Hydrodynamics structure the physiological trajectory and bloom dynamics of a harmful diatom species across neighboring coastal ecosystems
- 1Ifremer
Abstract
Hydrodynamics is a strong regulator of phytoplankton cell densities and population connectivity. However, the extent to which hydrodynamics, specifically dilution and advection, dictates the internal physiological state and overall bloom dynamics remains poorly understood. We conducted an integrated study of the harmful diatom Pseudo-nitzschia australis in two neighboring coastal bays with similar abiotic conditions but contrasting bloom trajectories. Using a combination of field observations, transcriptomics, domoic acid (DA) measurements, and hydrodynamic simulations, we show that a three-fold difference in dilution rates alone explains a 25-day shift in bloom timing and an order-of-magnitude difference in cell densities. Transcriptomic profiling revealed distinct metabolic and stress-associated gene modules that synchronized with hydrodynamically-mediated nutrient depletion rate, linking residence times to cellular mortality. Furthermore, directional connectivity between the bays may explain population-level toxin heterogeneity, as advection of older cells, releasing DA outside the cells, may have decreased the proportion of intracellular DA in the destination bay. Our results illustrate that hydrodynamics do not merely modulate population transport; they structure the full physiological life cycle of a bloom, from initiation to nutrient-driven demise. This highlights the necessity of considering hydrodynamics as a primary explanation for bloom dynamics with cascading effects on bloom onset, cell density, nutrient consumption, cell physiology and mortality.
Related
- Whole-genome characterization of Plasmodium falciparum population structure and drug resistance across Uganda and neighboring countries
- The Principal Component Life Trajectory (PCLT): Mapping Sex-Specific Physiological Change Across the Human Lifespan
- Riparian Tugai Forest Ecosystems of Azerbaijan: Vegetation Structure, Classification and Ecological Characteristics
- Tritrophic Interactions and Parasitoid Community Structure of Gall‐Inducing Herbivores in Arid Desert Ecosystems of Northern Xinjiang, China
- Bacterial dispersal and host specificity shape microbiome strain sharing among great ape species in neighboring zoo exhibits
BibTeX
@misc{gac2026hydrodynamics,
title = {{Hydrodynamics structure the physiological trajectory and bloom dynamics of a harmful diatom species across neighboring coastal ecosystems}},
author = {M. Le Gac and L. Prigent and J. Quere and F. Caradec and F. Herve and E. Rabiller and Z. Amzil and M. Plus},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.05.756714},
url = {https://www.biorxiv.org/content/10.64898/2026.10.05.756714v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Hydrodynamics structure the physiological trajectory and bloom dynamics of a harmful diatom species across neighboring coastal ecosystems
AU - M. Le Gac
AU - L. Prigent
AU - J. Quere
AU - F. Caradec
AU - F. Herve
AU - E. Rabiller
AU - Z. Amzil
AU - M. Plus
PY - 2026
DA - 2026/10/05
PB - bioRxiv
DO - 10.64898/2026.10.05.756714
UR - https://www.biorxiv.org/content/10.64898/2026.10.05.756714v1
AB - Hydrodynamics is a strong regulator of phytoplankton cell densities and population connectivity. However, the extent to which hydrodynamics, specifically dilution and advection, dictates the internal physiological state and overall bloom dynamics remains poorly understood. We conducted an integrated study of the harmful diatom Pseudo-nitzschia australis in two neighboring coastal bays with similar abiotic conditions but contrasting bloom trajectories. Using a combination of field observations, transcriptomics, domoic acid (DA) measurements, and hydrodynamic simulations, we show that a three-fold difference in dilution rates alone explains a 25-day shift in bloom timing and an order-of-magnitude difference in cell densities. Transcriptomic profiling revealed distinct metabolic and stress-associated gene modules that synchronized with hydrodynamically-mediated nutrient depletion rate, linking residence times to cellular mortality. Furthermore, directional connectivity between the bays may explain population-level toxin heterogeneity, as advection of older cells, releasing DA outside the cells, may have decreased the proportion of intracellular DA in the destination bay. Our results illustrate that hydrodynamics do not merely modulate population transport; they structure the full physiological life cycle of a bloom, from initiation to nutrient-driven demise. This highlights the necessity of considering hydrodynamics as a primary explanation for bloom dynamics with cascading effects on bloom onset, cell density, nutrient consumption, cell physiology and mortality.
ER -