Abstract
Cyanobacterial harmful algal blooms (cyanoHABs) can form in freshwater, and their toxins are harmful to flora and fauna, including humans. To assess the extent of cyanoHABs in urban waterways, seven creeks and Lady Bird Lake in Austin, TX USA were sampled from July to December 2024. Water chemistry was measured, cyanoHABs identified by microscopy, and cyanotoxins detected by LC-MS. Cyanobacteria, mostly genus Oscillatoria , was detected in all creeks sampled, and the primary cyanotoxin detected was cylindrospermopsin with levels varying between sampling locations and seasons. This study highlights the presence of cyanoHABs in creeks, and the potential risk they may pose.