Seasonal Shifts in Water Microbiota Inform Water Intake Planning

Using 16S rRNA gene sequencing to guide infrastructure decisions: an example from our NGS team

Over a six-month period in early 2025, a marine RAS facility in Norway conducted an extensive microbiological survey to determine the most suitable location for its future water intake system. By applying 16S-community next-generation sequencing (NGS), our PHARMAQ Analytiq team were able to characterize the microbial communities present at multiple sampling stations and track how these communities changed over time.

A Longitudinal Approach to Site Selection

Rather than relying solely on static water quality parameters, the team opted for a dynamic, data-driven approach. Monthly water samples were collected from several candidate intake locations from February through July, capturing the seasonal variability in microbial composition.

The sequencing results revealed that seasonal changes had a greater impact on microbiota composition than spatial differences between sampling points. Cold-adapted genera such as Colwellia and Psychrobium dominated in winter months, reflecting low biological activity and minimal organic load. As temperatures rose in spring and summer, the microbial landscape shifted toward more metabolically active and potentially pathogenic genera like Vibrio, Moritella, and Aliivibrio.

Key Findings

• Winter (Feb–Mar): Low microbial diversity and dominance of psychrophilic genera indicated stable, low-activity conditions.
• Spring (Apr): A marked increase in microbial diversity and emergence of genera associated with organic matter degradation and algal blooms.
• Summer (May–Jul): Declining diversity and rising prevalence of disease-associated bacteria, particularly Vibrio spp., suggesting increased biological activity and potential risks for aquaculture operations.

Interestingly, one particular station consistently showed higher levels of disease-associated bacteria, especially during warmer months, making it a less favorable candidate for water intake.

The Value of Microbiota NGS in Environmental Monitoring

This study underscores the power of 16S-community NGS as a tool for environmental assessment. By providing high-resolution insights into microbial dynamics, it enables more informed decisions about infrastructure placement, risk management, and ecosystem health.

As climate variability continues to influence marine environments, such approaches will be essential for ensuring sustainable and resilient operations in aquaculture and water resource management.