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Effect of increased CO2 on calcium homeostasis and signaling in a marine diatom Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-22 Zhen Zhang, Jie Ma, Fengyuan Chen, Shanshan Chen, Ke Pan, Hongbin Liu
Ocean acidification influences photosynthesis, respiration, and metabolism in marine diatoms, leading to changes in diatom growth performance and shifts in phytoplankton communities. Previous studies have demonstrated that increases in seawater CO2 concentrations affect the uptake of trace metals such as iron, zinc, copper, and cobalt by marine diatoms. However, the influence of increased CO2 on calcium
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Temporal evolution of plankton and particles distribution across a mesoscale front during the spring bloom Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-22 Thelma Panaïotis, Antoine Poteau, Émilie Diamond Riquier, Camille Catalano, Lucas Courchet, Solène Motreuil, Laurent Coppola, Marc Picheral, Jean‐Olivier Irisson
The effect of mesoscale features on the distribution of planktonic organisms are well documented. Yet, the interaction between these spatial features and the temporal scale, which can result in sudden increases of the planktonic biomass, is less known and not described at high resolution. A permanent mesoscale front in the Ligurian Sea (north‐western Mediterranean) was repeatedly sampled between January
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Elucidating carbon sources of hydrothermal vent animals using natural 14C abundances and habitat water temperature Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-20 Hidetaka Nomaki, Chong Chen, Nanako O. Ogawa, Yosuke Miyairi, Naohiko Ohkouchi, Akiko Makabe, Shinsuke Kawagucci, Yusuke Yokoyama, Motohiro Shimanaga
Deep‐sea hydrothermal vents host exceptional ecosystems with lush animal communities primarily relying on organic matter (OM) produced by chemoautotrophic microbes. Though energy sources and food webs at vents have been extensively studied, the exact carbon sources of chemosynthetic primary production, such as methane (CH4) and carbon dioxide (CO2) in the vent fluid or bottom water, have not been elucidated
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Using oxygen isotopes in phosphate to assess biological phosphorus cycling in a small and shallow freshwater lake system Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-16 Rong Yi, Takuya Ishida, Peixue Song, Tohru Ikeya, Noboru Okuda, Adina Paytan, Syuhei Ban
Reducing excess phosphorus (P) loads that cause eutrophication in aquatic systems is essential for meeting water quality standards. The oxygen isotopic composition of phosphate (δ18Op) is a powerful tool for tracking P sources and cycling in diverse natural ecosystems. Here, we use δ18Op distribution in a small freshwater body (a lagoon–lake system) with high biological activity. We report δ18Op values
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Contrasting responses of different mixotrophic protists to light and nutrient availability Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-12 Sebastiaan Koppelle, Marina Ivanković, Mia M. Bengtsson, Christian Preiler, Jef Huisman, Corina P. D. Brussaard, Julia C. Engelmann, Robert Ptáčník, Susanne Wilken
Mixotrophic protists are important members of aquatic microbial food webs where they can dominate bacterivory and strongly impact energy and nutrient flow. While light and nutrient availability are known to impact grazing rates by mixotrophs in laboratory studies, little is known about how changes in resource availability affect mixotrophic organisms in natural communities. Here, we performed a short‐term
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Significant dark inorganic carbon fixation in the euphotic zone of an oligotrophic sea Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-11 Tom Reich, Natalia Belkin, Guy Sisma‐Ventura, Ilana Berman‐Frank, Eyal Rahav
Estimates of primary productivity have traditionally disregarded dark inorganic carbon fixation by marine microorganisms. Currently, only limited data are available from different systems on this potentially ecologically important process. We present monthly dark inorganic carbon fixation and photosynthetic rates from the euphotic layer of the northern Gulf of Aqaba collected over a decade between
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The roles of seagrass litter decomposition in determining blue carbon sink capacity Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-08 Zhaxi Suonan, Seung Hyeon Kim, Shidong Yue, Eunhye Jo, Fei Zhang, Hyegwang Kim, Le‐Zheng Qin, Jaeho Cha, Yi Zhou, Kun‐Seop Lee
Seagrass litter is a crucial autochthonous source of sediment organic carbon (Corg) that contributes to Corg storage in coastal ecosystems. However, our understanding of seagrass litter decomposition effects on sediment Corg sequestration and the factors influencing the capacity for autochthonous carbon sequestration remains limited. We investigated Zostera marina litter decomposition dynamics in eelgrass
