PHYTOPLANKTON COMMUNITY COMPOSITION AND GENE EXPRESSION OF FUNCTIONAL GENES INVOLVED IN CARBON AND NITROGEN...

Area of Science:

• Marine biology
• Molecular ecology
• Microbial ecology

Background:

• Phytoplankton are crucial primary producers in marine ecosystems.
• Understanding phytoplankton community composition and activity is vital for marine ecosystem monitoring.
• Traditional methods for assessing phytoplankton can be labor-intensive and lack high-throughput capabilities.

Purpose of the Study:

• To develop and validate a functional gene microarray (phytoarray) for assessing phytoplankton community structure and gene expression.
• To investigate seasonal shifts in phytoplankton dominance in the English Channel using the phytoarray.
• To compare the utility of targeting different genes (RUBISCO and nitrate reductase) for phytoplankton community analysis.

Main Methods:

• Development of a functional gene microarray with oligonucleotide probes for key phytoplankton genes (rbcL and NR).
• Application of the phytoarray to analyze DNA and gene expression (cDNA) in English Channel samples.
• Detection and quantification of phytoplankton groups based on signal intensity of specific gene probes.

Main Results:

• The phytoarray detected five major eukaryotic phytoplankton groups based on the Type 1D rbcL gene, reflecting both presence and activity.
• Seasonal analysis revealed a shift from diatom dominance during the spring bloom to haptophyte and flagellate dominance in summer.
• Nitrate reductase (NR) probes provided higher phylogenetic resolution, identifying uncultivated diatom phylotypes as abundant and active.

Conclusions:

• The phytoarray is a high-resolution, high-throughput tool for assessing marine phytoplankton community composition and function.
• The study highlights seasonal dynamics in phytoplankton communities in the English Channel.
• The phytoarray approach offers a promising method for future marine ecological studies and monitoring.