Signatures of natural and human activities revealed from sediment archives : a case study of the Kenyan coral reef ecosystems Mwadzombo, N. N. Tole, M. P. Mwashimba, G. P. /Le Cornec, Florence Coral reef ecosystems Coastal development Enrichment factor Ecological risk index Multivariate analysis Use of an integrated approach to assess levels of trace metal from coral reef sediments to identify trace metal pollution source in three Kenyan coral reef ecosystems; Tana Delta Ziwayu Island, Watamu National Marine Park, and Shimoni Mupunguti Marine Reserve, showed that the concentration variation of the trace metals was in the order; Fe > Al > Mn > Zn > Cr > Ni > Y > As > Cu > Pb > Hg > Cd. The marine water quality of the investigated coral reef habitats was evaluated using sediment quality assessment tools (SQAT); enrichment factor (EF) and potential ecological risk index. The results on the EF for the metal variable of priority ranged between 0 > EF < 2 and 20 < EF < 40. Both the environmental marker for terrestrial inputs (e.g., Mn) recorded deficiency to minimal, whereas markers for human development (e.g., Cr, Cu, Pb, and Zn) recorded deficiency to minimal to very high enrichment, implying that both natural and anthropogenic activities were responsible for the trace metal influx in the investigated coral reef ecosystems. The order of EF for the metal variables was Mn < Cu = Pb < Cr < Ni < Zn. Trace metal enrichment across the investigated coral reef habitats was in the order; Watamu > Shimoni > Tana Delta. On the other hand, the evaluated potential ecological risk indices ranged between (0 <= 40), and all the investigated trace metal variable showed no potential pollution risk except for Cd at Tana Delta and Watamu. Moreover, the inferential statistical tools (multivariate analysis and Pearson correlation) revealed that, natural and human-induced drivers were responsible for 60.49 and 21.19% respectively of the observed concentration variation on the trace metal variables. Both the SQAT and the inferential statistical tools indicated that, the coral reef ecosystems at Tana Delta Ziwayu Island were mainly impacted by natural -induced drivers (continental crustal inputs), whereas reefs at Watamu and Shimoni were mainly impacted by human-induced drivers (e.g., coastal urbanization and maritime activities). 2025 text https://www.documentation.ird.fr/hor/fdi:010092235 fdi:010092235 Mwadzombo N. N., Tole M. P., Mwashimba G. P., Le Cornec Florence. Signatures of natural and human activities revealed from sediment archives : a case study of the Kenyan coral reef ecosystems. 2025, 41 (1), 25 [18 p.] EN KENYA OCEAN INDIEN