Laurence Besseau
Maître de Conférences
TEMPO
Environmental rhythms, biological clocks and shell biomineralisation
Project at a glance
2019-2023
Banyuls-sur-Mer (FR)
Mytilus galloprovincialis
Chronobiology
Sclerochronology
Biomineralisation
Ecophysiology
Context
Marine organisms live in environments structured by recurring temporal variations, including day-night cycles, tides, temperature fluctuations and changes in food availability. Biological clocks allow organisms to anticipate such predictable environmental changes and synchronise their physiology and behaviour accordingly.
TEMPO was developed within a broader interdisciplinary effort between the EcoEvoDevo team at BIOM, and the LECOB, both based at the Observatoire Océanologique de Banyuls-sur-Mer, to understand the temporal organisation of Mediterranean coastal ecosystems. Within this framework, the EcoEvoDevo team focused on a more mechanistic question: how are environmental rhythms integrated and can biological clocks control the temporal pattern of shell formation?
Using the Mediterranean mussel Mytilus galloprovincialis, TEMPO investigates the interaction between environmental variability, endogenous biological rhythms and shell biomineralisation.
Objectives
Understanding how environmental time is translated into rhythmic shell growth
The EcoEvoDevo contribution to TEMPO combines field observations, experimental chronobiology, molecular biology and sclerochronology to determine how environmental cycles and endogenous biological clocks interact in the regulation of shell formation in Mytilus galloprovincialis.
Key questions
1. How does shell biomineralisation vary across environmental contexts?
We compare mussel shell growth and increment deposition across contrasting Mediterranean environments and seasons to determine how local environmental conditions influence the temporal organisation of biomineralisation.
2. Which environmental cues synchronise mussel biological rhythms?
We investigate how recurrent environmental signals, particularly light, temperature, tidal conditions and trophic resources, contribute to the synchronisation of physiological rhythms and shell growth.
3. Are shell biomineralisation rhythms controlled by endogenous biological clocks?
Using molecular and experimental approaches, we test whether rhythmic biomineralisation persists when environmental cycles are removed or manipulated, and investigate the relationship between biological-clock activity and genes involved in shell formation.
Why mussels?
As sessile filter feeders, mussels experience environmental fluctuations directly and continuously. At the same time, their activity and physiology exhibit strong biological rhythms, while their shells preserve successive growth increments over time.
Mytilus galloprovincialis therefore provides a particularly powerful model for linking environmental cycles, endogenous timekeeping mechanisms and the formation of a physical biological archive. Its occurrence across contrasting Mediterranean habitats also makes it possible to investigate how the relative influence of environmental and intrinsic controls changes with local conditions.
Understanding the time recorded in shells
Bivalve growth increments are widely used to reconstruct environmental histories, yet their interpretation assumes that we understand what actually determines when an increment is deposited. Research conducted within TEMPO shows that this process cannot be explained by environmental variability alone.
Shell biomineralisation exhibits rhythmic molecular and structural patterns, and the periodicity of growth increments can change according to habitat and environmental context. Experimental evidence further supports the existence of endogenous circadian and circatidal regulation in M. galloprovincialis. Together, these findings reveal that shell growth emerges from a complex interaction between environmental cues and biological clocks, with important implications for both organismal chronobiology and the use of bivalve shells as environmental archives.
Project team and partners
BIOM - CNRS, Sorbonne Université
Laurence Besseau - Coordinator
Victoria Louis - PhD student
Victoria Louis - PhD student
LECOB - CNRS, Sorbonne Universitté
Franck Lartaud
Victoria Louis - PhD student
Victoria Louis - PhD student
Funding
CNRS 80|Prime MITI - TEMPO
Mission pour les Initiatives Transverses et Interdisciplinaires & 80|Prime interdisciplinary programme
2019-2020
2019-2020
Interested in this research?
Our projects regularly involve Master students, PhD candidates and postdoctoral researchers interested in marine Eco-Evo-Devo, ecotoxicology, behaviour and integrative biology.
