Highlights
- 45-days mesocosm experiment with whole-benthic community to mimic nature conditions
- Global warming (GW) and ocean acidification (OA) modify C dynamics on seagrasses.
- OA enhances GPP and NCP and synergistic effects when combined with GW.
- DOC production decreased with OA and GW separately, but increased when combined.
- Climate change potentially increases the blue carbon service of C. nodosa populations.
Abstract
Ocean acidification (OA) and global warming (GW) drive a variety of responses in seagrasses that may modify their carbon metabolism, including the dissolved organic carbon (DOC) fluxes and the organic carbon stocks in upper sediments. In a 45-day full-factorial mesocosm experiment simulating forecasted CO2 and temperature increase in a Cymodocea nodosa community, we found that net community production (NCP) was higher under OA conditions, particularly when combined with warming (i.e., synergistic effect). Moreover, under OA conditions, an increase in aboveground biomass and photosynthetic shoot area was recorded. Interestingly, DOC fluxes were reduced when exposed to OA; however, an increase occurred when both factors acted together (i.e., antagonistic effect), which was attributable to increased DOC release by plants. Our results suggest that C. nodosa populations in temperate latitude may favor blue carbon service in future scenarios of OA and GW by increasing the NCP, the DOC export with lower labile:recalcitrant ratio, and accumulating more organic carbon in upper sediments. These findings offer additional arguments for the urgent need to protect and conserve this valuable ecosystem.
Yamuza-Magdaleno A., Jiménez-Ramos R., Cavijoli-Bosch J., Brun F. G. & Egea L. G., 2025. Ocean acidification and global warming may favor blue carbon service in a Cymodocea nodosa community by modifying carbon metabolism and dissolved organic carbon fluxes. Marine Pollution Bulletin 212: 117501. doi: 10.1016/j.marpolbul.2024.117501. Article.
