Congratulations, Irene! (May 2021)
Irene Gallego received a 5 month Academic Transition Grant from Eawag to work on single-cell trait variation among phytoplankton taxa under resource limitation using high-throughput imaging. That means Irene will be sticking around with us for a while longer. We are so happy and proud of you, Irene.
Irene Gallego received a 5 month Academic Transition Grant from Eawag to work on single-cell trait variation among phytoplankton taxa under resource limitation using high-throughput imaging. That means Irene will be sticking around with us for a while longer. We are so happy and proud of you, Irene.
Welcome to the group!
Shannon Eckhardt, Lisa Marchand, Clara Fronda and Gabriella Mege are joining us this summer (2021).
Shannon joins us as a scientific assistant after completing her internship in the group early in the spring. Lisa and Clara are doing internships in the group this summer and will be working with Vanessa on phytoplankton metabolomics. Gabriella accepted a 3-year scientific assistant position in the group and will be working on the SNF-Funded project investigating the influence of temperature on competition in freshwater phytoplankton. Welcome everyone - we are so glad to have you join us.
Paper out in Ecology: Non-additive effects of foundation species determine the response of aquatic ecosystems to nutrient perturbation (May 2021).Eutrophication acts as a disturbance to aquatic ecosystems. Foundation species, or those species that are crucial in structuring communities and the functioning of ecosystems, are likely to be important for the resilience in the face of disturbance as well. We used outdoor experimental pond ecosystems to manipulate the presence of two foundation species, the macrophyte Myriophyllum spicatum and the mussel Dreissena polymorpha. We quantified ecosystem responses to multiple nutrient disturbances over two years. We used high-frequency measurements (every 15 min) from automated sondes to model whole-ecosystem metabolism, and to measure multiple ecosystems properties. Overall, both foundation species strongly affected the ecosystem responses to nutrient perturbation and initially suppressed the increase in phytoplankton abundance following nutrient additions. However, when both species were present, phytoplankton biomass increased substantially relative to other treatment combinations. The response was non-additive for multiple ecosystem metrics following the nutrient perturbations in both years. We demonstrate how interactions between foundation species can cause strong deviations from the expected responses of aquatic ecosystems to nutrient additions.
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Welcome to the group, Imran Khaliq (Jan 2021).
Imran is the BGB postdoc working on an ETH-Domain funded project on warming-related community turnover. He moved to Switzerland in March and is doing a fantastic job of wrangling enormous amounts of biodiversity, body size and thermal niche data.
Imran is the BGB postdoc working on an ETH-Domain funded project on warming-related community turnover. He moved to Switzerland in March and is doing a fantastic job of wrangling enormous amounts of biodiversity, body size and thermal niche data.
Paper out in Philosophical Transactions of the Royal Society B:
The evolution of competitive ability for essential resources (March 2020).
Competition and resource limitation are important determinants of biodiversity and community structure. However, competitive abilites are normally treated as fixed in models and empirical investigations of competition. In this paper we show that minimum resource requirements (R*) and other traits related to competition can evolve in response to selection under essential resource limitation. Our findings suggest that competition is a moving target, and ecological models of competitive community assembly should incoporate the potential for evolutionary change in competitive abilites. Surprisingly however, we did not find evidence supporting the widely held notion that an improved ability to compete for one resource should come at the cost of a loss of competitive ability for another. In fact, improvements in competitive ability were often positively associated. We did find support for a 'gleaner-opportunist' trade-off however, suggesting that one can either grow fast in replete environments or win in resource-limited environments, but not both. Read the full article and the other great papers that make up a part of this special issue of Phil Trans here.
The evolution of competitive ability for essential resources (March 2020).
Competition and resource limitation are important determinants of biodiversity and community structure. However, competitive abilites are normally treated as fixed in models and empirical investigations of competition. In this paper we show that minimum resource requirements (R*) and other traits related to competition can evolve in response to selection under essential resource limitation. Our findings suggest that competition is a moving target, and ecological models of competitive community assembly should incoporate the potential for evolutionary change in competitive abilites. Surprisingly however, we did not find evidence supporting the widely held notion that an improved ability to compete for one resource should come at the cost of a loss of competitive ability for another. In fact, improvements in competitive ability were often positively associated. We did find support for a 'gleaner-opportunist' trade-off however, suggesting that one can either grow fast in replete environments or win in resource-limited environments, but not both. Read the full article and the other great papers that make up a part of this special issue of Phil Trans here.
Paper out in Oecologia: Warming and Biodiversity drive CO2 dynamics in freshwaters (January 2020)
Climate change and biodiversity losses are occuring simulaneously around the world. Though we know that each of these changes can influence the properties and functioning of ecosytems, little is known about how they may interact, and how their effects on ecosystem properties may be driven by restructuring of communities. In this mesocosm experiment using freshwater foodwebs, we manipulated both phytoplankton species diversity and temperature, and investigated the influence of these factors on community structure, total phytoplankton biomass, and the dissolved concentrations of CO2. We found that while there were no interactive effects of warming and diversity on the CO2 concentrations of the water, each factor alone had substantial negative effects, with these effects being largely mediated by positive effects on total phytoplankton biomass. You can read the full article here.
