Publications associées à Colonne d'eau

Vertical distribution and seasonal dynamics of planktonic cyanobacteria communities in a water column of deep mesotrophic Lake Geneva

Tamar Kohn, Stéphane Joost, Oliver Michele Selmoni, Anna Carratala Ripolles, Charlotte Gisèle Weil, Natacha Tofield-Pasche, Hannah Elisa Chmiel, Annie Sandrine Guillaume, Coralie Chappelier

Background: Temperate subalpine lakes recovering from eutrophication in central Europe are experiencing harmful blooms due to the proliferation of Planktothrix rubescens, a potentially toxic cyanobacteria. To optimize the management of cyanobacteria blooms ...

Frontiers Media SA2023

Uptake without inactivation of human adenovirus type 2 by Tetrahymena pyriformis ciliates

Tamar Kohn, Margot Ninon Lauren Olive

Human adenoviruses are ubiquitous contaminants of surface water. Indigenous protists may interact with adenoviruses and contribute to their removal from the water column, though the associated kinetics and mechanisms differ between protist species. In this ...

2023

Controlling factors of phytoplankton distribution in the river–lake transition zone of a large lake

David Andrew Barry, Frédéric Charles Soulignac, Matthieu Fallet

River–lake transition zones have been identified as major drivers of phytoplankton growth. With climate change reducing the frequency of complete lake overturns, it is expected that the Rhône River, the main tributary to Lake Geneva (France/Switzerland), w ...

2023

Detritus-hosted methanogenesis sustains the methane paradox in an alpine lake

Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

Accumulation of methane in oxic waters of lakes and the ocean has been widely reported. Despite the importance for the greenhouse gas budget, mechanistic controls of such "methane paradox" remain elusive. Here, we use a combination of CH4 concentration and ...

American Society of Limnology and Oceanography2022

Insights into the Horizontal and Vertical Profiles of Microplastics in a River Emptying into the Sea Affected by Intensive Anthropogenic Activities in Northern China

Florian Frédéric Vincent Breider, Yang Liu, Wenxin Liu

Studies focused only on surface water may underestimate microplastic abundance in aquatic environments. This was the first survey to investigate the vertical (surface, intermediate, and bottom waters) distribution and composition of microplastics (MPs) in ...

2021

Mixing processes and their ecological implications: From vertical to lateral variability in stratified lakes

Oscar Rodrigo Sepúlveda Steiner

The physical environment of natural waters influences biogeochemical processes to generate specific ecological niches, promoting biophysical interactions. Bacteria and phytoplankton communities can form spatial structures, such as layers and patches. The p ...

EPFL2020

Model-based data analysis of the effect of winter mixing on primary production in a lake under reoligotrophication

Alfred Johny Wüest, Hugo Nicolás Ulloa Sánchez, Camille Roland Marie Minaudo, Shubham Krishna

Nutrient loading, in combination with climate change are important drivers of primary productivity in lakes. Understanding and forecasting future changes in primary production (PP) in response to local and global forcing are major challenges for developing ...

ELSEVIER2020

Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation

Nina Schuback

Evaluation of photosynthetic competency in time and space is critical for better estimates and models of oceanic primary productivity. This is especially true for areas where the lack of iron (Fe) limits phytoplankton productivity, such as the Southern Oce ...

2020

Hypolimnetic oxygen depletion rates in deep lakes: Effects of trophic state and organic matter accumulation

Alfred Johny Wüest, Robert Vincent Schwefel, Beat Mueller

This study investigated the consumption of oxygen (O-2) in 11 European lakes ranging from 48 m to 372 m deep. In lakes less than similar to 100 m deep, the main pathways for O-2 consumption were organic matter (OM) mineralization at the sediment surface an ...

American Society of Limnology and Oceanography2020

Oxygen consumption in seasonally stratified lakes decreases only below a marginal phosphorus threshold

Alfred Johny Wüest, Robert Vincent Schwefel

Areal oxygen (O-2) consumption in deeper layers of stratified lakes and reservoirs depends on the amount of settling organic matter. As phosphorus (P) limits primary production in most lakes, protective and remediation efforts often seek to reduce P input. ...

Springer Nature2019

Effects of non-uniform vertical constituent profiles on remote sensing reflectance of oligo- to mesotrophic lakes

Alfred Johny Wüest, Damien Bouffard, Vincent Maurice Nouchi

We investigate the impact on remote sensing reflectance by the vertical non-uniformities of water constituents. Reflectance simulated for 210 pairs of in situ measured chlorophyll-a and turbidity profiles (z = 0–20 m) from Lake Geneva are compared to simul ...

2018

Effect of TiO2 Nanoparticles and UV Radiation on Extracellular Enzyme Activity of Intact Heterotrophic Biofilms

Kristin Schirmer, Laura Sigg, Hannah Inka Schug

When introduced into the aquatic environment, TiO2 NP are likely to settle from the water column, which results in increased exposure of benthic communities. Here, we show that the activity of two extracellular enzymes of intact heterotrophic biofilms, bet ...

Amer Chemical Soc2014

Column studies to assess the effects of climate variables on redox processes during riverbank filtration

Urs von Gunten, Janet Gordon Hering

Riverbank filtration is an established technique used world-wide to produce clean drinking water in a reliable and cost-efficient way. This practice is, however, facing new challenges posed by climate change, as already observed during past heat waves with ...

Elsevier2014

Computational Quantum Chemical Studies on Radicals : from the Gas Phase to Aqueous Solution

Peter Rudolf Tentscher

Radicals play an important role in many areas of chemistry, such as atmospheric, aquatic, polymer, and biological, to name a few. Radicals are often highly reactive species which are short-lived and therefore harder to study by experimental techniques. In ...

EPFL2013

Spatio-Temporal Presence of Micropollutants and their Metabolites in Lake Geneva and Susceptibility to Direct and Indirect Photodegradation Processes

Florence Bonvin

Invisible to the human eye, yet ubiquitous... The occurrence and the potential adverse effects of micropollutants in the environment are uncontested. Due to incomplete removal by conventional wastewater treatment technologies, the aquatic environment is co ...

EPFL2013

Nutrient cycling in Lake Kivu

Alfred Johny Wüest, Natacha Tofield-Pasche, Martin Schmid

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top ∼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ∼ ...

Springer2012

Stratification, mixing and transport processes in Lake Kivu

Alfred Johny Wüest, Martin Schmid

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top â ¼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ...

Springer2012

Distribution of denitrifying bacterial communities in the stratified water column and sediment-water interface in two freshwater lakes and the Baltic Sea

We have studied the distribution and community composition of denitrifying bacteria in the stratified water column and at the sediment-water interface in lakes Plusee and Schohsee, and a near-shore site in the Baltic Sea in Germany. Although environmental ...

2011