Are We Underestimating Benthic Cyanotoxins? Extensive Sampling Results from Spain

Area of Science:

• Environmental toxicology
• Microbiology
• Ecotoxicology

Background:

• Microcystins (MCs) are hepatotoxins impacting aquatic ecosystems.
• Limited knowledge exists on MCs in non-planktonic habitats.
• Understanding MC distribution is vital for environmental and human health.

Purpose of the Study:

• To investigate the presence and distribution of microcystins in various Spanish aquatic and terrestrial habitats.
• To identify novel microcystin-producing species and toxin variants.
• To assess the significance of MC-LF and MC-LY in environmental samples.

Main Methods:

• Extensive sampling across diverse aquatic and terrestrial environments in Spain.
• Analysis of cyanobacterial strains for microcystin production.
• Identification of microcystin variants using analytical techniques.

Main Results:

• Over half of tested strains produced microcystins, with low concentrations compared to planktic communities.
• MC-LF and MC-LY were significant variants, ranging from 21.4% to 100% of total MCs.
• Seven new microcystin-producing species were identified in high mountain rivers and chasmoendolithic communities, including in *Geitlerinema*.

Conclusions:

• Microcystins are prevalent across all surveyed habitat types, including peat bogs.
• The study confirms Anatoxin-a in *Phormidium uncinatum*.
• Comprehensive identification of all microcystin variants is essential for accurate risk assessment.