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Sedimentary DNA reveals phytoplankton diversity loss in a deep maar lake during the Anthropocene Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-06 Dongna Yan, Maïlys Picard, Yongming Han, Zhisheng An, Dewen Lei, Xue Zhao, Luyuan Zhang, Eric Capo
Anthropogenic‐driven environmental change, including current climate warming, has influenced lake ecosystems globally during the Anthropocene. Phytoplankton are important indicators of environmental changes in lakes and play a fundamental role in maintaining the functioning and stability of these ecosystems. However, the extent to which lake phytoplankton were affected by anthropogenic or climatic
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Deep learning of estuary salinity dynamics is physically accurate at a fraction of hydrodynamic model computational cost Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-05 Galen Gorski, Salme Cook, Amelia Snyder, Alison P. Appling, Theodore Thompson, Jared D. Smith, John C. Warner, Simon N. Topp
Salinity dynamics in the Delaware Bay estuary are a critical water quality concern as elevated salinity can damage infrastructure and threaten drinking water supplies. Current state‐of‐the‐art modeling approaches use hydrodynamic models, which can produce accurate results but are limited by significant computational costs. We developed a machine learning (ML) model to predict the 250 mg L−1 Cl− isochlor
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Evolutionary adaptation to steady or changing environments affects competitive outcomes in marine phytoplankton Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-05 Isabell Hochfeld, Jana Hinners
The interplay of phytoplankton competition and adaptation affects how phytoplankton, and ultimately marine ecosystems, respond to global warming. However, current ecosystem models that are run under global warming scenarios do not include both processes simultaneously. To fill this gap, we developed an innovative ecosystem model for the Baltic Sea that simulates competition between three phytoplankton
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Strong and efficient summertime carbon export driven by aggregation processes in a subarctic coastal ecosystem Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-03 Stephanie H. O'Daly, Gwenn M. M. Hennon, Thomas B. Kelly, Suzanne L. Strom, Andrew M. P. McDonnell
Sinking marine particles, one pathway of the biological carbon pump, transports carbon to the deep ocean from the surface, thereby modulating atmospheric carbon dioxide and supplying benthic food. Few in situ measurements exist of sinking particles in the Northern Gulf of Alaska; therefore, regional carbon flux prediction is poorly constrained. In this study, we (1) characterize the strength and efficiency
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Promoting effects of aluminum addition on chlorophyll biosynthesis and growth of two cultured iron‐limited marine diatoms Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-04-02 Linbin Zhou, Fengjie Liu, Eric P. Achterberg, Anja Engel, Peter G.C. Campbell, Claude Fortin, Liangmin Huang, Yehui Tan
Aluminum (Al) may play a role in the ocean's capacity for absorbing atmospheric CO2 via influencing carbon fixation, export, and sequestration. Aluminum fertilization, especially in iron (Fe)‐limited high‐nutrient, low‐chlorophyll ocean regions, has been proposed as a potential CO2 removal strategy to mitigate global warming. However, how Al addition would influence the solubility and bioavailability
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Decadal changes in surface CO2 concentrations and CO2 fluxes in a mountain lake Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-29 Ulrike Obertegger, Stefano Corradini, Leonardo Cerasino, Linda C. Weiss
Climate warming impacts biogeochemical cycles in lakes. However, the factors controlling CO2 dynamics in mountain lakes over multidecadal scales are poorly understood. Here, we capitalized on long‐term monthly data (1995–2022) of oligotrophic mountain Lake Tovel and calculated surface CO2 concentrations and flux by applying geochemical relationships and the thin boundary layer approach. Advanced time‐series
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Adjusting metabolic rates and critical oxygen tension in planktonic copepods under increasing hypoxia in highly productive coastal upwelling zones Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-27 Leissing Frederick, Mauricio A. Urbina, Erika Jorquera, Ruben Escribano
Ongoing ocean deoxygenation is threatening marine organisms globally. In eastern boundary upwelling systems, planktonic copepods dominate the epipelagic zooplankton, being crucial in the marine food web. Yet, they must cope with severe hypoxia caused by shoaling of the oxygen minimum zone. Based on laboratory experiments during 2021, we found differential responses in the metabolic rate (MR) and critical