Climate change and biodiversity losses are occuring simulaneously around the world. Though we know that each of these changes can influence the properties and functioning of ecosytems, little is known about how they may interact, and how their effects on ecosystem properties may be driven by restructuring of communities. In this mesocosm experiment using freshwater foodwebs, we manipulated both phytoplankton species diversity and temperature, and investigated the influence of these factors on community structure, total phytoplankton biomass, and the dissolved concentrations of CO2. We found that while there were no interactive effects of warming and diversity on the CO2 concentrations of the water, each factor alone had substantial negative effects, with these effects being largely mediated by positive effects on total phytoplankton biomass. You can read the full article here.
Paper out in Proceedings of the Royal Society B
(October 16, 2019)
We performed whole-pond experimental manipulations to investigate how foundation species and their interactions can affect the functioning and stability of aquatic ecosystems in response to disturbance by nutrient inputs. We found that while each species alone was able to reduce the extent of algal blooms and keep the water clearer over time, this effect was reversed when both species occured together. In the presence of both foundation species, the sytems became turbid and recovered more slowly from larger and larger nutrient additions. This change in system behavior was associated with an increase in dominance by a small cyanobacterium - Synechococcus - and a drop in multivariate trait evenness. In turn, numerous chemical and physical properties of the systems also changed. To find out more, take a look here.
photo credit: Thomas Klaper
(October 16, 2019)
We performed whole-pond experimental manipulations to investigate how foundation species and their interactions can affect the functioning and stability of aquatic ecosystems in response to disturbance by nutrient inputs. We found that while each species alone was able to reduce the extent of algal blooms and keep the water clearer over time, this effect was reversed when both species occured together. In the presence of both foundation species, the sytems became turbid and recovered more slowly from larger and larger nutrient additions. This change in system behavior was associated with an increase in dominance by a small cyanobacterium - Synechococcus - and a drop in multivariate trait evenness. In turn, numerous chemical and physical properties of the systems also changed. To find out more, take a look here.
photo credit: Thomas Klaper
Mesocosms and more (April 24, 2019)
Setting up in-lake mesocosms
We are preparing for in-lake mesocosm experiments this summer, and there is a lot inolved.
Last week we went on a deep-lake dive with the Lake Greifen police. We played a game of hide and seek with our missing mesocosm buoy. The Lake Policeman was very kind and offered to put on his dry-suit to do his detective work. Lucky for us, X marked the right spot and he managed to retrieve the sunken buoy and anchors within a few hours.
We also had a great visit to Seeon, to visit Mia Stockenreiter. Mia gave us all the details on how to get mesocosms set up in lakes: from heat-sealing polyethylene bags, to scaring off birds. With her wise tips, we are ready to meet the challenge of manipulating resource availability in Lake Greifen.
Setting up in-lake mesocosms
We are preparing for in-lake mesocosm experiments this summer, and there is a lot inolved.
Last week we went on a deep-lake dive with the Lake Greifen police. We played a game of hide and seek with our missing mesocosm buoy. The Lake Policeman was very kind and offered to put on his dry-suit to do his detective work. Lucky for us, X marked the right spot and he managed to retrieve the sunken buoy and anchors within a few hours.
We also had a great visit to Seeon, to visit Mia Stockenreiter. Mia gave us all the details on how to get mesocosms set up in lakes: from heat-sealing polyethylene bags, to scaring off birds. With her wise tips, we are ready to meet the challenge of manipulating resource availability in Lake Greifen.
Paper in press at Oikos (March 26, 2019)
Temperature‐dependence of minimum resource requirements alters competitive hierarchies in phytoplankton
In this paper we measured the minimum resource requirements for light and nitrogen of six different phytoplankton species along a gradient of temperatures. We found that temperature can alter resource requirements and, as a result, shift competitive hierarchies for resources. Check it out!
Temperature‐dependence of minimum resource requirements alters competitive hierarchies in phytoplankton
In this paper we measured the minimum resource requirements for light and nitrogen of six different phytoplankton species along a gradient of temperatures. We found that temperature can alter resource requirements and, as a result, shift competitive hierarchies for resources. Check it out!
ChlamEE P* experiments up and running (March 21, 2019)
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The set-up of the last R* experiment to investigate how competitive abilities of Chlamydomonas reinhardtii evolve under long-term resource limitation is off to the races!
Hats off to this amazing, hard-working team. They may have broken a record on the number of people working simultaneously in a sterile hood. |
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Welcoming new folks to the group! (March 1, 2019)
Carolina Carvalho joins us today as a scientific assistant. She'll be a crucial member of our team as we run lake-mesocosm and lab evolution experiments this summer. Welcome Carolina!
Irene Gallego-Nogales will also join the group in April. Irene will be working on an SNF-funded postdoc in April to investigate the evolution of competitive ability in phytoplankton in natural communities. Irene joins us from Bas Ibeling's group at the University of Geneva, where she had been investigating the role of cell size in shaping niche and fitness differences that determine coexistence in phytoplankton. Check out her paper in the ISME J!
Irene Gallego-Nogales will also join the group in April. Irene will be working on an SNF-funded postdoc in April to investigate the evolution of competitive ability in phytoplankton in natural communities. Irene joins us from Bas Ibeling's group at the University of Geneva, where she had been investigating the role of cell size in shaping niche and fitness differences that determine coexistence in phytoplankton. Check out her paper in the ISME J!
Paper out in Nature Communications! (November 7, 2018)Proteome evolution under non-substitutable resource limitation
Our paper on the evoluiton of protein expression under long-term selection by resource limiation is out in Nature Communications. Also, check out the associated "Behind the paper" blogpost in Nature Ecology and Evolution. Take a look! |
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