Unveiling the unknown diversity of planktonic green algae (Chlorophyta) in urban ponds in the semiarid region of Northeastern Brazil.

This study examined the taxonomic composition and ecological aspects of planktonic green algae (Chlorophyta) in four urban ponds (Parque da Lagoa, Lagoa Grande, Laguneville, and Pindoba) in Feira de Santana, Bahia State, Brazil. We analyzed 96 samples collected bimonthly in 2022 and identified 54 taxa, with the majority (42) classified as uncommon or sporadic. The most common species were Monoraphidium circinale and Lemmermannia komarekii, found in 100% and 95.8% of samples, respectively. Parque da Lagoa had the highest number of taxa (43), followed by Lagoa Grande (40), Laguneville (31), and Pindoba (30). Most taxa were found in water with high levels of oxygenation (5.8-12.3 mg L-1) and conductivity (400-1000 μS cm-1), neutral to slightly alkaline conditions (pH 7-8), and moderate water temperature (26-27 °C). Significant differences in the composition of planktonic green algae and limnological variables were observed among ponds. These studies underscore the importance of implementing actions aimed at the restoration and conservation of urban ponds in Feira de Santana to avoid biodiversity loss and eutrophication while ensuring the provision of critical ecosystem services, such as local climate regulation.