Coastal microbial mat diversity along a natural salinity gradient

Area of Science:

• Ecology
• Microbiology
• Coastal Science

Background:

• The Dutch barrier island Schiermonnikoog features microbial mats initiating salt marsh succession.
• Natural elevation creates environmental gradients from low water to dunes.
• Dynamic salinity gradients are influenced by tides, rainfall, and wind.

Purpose of the Study:

• To investigate microbial community composition along a natural salinity gradient.
• To identify distinct microbial mat communities and their primary producers.

Main Methods:

• Sampling of 33 locations along the salinity gradient.
• Denaturing Gradient Gel Electrophoresis (DGGE) of rRNA gene fragments.
• Analysis of pigment composition.

Main Results:

• Three distinct microbial mat communities were identified: marine, brackish, and freshwater.
• The marine community was dominated by diatoms.
• The brackish and freshwater communities were dominated by Cyanobacteria, with freshwater green algae present in the latter.

Conclusions:

• Microbial mat composition varies significantly along the salinity gradient.
• Primary producers differ across the identified communities, reflecting adaptation to local salinity levels.