Limnology and Oceanography最新文献

{"title":"Issue Information & Copyright","authors":"","doi":"10.1002/lno.12727","DOIUrl":"10.1002/lno.12727","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 10","pages":"ii"},"PeriodicalIF":3.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12727","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487242","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.12729","DOIUrl":"10.1002/lno.12729","url":null,"abstract":"","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"69 10","pages":"iv"},"PeriodicalIF":3.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12729","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487533","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":"Grazer‐induced toxin production is energetically costly and significantly reduces growth of cylindrospermopsin‐producing cyanobacteria","authors":"Lamei Lei, Wei Liu, Zihan Chen, Liang Peng, Li‐Juan Xiao, Bo‐Ping Han, Brett A. Neilan","doi":"10.1002/lno.12721","DOIUrl":"https://doi.org/10.1002/lno.12721","url":null,"abstract":"Toxins have been proposed as a defense mechanism for phytoplankton against zooplankton grazing. However, the associated costs are not understood. Here, we aim to reveal the costs in terms of both physiological and molecular responses in the cylindrospermopsin (CYN)‐producing cyanobacterium <jats:italic>Raphidiopsis raciborskii</jats:italic>. Exposure of <jats:italic>R. raciborskii</jats:italic> to <jats:italic>Daphnia magna</jats:italic> resulted in a significant increase in its CYN cell quota which was grazer cell density‐dependent, indicating an inducible effect on CYN production. A negative and significant relationship between cellular growth rate and CYN production suggested a growth‐defense trade‐off, highlighting the costly nature of toxin production. Despite strong transcriptional responses (121 differentially expressed genes) in <jats:italic>R. raciborskii</jats:italic> under grazing pressure, the CYN gene cluster remained largely unaffected, implying post‐transcriptional regulation of CYN biosynthesis. Significant variation was observed in transcripts for phosphorus metabolism and photosynthesis‐related genes, and evidenced that energy (ATP) metabolic processes were stimulated. This study is the first to demonstrate the high energy requirements for CYN production and provide insight into the molecular basis underlying the costs of toxin production.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"78 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What controls the onset of winter stratification in a deep, dimictic lake?","authors":"Jay Austin","doi":"10.1002/lno.12704","DOIUrl":"https://doi.org/10.1002/lno.12704","url":null,"abstract":"The transition from summer stratification to winter stratification is considered for deep, dimictic Lake Superior. The fall transition is dynamically distinct from the better‐studied spring transition; it is characterized by a wind‐driven collapse of weakening summer stratification, a surface‐cooling–driven period during which the water column is essentially isothermal, and eventual onset of inverse (cold upper layer) stratification, after which sub‐thermocline water temperatures are largely fixed for the rest of the season. Due to the small value of thermal expansivity near the temperature of maximum density, temperature gradients do not impart much stability to the water column, and it is difficult for winter stratification to form immediately upon dropping below the temperature of maximum density. Instead, the water column continues to cool until the thermal expansivity is sufficiently large in magnitude to allow temperature gradients to impart stability. This observation implies that the temperature locked into the deep water for the winter season will be a consequence of the specific meteorological forcing experienced in a given year; there may be long‐term climate change driven trends in the timing of the onset of stratification but not trends in winter deep‐water temperature. To address this hypothesis, 15 yr of moored temperature data collected in Lake Superior are examined, and a scaling argument and climatological data are applied to better understand interannual variability in the onset of winter stratification.