Marie-Elodie Perga

Marie-Elodie Perga
University of Lausanne | UNIL · IDYST

PhD(Ecology)

About

133
Publications
32,942
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2,874
Citations
Additional affiliations
November 2004 - February 2006
University of Victoria
Position
  • PostDoc Position

Publications

Publications (133)
Article
Full-text available
Whiting events are transient phenomena commonly occurring in hardwater lakes and manifesting as a turquoise coloration of surface waters during massive calcium carbonate precipitation. While biological and physico‐chemical drivers of carbonate precipitation are known, their relative contributions in controlling whiting events' timing and spatial ex...
Article
Full-text available
The influence of human activities on the role of inland waters in the global carbon (C) cycle is poorly constrained. In this study, we investigated the impact of human land use on the sources and biodegradation of dissolved organic matter (DOM) and its potential impact on bacterial respiration in 10 independent catchments of the Lake Geneva basin....
Article
Full-text available
The gas transfer velocity (k) is a major source of uncertainty when assessing the magnitude of lake gas exchange with the atmosphere. For the diversity of existing empirical and process-based k models, the transfer velocity increases with the level of turbulence near the air–water interface. However, predictions for k can vary by a factor of 2 amon...
Article
Freshwater ecosystems are under new and increasing threats from anthropogenic change. Ability to detect and predict consequences of environmental perturbations on ecosystem function and water quality is limited by the lack of empirical data over relevant time scales. Paleoecological records present a unique opportunity to broaden understanding of e...
Article
Full-text available
Environmental sciences depend heavily on observational data. Successful studies of ecological processes in lakes require in-situ data that cover the relevant temporal scales from milliseconds to entire seasons. Temporal and spatial coverage requirements represent a non-trivial challenge in lake sciences, which have traditionally used sampling campa...
Preprint
Full-text available
The influence of human activities on the role of inland waters in the global carbon (C) cycle is poorly constrained. In this study, we investigated the impact of human land use on the degradation of terrestrial dissolved organic matter (DOM) and its potential impact on bacterial respiration in ten independent catchments of the Lake Geneva Basin. Si...
Preprint
Full-text available
The gas transfer velocity (k) is a major source of uncertainty when assessing the magnitude of lake gas exchange with the atmosphere. For the diversity of existing empirical and process-based k models, the transfer velocity increases with the level of turbulence near the air-water interface. However, predictions for k can vary by a factor of 2 amon...
Article
Global change transforms processes regulating carbon dioxide (CO2) concentrations in lakes, yet our understanding of the broad scale responses of lake CO2 to global and local human perturbation across heterogeneous landscapes and multidecadal time scales is limited. We examined decadal scale variability in the carbon isotope (δ¹³C) composition of s...
Article
Full-text available
Regime shifts are major reorganization of ecological processes, creating new sets of mechanisms that drive the new ecological regime. Such rearrangements can affect how and how much the system responds to pressures other than those that created the shift (interactive carryover). Lake Geneva still exhibits high levels of productivity despite reducti...
Article
Full-text available
In recent decades, research on mountains has become more inter- and transdisciplinary, but a greater effort is needed if such research is to contribute to a societal transformation toward sustainability. Mountain research centers are a crucial actor in this endeavor. Yet, the literature has not paid sufficient attention to how these centers should...
Article
Full-text available
• Zooplankton can spend winter actively under the ice cover of lakes. However, dietary resources under lake ice are both quantitatively and qualitatively limited, and feeding might not be energetically rewarding for most zooplankton species. Many zooplankters are expected to fast throughout the winter, exhausting their previously accumulated fat st...
Article
Full-text available
The epilimnion is the surface layer of a lake typically characterised as well mixed and is decoupled from the metalimnion due to a steep change in density. The concept of the epilimnion (and, more widely, the three-layered structure of a stratified lake) is fundamental in limnology, and calculating the depth of the epilimnion is essential to unders...
Article
Through the artificial manipulation of hydrological residence time, hydropower operations on alpine lakes should not only alter their hydro-biogeochemical characteristics but also modulate the degree of sensitivity of the lake to atmospheric forcing. These hypotheses were addressed by means of in situ observations that were combined with a three-di...
Preprint
Full-text available
The “epilimnion” is the surface layer of a lake typically characterised as well-mixed and is decoupled from the “metalimnion” due to a rapid change in density. The concept of the epilimnion, and more widely, the three-layered structure of a stratified lake, is fundamental in limnology and calculating the depth of the epilimnion is essential to unde...
Article
Full-text available
