Limnology and Oceanography Letters最新文献

{"title":"Warming-induced changes in benthic redox as a potential driver of increasing benthic algal blooms in high-elevation lakes","authors":"Stephanie E. Hampton,&nbsp;Jill S. Baron,&nbsp;Robert Ladwig,&nbsp;Ryan P. McClure,&nbsp;Michael F. Meyer,&nbsp;Isabella A. Oleksy,&nbsp;Anna Shampain","doi":"10.1002/lol2.10357","DOIUrl":"10.1002/lol2.10357","url":null,"abstract":"<p>Blooms of algae attached to the bottom of nearshore environments have increasingly been observed in clear, nutrient-poor lakes worldwide (Vadeboncoeur et al. <span>2021</span>). The phenomenon is puzzling for at least two reasons. First, such nearshore benthic blooms appear to be common across heterogeneous contexts—from the world's largest lake in Siberia to small mountain lakes in the Rocky Mountains of North America. Second, the blooms are enigmatic because they have been observed in the near absence of direct human disturbances, such as those in well-protected, remote mountain lakes. A recent review (Vadeboncoeur et al. <span>2021</span>) highlights the diversity of mechanisms through which these nearshore benthic blooms may be triggered—such as nutrient loading through atmospheric deposition or human activity within the watershed, changes in hydrodynamics associated with climate change, and food web alterations that reduce grazing pressure. Yet none of these potential drivers are common across the lakes where nearshore benthic algal blooms have been reported. Here, we suggest that a previously unappreciated driver is common across all lakes that experience warming associated with climate change—elevated nearshore temperatures that reduce oxygen and promote nutrient release from sediments under the biofilm. In principle, this phenomenon should be particularly notable in high-elevation lakes because water at higher elevation holds less oxygen at saturation, high-elevation lakes are warming more quickly than their lowland counterparts, and they can receive additional warming from relatively high solar radiation (Fig. 1). We briefly review the evidence in support of this concept, recognizing that the data necessary to rigorously test it do not yet exist; however, such data collection is feasible.</p><p>Algal taxa in oligotrophic systems are well adapted to naturally high-light and nutrient-poor conditions (Cantonati and Lowe <span>2014</span>). Because nutrients at the sediment–water interface can be rapidly cycled, nutrient concentrations in the water column may not be reliable indicators of nutrient availability for benthic primary producers (Vadeboncoeur and Power <span>2017</span>). Hot spots or hot moments of elevated nutrient concentrations in littoral regions favor green algae, leading to thick filamentous mats (also called filamentous algal blooms; Oleksy et al. <span>2021</span>; Vadeboncoeur et al. <span>2021</span>). These periphyton blooms appear to be an emergent response to changing environmental conditions in oligotrophic systems, yet the ultimate drivers behind their increased occurrence are debated and often obfuscated by confounding processes. For example, in Lake Baikal, increasing evidence has pointed to highly localized wastewater inputs leading to increased <i>Ulothrix</i> spp. and <i>Spirogyra</i> spp. abundance (Timoshkin et al. <span>2018</span>; Meyer et al. <span>2022</span>). Similarly, Lake Tahoe has experienced i","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10357","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71417584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Significant benthic fluxes of bioavailable dissolved amino acids to the ocean: Results from the East/Japan Sea","authors":"Hyekyung Park,&nbsp;Guebuem Kim,&nbsp;Sung-Han Kim,&nbsp;Jae Seong Lee","doi":"10.1002/lol2.10363","DOIUrl":"10.1002/lol2.10363","url":null,"abstract":"<p>We measured dissolved organic carbon (DOC) and total dissolved amino acid (TDAA) in seawater and sediment porewater of the Ulleung Basin in the East/Japan Sea. The DOC and TDAA concentrations were 1.1- and 1.4-fold higher in the euphotic zone, and 11- and 43-fold higher in sediment porewater, respectively, than those in the deep ocean. Consequently, in the deep ocean, TDAA and DOC input fluxes from porewater were 2- and 0.4-fold of those from the euphotic zone, respectively. This larger contribution of benthic flux for TDAA and its shorter residence time in the benthic boundary layer (BBL) (1.3 ± 0.9 yr) seem to result in steep TDAA increases in the BBL, although DOC concentrations remained relatively uniform throughout the entire deep ocean. AA-derived indices also show enhanced bioavailability of dissolved organic matter in the BBL. Benthic inputs seem to supply a significant amount of bioavailable TDAA to the deep ocean, fueling microbial activity.