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"55 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Size distribution of aggregates across different aquatic systems around Japan shows that stronger aggregates are formed under turbulence","authors":"Marika Takeuchi, Sarah L. C. Giering, Hidekatsu Yamazaki","doi":"10.1002/lno.12686","DOIUrl":"https://doi.org/10.1002/lno.12686","url":null,"abstract":"Marine aggregates, composed of various particles, play a crucial role in ocean carbon storage. The overall size distribution of the aggregates (number size spectra) is controlled by the balance between aggregation and disaggregation processes. Turbulence has been proposed to facilitate both aggregation and disaggregation by increasing the collision rate of aggregates or sometimes directly tearing them apart. Predominant processes driven by turbulence typically depend on the level of turbulence—relatively weak turbulence is associated with aggregation while stronger turbulence promotes disaggregation. Aggregate strength also plays a key role, as strongly bonded aggregates can withstand turbulence better, leading to lower disaggregation rates. While the relationship between turbulence and aggregate strength has been studied numerically and experimentally, field measurements remain limited. Here, we compare our number size spectra to turbulence intensity from the field measurements across different environmental settings around Japan to determine the effect of turbulence on aggregate strength. We combined measurements from 10 sites with different environmental settings and observed the flatter slopes (higher net aggregation rate) and shifts in the intersection lengths with an increase of turbulence, while strong turbulence is typically linked with disaggregation. Our findings suggested that stronger aggregates are formed under stronger turbulence and the overall population of strong aggregates also increases with an increase of turbulence intensity. We also compared our number size spectra with three other confounding factors (fluorescence, salinity, and aggregate compositions) to confirm the effects of turbulence are dominant in our aggregate dynamics.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"20 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nutrient enrichment—but not warming—increases nitrous oxide emissions from shallow lake mesocosms","authors":"Joachim Audet, Eti E. Levi, Erik Jeppesen, Thomas A. Davidson","doi":"10.1002/lno.12709","DOIUrl":"https://doi.org/10.1002/lno.12709","url":null,"abstract":"Shallow lakes and ponds play a crucial role in the processing of carbon and other nutrients. However, many lakes and ponds worldwide are affected by climate change and nutrient pollution. How these pressures affect the emission of the greenhouse gas nitrous oxide (N<jats:sub>2</jats:sub>O) is unclear. Warming and eutrophication are expected to increase the production and emission of N<jats:sub>2</jats:sub>O in lakes and ponds, but changes in ecological structure and function may complicate these seemingly straightforward relationships. In this study, we used the world's longest running, mesocosm‐based, freshwater climate change experiment to disentangle the effect of nutrient enrichment and warming on N<jats:sub>2</jats:sub>O emissions. We gathered a large dataset on N<jats:sub>2</jats:sub>O concentrations and ancillary variables, comprising three sampling campaigns between 2011 and 2020 and a total of 687 individual mesocosm measurements. Our results demonstrated that nutrient enrichment increased N<jats:sub>2</jats:sub>O emissions, while warming (+2.5–4.0°C and +3.75–6.0°C) had no discernable effect. Our study indicates that curtailing nitrogen influxes into lakes and ponds is the most effective strategy to minimize N<jats:sub>2</jats:sub>O emissions, and while warming may influence N<jats:sub>2</jats:sub>O emissions, it does not appear to be a direct driver. These findings underscore the importance of prioritizing nitrogen mitigation efforts to curb N<jats:sub>2</jats:sub>O emissions from shallow lakes and ponds.