Article
Environmental Sciences
David Levesque, Michel Lebeuf, Domynick Maltais, Caroline Anderson, Michel Starr
Summary: The role of organic matter inputs has been recognized as an important factor in understanding the issue of hypoxia, which is a worldwide expanding problem in estuaries and shelves due to eutrophication. This study investigated the transport and exchange of particulate and dissolved organic matter in the St. Lawrence Estuary, revealing the significance of organic matter in hypoxia.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Ecology
Anne-Sophie Fabris, Pierre Larouche, Jean-Carlos Montero-Serrano
Summary: This study characterized the particle size distribution of suspended particulate matter in the St. Lawrence Estuary, revealing significant variations between different seasons and regions. Coarse particles were found to play a key role in sedimentation in the Lower Estuary, with higher particle density during ice-covered conditions. The mineralogical and elemental composition of suspended detrital particles showed similarity throughout the estuary, indicating common sources.
REGIONAL STUDIES IN MARINE SCIENCE
(2021)
Article
Engineering, Civil
Fenfang Wang, Kai Xiao, Isaac R. Santos, Zeyang Lu, Joseph Tamborski, Yao Wang, Ruifeng Yan, Nengwang Chen
Summary: This study investigated a tidal creek in China with a significant mangrove-salt marsh gradient, revealing differences in nitrogen and phosphorus cycling between mangrove and salt marsh that have significant implications for coastal waters. Denitrification dominated nitrogen removal in both mangrove and salt marsh, with salt marsh having less capacity for ammonium production. The study highlighted the impact of mangrove-salt marsh ecotone on coastal eutrophication potential by modifying nutrient stoichiometry and porewater exchange.
JOURNAL OF HYDROLOGY
(2022)
Article
Environmental Sciences
Rob Williams, Robert C. Lacy, Erin Ashe, Ailsa Hall, Stephane Plourde, Ian H. McQuinn, Veronique Lesage
Summary: Despite management interventions, the endangered St. Lawrence Estuary beluga population has not recovered, with predicted effects of climate change being a significant driver. Aggressive mitigation of proximate threats is necessary to enhance population resilience.
MARINE POLLUTION BULLETIN
(2021)
Article
Environmental Sciences
Duc Huy Dang, Wei Wang, Gesche Winkler, Anique Chatzis
Summary: The study finds significant correlations between the accumulation of rare earth elements (REEs) and other elements in plankton, suggesting non-selective uptake of REEs into plankton. Furthermore, there are differences in the distribution of REEs between freshwater and marine environments, with freshwater plankton exhibiting enrichment of middle rare earth elements (MREEs) and marine plankton showing enrichment of light rare earth elements (LREEs). This study emphasizes the significant enrichment of REEs in freshwater primary producers and their accumulation pathway similar to other inorganic elements.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Review
Environmental Sciences
Columba Martinez-Espinosa, Sabine Sauvage, Ahmad Al Bitar, Pamela A. Green, Charles J. Vorosmarty, Jose Miguel Sanchez-Perez
Summary: Research on the nitrogen cycle has shown that the production of reactive nitrogen globally exceeds the natural ecosystem's capacity for removal through denitrification, leading to negative impacts on the environment and human health. Wetland ecosystems play a significant role in denitrification, but uncertainties remain in quantifying the denitrification capacity of natural wetlands globally.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Environmental
Duc Huy Dang, Lan Ma, Quang Khai Ha, Wei Wang
Summary: Differentiating anthropogenic signatures from natural processes is crucial for environmental regulation. This study investigates the variations in chemical concentrations and trace elements in different water masses along the St. Lawrence River-Estuary continuum, and analyzes the impact of wastewater discharge and the sources of minor elements.
Article
Computer Science, Interdisciplinary Applications
Columba Martinez-Espinosa, Sabine Sauvage, Ahmad Al Bitar, Jose Miguel Sanchez Perez
Summary: The Wetland Soils Denitrification Model (WSDM), developed for natural wetlands, incorporates satellite-based Earth Observations to measure soil moisture and temperature, and distinguishes different wetland typologies. This model is important in understanding nitrification/denitrification dynamics at various scales. The study found that climate anomalies intensify denitrification events, with flooded forests showing the highest denitrification rates.