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Multiple biotic interactions establish phytoplankton community structure across environmental gradients Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-26 Stephanie Dutkiewicz, Christopher L. Follett, Michael J. Follows, Fernanda Henderikx‐Freitas, Francois Ribalet, Mary R. Gradoville, Sacha N. Coesel, Hanna Farnelid, Zoe V. Finkel, Andrew J. Irwin, Oliver Jahn, David M. Karl, Jann Paul Mattern, Angelicque E. White, Jonathan P. Zehr, E. Virginia Armbrust
The combination of taxa and size classes of phytoplankton that coexist at any location affects the structure of the marine food web and the magnitude of carbon fluxes to the deep ocean. But what controls the patterns of this community structure across environmental gradients remains unclear. Here, we focus on the North East Pacific Transition Zone, a ~ 10° region of latitude straddling warm, nutrient‐poor
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Greenhouse gas emissions (CO2–CH4–N2O) along a large reservoir‐downstream river continuum: The role of seasonal hypoxia Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-25 Zetao Wu, Dan Yu, Qibiao Yu, Qian Liu, Mingzhen Zhang, Randy A. Dahlgren, Jack J. Middelburg, Liyin Qu, Quanlong Li, Weidong Guo, Nengwang Chen
Recent studies suggest that hypolimnetic respiration may be responsible for greenhouse gas (GHG) emissions from deep reservoirs. Currently, quantitative evaluation of aerobic vs. anaerobic processes and priming (enhanced processing of organic matter due to the addition of labile carbon) in regulating GHG production and emissions across the reservoir‐downstream continuum remains largely unknown. High‐resolution
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Functions of extracellular polymeric substances in partitioning suspended and sinking particles in the upper oceans of two open ocean systems Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-25 Yosuke Yamada, Akiko Ebihara, Hideki Fukuda, Shigeyoshi Otosaka, Satoshi Mitarai, Toshi Nagata
Marine particle dynamics and carbon export, involving extracellular polymeric substances (EPS) like transparent exopolymer particles (TEP) and Coomassie Brilliant Blue‐stained particles (CSP), are poorly understood. Although TEP adhesive properties may enhance carbon export by facilitating aggregate formation, their low density can also enhance particle suspension. Factors influencing TEP regulation
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Combined effect of warming, nutrients, and species pool size on the seasonal variability of phytoplankton composition: A modeling perspective Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-20 Károly Pálffy, Evangelia Smeti
The anticipated long‐term rise in temperature can have numerous effects on freshwater phytoplankton, however, there is a great deal of uncertainty about how biogeochemical processes modify community functioning under a warming climate. Previous works regarding a large shallow lake and a mesocosm study showed a positive relationship between the temporal variability of phytoplankton composition and mean
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Seasonal patterns of phytoplankton photoacclimation in a dimictic oligotrophic lake over 5 yr: Implications for chlorophyll as an estimate of biomass Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-16 Scott Girdner, Joshua Sprague
Chlorophyll a is commonly used as a surrogate for algal biomass in lakes and oceans even though phytoplankton can readily adjust intracellular chlorophyll concentration to changes in the environment through a cellular process termed photoacclimation. Marine studies have documented fluctuations in cellular chlorophyll to year‐round changes in light intensity and nutrients using the chlorophyll : carbon
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Fluorescently labeled prey surrogates in combination with fluorescence‐activated cell sorting successfully discriminate actively feeding mixotrophs in a lake water sample Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-14 Javier Florenza, Anna‐Maria Divne, Stefan Bertilsson
Mixotrophic protists are capable of acting both as primary producers and primary consumers at the base of the aquatic food web, thus constituting key organisms in ecosystems where they are abundant. However, their identity, abundance, ecological dynamics, and biogeochemical impact in aquatic ecosystems remain understudied in comparison to classically demarcated autotrophs or heterotrophs. In this study
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Detecting climate‐related shifts in lakes: A review of the use of satellite Earth Observation Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-12 Elisa Calamita, J. Jelle Lever, Clement Albergel, R. Iestyn Woolway, Daniel Odermatt