Large lakes of the world are habitats for diverse species, including endemic taxa, and are valuable resources that provide humanity with many ecosystem services. They are also sentinels of global and local change, and recent studies in limnology and paleolimnology have demonstrated disturbing evidence of their collective degradation in terms of dep...
Article
In March 2017, we joined a multi‐disciplinary expedition on Lake Onego, in the Russian Karelia, with the primary goal to investigate zooplankton strategies to survive deep winter under ice. We intended to focus on the large zooplankters, i.e. crustaceans of tenths to a few mm of body length, through sampling by horizontal and vertical trawls using...
Article
Full-text available
In this study, we experimentally investigated the degradation of dissolved organic matter (DOM) during lateral and vertical mixing of different water masses in a peri-alpine lake. River intrusions and vertical winter turnover in Lake Geneva (Switzerland, France) were simulated through short-term laboratory incubations by mixing riverine and lacustr...
Article
Full-text available
Fishponds built across streams can greatly affect their functioning, especially through loss of ecological continuity but also changes in water availability and trophic resources. Yet, their consequences on communities and stream functioning remain largely understudied. We investigated effects of fishpond dams on the trophic ecology of macroinverte...
Article
Full-text available
Despite PCBs being banned since the 1980's, some European peri-alpine lakes, and consequently their fish populations, are still contaminated by these xenobiotics. We investigated the relative contribution of physiological and trophic factors that could be implicated in fish PCB bioaccumulation in Lake Bourget (France), one of the most contaminated...
Chapter
Freshwater systems are continuously shaped by cyclical and directional forces of change, whether they be natural or anthropogenic. Beyond gradual transitions disturbances can reset their internal dynamics generating an abrupt ecological shift. Long-term data sets of gradual or abrupt change can be accessed by exhuming the physical, chemical, and bi...
Article
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The present paper aims at reviewing general knowledge of large European perialpine lakes as provided by sediment studies, and at outlining the contribution, from several lines of evidence, of modern paleolimnology in both interpreting past lake ecological evolution and forecasting lake responses to future human impacts. A literature survey mainly b...
Article
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The significance of methane production by lakes to the global production of greenhouse gas is well acknowledged while underlying processes sustaining the lacustrine methane budget remain largely unknown. We coupled biogeochemical data to functional and phylogenetic analyses to understand how sedimentary parameters characterize the methane cycle ver...
Article
Full-text available
Nonlinear responses to changing external pressures are increasingly studied in real‐world ecosystems. However, as many of the changes observed by ecologists extend beyond the monitoring record, the occurrence of critical transitions, where the system is pushed from one equilibrium state to another, remains difficult to detect. Paleo‐ecological reco...
Article
Trophic ecology is the study of feeding interactions and food acquisition by organisms. It includes the causes and consequences of those behaviours at all levels of biological organisation. As a field of research, it crosses many disciplinary boundaries and provides knowledge that is pertinent to many other areas of ecology. Here we list and catego...
Article
Full-text available
• Although parasites are expected to affect their host's fitness, quantitative proof for impacts of parasitism on wild populations is hampered by confounding environmental factors, including dietary resource. • Herein, we evaluate whether the physiological conditions of European perch (Perca fluviatilis) in three large peri‐alpine lakes (Geneva, An...
Article
Extreme weather events may be just as important as gradual trends for the long‐term trajectories of ecosystems. For alpine lakes, which are exposed to both exacerbated atmospheric warming and intense episodic weather events, future conditions might not be appropriately forecast by only climate change trends, i.e., warming, if extreme events have th...
Article
Hysteresis linked to alternative stable states may explain delays in water quality recovery despite reduced nutrient loadings in shallow lakes. Because deep lakes are assumed to be less prone to critical transitions, similar delays are attributed to the confounding effects of additional environmental disturbances, such as climate warming. Herein, w...
Article
Ecological dynamics often exhibit significant temporal variability and sudden shifts that characterize their non-equilibrium and nonlinear nature, challenging our ability to understand and predict their trajectories. Among a set of ecological time series originating from the long-term monitoring of three large and deep lakes, nonlinear forecasting...
Article
Full-text available
High-throughput sequencing of sedimentary DNA (sed-DNA) was utilized to reconstruct the temporal dynamics of microbial eukaryotic communities (MECs) at a centennial scale in two re-oligotrophicated lakes that were exposed to different levels of phosphorus enrichment. The temporal changes within the MECs were expressed in terms of richness, composit...
Article
