Within Evo-Eco-Paléo (EEP), Eiver Gelan Manzano explored the diversity of phytoplankton during the Paleozoic.
Eiver Gelan Manzano, chercheur·e au sein de Evo-Eco-Paléo (EEP) (Université de Lille).
Thèse soutenue en 2025 à l'école doctorale École doctorale Sciences de la matière, du rayonnement et de l'environnement (Lille ; 1992-....).
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
Eiver Gelan Manzano's thesis, titled "Diversity of Phytoplankton in Space and Time during the Lower and Middle Paleozoic," offers a fascinating and in-depth dive into the evolution of aquatic ecosystems through geological ages. By studying phytoplankton diversity, the author highlights crucial ecological dynamics that have shaped our oceans, as well as lakes and other aquatic environments. This research goes beyond a simple taxonomic analysis; it questions the environmental factors that influence the distribution and diversity of species, a matter of paramount importance in the current context of climate crisis. Indeed, understanding the interactions between phytoplankton and its environment is essential for anticipating the impacts of contemporary climate changes, which threaten the stability of aquatic ecosystems.
Multivariate analysis methods, such as hierarchical cluster analysis and non-metric multidimensional scaling, have allowed the author to process georeferenced data from various regions, including Northern Poland and Southern China. These data reveal significant temporal variations in phytoplankton diversity, underscoring the importance of conserving aquatic ecosystems. For example, fluctuations in temperature and salinity, as well as variations in the chemical composition of waters, are factors that influence phytoplankton diversity. These observations are particularly relevant in a context where human activities, such as intensive agriculture and urbanization, modify aquatic habitats.
The results of this thesis raise fundamental questions about how environmental disturbances, whether natural or anthropogenic, affect biodiversity. Deoxygenation events, often linked to excessive nutrient inputs, can lead to harmful algal blooms that disrupt aquatic food chains. The recommendations made by the author go beyond mere observation: they call for conservation policies based on a deep understanding of ecological dynamics. By encouraging further research on the impacts of environmental changes, Manzano paves the way for better anticipation of the effects of human activities on these essential communities.
It is imperative that decision-makers take these results into account to develop effective conservation strategies. Research on phytoplankton, although often overlooked, is crucial for the health of aquatic ecosystems and, by extension, for overall biodiversity. Indeed, phytoplankton plays a key role in the primary production of oceans, thus contributing to the regulation of biogeochemical cycles, notably the carbon cycle. In summary, this thesis enriches our understanding of phytoplankton ecology during the Paleozoic and lays the groundwork for reflection on contemporary issues of aquatic biodiversity.
To illustrate the importance of this research, let us take the example of recent conservation efforts in regions like Benin, West Africa. The aquatic ecosystems of this region, rich in biodiversity, are threatened by pollution and climate change. By integrating the results of Manzano's thesis, biodiversity managers could better understand how changes in phytoplankton diversity can affect the entire aquatic ecosystem. This could lead to more targeted conservation initiatives aimed at restoring and protecting these vital habitats.
In conclusion, Eiver Gelan Manzano's thesis does not merely describe phytoplankton diversity during the Paleozoic; it compels us to reflect on the implications of this diversity for the health of modern aquatic ecosystems. By highlighting the importance of phytoplankton research, Manzano underscores the need for an integrated approach to biodiversity conservation that takes into account the complex interactions between species and their environment. This research is a call to action for scientists, decision-makers, and the general public to protect our aquatic resources for future generations.
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Sources et accès
Eiver Gelan Manzano. Diversity of phytoplankton in space and time in the early and middle Paleozoic. Earth Sciences. Université de Lille, 2025. English. ⟨NNT : 2025ULILR033⟩. ⟨tel-05593367⟩