Climate change exerts a profound impact on lakes, eliciting responses that range from gradual to abrupt transitions. When reaching critical tipping points, the established lake dynamics stand to undergo substantial modifications, setting off a chain reaction that reverberates through the entire ecosystem. This lake shift ripples into related ecosystem services and even influences the well‐being of
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Changes in isotope fractionation during nitrate assimilation by marine eukaryotic and prokaryotic algae under different pH and CO2 conditions Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-11 Yawen Chen, Jin‐Yu Terence Yang, Jin‐Ming Tang, Haizheng Hong, Shuh‐Ji Kao, Minhan Dai, Dalin Shi
The impact of environmental factors on nitrogen (N) and oxygen (O) isotope effects during algal nitrate assimilation causes uncertainty in the field application of sedimentary N isotope records and nitrate isotopes to understand the marine nitrogen cycle. Ocean acidification is predicted to change nitrogen cycling including nitrate assimilation, but how N and O isotope effects during algal nitrate
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Vertical trophic structure and niche partitioning of gelatinous predators in a pelagic food web: Insights from stable isotopes of siphonophores Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-09 Elizabeth D. Hetherington, Hilary G. Close, Steven H. D. Haddock, Alejandro Damian‐Serrano, Casey W. Dunn, Natalie J. Wallsgrove, Shannon C. Doherty, C. Anela Choy
Gelatinous zooplankton are increasingly recognized as key components of pelagic ecosystems, and there have been many recent insights into their ecology and roles in food webs. To examine the trophic ecology of siphonophores (Cnidaria, Hydrozoa), we used bulk (carbon and nitrogen) and compound‐specific (nitrogen) isotope analysis of individual amino acids (CSIA‐AA). We collected samples of 15 siphonophore
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Warm‐adapted sponges resist thermal stress by reallocating carbon and nitrogen resources from cell turnover to somatic growth Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-06 Maggioni Federica, Raimbault Patrick, Chateau Olivier, Pujo‐Pay Mireille, Letourneur Yves, Rodolfo‐Metalpa Riccardo
Ocean warming will affect the functioning of coral reef ecosystems with unknown cascading effects. Any perturbation in the ability of sponges to recycle the dissolved organic matter released by primary producers and make it available to higher trophic levels, might have unknown consequences for the reef trophic chain. Biogeochemical processes were measured in the sponge Rhabdastrella globostellata
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Internal wave resonance, surges, and strong nonlinear damping differentiated in two elongated lakes with the aid of an original Green's function Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-06 James P. Long, John D. Halfman, Nathan Hawley
While the analogy between the wind‐pumped internal seiche in a lake and the driven damped‐harmonic oscillator is recognized, use of a damped‐oscillator model to understand internal‐wave behavior is seldom attempted due to the irregular waveforms arising from variable winds, and to the presence of nonlinear waves like surges. Using a new variable‐frequency Green's function derived for a damped oscillator
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Grazing strategies determine the size composition of phytoplankton in eutrophic lakes Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-03-02 Sze‐Wing To, Esteban Acevedo‐Trejos, Subhendu Chakraborty, Francesco Pomati, Agostino Merico
Although the general impacts of zooplankton grazing on phytoplankton communities are clear, we know comparatively less about how specific grazing strategies interact with environmental conditions to shape the size structure of phytoplankton communities. Here, we present a new data‐driven, size‐based model that describes changes in the size composition of lake phytoplankton under various environmental
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Isotope effects of O2 consumption in a deep lake as means for understanding partitioning of O2 demand among microorganisms, particles, and sediment Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-29 Israela Musan, Hezi Gildor, Thomas Gonsiorczyk, Hans‐Peter Grossart, Boaz Luz
The isotopic ratio 18O/16O of dissolved O2 in aquatic systems is affected by the preferential biological uptake of 16O (ε). Studies over the past six decades reveal that during incubation experiments, the isotopic effect of microorganism respiration (εorganism) varies in the range of −18‰ to −22‰. In contrast, natural variations in the deep‐ocean O2 concentration and δ18O levels show a considerably
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Zooplankton in northern lakes show taxon‐specific responses in fatty acids across climate‐productivity and ecosystem size gradients Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-29 Fernando Chaguaceda, Danny C. P. Lau, Willem Goedkoop, Mariem Fadhlaoui, Isabelle Lavoie, Tobias Vrede