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"4 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptation of a keystone aquatic crustacean to cold temperatures on the Qinghai–Tibetan Plateau","authors":"Xiuping Zhang, Lugege Wang, Zhixiong Deng, David Blair, Wei Hu, Mingbo Yin","doi":"10.1002/lno.12693","DOIUrl":"https://doi.org/10.1002/lno.12693","url":null,"abstract":"Understanding the genomic architecture of temperature adaptation is critical for characterizing and predicting the effects of temperature changes on natural populations. However, our understanding of these mechanisms is still limited, especially concerning adaptation to a cold climate. Here, we looked for adaptive phenotypic features that may help high‐elevation waterflea (<jats:italic>Daphnia sinensis</jats:italic>) clones to cope with the low temperatures of the Qinghai–Tibetan Plateau (QTP) and explored possible genomic signatures of adaptation to cold. We used an experimental approach to compare transcriptional responses, in high‐elevation and lowland <jats:italic>D. sinensis</jats:italic> ecotypes from China to different experimental temperatures (16°C <jats:italic>vs</jats:italic>. 20°C). We ran life table experiments and found that high‐elevation clones (from the QTP) produced more offspring in their 1<jats:sup>st</jats:sup> clutch (or over the 1<jats:sup>st</jats:sup> two clutches) than lowland clones when grown at a lower temperature. This temperature‐dependent life history difference was associated with strong genomic signatures of temperature adaptation: the gene <jats:italic>SLC4A11</jats:italic> (encoding a transmembrane protein transporting Na<jats:sup>+</jats:sup> and H<jats:sup>+</jats:sup>), together with its encompassing genomic island, might contribute to the adaptive evolution to the cold temperature experienced by high‐elevation clones. We noted that a set of candidate genes specific to the high‐elevation clones was associated with lipid metabolism, cuticle production, and cellular proliferation, possibly involved in the mechanism of temperature adaptation of these clones to the climate on the QTP. Our findings advance the understanding of how organisms have evolved to cope with cold environments.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"228 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DNA metabarcoding reveals distinct bacterial and phytoplankton assemblages in the Agulhas Current and the adjacent coastal shelf","authors":"Ross‐Lynne A. Gibb, Danielle K. L. Botha, Siddarthan Venkatachalam, Mfundo Bizani, Thomas G. Bornman, Rosemary A. Dorrington","doi":"10.1002/lno.12703","DOIUrl":"https://doi.org/10.1002/lno.12703","url":null,"abstract":"The Agulhas Current is a globally important western boundary current that influences numerous processes (e.g., upwelling, biogeochemical fluxes and distribution of marine taxa) in the southwestern Indian Ocean. The oceanographic processes of the Agulhas Current are well understood, but precisely how they influence coastal ecosystem productivity remains to be elucidated. In the present foundational study, we characterized the bacterial (16S rRNA gene) and phytoplankton (chloroplast 16S rRNA, <jats:italic>rbcL</jats:italic>, and eukaryotic 18S rRNA genes) community structures of the Agulhas Current system using a metabarcoding approach. All four markers provided consistent data on the bacterial and phytoplankton communities in the Agulhas Current and coastal sites. The study revealed distinct, conserved communities and similar patterns of dominance by taxa adapted to oligotrophic conditions within the Agulhas Current, sampled 2 yr apart. By contrast, there was significant variability in taxonomic diversity and abundance of phytoplankton communities in the adjacent coastal waters that could be linked to localized upwelling. While the Agulhas Current bacterial and phytoplankton communities were diverse and represented many functional groups, the coastal sites were more diatom‐dominated and included genera typically associated with upwelling, for example, <jats:italic>Thalassiosira</jats:italic> spp. Based on their relative abundance profiles, phytoplankton communities were more responsive to environmental variability than bacteria and may therefore prove more useful in linking ecosystem dynamics to environmental variability in marine systems.