Increased invasion of submerged macrophytes makes native species more susceptible to eutrophication in freshwater ecosystems

Algae removal and degradation of microcystins by UV-C system: A review

Harmful algal blooms (HABs), driven by eutrophication, are a growing ecological threat, compromising water quality and ecosystem health through the release of toxic microcystins (MCs). These toxins pose significant risks to both aquatic life and human health. Among the emerging solutions, UV-C technology has gained attention for its efficiency in inhibiting algal growth and degrading MCs, offering a cost-effective and environmentally friendly approach with minimal secondary pollution. However, existing studies often overlook key aspects, including the variability in algae sensitivity to UV-C wavelengths, the stability of treatment across diverse aquatic conditions, and the toxicity of degradation byproducts. This review highlights the mechanisms underlying UV-C-based algae removal, explores its potential limitation, such as algal resistance, and compares its efficacy with other remediation methods. Notably, the lack of comprehensive research on wavelength-specific sensitivity and real-world application efficacy represents a significant knowledge gap. Further investigation into these areas is essential to optimize UV-C technology for mitigating HABs and improving water safety in eutrophic environments. PRACTITIONER POINTS: The choice of UV band should be adjusted to the algae species. The UV-C system, with limited studies and applications in natural water bodies, demonstrates instability. Combining UV-C with other technologies substantially enhances the efficiency of algal control. Future research should emphasize strategies to prevent the rapid release of microcystins (MCs) from this system due to cell lysis and extracellular release within a short time frame.

Alien emergent aquatic plants develop better ciprofloxacin tolerance and metabolic capacity than one native submerged species

Antibiotic pollution and biological invasion pose significant risks to freshwater biodiversity and ecosystem health. However, few studies have compared the ecological adaptability and ciprofloxacin (CIPR) degradation potential between alien and native macrophytes. We examined growth, physiological response, and CIPR accumulation, translocation and metabolic abilities of two alien plants (Eichhornia crassipes and Myriophyllum aquaticum) and one native submerged species (Vallisneria natans) exposed to CIPR at 0, 1 and 10 mg/L. We found that E. crassipes and M. aquaticum's growth were unaffected by CIPR while V. natans was significantly hindered under the 10 mg/L treatment. CIPR significantly decreased the maximal quantum yield of PSII, actual quantum yield of PSII and relative electron transfer rate in E. crassipes and V. natans but didn't impact these photosynthetic characteristics in M. aquaticum. All the plants can accumulate, translocate and metabolize CIPR. M. aquaticum and E. crassipes in the 10 mg/L treatment group showed greater CIPR accumulation potential than V. natans indicated by higher CIPR contents in their roots. The oxidative cleavage of the piperazine ring acts as a key pathway for these aquatic plants to metabolize CIPR and the metabolites mainly distributed in plant roots. M. aquaticum and E. crassipes showed a higher production of CIPR metabolites compared to V. natans, with M. aquaticum exhibiting the strongest CIPR metabolic ability, as indicated by the most extensive structural breakdown of CIPR and the largest number of potential metabolic pathways. Taken together, alien species outperformed the native species in ecological adaptability, CIPR accumulation and metabolic capacity. These findings may shed light on the successful invasion mechanisms of alien aquatic species under antibiotic pressure and highlight the potential ecological impacts of alien species, particularly M. aquaticum. Additionally, the interaction of antibiotic contamination and invasion might further challenge the native submerged macrophytes and pose greater risks to freshwater ecosystems.

New Alien Plant Taxa for Italy and Europe: An Update

Despite the wide amount of scientific contributions published on alien plant species, their diffusion dynamics, and their interactions with native taxa, it is increasingly difficult to slow down their spreading and their negative impact on habitats. Last recent years, in fact, a sharp rise in the number of new alien plant taxa introduced in Italy and Europe has been recorded. The aim of this work is to investigate most of the Italian territory in order to verify whether this alarming trend is still underway. Specimen collections and/or observations of alien plants have been performed in as many as 12 Italian regions. All the collected specimens are stored in public or private herbaria. Taxa have been identified according to the literature from the countries of origin of the investigated taxa, while the nomenclature followed the current international references. Updates on 106 taxa are reported. In particular, among 117 new records, 89 are first records, 27 are changes to status and there is 1 extinction. Seven new taxa for Italian alien flora are reported, two of which are new to Europe. The administrative regions with the highest number of records are Calabria (48), Sardegna (17) and Sicilia (15). Five of the surveyed taxa, for the first time, have been considered invasive aliens to Italian territory. The unfrequent amount of original results provided by this work, over the simple importance of data itself, proves how floristic investigation, still today, represents one of the most effective tools in broadening the current knowledge about alien taxa and their dynamics.