Ian Struewing
Kale Clausen
Nathan Reetz
Ned Fairchild
Lacey Goeres-Priest
Theo Dreher
Rochelle Labiosa
Kurt D. Carpenter
Barry Rosen
Eric Villegas
Jingrang Lu
Youchul Jeon
2025
<p><span>The excessive growth of harmful cyanobacteria, including </span><i>Dolichospermum</i><span> (formerly known as </span><i>Anabaena</i><span>), in freshwater bodies has become a pressing global concern. However, detailed information about the role of </span><i>Dolichospermum</i><span> in shaping bloom dynamics and producing cyanotoxins is limited. In this study, a bloom event dominated by </span><i>Dolichospermum</i><span> spp. at Detroit Lake (Oregon, USA) was examined from 2019 to 2021. In 2019, early summer cyanobacterial community succession reached up to 8.7 % of total phytoplankton abundance. </span><i>Dolichospermum</i><span> was the major microcystin (MC)-producing genus, with peak MC levels of 7.34 μg </span><i>L</i><sup>−1</sup><span>. The presence of MCs was strongly correlated with the abundance of </span><i>Dolichospermum</i><span> (</span><i>r</i><span> = 0.84, </span><i>p</i><span> < 0.05) and MC synthetase gene, </span><i>mcyE-Ana</i><span> (</span><i>r</i><span> = 0.63, </span><i>p</i><span> < 0.05). Metabolic analyses further showed that the presence of </span><i>nif</i><span>/</span><i>pst</i><span> genes linked to nitrogen and phosphorus metabolism was dominated by </span><i>Dolichospermum</i><span> from the bloom onset until September. In addition, the abundance of </span><i>Dolichospermum</i><span> was significantly correlated with the abundance of nitrogen-fixing </span><i>nif-Ana</i><span> gene (</span><i>r</i><span> = 0.62, </span><i>p</i><span> < 0.05). As the lake experienced a longer N and P scarcity period (May to September), the N</span><sub>2</sub><span>-fixing </span><i>Dolichospermum</i><span> was able to dominate over other non-fixing cyanobacteria present, including </span><i>Microcystis</i><span> and </span><i>Planktothrix</i><span>. Overall, our results facilitate a better understanding of the organism and will help working toward managing/predicting future blooms.</span></p>
application/pdf
10.1016/j.hal.2025.102802
en
Elsevier
Dominant Dolichospermum and microcystin production in Detroit Lake (Oregon, USA)
article