Early soil development on Surtsey Island: insights from 20 profile descriptions

Surtsey, a young volcanic island under strict protection from human activities, provides a unique natural laboratory to study soil formation on newly formed land. In July 2024, we examined 20 soil profiles across the island under varying influence of seabird activity and vegetation cover. Although all profiles reflected early-stage pedogenesis, seabird activity and vegetation clearly enhanced horizon development and organic matter accumulation, as reflected by frequent O and Bw horizons at vegetated sites within bird colonies. In contrast, sparsely vegetated or barren sites outside seabird colonies showed minimal organic matter accumulation, with no O-horizons and only occasional weakly developed Bw horizons. Our visual descriptions of soil profiles corroborate previous studies showing the strong role of ornithogenic inputs in organic matter and nutrient accumulation on the island. Future research should aim to better understand the influence of ornithogenic inputs and vegetation on weathering processes and the formation of secondary pedogenic minerals in soils of the island.