The modulating role of natural variability in the biological response to ocean acidification

Details

Supervisors

Dupont, Sam ; Schtickzelle, Nicolas

Faculty

Faculté des sciences

Degree label

Master [120] en biologie des organismes et écologie, à finalité approfondie

Abstract

FOREWARD : I present this thesis in the form of a scientific article, following the authors guidelines of Ecology Letters. The type of article selected is Letters. Therefore, the main text (excluding title, abstract, acknowledgements, references, table and figure legends, and appendices) has a maximum of 5000 words. Ocean acidification (OA) is the consequence of the uptake of excess carbon dioxide from the atmosphere. Along the coastal zone, ocean acidification is influenced by other processes such as biology and currents, leading to high levels of natural variability in pH. While the impact of pH on marine organisms is better resolved, the modulating role of this natural variability is poorly understood. This master's thesis aimed at evaluating diel pH fluctuations using the larval stages of the brittle star Amphiura filiformis. Results revealed the importance of acknowledging pH variations with individuals exhibiting higher fitness. Diel analyses also underscored the existence of an intrinsic circadian cycle where larvae would grow more during the daytime than nighttime, possibly explained by better conditions encountered during the day. In addition, we demonstrated a carryover effect that could also be associated with a stage sensitivity. We suggest that future studies should integrate natural variations and delve into the different species' adaptations as they have an important role in the biological responses to upcoming OA.