Ökosysteme

Ökosysteme verstehen

Warum lebt die eine Krötenart im Teich und eine andere auf den Kiesbänken? Wie verändert sich die Lebensgemeinschaft im Bergbach, wenn der Gletscher weggeschmolzen ist? Und wie beeinflussen invasive Arten ihren neuen Lebensraum? Nur mit Antworten auf solche Fragen lassen sich ganze Ökosysteme verstehen und in einem gewissen Mass auch bewirtschaften.

News

Ökotoxikologische Wirkungen durch Pflanzenschutzmittel in Bachsedimenten

12. Dezember 2019

Pflanzenschutzmittel in Bachsedimenten führen zu schädlichen Wirkungen auf Organismen. Das haben das Oekotoxzentrum und das Wasserforschungsinstitut Eawag im Rahmen einer Überwachung von fünf Bächen in Landwirtschaftsgebieten herausgefunden. Betroffen waren vor allem Kleinkrebse. Mehrere Insektizide, darunter Chlorpyrifos und Pyrethroide, überschritten Effektschwellen, so dass die Sedimentqualität beeinträchtigt war.

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Hybride fördern Fischvielfalt der ostafrikanischen Seen

5. Dezember 2019

In den Seen Ostafrikas leben besonders viele verschiedene Arten von Buntbarschen. Diese Vielfalt entwickelte sich unter anderem dank Hybriden, denen es gelang, neue ökologische Nischen in ihren Lebensräumen zu erobern. Das fanden Wissenschaftlerinnen und Wissenschaftler des Wasserforschungsinstituts Eawag und der Universität Bern heraus.

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Weitere News

Veranstaltungen

28. - 29.04.​2020,
Eawag Dübendorf
Moose in Fliessgewässern: Erkennen und Kartieren - eine Methode des MSK Makrophyten
13.05.​2020,
9:00 Uhr
Eawag Dübendorf
Wirkungskontrolle Revitalisierung: Konzept und Habitatsvielfalt - T1
14.05.​2020,
9:00 Uhr
Eawag Dübendorf
Wirkungskontrolle Revitalisierung: Konzept und Habitatsvielfalt - T2

Wissenschaftliche Publikationen

Consumer-resource dynamics is an eco-evolutionary process in a natural plankton community

When traits affecting species interactions evolve rapidly, ecological dynamics can be altered while they occur. These eco-evolutionary dynamics have been documented repeatedly in laboratory and mesocosm experiments. We show here that they are also important for understanding community functioning in a natural ecosystem. Daphnia is a major planktonic consumer influencing seasonal plankton dynamics in many lakes. It is also sensitive to succession in its phytoplankton food, from edible algae in spring to relatively inedible cyanobacteria in summer. We show for Daphnia mendotae in Oneida Lake, New York, United States, that within-year ecological change in phytoplankton (from spring diatoms, cryptophytes and greens to summer cyanobacteria) resulted in consumers evolving increasing tolerance to cyanobacteria over time. This evolution fed back on ecological seasonal changes in population abundance of this major phytoplankton consumer. Oneida Lake is typical of mesotrophic lakes broadly, suggesting that eco-evolutionary consumer-resource dynamics is probably common.
Schaffner, L. R.; Govaert, L.; De Meester, L.; Ellner, S. P.; Fairchild, E.; Miner, B. E.; Rudstam, L. G.; Spaak, P.; Hairston, N. G. J. (2019) Consumer-resource dynamics is an eco-evolutionary process in a natural plankton community, Nature Ecology & Evolution, 3(9), 1351-1358, doi:10.1038/s41559-019-0960-9, Institutional Repository

Ecosystem tipping points in an evolving world

There is growing concern over tipping points arising in ecosystems because of the crossing of environmental thresholds. Tipping points lead to abrupt and possibly irreversible shifts between alternative ecosystem states, potentially incurring high societal costs. Trait variation in populations is central to the biotic feedbacks that maintain alternative ecosystem states, as they govern the responses of populations to environmental change that could stabilize or destabilize ecosystem states. However, we know little about how evolutionary changes in trait distributions over time affect the occurrence of tipping points and even less about how big-scale ecological shifts reciprocally interact with trait dynamics. We argue that interactions between ecological and evolutionary processes should be taken into account in order to understand the balance of feedbacks governing tipping points in nature.
Dakos, V.; Matthews, B.; Hendry, A. P.; Levine, J.; Loeuille, N.; Norberg, J.; Nosil, P.; Scheffer, M.; De Meester, L. (2019) Ecosystem tipping points in an evolving world, Nature Ecology & Evolution, 3(3), 355-362, doi:10.1038/s41559-019-0797-2, Institutional Repository

From clear lakes to murky waters – tracing the functional response of high-latitude lake communities to concurrent 'greening' and 'browning'

