Metabolic Profiling Reveals Biochemical Pathways Responsible for Eelgrass Response to Elevated CO₂ and Temperature

Area of Science:

• Marine biology
• Plant physiology
• Biogeochemistry

Background:

• Rising atmospheric and oceanic carbon dioxide (CO2) levels present challenges and opportunities for marine ecosystems.
• Seagrasses, vital ecosystem engineers, show potential for enhanced productivity and thermal tolerance under elevated CO2.
• The metabolic mechanisms underlying seagrass responses to increased CO2 remain largely unexplored.

Purpose of the Study:

• To investigate the metabolic shifts in eelgrass (Zostera marina L.) in response to elevated CO2.
• To compare the whole-plant performance and metabolic profiles of two distinct eelgrass populations under CO2 enrichment.

Main Methods:

• Analysis of whole-plant performance metrics including size, growth, and survival.
• Metabolomic profiling to identify changes in plant metabolites.
• Comparative analysis of two geographically distinct Zostera marina populations.

Main Results:

• CO2 enrichment significantly enhanced eelgrass plant size, growth, and survival.
• Elevated CO2 increased the abundance of Calvin Cycle and nitrogen assimilation metabolites.
• Stress-related metabolites were suppressed under high CO2 conditions, and population-specific metabolome differences were observed.

Conclusions:

• Seagrass populations exhibit variable responses to elevated CO2, with some phenotypes better adapted to changing ocean conditions.
• Metabolic shifts, particularly in carbon and nitrogen pathways, drive the positive response of eelgrass to increased CO2.
• Seagrasses may provide negative feedback to climate change by positively responding to rising CO2 concentrations.