Intraspecific interactions between algae with different nutritional histories

Area of Science:

• Marine biology
• Microbial ecology
• Physiological ecology

Background:

• The diatom Phaeodactylum tricornutum exhibits phenotypic plasticity in response to varying environmental conditions.
• Nutritional history can influence cellular composition and physiological state, potentially affecting competitive abilities.

Purpose of the Study:

• To investigate how prior growth conditions affect the competitive interactions between Phaeodactylum tricornutum populations.
• To determine if nutritional background confers an advantage in new environmental settings.

Main Methods:

• Culturing Phaeodactylum tricornutum under five distinct growth regimes (varying NH4+ and GeO2 concentrations).
• Mixing pairs of populations with different nutritional histories in a novel communal culture regime.
• Quantifying population ratios using flow cytometry after 6 hours of interaction.

Main Results:

• Significant alterations in population ratios were observed when cells grown at 1 mM NH4+ were mixed with those from GeO2- or 0.5 mM NH4+-limited conditions.
• These ratio changes indicate differential competitive success based on prior nutritional status.
• The findings suggest that nutritional background influences a population's fitness and reproductive potential in new environments.

Conclusions:

• Prior nutritional conditions significantly impact the competitive interactions and relative success of diatom populations.
• Differences in expressed proteome and regulatory response tools likely mediate these competitive interactions.
• This has implications for understanding the persistence of neutral variants within populations adapting to changing environments.