Climate change and the intensification of land use practices are causing widespread eutrophication of subarctic lakes. The implications of this rapid change for lake ecosystem function remain poorly understood. To assess how freshwater communities respond to such profound changes in their habitat and resource availability, we conducted a space-for-time analysis of food-web structure in 30 lakes situated across a temperature-productivity gradient equivalent to the predicted future climate of subarctic Europe (temperature +3°C, precipitation +30% and nutrient +45 μg L–1 total phosphorus). Along this gradient, we observed an increase in the assimilation of pelagic-derived carbon from 25 to 75% throughout primary, secondary and tertiary consumers. This shift was overwhelmingly driven by the consumption of pelagic detritus by benthic primary consumers and was not accompanied by increased pelagic foraging by higher trophic level consumers. Our data also revealed a convergence of the carbon isotope ratios of pelagic and benthic food web endmembers in the warmest, most productive lakes indicating that the incorporation of terrestrial derived carbon into aquatic food webs increases as land use intensifies. These results, reflecting changes along a gradient characteristic of the predicted future environment throughout the subarctic, indicate that climate and land use driven eutrophication and browning are radically altering the function and fuelling of aquatic food webs in this biome.
Hayden, B.; Harrod, C.; Thomas, S. M.; Eloranta, A. P.; Myllykangas, J. -P.; Siwertsson, A.; Præbel, K.; Knudsen, R.; Amundsen, P. -A.; Kahilainen, K. K. (2019) From clear lakes to murky waters – tracing the functional response of high-latitude lake communities to concurrent 'greening' and 'browning', Ecology Letters, 22(5), 807-816, doi:10.1111/ele.13238, Institutional Repository

Interference of silver nanoparticles with essential metal homeostasis in a novel enterohepatic fish in vitro system

Silver nanoparticle toxicity has been extensively studied in several vertebrate cells. Its interaction with cellular essential metals homeostasis, however, has largely been overlooked. In this study, we used a novel in vitro model of the fish enterohepatic system to investigate the effect of citrate-coated AgNP (cit-AgNP) and AgNO3 on the homeostasis of copper, iron and zinc. The intestine and the liver are key tissues for whole body absorption and processing of metals. The enterohepatic system is based on a co-culture of intestinal cells (rainbow trout gut, RTgutGC) grown on permeable supports and hepatic cells (rainbow trout liver, RTL-W1) grown in the sub-located well. We have investigated early responses to sub-toxic and toxic doses of cit-AgNP and AgNO3. Viability assays indicated that lysosomes were a target of cit-AgNP. Moreover, in comparison to AgNO3, cit-AgNPs elicit a similar but attenuated metal stress response (induction of MT mRNA and ATP7A protein trafficking). Metal quantification revealed that, while intestinal cells accumulated similar amounts of silver following non-toxic exposure to equivalent amounts of either AgNO3 or cit-AgNP, cells exposed to AgNO3 excreted significantly more Ag to the basolateral chamber resulting in higher Ag accumulation in RTL-W1 cells. In addition, the application of toxic doses of AgNO3 resulted in a reduction of intracellular zinc and iron. Silver nanoparticles were detected by STEM/EDX in RTgutGC after 3 hours of exposure but not after 24 hours suggesting rapid intracellular dissolution. Thus, Ag is a potent disruptor of essential metals homeostasis and cit-AgNP, which tend to be more difficult to excrete by the cell, can prolong this effect.
Minghetti, M.; Schirmer, K. (2019) Interference of silver nanoparticles with essential metal homeostasis in a novel enterohepatic fish in vitro system, Environmental Science: Nano, 1777-1790, doi:10.1039/C9EN00310J, Institutional Repository

Fish-gut-on-chip: development of a microfluidic bioreactor to study the role of the fish intestine in vitro