Northern lakes are facing rapid environmental alterations—including warming, browning, and/or changes in nutrient concentrations—driven by climate change. These environmental changes can have profound impacts on the synthesis and trophic transfer of polyunsaturated fatty acids (PUFA), which are important biochemical molecules for consumer growth and reproduction. Zooplankton are a key trophic link
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Switches between nitrogen limitation and nitrogen–phosphorus co‐limitation in the subtropical North Atlantic Ocean Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-27 Zhongwei Yuan, Eric P. Achterberg, Anja Engel, Minhan Dai, Thomas J. Browning
Concentrations of bioavailable inorganic nitrogen (N) and phosphorus (P) are simultaneously depleted in the (sub)tropical North Atlantic Ocean, but it remains unclear if phytoplankton growth rates are N limited or N–P co‐limited. Here we present findings from three bottle‐scale experiments using a four‐by‐four matrix of low‐level N and P additions, conducted at one site in the subtropical North Atlantic
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Salinity as a key factor affecting viral activity and life strategies in alpine lakes Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-26 Lin Zang, Yongqin Liu, Nianzhi Jiao, Kevin Xu Zhong, Xuanying Song, Yunlan Yang, Lanlan Cai, Keshao Liu, Guannan Mao, Mukan Ji, Rui Zhang
Viruses are major players in the biosphere, yet little is known about their dynamics and life strategies in alpine lakes, particularly those on the Tibetan Plateau. We investigated microbial abundance, viral dynamics, and viral life strategies in 10 high‐altitude Tibetan lakes and found that they harbor high levels of active viruses. Salinity was identified as a crucial factor influencing viral abundance
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Omnivorous summer feeding by juvenile Antarctic krill in coastal waters Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-24 John A. Conroy, Deborah K. Steinberg, Schuyler C. Nardelli, Oscar Schofield
The Antarctic krill Euphausia superba is often considered an herbivore but is notable for its trophic flexibility, which includes feeding on protistan and metazoan zooplankton. Characterizing krill trophic position (TP) is important for understanding carbon and energy flow from phytoplankton to vertebrate predators and to the deep ocean, especially as plankton composition is sensitive to changing climate
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Variability in the phytoplankton response to upwelling across an iron limitation mosaic within the California current system Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-24 YuanYu Lin, Olivia Torano, Logan Whitehouse, Emily Pierce, Claire P. Till, Matthew Hurst, Robert Freiberger, Travis Mellett, Maria T. Maldonado, Jian Guo, Mariam Sutton, David Zeitz, Adrian Marchetti
Coastal upwelling currents such as the California Current System (CCS) comprise some of the most productive biological systems on the planet. Diatoms dominate these upwelling events in part due to their rapid response to nutrient entrainment. In this region, they may also be limited by the micronutrient iron (Fe), an important trace element primarily involved in photosynthesis and nitrogen assimilation
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River network‐scale drying impacts the spatiotemporal dynamics of greenhouse gas fluxes Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-23 Teresa Silverthorn, Naiara López‐Rojo, Romain Sarremejane, Arnaud Foulquier, Vincent Chanudet, Abdelkader Azougui, Rubén del Campo, Gabriel Singer, Thibault Datry
Rivers significantly contribute to global biogeochemical cycles; however, we have a limited understanding of how drying may influence these cycles. Drying fragments river networks, thereby influencing important ecosystem functions such as the processing of carbon and nitrogen, and associated fluxes of greenhouse gases (GHGs) both locally, and at the river network scale. Our objective was to assess
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Stimulation of small phytoplankton drives enhanced sinking particle formation in a subtropical ocean eddy Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-23 Haoran Liu, Thomas J. Browning, Edward A. Laws, Yibin Huang, Lei Wang, Yiwei Shang, Xiaogang Xing, Kuanbo Zhou, Zong‐Pei Jiang, Xin Liu, Bangqin Huang, Minhan Dai
Nutrient transfer into the sunlit surface ocean by cyclonic eddies is potentially crucial for sustaining primary productivity in the stratified subtropical gyres. However, the nature of productivity enhancements, including the flow of matter to higher trophic levels and its impact on carbon fluxes, remain poorly resolved. Here, we report a detailed assessment of the biogeochemical response to a cyclonic