ENVIRONMENTAL MODELLING & SOFTWARE
(2022)
Article
Environmental Sciences
Jean-Christophe Picard, Gabriel Munoz, Sung Vo Duy, Sebastien Sauve
Summary: This study reports the concentrations of 90 CECs in the St. Lawrence Estuary and Gulf, including pesticides, pharmaceuticals, steroid hormones, and PFASs. Most of the contamination originates from upstream riverine sources, and the vertical transfer to the deep water layer is limited.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Chemistry, Multidisciplinary
Duc Huy Dang, Dario Omanovic, Alfonso Mucci, Wei Wang, Allison Sikma, Anique Chatzis
Summary: This study reports the platinum concentrations in the Estuary and Gulf of St. Lawrence (EGSL) during winter, and compares its behavior with that of cadmium. The results show that the dissolved platinum concentrations in the EGSL during winter are higher than in most river systems and marine endmembers, likely due to the geology of the drainage basins and atmospheric deposition. In addition, the mixing behavior of platinum and cadmium in the surface waters of the EGSL during winter is near-conservative, while the concentrations increase in bottom waters, possibly due to various factors. This highlights the importance of considering winter and oxygen-depleted conditions in future platinum budget calculations.
Article
Chemistry, Multidisciplinary
Justine Dore, Julien Thebault, Virginie Roy, Fabien Dewilde, Gwenaelle Chaillou
Summary: This study introduces a new method based on chemochronology to accurately date Mactromeris polynyma shells by analyzing Ba/Ca and Sr/Ca ratio profiles. The method can precisely locate annual growth lines and study variations in growth rates, making it an alternative to traditional sclerochronology techniques for difficult-to-age species.
Article
Oceanography
Y. Li, H. Xie, M. G. Scarratt, E. Damm, P. S. Galbraith, N. Lambert, L. Geng, D. W. R. Wallace
Summary: This study presents the first data set of dissolved methane in the water column of the Estuary and Gulf of St. Lawrence. The Estuary and Gulf of St. Lawrence contribute a small proportion to global estuarine methane emissions, and complex physical-biogeochemical interactions control methane cycling and isotopic composition in this estuarine system.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Environmental Sciences
Alexandre Bernier-Graveline, Veronique Lesage, Jory Cabrol, Stephane Lair, Robert Michaud, Maikel Rosabal, Jonathan Verreault
Summary: Studies on the endangered St. Lawrence Estuary (SLE) beluga population have shown a decline in energy reserves over the past two decades, as indicated by a significant decrease in blubber Sigma(9)fatty acid concentrations. Higher concentrations of certain lipid metabolites were found in belugas in poor body condition, suggesting changes in lipid metabolism. Therefore, concentrations of membrane lipids such as phosphatidylcholine could be used as indicators of body condition and energy reserve status in blubber of marine mammals.
ENVIRONMENTAL RESEARCH
(2021)
Article
Ecology
Cynthia Nevison, Peter Hess, Christine Goodale, Qing Zhu, Julius Vira
Summary: This study evaluates the nitrogen cycling in two Earth System Models (ESMs), finding significant differences in global mineralization, immobilization, plant N uptake, nitrification, and denitrification fluxes between the models. The study also suggests underestimated ratios of nitrification:denitrification and highlights the need for more observational constraints on soil nitrogen fluxes.
ECOLOGICAL APPLICATIONS
(2022)
Article
Environmental Sciences
Karine Blouin, Florentine Malaise, Jonathan Verreault, Stephane Lair, Zhe Lu
Summary: This study investigated the occurrence and temporal trends of contaminants in the blubber and liver of St. Lawrence Estuary belugas, and found tissue- and sex-specific accumulation patterns for BHTQ, UV329, and BP3.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Meteorology & Atmospheric Sciences
J. Dumas, D. Gilbert
Summary: This study compares satellite sea surface salinity (SSS) data from SMOS and SMAP with in situ SSS observations and finds that despite the cold water and proximity to land and sea ice, the satellite SSS is able to capture the interannual variability and annual cycle of SSS in the Gulf of St. Lawrence. The satellite SSS data products were also able to detect the occurrence of a very low salinity year in the Southern Gulf of St. Lawrence in 2017.
