Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG40] Coastal Ecosystems - 1. Water Cycle and Land-Ocean Interactions

Tue. May 28, 2019 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Masahiko Fujii(Faculty of Environmental Earth Science), Makoto Yamada(Faculty of Economics, Ryukoku University), Jun Shoji(The University of Tokyo), Ryo Sugimoto(Faculty of Marine Biosciences, Fukui Prefectural University)

[ACG40-P03] Construction of an artificial outlet channel affects organic carbon accumulation in a coastal lagoon

*Kenta Watanabe1, Tomohiro Kuwae1 (1.Port and Airport Research Institute)

Keywords:organic carbon storage, seagrass meadows, saltmarshes, coastal construction, age-depth modelling

Organic carbon (Corg) storage is one of the important functions of vegetated coastal ecosystems for mitigating the adverse effects of climate change. The artificial alteration of landforms by coastal constructions would impact on habitats, hydrological conditions, and sediment loads. However, how the coastal constructions change Corg accumulation in vegetated coastal ecosystems is poorly understood. In this study, the sediment profiles of geological and biogeochemical characteristics were measured in Komuke Lagoon, Hokkaido. Stable isotope ratios and 210Pb profiles were used to investigate the origin of Corg and sediment age. We showed that Corg accumulation rates and the origin of accumulated Corg significantly changed after the construction of an artificial outlet channel. Corg accumulation was enhanced, the contribution of terrestrial-derived Corg decreased, and that of microalgae- and seagrass-derived Corg increased after the coastal construction at the site. These findings indicate that the construction of an artificial outlet channel alters the frequency of seawater exchange and affects habitat types and Corg accumulation.