Modelling diatom growth in turbulent waters

Area of Science:

• Environmental modeling
• Aquatic ecology
• Water quality management

Background:

• Algal bloom prediction models often oversimplify water mixing processes, leading to inaccuracies.
• Turbulent mixing in surface waters can significantly influence algal growth dynamics.

Purpose of the Study:

• To develop and test a 3-D algal model (HYDRO-3D) for predicting algal growth in turbulent aquatic environments.
• To assess the impact of turbulent mixing on the growth of the diatom Skeletonema costatum.

Main Methods:

• Development of a 3-D Eulerian water quality model (HYDRO-3D) incorporating algal growth.
• Outdoor mesocosm experiments to evaluate diatom growth under varying light and turbulence conditions.
• Calibration and validation of the model using mesocosm and field data from Poplar Dock.

Main Results:

• Diatom growth (Skeletonema costatum) showed no significant response to light/dark fluctuations from turbulent mixing.
• The 3-D algal model was successfully calibrated and validated against empirical data.
• Simulations indicated minimal differences between 3-D and 1-D model representations for complex water bodies.

Conclusions:

• Direct effects of turbulence on phytoplankton physiology may not be essential for algal growth models.
• The study could not definitively establish the superiority of 3-D over 1-D models for simulating complex flows in natural waters.
• Further research is needed to determine the optimal model dimensionality for accurate algal bloom prediction.