Article
Limnology
Maciej Bartosiewicz, Jessica Venetz, Saskia Laeubli, Oscar Sepulveda Steiner, Damien Bouffard, Jakob Zopfi, Moritz F. F. Lehmann
Summary: The study reveals the existence of methane paradox in oxygenated waters of a lake and identifies the factors contributing to the variability in its magnitude. It also suggests that methanogenesis in zooplankton detritus is stimulated through the addition of methylphosphonate.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Limnology
Claudia Frey, Xin Sun, Laura Szemberski, Karen L. Casciotti, Emilio Garcia-Robledo, Amal Jayakumar, Colette L. Kelly, Moritz F. Lehmann, Bess B. Ward
Summary: Marine oxygen-deficient zones serve as a natural source of nitrous oxide (N2O), a powerful greenhouse gas and ozone-depleting agent. Through experiments conducted in the Eastern Tropical North Pacific, it was found that ammonia oxidation (AO) is controlled by oxygen (O-2) and ammonium (NH4+) concentrations, leading to N2O production. The study also showed that the yield of N2O from AO is solely influenced by O-2 concentration.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Environmental Sciences
J. O. Goyette, M. Botrel, G. Billen, J. Garnier, R. Maranger
Summary: This study analyzed the nitrogen and phosphorus fluxes in 78 watersheds of the St. Lawrence Basin in eastern Canada from 1901 to 2011 and found that the shift from sustainable to unsustainable agricultural practices over the past century has led to environmental losses. The study suggests reducing nutrient flux and reconnecting crop and animal farming to mitigate these losses.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Zhanchao Shao, Karin R. Bryan, Moritz K. Lehmann, Conrad A. Pilditch
Summary: Sentinel-2 imagery with high temporal and spatial resolution is suitable for assessing estuarine water quality. However, it is challenging to separate the seabed reflectance from water properties. In this study, we use Lyzenga's model to estimate water quality properties and show that it can be applied with known seabed reflectance and multiple observations of reflectance from different water depths. We also demonstrate that the methodology works best at water depths less than 6.4 m and allows for the estimation of key parameters like K-d and R-w.
Article
Biodiversity Conservation
Morgan Botrel, Roxane Maranger
Summary: Submerged aquatic vegetation (SAV) in lake littoral zones is vital for maintaining ecosystem services, but global trends and drivers of SAV quantities remain unclear. This study provides a comprehensive synthesis of SAV trends using long-term time series data, revealing the dominant drivers of change in different regions. It highlights the urgent need for research and management actions to address knowledge gaps and preserve SAV and its crucial role in lake ecosystems.
GLOBAL CHANGE BIOLOGY
(2023)
Article
Marine & Freshwater Biology
Laura T. Kelly, Lisa Reed, Jonathan Puddick, Ian Hawes, Brendan J. Hicks, Mathew G. Allan, Moritz K. Lehmann, Susanna A. Wood
Summary: Remote sensing using satellite imagery has been proposed to enhance cyanobacterial monitoring by establishing relationships between water body reflectance spectra and cyanobacterial abundance. However, the optical properties of cyanobacteria vary due to their physiological state and environment, posing challenges to this method. This study investigates the effects of growth stage, nutrient status, and irradiance on pigment concentrations and absorption spectra in two common cyanobacteria species. The results show distinguishable absorption spectra between the species, indicating that hyperspectral absorption spectra can differentiate the species. However, the per-cell pigment concentrations of the species respond differently to light intensity and nitrate exposure, emphasizing the need to consider species composition and growth stage in estimating biovolumes from reflectance spectra.
