Carbon storage in tidal marsh sediments in the Bay of Fundy : the role of vegetation and depth

Abstract

Tidal marshes have the ability to sequester and store atmospheric CO₂ and thus contribute a valuable ecosystem service. Globally, tidal marshes have declined due to environmental damage and habitat conversion—however, restoration has become a promising mode of revitalization of these ecosystems. Little is known about carbon storage differences between restored and natural marshes or the factors that influence carbon storage in these systems. This study compares belowground carbon stocks in three tidal marshes (new restoration, old restoration, natural reference). Carbon content was sampled using a Russian peat corer at three locations in Spartina alterniflora vegetation at each marsh. Two sediment cores were taken at each sampling location, one from an area with live plants and one from bare mud, and each core subdivided into three depths: surface (<3cm), rhizosphere (3cm-30cm) and below-rhizosphere (<30cm). Statistical analysis showed that depth had no significant effect. Given this, it appears that the depth at which carbon is buried does not impact long-term carbon storage within tidal marshes. The older restoration and natural sites contained a similar amount of buried carbon as the new restoration site. There was no significant difference in carbon storage between vegetated versus unvegetated areas across all marshes. Further studies should explore the role of sedimentation and its influence on carbon storage within these systems. In addition, the impact of climate change should also be monitored within tidal marshes to ensure correct methods for conservation and restoration are being employed.