[A-CG43] 沿岸海洋生態系──２．サンゴ礁・藻場・マングローブ

[ACG43-05] 沿岸植生域の堆積環境変化と再配置が有機炭素貯留速度に与える影響

*渡辺 謙太¹、清家 弘治²、梶原 瑠美子³、所 立樹¹、田多 一史¹、門谷 茂⁴、桑江 朝比呂¹ (1.港湾空港技術研究所、2.産業技術総合研究所・地質調査総合センター、3.寒地土木研究所、4.北海道大学)

キーワード：海草藻場、塩性湿地、炭素貯留、同位体分析、堆積年代推定

Vegetated coastal ecosystems store substantial amounts of organic carbon (C_org), and the conservation and restoration of these habitats are considered as important measures for mitigating climate change. Although various geophysical and biogeochemical factors control C_org storage in the sediment of these habitats, how spatiotemporal variations in the depositional environment (e.g., relative sea-level change, geological settings, habitat type) affect C_org accumulation rate is uncertain. In this study, we showed that depositional environment changes and the subsequent habitat relocation regulate C_org accumulation rate in boreal contiguous seagrass-saltmarsh habitats by using the historical depositional records. In particular, the C_org accumulation rate was accelerated with relative sea-level rise which would be driven by post-seismic land subsidence in this region. Our findings provide historical analogues for the future impact of sea-level change on C_org accumulation rate in vegetated coastal ecosystems.