Article
Ecology
Guangyi Su, Moritz F. Lehmann, Jana Tischer, Yuki Weber, Fabio Lepori, Jean-Claude Walser, Helge Niemann, Jakob Zopfi
Summary: We investigated the microbial methane oxidation in Lake Lugano, Switzerland. Anaerobic methane oxidation (AOM) coupled to nitrite reduction by Candidatus Methylomirabilis was found in the water column of the meromictic North Basin. However, aerobic methanotrophs prevailed in the more dynamic South Basin and no evidence of nitrite-dependent AOM was found. Our study highlights the importance of physical processes and ecosystem stability in controlling the community composition of aerobic and anaerobic methanotrophs.
Article
Limnology
Morgan Botrel, Christiane Hudon, Pascale M. Biron, Roxane Maranger
Summary: Measuring biomass of freshwater submerged aquatic vegetation (SAV) at large spatial scales is challenging. The combination of quadrat-scuba diver technique, fast rake sampling, and large-scale echosounding can provide more accurate estimates. The relationship between quadrat and rake biomass varies with substrate type and SAV growth form, while rake biomass can be accurately estimated from biovolume derived from echosounding. Sequential application of calibrations can yield accurate predictions, with echosounding being more accurate at larger scales. A step-by-step guideline is developed to decide when to use each technique.
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2023)
Correction
Multidisciplinary Sciences
Moritz K. Lehmann, Daniela Gurlin, Nima Pahlevan, Krista Alikas, Ted Conroy, Janet Anstee, Sundarabalan V. Balasubramanian, Claudio C. F. Barbosa, Caren Binding, Astrid Bracher, Mariano Bresciani, Ashley Burtner, Zhigang Cao, Arnold G. Dekker, Courtney Di Vittorio, Nathan Drayson, Reagan M. Errera, Virginia Fernandez, Dariusz Ficek, Cedric G. Fichot, Peter Gege, Claudia Giardino, Anatoly A. Gitelson, Steven R. Greb, Hayden Henderson, Hiroto Higa, Abolfazl Irani Rahaghi, Cedric Jamet, Dalin Jiang, Thomas Jordan, Kersti Kangro, Jeremy A. Kravitz, Arne S. Kristoffersen, Raphael Kudela, Lin Li, Martin Ligi, Hubert Loisel, Steven Lohrenz, Ronghua Ma, Daniel A. Maciel, Tim J. Malthus, Bunkei Matsushita, Mark Matthews, Camille Minaudo, Deepak R. Mishra, Sachidananda Mishra, Tim Moore, Wesley J. Moses, Ha Nguyen, Evlyn M. L. M. Novo, Stefani Novoa, Daniel Odermatt, David M. O'Donnell, Leif G. Olmanson, Michael Ondrusek, Natascha Oppelt, Sylvain Ouillon, Waterloo Pereira Filho, Stefan Plattner, Antonio Ruiz Verdu, Salem I. Salem, John F. Schalles, Stefan G. H. Simis, Eko Siswanto, Brandon Smith, Ian Somlai-Schweiger, Mariana A. Soppa, Evangelos Spyrakos, Elinor Tessin, Hendrik J. van der Woerd, Andrea Vander Woude, Ryan A. Vandermeulen, Vincent Vantrepotte, Marcel R. Wernand, Mortimer Werther, Kyana Young, Linwei Yue
Article
Multidisciplinary Sciences
Moritz K. Lehmann, Daniela Gurlin, Nima Pahlevan, Krista Alikas, Janet Anstee, Sundarabalan V. Balasubramanian, Claudio C. F. Barbosa, Caren Binding, Astrid Bracher, Mariano Bresciani, Ashley Burtner, Zhigang Cao, Arnold G. Dekker, Courtney Di Vittorio, Nathan Drayson, Reagan M. Errera, Virginia Fernandez, Dariusz Ficek, Cedric G. Fichot, Peter Gege, Claudia Giardino, Anatoly A. Gitelson, Steven R. Greb, Hayden Henderson, Hiroto Higa, Abolfazl Irani Rahaghi, Cedric Jamet, Dalin Jiang, Thomas Jordan, Kersti Kangro, Jeremy A. Kravitz, Arne S. Kristoffersen, Raphael Kudela, Lin Li, Martin Ligi, Hubert Loisel, Steven Lohrenz, Ronghua Ma, Daniel A. Maciel, Tim J. Malthus, Bunkei Matsushita, Mark Matthews, Camille Minaudo, Deepak R. Mishra, Sachidananda Mishra, Tim Moore, Wesley J. Moses, Ha Nguyen, Evlyn M. L. M. Novo, Stefani Novoa, Daniel Odermatt, David M. O'Donnell, Leif G. Olmanson, Michael Ondrusek, Natascha Oppelt, Sylvain Ouillon, Waterloo Pereira Filho, Stefan Plattner, Antonio Ruiz Verdu, Salem I. Salem, John F. Schalles, Stefan G. H. Simis, Eko Siswanto, Brandon Smith, Ian Somlai-Schweiger, Mariana A. Soppa, Evangelos Spyrakos, Elinor Tessin, Hendrik J. van der Woerd, Andrea Vander Woude, Ryan A. Vandermeulen, Vincent Vantrepotte, Marcel R. Wernand, Mortimer Werther, Kyana Young, Linwei Yue
