Journal article
Wet and dry seasons modulate coastal coccolithophore dynamics off South-western Nigeria (Gulf of Guinea)
Biogeosciences, Vol.22(23), pp.7865-7880
09/12/2025
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Abstract
Coccolithophores are calcifying unicellular phytoplankton at the base of the marine food web, playing a key role in pelagic calcium carbonate production. While their sensitivity to environmental change is well established, their ecological importance in tropical coastal systems remains underexplored, particularly along the African coastline. Here, we present the first multi-seasonal assessment of living coccolithophore communities off Lagos, southwest Nigeria, in the Gulf of Guinea. Periodic sampling was conducted at three coastal stations from December 2018 to April 2021 to evaluate species composition, standing stocks, diversity, and ecological drivers. Coccolithophore abundances showed clear seasonal patterns, with significantly higher (p<0.05) standing stocks and diversity during the wet season. Total abundances ranged from 0.3x103 cells L-1 in the dry season to 5.5x103 cells L-1 in the wet season, with Gephyrocapsa oceanica dominating dry periods and Emiliania huxleyi prevailing during the wet season. Seasonal changes were linked to the migration of the Intertropical Convergence Zone (ITCZ), which modulates precipitation and current direction along the Gulf of Guinea. Interestingly, chlorophyll a concentrations appeared decoupled from coccolithophore abundance, suggesting other phytoplankton groups may drive primary productivity in this region. Despite regional differences in oceanographic settings, the observed standing stocks fall within the global range of coastal coccolithophore assemblages, supporting the hypothesis that these communities are shaped by a set of common ecological constraints. As tropical coastal regions already face multiple pressures from climate change, projected southward shifts of the ITCZ could alter precipitation regimes and current dynamics, with potential implications for coccolithophore community composition and coastal biogeochemical cycling.
Details
- Title
- Wet and dry seasons modulate coastal coccolithophore dynamics off South-western Nigeria (Gulf of Guinea)
- Creators
- Falilu o. Adekunbi - University of LagosMichael Grelaud - Universitat Autònoma de BarcelonaGerald Langer - Universitat Autònoma de BarcelonaLucian O. Chukwu - University of LagosMarta Alvarez - Instituto Español de OceanografíaShakirudeen Odunuga - University of LagosKai G Schulz - Southern Cross UniversityPatrizia Ziveri - Institució Catalana de Recerca i Estudis Avançats
- Publication Details
- Biogeosciences, Vol.22(23), pp.7865-7880
- Publisher
- Copernicus Publications
- Number of pages
- 16
- Grant note
- This research has been supported by the financial support of the Spanish Ministry of Science, Innovation and Universities, BIOCAL Project (PID2020-113526RBI00), the BONITOS Project (International program DFG-AEI 2023 – Grant PCI2025-163190, 541693727), the Marine and Environmental Biogeosciences Research Group (MERS) Generalitat de Catalunya (2021 SGR 00640).
- Identifiers
- 991013372615302368
- Copyright
- © Author(s) 2025.
- Academic Unit
- Faculty of Science and Engineering; Science
- Language
- English
- Resource Type
- Journal article