Abstract
Cyanobacterial harmful algal blooms (HABs) are a growing challenge for freshwater management, traditionally addressed through phosphorus (P) limitation strategies. However, increasing evidence highlights nitrogen (N) availability as a key driver of bloom initiation and persistence. Here, we report extracellular voltage recordings from Oscillatoria cohorts exposed to four days of N starvation followed by ammonium (NH₄⁺) repletion using 5 mg L−1. Under N deprivation, electrical signalling developed progressively with a median of 1–2 events min−1 and amplitudes between 3-4 µV on day 1 and 2, following a marked increase in activity by days 3 and 4, with median spike rates of 5 events min−1 and amplitudes up to 17 µV. Following NH4+ repletion, signalling activity declined within 24 h, indicating rapid restoration of N balance. These results suggest that electrophysiological monitoring can serve as a real-time, non-invasive indicator of nutrient stress in Oscillatoria and provides a potential early warning tool for HAB onset and associated taste and odour (T&O) outbreaks in freshwater systems.
| Original language | English |
|---|---|
| Pages (from-to) | 2712-2718 |
| Number of pages | 7 |
| Journal | MRS Advances |
| Volume | 10 |
| Early online date | 15 Dec 2025 |
| DOIs | |
| Publication status | Published - 15 Dec 2025 |
Data Availability Statement
Supplementary data are available upon request to the authors.Funding
Paulo R.F. Rocha acknowledges the support and funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 947897). Damiano Duci and Paulo R.F. Rocha gratefully acknowledge technical support from Luis Lopes from the LIP, Department of Physics, University of Coimbra. Access to TAIL-UC facility funded under QREN—Mais Centro Project ICT/2009/02/012/1890 is gratefully acknowledged by all authors. SEM data obtained by access to TAIL-UC facility funded under QREN-Mais Centro Project ICT/2009/02/012/1890.