids) nitrogen-15 sources during August and September 2020 in the central Baltic Sea. Phytoplankton community and group-specific uptake rates were obtained using an elemental analyzer isotope ratio mass spectrometer (EA-IRMS) and nano secondary-ion mass spectrometry (NanoSIMS). Picocyanobacteria contributed greater than one third of the ammonium, urea, amino acids, and inorganic carbon community uptake/fixation in September but &lt; 10% in August when phytoplankton biomass was higher. Overall, single-cell ammonium and urea uptake rates were significantly higher for single-celled compared to colonial picocyanobacteria. In a 6-yr offshore central Baltic Sea time series (2015–2020), summer abundances of colonial picocyanobacteria reached up to 10⁵ cells mL⁻¹ and represented &gt; 5% of the average phytoplankton biomass, suggesting that they are periodically important for the ecosystem. Colonial strain identification was not distinguishable using 16S rRNA gene amplicon data, highlighting a need for refined tools for identification of colonial forms. This study shows the significance of single-celled brackish picocyanobacteria to nutrient cycling and the importance of considering uptake and lifestyle strategies when assessing the role of picocyanobacteria in aquatic ecosystems.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12636","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Migrating ripples create streambed heterogeneity altering microbial diversity and metabolic activity","authors":"Anna Oprei,&nbsp;José Schreckinger,&nbsp;Norbert Kamjunke,&nbsp;Anja Worrich,&nbsp;Michael Mutz,&nbsp;Ute Risse-Buhl","doi":"10.1002/lno.12631","DOIUrl":"10.1002/lno.12631","url":null,"abstract":"<p>Sandy sediments of lowland streams are typically transported at low flow in the form of migrating ripples. In these bedforms, microbial communities spanning all trophic guilds (heterotrophic bacteria, fungi, photoautotrophic and phagotrophic protists) are exposed to highly frequent moving–resting cycles of sediment grains. Up to date, it is unknown to what extent ripple migration impacts community metabolism and composition as well as the vertical zonation of sediment-associated multitrophic microbial communities compared to stationary sediments. We hypothesize that, as a result of mechanical abrasion and limited light supply, migrating ripple sediments have lower microbial abundance, diversity, metabolism and resource acquisition and no vertical zonation compared to stationary sediments. We collected samples from five lowland streams in north-eastern Germany between May and June 2020. The coarser and better sorted sediments of migrating ripples had a higher oxygen concentration and less organic matter than stationary sediments. Photosynthetic pigments, potential extracellular enzyme activities, bacterial cell counts, and fungal gene copies were lower in migrating ripples than in stationary sediments. In contrast, cell-specific bacterial production was higher in migrating ripples. Metabarcoding revealed that bedform migration was important in shaping the community structure of bacteria, fungi, and phagotrophic protists. Dry mass-related net community production, respiration, and bacterial production were higher in superficial compared to underlying layers irrespective of sediment transport. By modulating the abundance, diversity, and structure of different trophic guilds of microbial communities and their resource acquisition, migrating bedforms create streambed heterogeneity, shaping regional biodiversity and the flow of matter through the benthic food web.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12631","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zooplankton grazing reduces the persistence of an anthropogenic pollution marker in lake water","authors":"Giulia Borgomaneiro,&nbsp;Andrea Di Cesare,&nbsp;Cristiana Callieri,&nbsp;Gianluca Corno,&nbsp;Diego Fontaneto,&nbsp;Roberta Piscia,&nbsp;Ester M. Eckert","doi":"10.1002/lno.12630","DOIUrl":"10.1002/lno.12630","url":null,"abstract":"<p>Wastewater treatment plant effluents release microbiological pollutants, including the <i>intI</i>1 gene (integrases of class 1 integron), which has been proposed as a target for monitoring anthropogenic pollution in surface waters. This gene correlates with antibiotic resistance genes, making it an important proxy for genetic contamination in aquatic environments. It is currently unclear whether <i>intI</i>1 found in lake water is mainly present due to continuous seeding or if autochthonous bacteria harbor this gene. To better understand the fate and dynamics of class 1 integrons in aquatic systems, we resorted to classical limnological monitoring of <i>intI</i>1 (qPCR) over multiple years in three different size fractions: free-living bacteria, particle-attached bacteria, and zooplankton-attached bacteria. We also conducted experiments to elucidate the impact of grazers on the abundance of <i>intI</i>1. The monitoring of different size fractions of the Lake Maggiore microbial community showed a particle-bound lifestyle for <i>intI</i>1-hosting bacteria. Most of these bacteria originated from both a wastewater effluent that discharges into Lake Maggiore and the lake water itself (amplicon sequencing). We hypothesize that these bacteria grow on particles in open waters, making them particularly vulnerable to grazing by large filter feeders such as <i>Daphnia</i>. Therefore, the presence of <i>Daphnia</i> reduced the abundance of <i>intI</i>1 in lake water, whereas this was not true for other grazers such as <i>Rotaria macrura</i> or <i>Poterioochromonas</i> sp. Our study shows that the food web structure and temporal changes in the lake influence the abundance of <i>intI</i>1 and consequently the assessment of anthropogenic pollution.