Research
Every organism consumes energy and resources to live, grow and reproduce. These transformations of energy move through populations and communities, fueling biological production and ecosystem processes such as the production of oxygen and the cycling of carbon.
The aim of the Functional Ecology group is to explore how the environment, including the interactions within and between species, regulates the rate at which organisms use energy. Our goal is to identify general rules for how organismal processes scale up to determine the functioning of ecosystems.
We combine experimental manipulations of multi-species communities with high-throughput phenotyping of individual organisms to study the ecological and evolutionary mechanisms that influence metabolism and related traits, such as body size, population dynamics and competitive ability. Our main model organisms are marine phytoplankton — tiny algae that are key players in ocean productivity and carbon uptake.
The aim of the Functional Ecology group is to explore how the environment, including the interactions within and between species, regulates the rate at which organisms use energy. Our goal is to identify general rules for how organismal processes scale up to determine the functioning of ecosystems.
We combine experimental manipulations of multi-species communities with high-throughput phenotyping of individual organisms to study the ecological and evolutionary mechanisms that influence metabolism and related traits, such as body size, population dynamics and competitive ability. Our main model organisms are marine phytoplankton — tiny algae that are key players in ocean productivity and carbon uptake.
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How does competition affect organismal metabolism?
Energy use often varies widely among individuals of the same species and size. Some of this variation can be explained by differences in population densities because organisms typically reduce metabolism in crowded conditions. But what drives metabolic suppression and what are its fitness consequences? Food certainly plays a role but we have discovered that cues from conspecifics reduce metabolism even when resources are abundant. We are currently exploring similar mechanisms of metabolic regulation in phytoplankton, including interspecific chemical communication and the effects of competition on the evolution of metabolic traits. Understanding these mechanisms helps us predicting how populations grow because metabolism affects the ability of an organism to compete and reproduce. Relevant papers: Ghedini & Marshall 2023, Lovass et al. 2020, Ghedini et al. 2017 Photo: Phaeodactylum tricornutum by Moritz Klaassen. |
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Scaling patterns in communities
The metabolism of organisms scales predictably with size for many species. So theory predicts that we could infer the metabolism of an entire community based on the scaling of metabolism with size for the species in this community. However we found that across species scaling relationships often do not reflect the scaling of metabolism with size in communities. We are now studying metabolic plasticity and its density regulation to explain this variation. By doing so, we aim to find general principles for how density-dependent processes affect organismal metabolism and, in turn, the productivity and stability of communities. Relevant papers: Ghedini et al. 2020, Ghedini et al. 2018. |
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What are the temporal patterns of energy use in communities?
In the 1960s, ecologists made predictions for how fluxes of energy and resources should change over time in communities (e.g., Odum and MacArthur's work). These predictions have remained largely untested because of past methodological limitations. We leverage high-throughput technologies that allow us to measure changes in resource use, metabolic costs and efficiency of whole communities over time to determine how these fluxes vary with respect to the strength of competition, biodiversity and disturbance. Simultaneously we track the trajectory of species energy use and correlated traits (e.g. size) to explain how community-level patterns emerge. Relevant papers: Ghedini et al. 2022, Ghedini et al. 2020. |
Funding
The lab is supported by a fellowship to Giulia Ghedini from ”la Caixa” Foundation and from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 847648 (LCF/BQ/PI21/11830001).
The lab is supported by a fellowship to Giulia Ghedini from ”la Caixa” Foundation and from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 847648 (LCF/BQ/PI21/11830001).