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"193 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prey morphotype and abundance controls plastid retention and bloom dynamics for a mixotrophic dinoflagellate","authors":"Megan Ladds, Heidi M. Sosik, Christopher J. Gobler","doi":"10.1002/lno.12708","DOIUrl":"https://doi.org/10.1002/lno.12708","url":null,"abstract":"<jats:italic>Dinophysis</jats:italic> is an obligate mixotroph that relies on consumption of the ciliate, <jats:italic>Mesodinium rubrum</jats:italic>, to grow and form harmful algal blooms (HABs). In this study, blooms of <jats:italic>Dinophysis acuminata</jats:italic> in two NY, USA, estuaries were studied over the course of 3 yr (2019–2021) using discrete samples and an Imaging FlowCytobot (IFCB) to capture images of plankton 20–150 <jats:italic>μ</jats:italic>m. The darkness of <jats:italic>Dinophysis</jats:italic> images on the IFCB was used to quantify the “fullness” or feeding state of <jats:italic>Dinophysis</jats:italic> cells. Culture experiments performed to ground truth this approach revealed a highly significant correlation (<jats:italic>R</jats:italic> = 0.98; <jats:italic>p</jats:italic> &lt; 0.001) between the darkness of <jats:italic>Dinophysis</jats:italic> cells and the abundance of <jats:italic>Mesodinium</jats:italic>. With a quantitative scale developed to track the fullness of <jats:italic>Dinophysis</jats:italic> cells, ecosystem observations revealed the percentage of “full” <jats:italic>Dinophysis</jats:italic> cells increased during blooms of a large‐morphotype <jats:italic>Mesodinium</jats:italic> that preceded the initiation of <jats:italic>Dinophysis</jats:italic> blooms. A smaller morphotype <jats:italic>Mesodinium</jats:italic> appeared during <jats:italic>Dinophysis</jats:italic> bloom peaks suggesting they supported bloom maintenance. While the relative abundance of diatoms was elevated before <jats:italic>Dinophysis</jats:italic> blooms, other dinoflagellates and tintinnids increased in abundance during these HABs indicating they emerged within a consortium of heterotrophs and mixotrophs that may have collectively filled the same open niche as <jats:italic>Dinophysis</jats:italic>. This study reveals the manner in which different <jats:italic>Mesodinium</jats:italic> populations co‐bloom with <jats:italic>Dinophysis</jats:italic> to support plastid acquisition, bloom initiation, and bloom maintenance and contextualizes these changes within the larger plankton community succession associated with these HABs.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"123 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 7‐yr spatial time series resolves the island mass effect and associated shifts in picocyanobacteria abundances near O'ahu, Hawai'i","authors":"Christina M. Comfort, Chris Ostrander, Craig E. Nelson, David M. Karl, Margaret A. McManus","doi":"10.1002/lno.12711","DOIUrl":"https://doi.org/10.1002/lno.12711","url":null,"abstract":"Islands in oligotrophic oceans act as local sources of nutrients. These nutrients originate from land and from deep oceanic nutrients introduced to the photic zone by tides, currents, and internal waves interacting with island bathymetry. These processes create the island mass effect (IME), in which increased chlorophyll <jats:italic>a</jats:italic> (Chl <jats:italic>a</jats:italic>) is found near islands compared to oceanic waters. The IME has been described via satellite observations, but the effects on phytoplankton community structure are not well documented. From 2013 to 2020, chlorophyll, nutrient, and picoplankton samples were collected from multiple depths on quarterly cruises at two sites south of O'ahu, Hawai'i. <jats:italic>Prochlorococcus</jats:italic>, <jats:italic>Synechococcus</jats:italic>, picoeukaryotes, and heterotrophic bacteria were enumerated using flow cytometry. We compared nearshore results to Sta. ALOHA, 100 km from O'ahu. Consistent with the expected IME, Chl <jats:italic>a</jats:italic> concentrations were significantly enhanced at both nearshore sites compared to Sta. ALOHA. <jats:italic>Prochlorococcus</jats:italic> concentrations increased with greater distance from shore, particularly below 50 m; mixed layer concentrations of <jats:italic>Synechococcus</jats:italic> and picoeukaryotes significantly decreased with greater distance from shore, as did concentrations of nitrate and phosphate below the mixed layer. Heterotrophic bacteria concentrations did not show a spatial trend. Carbon‐based biomass estimates of the picoplankton population indicated that the IME‐associated Chl <jats:italic>a</jats:italic> increases near the island are likely driven by larger phytoplankton classes. This study describes the IME‐associated shift in the picophytoplankton community distribution, which has implications for nutrient cycling, food web dynamics and fisheries in oligotrophic island ecosystems, and adds to the understanding of spatial heterogeneity in carbon fixation in the ocean.","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"2 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}