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71417555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Hydrology, rather than wildfire burn extent, determines post-fire organic and black carbon export from mountain rivers in central coastal California","authors":"Riley Barton,&nbsp;Christina M. Richardson,&nbsp;Evelyn Pae,&nbsp;Maya S. Montalvo,&nbsp;Michael Redmond,&nbsp;Margaret A. Zimmer,&nbsp;Sasha Wagner","doi":"10.1002/lol2.10360","DOIUrl":"10.1002/lol2.10360","url":null,"abstract":"<p>Coastal mountain rivers export disproportionately high quantities of terrestrial organic carbon (OC) directly to the ocean, feeding microbial communities and altering coastal ecology. To better predict and mitigate the effects of wildfires on aquatic ecosystems and resources, we must evaluate the relationships between fire, hydrology, and carbon export, particularly in the fire-prone western United States. This study examined the spatiotemporal export of particulate and dissolved OC (POC and DOC, respectively) and particulate and dissolved black carbon (PBC and DBC, respectively) from five coastal mountain watersheds following the 2020 CZU Lightning Complex Fires (California, USA). Despite high variability in watershed burn extent (20–98%), annual POC, DOC, PBC, and DBC concentrations remained relatively stable among the different watersheds. Instead, they correlated significantly with watershed discharge. Our findings indicate that hydrology, rather than burn extent, is a primary driver of post-fire carbon export in coastal mountain watersheds.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10360","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Acoustic twilight: A year-long seafloor monitoring unveils phenological patterns in the abyssal soundscape","authors":"Tzu-Hao Lin,&nbsp;Shinsuke Kawagucci","doi":"10.1002/lol2.10358","DOIUrl":"10.1002/lol2.10358","url":null,"abstract":"<p>Despite the perpetual darkness of the deep sea, contrasting the sunlit epipelagic waters, many deep-sea organisms exhibit rhythmic activities. To discern environmental cues that may serve as entrainment signals for deep-sea organisms, this study investigated the soundscape of the abyssal plain south of Minamitorishima Island. Our analysis revealed clear diel and seasonal patterns, primarily driven by evening fish choruses and marine mammal vocalizations. These evening choruses, discernible above the background noise, likely serve as a circadian time cue for organisms capable of perceiving them within the aphotic depths. In addition, the frequent detection of whistles and echolocation clicks suggests this region functions as a foraging ground for marine mammals. These acoustic cues might guide organisms with auditory capabilities toward habitats rich in sinking food debris and whale falls. By elucidating the ecological processes shaping abyssal soundscape dynamics, these findings open new directions for further exploration in deep-sea chronobiology.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10358","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Relative importance of bacterivorous mixotrophs in an estuary-coast environment","authors":"Qian Li,&nbsp;Kaiyi Dong,&nbsp;Ying Wang,&nbsp;Kyle F. Edwards","doi":"10.1002/lol2.10362","DOIUrl":"10.1002/lol2.10362","url":null,"abstract":"<p>Mixotrophic eukaryotes are important bacterivores in oligotrophic open oceans, but their significance as grazers in more nutrient-rich waters is less clear. Here, we investigated the bacterivory partition between mixotrophs and heterotrophs in a productive, estuary-influenced coastal region in the East China Sea. We found ubiquitous, actively feeding phytoplankton populations and taxa with mixotrophic potential by identifying ingestion of fluorescent prey surrogate and analyzing community 18S rRNA gene amplicons. Potential and active mixotrophs accounted for 10–63% of the total eukaryotic community and 17–69% of bacterivores observed, respectively, contributing 6–48% of estimated in situ bacterivory. The much higher mixotroph fitness outside of the turbid plume was potentially driven by increased light and decreased nutrient availability. Our results suggest that, although heterotrophs dominated overall in situ bacterivory, mixotrophs were abundant and important bacterivores in this low-latitude mesotrophic coastal region.