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Nonlinear responses in interannual variability of lake ice to climate change Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-21 David C. Richardson, Alessandro Filazzola, R. Iestyn Woolway, M. Arshad Imrit, Damien Bouffard, Gesa A. Weyhenmeyer, John Magnuson, Sapna Sharma
Climate change is contributing to rapid changes in lake ice cover across the Northern Hemisphere, thereby impacting local communities and ecosystems. Using lake ice cover time-series spanning over 87 yr for 43 lakes across the Northern Hemisphere, we found that the interannual variability in ice duration, measured as standard deviation, significantly increased in only half of our studied lakes. We
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Blue carbon additionality: New insights from the radiocarbon content of saltmarsh soils and their respired CO2 Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-22 Alex Houston, Mark H Garnett, William E. N. Austin
International policy frameworks recognize the net drawdown and storage of atmospheric greenhouse gases through management interventions on blue carbon ecosystems (saltmarshes, mangroves, seagrasses) as potential emissions offset strategies. However, key questions remain around the “additionality” of the carbon sequestered by these ecosystems, and whether some fraction of the organic carbon (OC) that
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Light-use efficiency for coral reef communities and benthic functional types Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-21 Eric J. Hochberg, Chiara Pisapia, Robert C. Carpenter, Siarah Hall
Coral reef metabolism is dominated by benthic photoautotrophic communities that comprise varying combinations of algae, coral, and sand. Rates of daily gross primary production (GPP) for these benthic functional types (BFTs) are remarkably consistent across biogeographical regions, supporting the idea that reefs exhibit modal metabolism. Most variability in reported rates likely arises from differences
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Detritivore physiology and growth benefit from algal presence during microbial leaf colonization Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-16 Alexander Feckler, Sebastian Pietz, Sara Gonçalves, Verena Gerstle, Ute Risse-Buhl, Mirco Bundschuh
In headwater streams, riparian leaf litter is the primary food source for detritivores. While it is well known that aquatic fungi improve the nutritious quality of leaves, our understanding on whether and how benthic algae influence this process remains limited. Here, we hypothesized that the interplay between algae and fungi, termed “algal priming”, further enhances food quality. In a 40-d microcosm
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Environmental driving forces and phytoplankton diversity across the Ross Sea region during a summer–autumn transition Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-16 Antonia Cristi, Cliff S. Law, Matt Pinkerton, Adriana Lopes dos Santos, Karl Safi, Andres Gutiérrez-Rodríguez
The Ross Sea is a highly productive system characterized by a seasonal succession of phytoplankton groups. However, most of the current understanding is based on observations on the continental shelf in spring and summer at relatively coarse taxonomic resolution. Here, we characterize community composition (class to species) using V4-18S rRNA gene metabarcoding on transects to and across the Ross Sea
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Contribution of gas concentration and transfer velocity to CO2 flux variability in northern lakes Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-15 David Rudberg, Jonathan Schenk, Gustav Pajala, Henrique Sawakuchi, Anna Sieczko, Ingrid Sundgren, Nguyen Thanh Duc, Jan Karlsson, Sally MacIntyre, John Melack, David Bastviken
The CO2 flux (FCO2$$ {F}_{{\mathrm{CO}}_2} $$) from lakes to the atmosphere is a large component of the global carbon cycle and depends on the air–water CO2 concentration gradient (ΔCO2) and the gas transfer velocity (k). Both ΔCO2 and k can vary on multiple timescales and understanding their contributions to FCO2$$ {F}_{{\mathrm{CO}}_2} $$ is important for explaining variability in fluxes and developing
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Oxygen dynamics in a deep-silled fjord: Tight coupling to the open shelf Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-08 Charles G. Hannah, Sophia C. Johannessen, Cynthia A. Wright, Stephen J. Page
Oxygen is declining globally in subsurface seawater. Fjords are particularly susceptible to hypoxia, because entrance sills restrict water circulation. We studied the oxygen dynamics of the Kitimat Fjord System on the west coast of Canada, using 3 yr of data from moored sensors and water column profiles. Subsurface oxygen within the fjord system is principally controlled by the connection to Hecate
