Sindia M. Sosdian, Michael K. Gagan, Danny H. Natawidjaja, Alena K. Kimbrough, Bambang W. Suwargadi, Hamdi Rifai, Heather Scott-Gagan, Dudi Prayudi, Imam Suprihanto, Wahyoe S. Hantoro
On 28 March 2005, the Indonesian islands of Nias and Simeulue experienced a powerful Mw 8.6 earthquake and coseismic uplift and subsidence. In areas of coastal uplift (up to ~ 2.8 m), fringing reef coral communities were killed by exposure, while deeper corals that survived were subjected to habitats with altered runoff, sediment and nutrient regimes. Here we present time-series (2000–2009) of Mn/Ca, Y/Ca and Ba/Ca variability in massive Porites corals from Nias to assess the environmental impact of a wide range of vertical displacement (+ 2.5 m to − 0.4 m). High-resolution LA-ICP-MS measurements show that skeletal Mn/Ca increased at uplifted sites, regardless of reef type, indicating a post-earthquake increase in suspended sediment delivery. Transient and/or long-term increases in skeletal Y/Ca at all uplift sites support the idea of increased sediment delivery. Coral Mn/Ca and Ba/Ca in lagoonal environments highlight the additional influences of reef bathymetry, wind-driven sediment resuspension, and phytoplankton blooms on coral geochemistry. Together, the results show that the Nias reefs adapted to fundamentally altered hydrographic conditions. We show how centuries of repeated subsidence and uplift during great-earthquake cycles along the Sunda megathrust may have shaped the modern-day predominance of massive scleractinian corals on the West Sumatran reefs. © The Author(s) 2024.
School of Earth and Environmental Sciences, Cardiff University, Cardiff, CF10 3AT, United Kingdom; Research School of Earth Sciences, The Australian National University, Canberra, 2601, ACT, Australia; School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, 2522, NSW, Australia; School of the Environment, The University of Queensland, St Lucia, 4072, QLD, Australia; Research Center for Geological Disaster, National Research and Innovation Agency (BRIN), Bandung, 40135, Indonesia; Research Center for Geotechnology, Indonesian Institute of Sciences (LIPI), Bandung, 40135, Indonesia; Department of Physics, Universitas Negeri Padang, Padang, 25131, Indonesia
