A planktonic diatom displays genetic structure over small spatial scales

Area of Science:

• Marine biology
• Population genetics
• Microalgal ecology

Background:

• Marine planktonic microalgae possess high dispersal potential, yet gene flow is often limited.
• Geographic isolation and oceanographic connectivity are known drivers of population divergence at larger scales (>200 km).

Purpose of the Study:

• To investigate if geographic isolation and oceanographic connectivity structure populations of marine planktonic diatoms at smaller spatial scales (6–152 km).
• To identify factors influencing gene flow and population divergence in Skeletonema marinoi within the Archipelago Sea.

Main Methods:

• Collection of 425 clonal cultures of Skeletonema marinoi from 11 sites in the Archipelago Sea.
• Analysis of genetic differentiation using eight microsatellite markers and F-statistics.
• Application of Bayesian cluster analysis to identify genetic groups.

Main Results:

• Significant genetic differentiation was observed between several sampling sites.
• Two distinct genetic groups of Skeletonema marinoi were identified across the study area.
• Geographic isolation and oceanographic connectivity did not fully explain the observed genetic patterns.

Conclusions:

• Hierarchical genetic structuring exists in Skeletonema marinoi even at small spatial scales.
• Biological characteristics and historical events appear to be more significant than physical barriers in shaping gene flow at these smaller scales.
• This challenges the assumption that high dispersal potential negates population structuring in marine microalgae over short distances.