Eukaryotic phytoplankton community spatiotemporal dynamics as identified through gene expression within a eutrophic...

Area of Science:

• Environmental microbiology
• Estuarine ecology
• Metatranscriptomics

Background:

• Eutrophic estuaries are complex ecosystems influenced by biotic and abiotic factors.
• Understanding phytoplankton metabolic strategies is crucial for estuarine health.
• The Neuse River Estuary (NRE) provides a model system for studying these dynamics.

Purpose of the Study:

• To investigate spatial variations in phytoplankton metabolic strategies along the NRE.
• To identify the key environmental drivers of these metabolic differences.
• To link phytoplankton gene expression to water quality parameters.

Main Methods:

• Metatranscriptomic sequencing was employed to analyze gene expression in phytoplankton communities.
• Water quality parameters were measured throughout the NRE over a one-year period.
• Phylogenetic and functional gene analyses were performed on sequencing data.

Main Results:

• Distinct metabolic profiles were observed between the upper and lower NRE.
• Upper estuary phytoplankton showed higher expression of genes related to cellular component synthesis and carbon metabolism.
• Lower estuary phytoplankton exhibited elevated expression of genes for nutrient metabolism, transport, and polysaccharide synthesis, indicating potential nutrient limitation and microbial interactions.

Conclusions:

• Phytoplankton metabolic activity varies spatially in the NRE, with higher growth rates suggested in the upper estuary.
• Nutrient limitation, particularly nitrogen availability, is the primary factor driving the observed spatial divergence in phytoplankton metabolism.
• These findings highlight the sensitivity of phytoplankton communities to environmental gradients in estuarine systems.