<p>Trait-based approaches have been widely employed to advance the understanding of the relationships between species diversity and ecosystem functioning. However, limited knowledge exists regarding how shifts in nutrient levels influence functional traits dynamics during the colonization process of periphytic algae. In this study, it is hypothesized that nutrient availability drives algal colonization through functional trait assembly, and that algal functional diversity is shaped by substrate geometry. A 13-week in situ experiment was conducted to evaluate the colonization of periphytic algae on two types of artificial substrates (perforated and unperforated granite) in both eutrophic and oligotrophic lakes using a trait-based approach. The results of this study revealed that in the nutrient-rich, light-constrained lake, colonization was initially dominated by small-celled, nonattached taxa, followed by stalk-attached and subsequently filamentous taxa; taxa forming arbuscular or irregular colonies and those possessing phycocyanin predominated throughout most of the colonization period. In contrast, in the nutrient-deficient, light-sufficient lake, colonization was initiated by large-celled, adnate-attached, unicellular species, succeeded by filamentous taxa, with nitrogen-fixing taxa contributing substantially to the community. Across substrate types, significantly higher taxonomic and functional diversities of periphytic algae were observed on perforated substrates compared with unperforated substrates in the oligotrophic lake, whereas no such pattern was detected in the eutrophic lake. These findings demonstrate that incorporating functional traits into periphytic algae research can substantially enhance the understanding of how nutrients and substrate characteristics shape key ecological functions during colonization processes.</p>