Coastal vegetated ecosystems have received global interest for their possible role in climate change mitigation. To date, studies on aquatic plants have mainly focused on the role of mono-specific seagrass stands, typically ignoring that the coastal zone can be heterogeneous, where multiple species with a range of trait characteristics may influence carbon storage differently across seasons. With few studies having assessed how functional traits link to carbon storage in aquatic plant communities, we sought to explore (i) the relationship between functional community composition and biomass-bound carbon stocks, and (ii) seasonal fluctuations of non-structural carbohydrates in different plant species. We conducted multiple field surveys (i.e., October, March, June and August) in the Baltic Sea, Finland, where we sampled six soft-bottom communities dominated by aquatic vascular plants and measured nine traits that capture the key variation in plant life-history strategies. We found that functional composition was associated with plant carbon stocks and this relationship was mediated by seasonality. Non-structural carbohydrates varied significantly through time, with the amount stored in leaf tissue throughout winter being tied to functional characteristics of the leaves. Our results indicate that the underlying biological mechanisms influencing carbon storage are affected by community trait composition, underlining the importance of using functional traits as a tool to assess the role of aquatic plant biodiversity for ecosystem functioning.

Primary Presenter: Roel Lammerant, University of Helsinki (roel.lammerant@helsinki.fi)

Authors:

Roel Lammerant, University of Helsinki  (roel.lammerant@helsinki.fi)

Eva Rohlfer, University of Helsinki  ()

Alf Norkko, University of Helsinki  ()

Camilla Gustafsson, University of Helsinki  ()