In this study we present the first fish-gut-on-chip model. This model is based on the reconstruction of the intestinal barrier by culturing two intestinal cell lines from rainbow trout, namely epithelial RTgutGC and fibroblastic RTgutF, in an artificial microenvironment. For a realistic mimicry of the interface between the intestinal lumen and the interior of the organism we i) developed ultrathin and highly porous silicon nitride membranes that serve as basement membrane analogues and provide a culture interface for the fish cells; ii) constructed a unique micro-well plate-based microfluidic bioreactor that enables parallelization of experiments and creates realistic fluid flow exposure scenarios for the cells; iii) integrated electrodes in the reactor for non-invasive impedance sensing of cellular well-being. In a first approach, we used this reactor to investigate the response of epithelial fish cells to in vivo-like shear stress rates of 0.002–0.06 dyne per cm2, resulting from fluid flow within the intestinal lumen. Moreover, we investigated the interplay of epithelial and fibroblast cells under optimal flow conditions to carefully evaluate the benefits and drawbacks of the more complex reconstruction of the intestinal architecture. With our fish-gut-on-chip model we open up new strategies for a better understanding of basic fish physiology, for the refinement of fish feed in aquaculture and for predicting chemical uptake and bioaccumulation in fish for environmental risk assessment. The basic principles of our reactor prototype, including the use of ultrathin membranes, an open microfluidic circuit for perfusion and the micro-well plate-based format for simplified handling and avoidance of air-bubbles, will as well be of great value for other barrier-on-chip models.
Drieschner, C.; Könemann, S.; Renaud, P.; Schirmer, K. (2019) Fish-gut-on-chip: development of a microfluidic bioreactor to study the role of the fish intestine in vitro, Lab on a Chip, 19(19), 3268-3276, doi:10.1039/C9LC00415G, Institutional Repository
Zur Bibliothek

Publikationen für die Praxis

Climate change and freshwater ecosystems. Impacts on water quality and ecological status

Climate change is one of the largest and possibly most impactful ongoing but also future environmental drivers. Understanding effects of climate change on aquatic ecosystems and their function is thus of high importance. Within the framework of the Hydro-CH2018 project, the Swiss Federal Office for the Environment (FOEN) initiated a synthesis of climate change effects on water quality and the ecological status of freshwater ecosystems. The present report is the result of these synthesis efforts.

Our goal was to summarize available knowledge on how climatic change affects freshwater ecosystems in Switzerland. The work was performed between fall 2017 and fall 2018. We aimed to provide a synthesis of existing knowledge that is as consistent and complete as possible, but also to identify possible knowledge gaps. The work is based on extensive literature surveys and expert interviews. Whenever possible, we included quantitative conclusions. At the same time, we also wanted to be specific and relevant for natural Swiss water systems, so we also included qualitative effects and case studies. While many of the major ongoing and expected effects of climate change on aquatic systems are already well known, we also faced several challenges. For example: (i) some effects of climate change are still only partly understood, (ii) many of the focal endpoints, both with respect to water quality and ecological status, are not only affected by climate change, but also by other anthropogenic drivers, and disentangling these drivers is challenging if not infeasible, (iii) specific effects can be dependent on specific local factors, and (iv) the research field is so vast that the available resources for this one-year synthesis did not allow us to go into as much detail and data analysis as the topic would deserve. As a result, our report is a snapshot of scientific knowledge, at the period of realization, of the effects of climate change on aquatic ecosystems in Switzerland, set into the context of other environmental drivers.

While we see that climate change will have major effects on Swiss water systems, we also identify possible ways of mitigating these effects. We thereby hope that our synthesis is not only an overview of current and future changes, but will also help in policy- and decisionmaking about how to best deal with these changes and challenges.
Benateau, S.; Gaudard, A.; Stamm, C.; Altermatt, F. (2019) Climate change and freshwater ecosystems. Impacts on water quality and ecological status, 111 p, Institutional Repository

Beratung und Wissenstransfer

Programm Fliessgewässer Schweiz

Merkblattsammlung Wasserbau und Ökologie (BAFU)

Modul-Stufen-Konzept (BAFU)

«Fischabstieg» - ein gemeinsames Projekt  mit den Aare-Rhein-Kraftwerken und der VAW

Integrales Gewässermanagement

Abteilungen, die sich zentral mit dem Thema «Ökosysteme» befassen

Expertinnen und Experten

Prof. Dr. Rik Eggen
  • Aquatische Ökotoxikologie
  • Mikroverunreinigungen
  • Oberflächengewässer
Dr. Philine Feulner
Dr. David Johnson
Prof. Dr. Jukka Jokela
  • Algen
  • Aquatische Ökotoxikologie
  • Fische
  • Genetik
  • Plankton
  • Proteomik
Dr. Hans Peter Kohler
  • Mikroverunreinigungen
  • Organische Verunreinigungen
  • Trinkwasser
Dr. Blake Matthews
  • Biodiversität
  • Plankton
  • Evolution
  • Ökosysteme
Dr. Carlos Melian
Dr. Anita Julianne Tricia Narwani
Dr. Christopher Robinson
Prof. Dr. Carsten Schubert
  • Isotope
  • Oberflächengewässer
Prof. Dr. Ole Seehausen
  • Fische
  • Genetik
  • Ökologie
  • Evolution
PD Dr. Piet Spaak
  • Plankton
  • Sedimente
Dr. Colette vom Berg
  • Fische
  • Molekulare Ökotoxikologie
Prof. Dr. Alfred Johny Wüest
  • Aquatische Ökologie
  • Wasserqualität
  • Stoffhaushalt und Gewässerschutz in Seen