Guillaume Le Gland

Guillaume Le Gland
Institut de Ciències del Mar · Department of Marine Biology

Doctor of Philosophy

About

12
Publications
2,038
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
32
Citations
Introduction
https://oceanglobe.org - # I currently work on the SPEAD (Simulating Plankton Evolution Through Adaptive Dynamics) project, which goal is to introduce evolution in trait-based plankton community models. I investigate i) the processes enabling the coexistence of multiple phytoplankton species competing for the same nutrients ("paradox of the plankton"), ii) the effect of evolution on the outcome of competition and iii) the effect of climate change on phytoplankton communities.
Additional affiliations
November 2018 - present
Institut de Ciències del Mar
Position
  • PostDoc Position
Description
  • Simulating Planton Evolution with Adaptive Dynamics (SPEAD)
October 2014 - February 2018
Université de Bretagne Occidentale
Position
  • PhD Student
Description
  • Constraining the coast - open ocean exchanges and the biological carbon pump by inverse modeling of two radio-isotopes (radium 228 and thorium 234)
March 2014 - August 2014
Ifremer
Position
  • Internship
Description
  • 0D modeling of Alexandrium blooms in the bay of Brest in inter-specific competition

Publications

Publications (12)
Article
Full-text available
Understanding the phenology of phytoplankton species is a challenge and despite a lot of theoretical work on competition for resources, this process is under-represented in deterministic models. To study the main driver of the species selection, we used a trait-based model that keeps phenotypic variability through physiological trait parameterizati...
Article
Full-text available
Radium-228 (²²⁸Ra), an almost conservative trace isotope in the ocean, supplied from the continental shelves and removed by a known radioactive decay (T1∕2 = 5. 75 years), can be used as a proxy to constrain shelf fluxes of other trace elements, such as nutrients, iron, or rare earth elements. In this study, we perform inverse modeling of a global...
Thesis
Full-text available
Les cycles océaniques du carbone et des principaux nutriments sont mal connus car ils sont affectés par de nombreux puits et sources physiques, chimiques ou biologiques difficiles à estimer par des mesures directes. Une manière de mieux contraindre ces processus importants est d’utiliser l’information contenue dans des traceurs plus simples : les p...
Article
Full-text available
Thorium-234 (Th-234), an insoluble radioisotope scavenged by marine particles, can be used as a proxy of the biological carbon pump. Thorium-234 observations can constrain biogeochemical models, but a necessary first step is to estimate the poorly known partition coefficients between particulate and dissolved phases. In this study, the Th-234 parti...
Article
Full-text available
Diversity plays a key role in the adaptive capacity of marine ecosystems to environmental changes. However, modelling the adaptive dynamics of phytoplankton traits remains challenging due to the competitive exclusion of sub-optimal phenotypes and the complexity of evolutionary processes leading to optimal phenotypes. Trait diffusion (TD) is a recen...
Preprint
Full-text available
The fossil record of marine invertebrates has long fueled the debate on whether or not there are limits to global diversity in the sea1–4⁠. Ecological theory states that as diversity grows and ecological niches are filled, the strengthening of biological interactions imposes limits on diversity5–7⁠. However, the extent to which biological interacti...
Presentation
Full-text available
SPEAD 1.0 is an eco-evolutionary phytoplankton model where phytoplankton are characterized by two traits: the half-saturation constant for a nutrient, and the optimal temperature for growth. Contemporary evolution is allowed through a recently developed method called trait diffusion. After explaining how its equations are derived, this presentation...
Preprint
Full-text available
Diversity plays a key role in the adaptive capacities of marine ecosystems to environmental changes. However, modeling phytoplankton trait diversity remains challenging due to the strength of the competitive exclusion of sub-optimal phenotypes. Trait diffusion (TD) is a recently developed approach to sustain diversity in plankton models by allowing...
Preprint
Full-text available
Diversity plays a key role in the adaptive capacities of marine ecosystems to environmental changes. However, modeling phytoplankton trait diversity remains challenging due to the strength of the competitive exclusion of sub-optimal phenotypes. Trait diffusion (TD) is a recently developed approach to sustain diversity in plankton models by allowing...
Article
Full-text available
Radium 228 (²²⁸Ra), an almost conservative trace isotope of the ocean, supplied from the continental shelves and removed by a known radioactive decay (T1/2 = 5.75 yr), can be used as a proxy to constrain shelf fluxes of other trace elements, such as nutrients, iron, or rare earth elements. In this study, we perform inverse modeling of a global ²²⁸R...
Article
Full-text available
Understanding the phenology of phytoplankton species is a challenge and despite a lot of theoretical work on competition for resources, this process is under-represented in deterministic models. To study the main driver of the species selection, we used a trait-based model that keeps phenotypic variability through physiological trait parameterizati...

Network

Cited By

Projects

Projects (2)
Project
Global ocean ecosystem models should include the ecology & evolution (eco-evo) of microbial plankton to accurately simulate the expected changes in the patterns of diversity, community assembly and ecosystem functioning (i.e. productivity, stability) under future global warming conditions. The GOMMA'21 project goals are: 1) to include eco-evo dynamics in a model of microbial plankton at the global ocean scale; 2) to simulate several evolving populations with the eco-evo model, each of them with adaptive capacity along a three-dimensional fitness landscape (nutrients, temperature, irradiance); 3) to simulate the eco-evolutionary trajectories of microbial plankton to the future (2000 - 2100) using IPCC scenarios of climate change. Ecological indicators of ecosystem functioning such as primary production, biological carbon pump, community trait diversity, and food web structure, will be computed, analysed and compared to simulations using the same model without eco-evo dynamics. The overarching goal is to evaluate the potential of adaptive evolution to impact the response of marine ecosystems to current and future environmental changes.
Project
«Simulating Plankton Evolution with Adaptive Dynamics (SPEAD)» The project SPEAD is based on the notion of dynamic fitness landscapes (DFL), which gives the relationship between genotype and survival fitness for non-constant environmental conditions, to simulate the ecological evolution (eco-evo) of planktonic organisms for the global ocean. The aims of this project are: i) to develop a marine ecosystem model that includes the adaptive evolution of planktonic organisms along several environmental gradients (nutrients, temperature, irradiance) in order ii) to better predict the response of marine ecosystems to future climate change scenarios. To achieve this goal we propose to combine within the same modelling framework two approaches that are so far being developed independently of each other. The classical approach to simulate the dynamics of plankton communities relies on solving phytoplankton populations as discrete entities with fixed environmental optima (Nopt, Topt, Iopt) that do not change over time. A newer alternative approach includes adaptive dynamics using trait diffusion (TD) to solve the temporal evolution of these physiological traits for a single population. The SPEAD project seeks to combine both approaches in order to build a unified model that is able to resolve the adaptive evolution of species-traits for many populations of phytoplankton simultaneously.