PNNL

Abstract

As CO2 levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may shift the ocean’s ecology, generating ecological losers and winners. Increased ocean CO2 concentrations have shown to enhance seagrasses productivity and survival during summer high temperatures. Seagrasses are critical in marine ecosystems, however, the physiological factors driving this positive response to CO2 are still unknown. We analyzed the metabolic profiles of two natural Zostera marina L. eelgrass populations originated from contrasted environments and exposed to different CO2 enrichment treatments. We uncovered that CO2 stimulation enhanced the abundance of Calvin cycle and N assimilation metabolites, whereas stress-related compounds increased in plants under ambient CO2. Overall metabolome differences between eelgrass populations further suggest that particular phenotypes will be more suited to cope with changing global conditions. Our results suggest that seagrass populations will respond variably but overall positively to increasing CO2 concentrations, generating negative feedbacks to climate change.