Summary: The development of algorithms for remote sensing of water quality requires a large amount of in situ data to consider the bio-geo-optical diversity of inland and coastal waters. The GLORIA dataset includes 7,572 curated hyperspectral remote sensing reflectance measurements at 1 nm intervals within the 350 to 900 nm wavelength range, contributed by researchers affiliated with 59 institutions worldwide. This dataset provides a comprehensive reference for practitioners planning similar measurements and enables scientific and technological advancement towards operational regional and global water quality monitoring.
Article
Meteorology & Atmospheric Sciences
Zeliang Wang, David Brickman, Blair Greenan, James Christian, Brendan Detracey, Denis Gilbert
Summary: This study examines the results of 22 CMIP6 Earth System Model simulations for four regions in the Scotian Shelf and Gulf of Maine. The findings suggest that eddy-permitting models do not perform better than coarse-resolution non-eddy permitting models in terms of long-term trends. Additionally, the simulations show limited skill for historical bottom temperature in these shelf regions. Climate projections indicate that the largest seasonal SST increase will occur in summer, and the changes in SST are likely underestimated while the changes in bottom temperature are likely overestimated.
Article
Environmental Sciences
Stephanie Shousha, Roxane Maranger, Jean-Francois Lapierre
Summary: This study investigates the long-term trends in carbon (C), nitrogen (N), and phosphorus (P) exports in a river system in Quebec, Canada. The results show that N exports have increased over time, largely driven by changes in precipitation and net anthropogenic N inputs on land. On the other hand, P exports have tended to decrease, despite higher net anthropogenic P inputs. The study also reveals changes in ecosystem stoichiometry over the years, reflecting the differential elemental exports influenced by natural and anthropogenic drivers.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Multidisciplinary Sciences
Benedikt Ehrenfels, Kathrin B. L. Baumann, Robert Niederdorfer, Athanasio S. Mbonde, Ismael A. Kimirei, Thomas Kuhn, Paul M. Magyar, Daniel Odermatt, Carsten J. Schubert, Helmut Burgmann, Moritz F. Lehmann, Bernhard Wehrli, Cameron M. Callbeck
Summary: This study investigates the distribution of nitrogen fixation in Lake Tanganyika and reveals the significant influence of stratification and upwelling conditions on nitrogen fixation rates. Under stratified conditions, limited inorganic nitrogen supply combined with greater light penetration promotes the activity of photoautotrophic diazotrophs. In contrast, upwelling conditions support heterotrophic diazotrophs adapted to a more dynamic nutrient landscape. Understanding the role of hydrodynamic regimes in modulating nitrogen fixation is crucial for accurate nitrogen budgets in aquatic environments.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Kun Huang, Wolfram Eschenbach, Jing Wei, Damian Hausherr, Claudia Frey, Andre Kupferschmid, Jens Dyckmans, Adriano Joss, Moritz F. Lehmann, Joachim Mohn
Summary: This study developed an automated sample preparation unit coupled with a mass spectrometer to analyze the atom % N-15 in NH4+, NO2-, and NO3- online and quasi-simultaneously. The feasibility study demonstrated the potential of this technique, in combination with Fourier-transform infrared spectroscopy, to identify N transformations and sources of N2O.