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A multiple baseline approach for marine heatwaves Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-07 Luis Giménez, Maarten Boersma, Karen H. Wiltshire
Marine heatwaves and other extreme temperature events can drive biological responses, including mass mortality. However, their effects depend on how they are experienced by biological systems (including human societies). We applied two different baselines (fixed and shifting) to a time series of North Sea water temperature to explore how slowly vs. quickly adapting systems would experience extreme
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Watershed, lake, and food web factors influence diazotrophic cyanobacteria in mountain lakes Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-03 Lara S. Jansen, Daniel Sobota, Yangdong Pan, Angela L. Strecker
Cyanobacterial blooms can occur in freshwater ecosystems largely isolated from development and not experiencing extensive cultural eutrophication. For example, remote mountain lakes can experience intense blooms of diazotrophic (nitrogen-fixing) cyanobacteria caused by factors acting at different spatial and temporal scales. In this study, we examined how cross-scale interactions among watershed, lake
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Water aging and the quality of organic carbon sources drive niche partitioning of the active bathypelagic prokaryotic microbiome Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-03 Marta Sebastián, Pablo Sánchez, Guillem Salazar, Xosé A. Álvarez-Salgado, Isabel Reche, Xosé Anxelu G. Morán, Maria Montserrat Sala, Carlos M. Duarte, Silvia G. Acinas, Josep M. Gasol
Due to the scarcity of organic matter (OM) sources in the bathypelagic (1000–4000 m depth), prokaryotic metabolism is believed to be concentrated on particles originating from the surface. However, the structure of active bathypelagic prokaryotic communities and how it changes across environmental gradients remains unexplored. Using a combination of 16S rRNA gene and transcripts sequencing, metagenomics
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Seasonality strongly affects short-term C-storage in coastal macrophyte communities Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-02-01 Roel Lammerant, Eva Karin Rohlfer, Alf Norkko, Camilla Gustafsson
Ecosystem functions provided by aquatic plants are context dependent and mediated by environmental conditions and plant growth form. This impedes our ability to predict the carbon (i.e., C) sink potential of multispecies coastal meadows characterized by marked seasonal succession of environmental conditions, causing a clear need to explore the distinct patterns of both C capture and release associated
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Denitrification, anammox, and DNRA in oligotrophic continental shelf sediments Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-01-25 Henry L. S. Cheung, Jenny R. Hillman, Conrad A. Pilditch, Candida Savage, Isaac R. Santos, Ronnie N. Glud, Francisco J. A. Nascimento, Simon F. Thrush, Stefano Bonaglia
Continental shelf sediments are considered hotspots for nitrogen (N) removal. While most investigations have quantified denitrification in shelves receiving large amounts of anthropogenic nutrient supply, we lack insight into the key drivers of N removal on oligotrophic shelves. Here, we measured rates of N removal through denitrification and anammox by the revised-isotope pairing technique (r-IPT)
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Effects of year-long exposure to elevated pCO2 on the metabolism of back reef and fore reef communities Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-01-24 Peter J. Edmunds, Steve S. Doo, Robert C. Carpenter
The implications of ocean acidification are acute for calcifying organisms, notably tropical reef corals, for which accretion generally is depressed and dissolution enhanced at reduced seawater pH. We describe year-long experiments in which back reef and fore reef (17-m depth) communities from Moorea, French Polynesia, were incubated outdoors under pCO2 regimes reflecting endpoints of representative
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Organic matter, eutrophication, and increased mass accumulation rates in the Anthropocene are the main drivers of mercury concentrations and historical enrichment in Canadian lake sediments Limnol. Oceanogr. (IF 4.5) Pub Date : 2024-01-24 Marieke Beaulieu, Marc Amyot, Katherine Griffiths, Ashu Dastoor, Adam Jeziorski, Irene Gregory-Eaves
Mercury (Hg) contamination in the environment is a persistent issue as emissions from industry are ongoing and legacy cycling is prolonged. To quantify total mercury (total Hg) and methylmercury (MeHg) concentrations in lake sediments across a wide suite of temperate to subarctic lakes, measurements and modeling were conducted for 320 sites across Canada. Total Hg varied from 7 to 567 ng g−1 dry sediment