Macroalgal Blooms Trigger the Breakdown of Seagrass Blue Carbon

• DOI: 10.1021/acs.est.0c03720
• Publication Date: 2020-10-26T13:50:05Z
• Authors: Songlin Liu; Stacey M. Trevath...; Carolyn J. Ewers ...; Xiaoping Huang; Peter I. Macreadie
• Keywords: Detritus; Blue carbon; Microbial loop

Intensive macroalgal blooms, a source of labile organic carbon (LOC) induced by coastal nutrient loading in some seagrass ecosystems, create ideal conditions for enhanced recalcitrant (ROC) loss via the cometabolism effect. Here, we carried out 62-day laboratory experiment to see if density-dependent addition biomass can influence decomposition process, including detritus chemistry, greenhouse emissions, and bacterial communities. We found that higher density stimulated microbes decompose ∼20% more compared other treatments, which was also reflected (∼twofold) gas emissions. Although composition seagrass-associated microbiome communities unaffected macroalgae, showed high caused relative depletion ROC as lignin lipid compounds, well δ13C δ15N enrichment detritus. These results suggest blooms may stimulate remineralization components cometabolism, possibly through providing available energy or resources synthesis ROC-degrading enzymes within resident microbial population. This study provides evidence be mechanism leading reduced blue sequestration preservation.