Work

Disentangling effects of protection on seabed organic carbon and biodiversity in a rare highly protected mud-dominated MPA

Year: 2026

Type: article

Abstract: Soft sediment habitats on the European shelf have endured centuries of bottom trawling, causing major biodiversity loss and long-term degradation. Due to sustained value to commercial fisheries and perceptions of low biodiversity value, they have been overlooked in the designation of MPAs. Recently, the role these habitats and their ecological communities may play in carbon storage has emerged as a compelling argument for strict protection. We investigated the effects of protection on biodiversity and sediment organic carbon (OC) in a rare, highly protected, mud dominated MPA, the South Arran Marine Protected Area. Despite the challenge of confounding environmental variables inherent to coastal MPAs, we showed strong positive responses of epifaunal and infaunal communities exclusively to protection, with shifts in fish community structure. Organic carbon concentration was driven primarily by sediment mud content; however, protection increased the total organic carbon–to–mud ratio and stabilized the positive mud–organic carbon relationship which was significantly less reliable in the unprotected zone. Our results demonstrate that protecting soft sediments can enhance biodiversity and may contribute to climate mitigation. We call for their consideration in the establishment of strict, well-enforced MPAs as an opportunity to re-calibrate chronically shifted ecological baselines, and to understand their potential in carbon storage.

Source: Estuarine Coastal and Shelf Science

DOI: 10.1016/j.ecss.2026.109881