Importance of sampling frequency when collecting diatoms

Area of Science:

• Ecology
• Environmental Science
• Aquatic Biology

Background:

• Diatom-based bio-assessment is increasingly utilized for monitoring freshwater ecosystems.
• A significant knowledge gap exists regarding the optimal sampling frequency (ASF) for capturing diatom temporal dynamics.

Purpose of the Study:

• To determine the appropriate sampling frequency (ASF) for riverine diatoms.
• To understand the influence of seasonality and hydrological conditions on diatom temporal dynamics.
• To inform freshwater bio-monitoring protocols.

Main Methods:

• Daily riverine diatom samples were collected over one year.
• Kohonen Self-Organizing Map (SOM) was used to cluster species composition data.
• Appropriate sampling frequencies (ASF) were calculated for different temporal clusters.

Main Results:

• Appropriate sampling frequencies (ASF) varied significantly by season, ranging from 13 to 25 days in specific periods.
• No specific ASF was identified for certain periods, indicating stable or highly dynamic diatom communities.
• ASF was negatively correlated with hydrological wetness, suggesting reduced sampling intervals during wetter conditions.

Conclusions:

• Diatom temporal dynamics exhibit strong seasonality and are influenced by hydrological wetness.
• Freshwater bio-monitoring protocols require consideration of ASF to accurately track algal temporal dynamics.
• Optimizing sampling frequency is essential for robust diatom-based bio-assessment and effective freshwater management.