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10362","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Direct contribution of invertebrate holobionts to methane release from coastal sediments","authors":"Tobia Politi,&nbsp;Mindaugas Zilius,&nbsp;Marco Bartoli,&nbsp;Ulisse Cardini,&nbsp;Ugo Marzocchi,&nbsp;Stefano Bonaglia","doi":"10.1002/lol2.10361","DOIUrl":"10.1002/lol2.10361","url":null,"abstract":"<p>Sediment macrofauna play a vital role in sustaining aquatic food webs and biogeochemical cycles. Previous research demonstrated that bioturbation indirectly affects methane (CH₄) dynamics through mobilization of porewater and alteration of microbial processes in the surrounding sediment. However, little is known on the direct contribution of macrofauna holobionts (the assemblage of invertebrate host and associated microbiome) to biogeochemical fluxes. Here, we investigated how 19 taxa of macrofauna holobionts, from different estuarine habitats spanning 40° to 63° latitude, directly contribute to CH₄ fluxes. Deep burrowing infauna and deposit feeders were responsible for the highest CH₄ production, whereas epifauna and filter feeders promoted oxidative CH₄ consumption. Among the different environmental parameters, salinity was inversely correlated with CH₄ production by macrofauna holobionts, with the process suppressed at high salinity (≥ 33). This study provides empirical evidence on how functional traits and environmental factors influence sediment invertebrates' contribution to CH₄ fluxes.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10361","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50165084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Sustained upward groundwater discharge through salt marsh tidal creeks","authors":"Lucheng Zhan,&nbsp;Pei Xin,&nbsp;Jiansheng Chen,&nbsp;Xiaogang Chen,&nbsp;Ling Li","doi":"10.1002/lol2.10359","DOIUrl":"10.1002/lol2.10359","url":null,"abstract":"<p>Salt marshes can export considerable nutrients and carbon to the ocean through submarine groundwater discharge (SGD). However, the complicated SGD processes in salt marshes remain poorly understood. Here, we first report the phenomenon of numerous highly saline artesian springs found in a salt marsh system of East China. Multiple methods including time-series thermal monitoring, isotope signatures, and high-resolution electrical resistivity tomography were combined to determine their origin and trajectory. Strong evidence suggests that these springs keep discharging even during high tide and represent a long-term re-distribution process of the ancient marine water trapped in the unconfined aquifer. This new pattern of spring-derived groundwater flow indicates a hidden SGD pathway and has significant implications for studies concerning SGD-derived fluxes in similar multi-aquifer-aquitard coastal systems.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10359","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50165289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"How low can you go? Widespread challenges in measuring low stream discharge and a path forward","authors":"Erin C. Seybold,&nbsp;Anna Bergstrom,&nbsp;C. Nathan Jones,&nbsp;Amy J. Burgin,&nbsp;Sam Zipper,&nbsp;Sarah E. Godsey,&nbsp;Walter K. Dodds,&nbsp;Margaret A. Zimmer,&nbsp;Margaret Shanafield,&nbsp;Thibault Datry,&nbsp;Raphael D. Mazor,&nbsp;Mathis L. Messager,&nbsp;Julian D. Olden,&nbsp;Adam Ward,&nbsp;Songyan Yu,&nbsp;Kendra E. Kaiser,&nbsp;Arial Shogren,&nbsp;Richard H. Walker","doi":"10.1002/lol2.10356","DOIUrl":"10.1002/lol2.10356","url":null,"abstract":"<p>Water resource management is facing mounting challenges associated with water scarcity, including interactive effects of a changing climate and increased water demand (Craig et al. <span>2017</span>). Climate change is increasing drought severity in many regions (Cook et al. <span>2020</span>), while demand for limited water supplies depletes water resources (de Graaf et al. <span>2019</span>). Combined, these stressors result in lower and more variable flows in streams and rivers (Zipper et al. <span>2021</span>), particularly in arid regions (Hammond et al. <span>2021</span>). Despite challenges posed by low-flow conditions, the majority of resources (e.g., time, funding) for monitoring streamflow have historically focused on high-water concerns, such as ensuring navigation and predicting floods (Vörösmarty et al. <span>2001</span>; Ruhi et al. <span>2018</span>), in larger, perennially-flowing systems (Krabbenhoft et al. <span>2022</span>).</p><p>Low-flow conditions (Mauger et al. <span>2021</span>), which we define as streams or rivers with little downstream surface water flow caused by small volumes or very low downstream velocities (i.e., slackwater), are increasingly prevalent and thus necessitate greater focus on quantification approaches. Streamflow is the underlying physical template structuring biotic and abiotic processes, biogeochemical cycling, and ecological communities in river systems; thus, inaccurate low-flow measurements can propagate to and hinder diverse analyses requiring accurate low-flow data, ranging from drought characterization (Hammond et al. <span>2022</span>), environmental flow allocations (Neachell and Petts <span>2019</span>), ecological function assessments (Leigh and Datry <span>2017</span>), species conservation plans (Lopez et al. <span>2022</span>), and streamflow forecasting (Forzieri et al. <span>2014</span>).