Publications associées à Zone de minimum d'oxygène

Iron Reduction in Profundal Sediments of Ultraoligotrophic Lake Tahoe under Oxygen-Limited Conditions

Increased periods of bottom water anoxia in deep temperate lakes due to decreasing frequency and depth of water column mixing in a warming climate may result in the reductive dissolution of iron minerals and increased flux of nutrients from the sediment in ...

2023

Evidence that Pacific tuna mercury levels are driven by marine methylmercury production and anthropogenic inputs

Hélène Paule Angot

Pacific Ocean tuna is among the most-consumed seafood products but contains relatively high levels of the neurotoxin methylmercury. Limited observations suggest tuna mercury levels vary in space and time, yet the drivers are not well understood. Here, we m ...

National Academy of Sciences2022

Nutrient pollution enhances productivity and framework dissolution in algae- but not in coral-dominated reef communities

Nils Rädecker, Hal Hunt Jones II

Ecosystem services provided by coral reefs may be susceptible to the combined effects of benthic species shifts and anthropogenic nutrient pollution, but related field studies are scarce. We thus investigated in situ how dissolved inorganic nutrient enrich ...

2021

Importance of mixotrophic flagellates during the ice-free season in lakes located along an elevational gradient

Hannes Markus Peter

Mixotrophy seems to be widespread among phytoplankton, but whether this strategy is more relevant in oligotrophic lakes remains unclear. Here, we tested the hypothesis that the relative abundance of mixotrophic flagellates in lakes increases along an eleva ...

Springer2019

Personal CO2 cloud: laboratory measurements of metabolic CO2 inhalation zone concentration and dispersion in a typical office desk setting

Dusan Licina, Shichao Liu

Inhalation exposure to pure and metabolic elevated carbon dioxide (CO2) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO2 was cont ...

2019

Sources and variability of CO 2 in a pre‐alpine stream gravel bar

Tom Ian Battin

Gravel bars (GBs) contribute to carbon dioxide (CO2) emissions from stream corridors, with CO2 concentrations and emissions dependent on prevailing hydraulic, biochemical, and physicochemical onditions. We investigated CO2 concentrations and fluxes across ...

2019

Using small-scale measurements to estimate hypolimnetic oxygen depletion in a deep lake

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Low oxygen concentrations in lakes and reservoirs are an ongoing environmental concern, particularly in light of increasing anthropogenic activity and climate change. Oxygen depletion processes in lakes are still not completely understood and a variety of ...

American Society of Limnology and Oceanography2018

Fast Potentiometric CO2 Sensor for High-Resolution in Situ Measurements in Fresh Water Systems

Nadezda Pankratova, Bernhard Wehrli

We present a new potentiometric sensor principle and a calibration protocol for in situ profiling of dissolved CO2 with high temporal and spatial resolution in fresh water lakes. The sensor system is based on the measurement of EMF between two solid-contac ...

AMER CHEMICAL SOC2018

Scaling as a key conceptual tool for the interpretation of empirical and experimental patterns in ecology and biology

Silvia Zaoli

This thesis is concerned with regular patterns found in ecology and biology, their linkages and the statistical description of their fluctuations around average trends. Among such patterns, often conforming to power laws, well-known examples include the Sp ...

EPFL2018

Oxygen depletion in Lake Geneva

Robert Vincent Schwefel

Low oxygen concentrations remain a global concern for the ecological health of lakes. High nutrient inputs and climate-induced changes in stratification and mixing are anthropogenic threats which largely impact aquatic oxygen budgets and overall ecosystem ...

EPFL2017

Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

Anders Meibom, Stéphane Laurent Escrig, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna ...

Public Library of Science2017

Scaling oxygen microprofiles at the sediment interface of deep stratified waters

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel, Miki Hondzo

Dissolved oxygen microprofiles at the sediment-water interface of Lake Geneva were measured concurrently with velocities 0.25 to 2m above the sediment. The measurements and scaling analyses indicate dissolved oxygen fluctuations and turbulent fluxes in exc ...

American Geophysical Union2017

Nitrification increases nitrogen export from a tropical river network

Janine Rüegg

Scaling aquatic ecosystem processes like nutrient removal is critical for assessing the importance of streams and rivers to watershed nutrient export. We used pulse NH4+ enrichment experiments and measured net NH4+ uptake in 7 streams throughout a mountain ...

Univ Chicago Press2017

Effects of climate change on deep-water oxygen and winter mixing in a deep lake (Lake Geneva)

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Oxygen is the most important dissolved gas for lake ecosystems. Because low oxygen concentrations are an ongoing problem in many parts of the oceans and numerous lakes, oxygen depletion processes have been intensively studied over the last decades and were ...

2016

Oxygen depletion in stratified lakes - why shallow and deep lakes react differently

Alfred Johny Wüest, Robert Vincent Schwefel

Oxygen is the most important element in natural waters for any higher aquatic life, such as fish. As with humans, almost all members of aquatic ecosystems need oxygen to breathe. Building on this, treatment of drinking water is easier for oxic than for ano ...

2016

Are flood-driven turbidity currents hot spots for priming effect in lakes?

Damien Bouffard

In deep stratified lakes, such as Lake Geneva, flood-driven turbidity currents are thought to contribute to the replenishment of deep oxygen by significant transport of river waters saturated with oxygen into the hypolimnion. The overarching aim of this st ...

Copernicus GmbH2016

Mechanistic Study on the Formation of Cl-/Br-/I-Trihalomethanes during Chlorination/Chloramination Combined with a Theoretical Cytotoxicity Evaluation

Urs von Gunten

Chlorination followed by chloramination can be used to mitigate the formation of potentially toxic iodinated disinfection byproducts (I-DBPs) while controlling the formation of regulated chloro-bromo-DBPs (Cl-/Br-DBPs). Water samples containing dissolved o ...

American Chemical Society2015

Factors affecting the development and dynamics of hypoxia in a large shallow stratified lake: Hourly to seasonal patterns

Damien Bouffard

[1] The examination of hypoxia in the hypolimnion of large lakes traditionally focuses on the assessment of its spatial and temporal extent and its effect on water quality. In Lake Erie, hypoxia typically occurs between July and October in the central basi ...

American Geophysical Union2013

Seawater intrusion processes, investigation and management: Recent advances and future challenges

David Andrew Barry

Seawater intrusion (SI) is a global issue, exacerbated by increasing demands for freshwater in coastal zones and predisposed to the influences of rising sea levels and changing climates. This review presents the state of knowledge in SI research, compares ...

Elsevier2013

Hypolimnetic Oxygen Depletion in Eutrophic Lakes

Alfred Johny Wüest, Beat Mueller

The oxygen-consuming processes in the hypolimnia of freshwater lakes leading to deep-water anoxia are still not well understood, thereby constraining suitable management concepts. This study presents data obtained from 11 eutrophic lakes and suggests a mod ...

Amer Chemical Soc2012