Ocean Acidification Amplifies the Olfactory Response to 2-Phenylethylamine: Altered Cue Reception as a Mechanistic...

Area of Science:

• Marine biology
• Chemical ecology
• Oceanography

Background:

• Rising atmospheric carbon dioxide (CO2) causes ocean acidification, lowering pH and threatening marine life.
• The impact of decreasing ocean pH on chemical communication and ecological processes remains largely unknown.
• Hermit crabs inhabit intertidal zones, experiencing natural pH fluctuations alongside anthropogenic ocean acidification.

Purpose of the Study:

• To investigate how ocean acidification affects chemical communication in hermit crabs.
• To explore the mechanisms behind pH-dependent changes in olfactory perception.
• To understand the ecological implications of altered predator cue detection.

Main Methods:

• Behavioral assays with hermit crabs (Pagurus bernhardus).
• Computational chemistry, including quantum chemical calculations.
• NMR spectroscopy to characterize protonation states of 2-phenylethylamine (PEA).
• Assessment of PEA's conformational and charge properties at different pH levels.

Main Results:

• The predator cue 2-phenylethylamine (PEA) acts as an attractant for hermit crabs.
• The attractive potency of PEA increases as ocean pH decreases.
• Protonation of PEA at lower pH levels alters its properties, potentially affecting receptor binding.
• A model receptor (human TAAR1) was used to explore potential pH-dependent receptor-ligand interactions.

Conclusions:

• Ocean acidification enhances the detectability and attractiveness of predator cues for hermit crabs.
• Changes in PEA's chemical properties due to lower pH are a likely mechanism for increased potency.
• This pH-dependent olfactory response could significantly alter predator-prey interactions and food web dynamics in marine ecosystems.
• The study highlights the vulnerability of marine chemical communication to ocean acidification.