</p><p>We posit that a lack of low-flow measurement techniques leaves monitoring networks ill-equipped to inform water management, which is a fundamental challenge that must be addressed to ensure sustainable water management in the future. Our objectives are to: (1) demonstrate the widespread challenges in low-flow measurement across an existing monitoring network in the United States, (2) discuss limitations of current streamflow measurement methods in low-flow conditions, (3) present a DST for choosing among existing measurement methods, and (4) highlight important methodological developments needed to improve low-flow measurement and monitoring. Such methodological progress is a prerequisite for understanding how low flows will respond to changing climate and human demands, thereby supporting management and policy actions seeking to avoid or minimize these impacts.</p><p>Point measurements of streamflow are essential for short- and long-term studies and monitoring, and can be made using many different methods (Turnipseed and Sauer <span>2010</span>). If conducted over a range of flow conditions","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10356","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50165299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Decoupled growth and grazing rates of diatoms and green algae drive increased phytoplankton productivity on HNLC sub-Antarctic plateaux","authors":"Andres Gutiérrez-Rodríguez,&nbsp;Mikel Latasa,&nbsp;Karl Safi,&nbsp;Matthew H. Pinkerton,&nbsp;Scott D. Nodder","doi":"10.1002/lol2.10355","DOIUrl":"10.1002/lol2.10355","url":null,"abstract":"<p>The combination of iron limitation and microzooplankton grazing controls phytoplankton productivity and taxonomic composition in high-nutrient low-chlorophyll (HNLC) regions. While increased productivity and diatom contribution triggered by iron enrichment support this view, direct measurements of underpinning group-specific growth and grazing rates are scarce for the Southern Ocean. To assess these rates, we conducted dilution experiments coupled to high-performance liquid chromatography and flow-cytometry in sub-Antarctic waters on and off Campbell Plateau, southeast of Aotearoa-New Zealand. Off the plateau, growth and grazing were closely balanced for all groups despite a two-fold difference between slow- and fast-growing groups. On Campbell Plateau, where HNLC conditions were alleviated, the balance was disrupted, mainly by the preferential growth of diatoms and green algae, which was stimulated beyond grazing. Our results expand the recognized ability of diatoms to escape grazing control to picoplanktonic green algae that also avoid grazing and contribute significantly to phytoplankton productivity and biomass accumulation.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://aslopubs.onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10355","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71416917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Phytoplankton as indicators of global warming?","authors":"James E. Cloern,&nbsp;Tara S. Schraga,&nbsp;Erica Nejad,&nbsp;Taylor Eddy","doi":"10.1002/lol2.10354","DOIUrl":"10.1002/lol2.10354","url":null,"abstract":"<p>Terrestrial plants are sensitive indicators of global warming because their annual cycles of growth and senescence are changing as warming proceeds. Single celled algae are distinct life forms capable of population bursts in any season, so there is uncertainty about phytoplankton phenology as a comparable indicator of global warming. We analyzed 4+ decades of monthly chlorophyll <i>a</i> measurements at two sites in San Francisco Bay and found abrupt shifts during summer months leading to a 48-day advance in the annual pattern of chlorophyll-a accumulation at one site and a 36-day delay at the other. These large phenological changes were not associated with changing temperature, but they were associated with changes in top–down control by bivalve filter feeders as biological communities were restructured by (1) introduction of a non-native clam, and (2) a shift in atmospheric forcing of the NE Pacific. This study illustrates that changes in phytoplankton phenology are not necessarily responses to or indicators of global warming. However, they can be indicators of human disturbances and natural climate oscillations having effects large enough to mask the effect of climate warming.</p>","PeriodicalId":18128,"journal":{"name":"Limnology and Oceanography Letters","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lol2.10354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48966806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}