Biological invasions exert multiple pervasive effects on ecosystems, potentially disrupting species interactions and global ecological processes. Our ability to successfully predict and manage the ecosystem-level impacts of biological invasions is strongly dependent on our capacity to empirically characterize complex biological interactions and the...
Book
Biological invasions exert multiple pervasive effects on ecosystems, potentially disrupting species interactions and global ecological processes. Our ability to successfully predict and manage the ecosystem-level impacts of biological invasions is strongly dependent on our capacity to empirically characterize complex biological interactions and the...
Conference Paper
Based on the coupling between paleoecology and high-throughput sequencing of DNA, we analyzed the sedimentary records from two lakes (Lake Annecy and Lake Bourget, French Alps) in order to reconstruct the temporal dynamics of their microbial eukaryotes communities. We aimed to reveal the effects of environmental changes in these two lakes both simi...
Article
Full-text available
Cold aquatic ecosystems, such as high-altitude alpine lakes, are expected to act as long-term sinks of polychlorinated biphenyls (PCBs), the burden of which might even be intensified by global warming. Since the physical, chemical and biological structures of high altitude lakes are highly responsive to climate change, both PCB exposure and bioaccu...
Article
Full-text available
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 study was to test directly this long-standing hypothesis. It combines direct observational data...
Article
Full-text available
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 supersaturated with oxygen into the hypolimnion. The overarching aim of this study was to test directly this long-standing hypothesis. It combines direct observational...
Article
Full-text available
Now that evasion of carbon dioxide (CO2) from inland waters is accounted for in global carbon models, it is crucial to quantify how these fluxes have changed in the past and forecast how they may alter in the future in response to local and global change. Here we developed a sediment proxy for the concentration of summer surface dissolved CO2 conce...
Article
Full-text available
In accordance with their mission and as part of their long-term observation work, Ecrins National Park (NP) is making important contributions to the study and monitoring of phenomena related to climate change. Its work takes information collected at different meteorological stations and supplements it with analyses of vegetation changes through aer...
Article
Full-text available
Anthropogenic environmental changes are considered critical drivers of the genetic structure of populations and communities through, for example, the facilitation of introgressive hybridization between syntopic species. However, the mechanisms by which environmental perturbations trigger changes in the genetic structure of populations and communiti...
Article
The spread of hypoxia is a threat to aquatic ecosystem functions and services as well as to biodiversity. However, sparse long-term monitoring of lake ecosystems has prevented reconstruction of global hypoxia dynamics while inhibiting investigations into its causes and assessing the resilience capacity of these systems. This study compiles the onse...
Article
We investigated whether polychlorinated biphenyls (PCBs) partitioning between the dissolved and particulate phases in two high altitude alpine lakes was determined by the quantity, size structure or composition of suspended particles. Within- and between-lakes differences in water-particulate phase partition coefficient (Kp) were not related to tot...
Article
Full-text available
Varved lake sediments provide opportunities for high-resolution paleolimnological investigations that may extend monitoring surveys in order to target priority management actions under climate warming. This paper provides the synthesis of an international research program relying on >150 years-long, varved records for three managed perialpine lakes...
Conference Paper
Full-text available
Long-range atmospheric transport of semivolatile organic compounds (SVOCs) like polychlorinated biphenyls (PCB) is responsible for the contamination of remote area such as alpine lakes. In high altitude lakes, cold temperature decrease volatilization of deposited PCB that could promotes their accumulation and therefore might increase their contamin...
Article
Full-text available
Varved lake sediments provide opportunities for high-resolution paleolimnological investigations that may extend monitoring surveys in order to target priority management actions under climate warming. This paper provides the synthesis of an international research program relying on >150 years-long, varved records for three managed perialpine lakes...
Article
1. The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladoce...
Article
Full-text available
Stable C isotope ratio (δ(13)C) values of chironomid remains (head capsules; HC) were used to infer changes in benthic C sources over the last 150 years for two French sub-Alpine lakes. The HCs were retrieved from a series of sediment cores from different depths. The HC δ(13)C values started to decrease with the onset of eutrophication. The HC δ(13...
Article
Full-text available
We investigated the major sources of PCB and interpretated the environmental fate processes of these persistent organic pollutants in the past and current PCB contamination of three large, urbanized, French peri-alpine lakes. Dated sediment cores were analyzed in order to reconstruct and compare the historical contamination in all three lakes. Stra...