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12630","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information & Members","authors":"","doi":"10.1002/lno.12646","DOIUrl":"https://doi.org/10.1002/lno.12646","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12646","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information & Masthead","authors":"","doi":"10.1002/lno.12643","DOIUrl":"https://doi.org/10.1002/lno.12643","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12643","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information & TOC","authors":"","doi":"10.1002/lno.12645","DOIUrl":"https://doi.org/10.1002/lno.12645","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12645","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seafloor bioturbation intensity on the deep sea: More complex than organic matter","authors":"Olmo Miguez-Salas,&nbsp;Hanieh Saeedi,&nbsp;Angelika Brandt,&nbsp;Torben Riehl","doi":"10.1002/lno.12632","DOIUrl":"10.1002/lno.12632","url":null,"abstract":"<p>Deep-sea benthic communities are strongly controlled by the quantity and quality of organic matter sinking from the ocean surface. The interaction between benthic fauna and seafloor sediments mainly occurs through bioturbation that modifies substrate properties (e.g., geochemical profiles). The intensity of the bioturbation has long been linked with organic matter and measured as a diffusive process by considering the vertical particle reworking (endobenthic bioturbation), disregarding the seafloor horizontal mixing (epibenthic bioturbation). Here, a novel approach to quantify horizontal mixing is presented: Seafloor Bioturbation Intensity (SBI). SBI calculations were based on seafloor image datasets from eight stations that reflected different environmental conditions in the north-western Pacific (e.g., chlorophyll <i>a</i>, silicate). To calculate SBI, we characterized the area occupied by all different types of traces (i.e., lebensspuren) related to epibenthic bioturbation, trace makers, and their ingested sediment thickness. Our results showed a weak negative correlation between organic matter and SBI. This relationship contrast with the traditionally held view on vertical bioturbation intensity, where a dominant positive correlation is expected. It is demonstrated that lebensspuren morphotypes contributed differently to SBI. Not all morphotypes—and, by extension, their corresponding trace makers—are equally controlled by the same environmental factors. This investigation does not dismiss the importance of organic matter content, but emphasizes the importance of other environmental variables that need to be considered when determining the long-term relation between epibenthic fauna and bioturbation intensity. Finally, we emphasize the importance of characterizing horizontal bioturbation for approaching global biogeochemical cycles and conservational strategies.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12632","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic matter accumulation drives methylotrophic methanogenesis and microbial ecology in a hypersaline coastal lagoon","authors":"Christopher Keneally,&nbsp;Matilda Southgate,&nbsp;Daniel Chilton,&nbsp;Virginie Gaget,&nbsp;David T. Welsh,&nbsp;Luke Mosley,&nbsp;Dirk V. Erler,&nbsp;Stephen P. Kidd,&nbsp;Justin Brookes","doi":"10.1002/lno.12637","DOIUrl":"10.1002/lno.12637","url":null,"abstract":"<p>Hypersalinity is common in coastal wetlands throughout warm, tropical, and arid regions. Climate-induced changes in rainfall, sea level, and anthropogenic modification to basins and coastlines are likely to further increase salinization in these ecosystems. Yet, carbon cycling in hypersaline coastal wetlands is not well understood, and poorly constrained in climate models. In the Coorong, a eutrophic, hypersaline coastal lagoon, recognized as internationally important under the Ramsar convention, organic matter rapidly accumulates in deeper areas of the lagoon, through the settling of fine detrital particles, phytoplankton and suspended sediments. During initial surveys, elevated surface water methane (CH₄) concentrations were observed above these fine depositional sediments. To identify the drivers of CH₄ production, organic matter and sediment characteristics were assessed in surface sediments. Genetic markers (i.e., 16rDNA and the <i>mcrA</i> functional gene) were used to characterize microbial communities. With multiple lines of evidence, this study identifies organic matter, methanogen abundance, and salinity as important drivers of CH₄ production, which is concentrated in depositional zones. Archaea were also more abundant in depositional zones, including methylotrophic methanogens: Methanofastidiosales, Methanomasiliicoccales, <i>Methermicoccaceae</i>, and <i>Methanococcoides</i>. These methanogens were highly correlated to CH₄ in porewater, suggesting an influence of methylotrophic methanogenesis. To investigate further, metabolic genes were predicted from 16S rRNA with PICRUSt2. This represents the first effort to analyze CH₄ dynamics in the Coorong, underscoring the need to integrate these unique ecosystems into global climate models to enhance our understanding of greenhouse gas dynamics and emissions in a changing climate.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information & Copyright","authors":"","doi":"10.1002/lno.12644","DOIUrl":"https://doi.org/10.1002/lno.12644","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12644","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Different temperature sensitivities of key physiological processes lead to divergent trait response patterns in Arctic phytoplankton","authors":"Linda Rehder,&nbsp;Sebastian D. Rokitta,&nbsp;Clara J. M. Hoppe,&nbsp;Isabelle Buschmann,&nbsp;Levke Jasper,&nbsp;Björn Rost","doi":"10.1002/lno.12633","DOIUrl":"10.1002/lno.12633","url":null,"abstract":"<p>Ocean warming is especially pronounced in the Arctic, and phytoplankton will face thermodynamically driven changes in their physiology, potentially pushing them beyond their thermal optimum. We assessed temperature responses of multiple functional traits over their entire thermal window (growth rates, quotas of particulate organic carbon, nitrogen, and chlorophyll <i>a</i>, as well as photophysiological parameters) in three different Arctic phytoplankton species (<i>Thalassiosira hyalina</i>, <i>Micromonas pusilla</i>, and <i>Nitzschia frigida</i>). Temperature response patterns in growth and biomass production rates indicated that all species exhibit wide thermal windows with highest rates at temperatures that exceed current polar temperatures. Species showed different temperature response patterns in cellular elemental quotas, which originate from the interplay of cell division and biomass production: These processes differ in their temperature sensitivity and optima, resulting in U-shaped, bell-shaped, or linear patterns of elemental quotas. Despite unaltered light intensity, higher temperatures increased light acclimation indices in all species while lifetimes of photosystem II reopening decreased in all species, suggesting that warming causes a transition from light saturation to light limitation. Our findings on temperature sensitivities of cell division and biomass production not only indicate that Arctic phytoplankton may benefit from moderate warming, but also highlight that meaningful interpretations of cellular quotas require a consideration of the underlying processes.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141730588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}