Priority effects in a planktonic bloom-forming marine diatom

Area of Science:

• Ecology
• Population Genetics
• Marine Biology

Background:

• Priority effects are known to influence community structure, where earlier arriving species gain a competitive advantage.
• Within-species competition and its role in population differentiation are less understood.
• Skeletonema marinoi, a marine diatom, exhibits significant genetic differentiation across small geographic scales.

Purpose of the Study:

• To investigate the role of priority effects in driving population genetic differentiation within Skeletonema marinoi.
• To determine if historical colonization order influences the success of subsequent genotypes in S. marinoi populations.

Main Methods:

• Microcosm experiments were designed with successive inoculations of different Skeletonema marinoi strains.
• The relative abundance of early and late-arriving strains was monitored over time.
• Genetic differentiation patterns were analyzed in relation to arrival order.

Main Results:

• Significant priority effects were detected in S. marinoi, even when early-arriving strains lacked a numerical advantage.
• The order of strain introduction influenced the relative success and abundance of S. marinoi genotypes.
• Experimental results suggest a mechanism for rapid genetic divergence.

Conclusions:

• Priority effects are a crucial factor in shaping population genetic structure within S. marinoi.
• These findings highlight the importance of historical contingency in microbial population dynamics.
• Priority effects may be a key mechanism initiating population genetic differentiation in ecologically important species.