Changes in environmental factors and genetic diversity of bacterioplankton communities using 454 pyrosequencing in a semi-closed bay in South Korea

Abstract

Bacterioplankton serve a critical function in marine ecosystems (nutrients, dissolved inorganic nitrogen, as well as facilitating interactions among other biota) and can also serve as indicators of the marine environment. Bacterioplankton communities in the surface seawater of a semi-closed bay (Jangmok Bay of South Korea) were analysed using a 16S rDNA multiplex 454 pyrosequencing approach. The following conclusions were drawn: 1) Diversity and abundance are the highest in cold water seasons and lowest in warm water seasons 2) During cold water seasons, alpha-proteobacteria respond rapidly to the pulse of inorganic phosphorus enrichment 3) During warm water seasons, gamma-proteobacteria are the most active type of bacterioplankton present in high dissolved organic carbon, rainfall, chemical oxygen demand, and primary production, but low nutrient concentration 4) Cyanobacteria, a minor group that occupied 4.58% of the total bacterioplankton, was higher in abundance in low temperatures 5) The Cytophaga-Flavobacter group was higher in abundance in nutrient rich conditions including high concentrations of dissolved organic carbon and inorganic nutrients this group also demonstrated a time-lag of declined in abundance following summer phytoplankton blooms 6) Community-level changes in 16S-based diversity and metagenomic profiles are best explained by seasonal patterns. In the absence of predator pressure, the pronommunities in the surface seawater of a semi-closed bay (Jangmok Bay of South Korea) were analysed using a 16S rDNA multiplex 454 pyrosequencing approach. The following conclusions were drawn: 1) Diversity and abundance are the highest in cold water seasons and lowest in warm water seasons 2) During cold water seasons, alpha-proteobacteria respond rapidly to the pulse of inorganic phosphorus enrichment 3) During warm water seasons, gamma-proteobacteria are the most active type of bacterioplankton present in high dissolved organic carbon, rainfall, chemical oxygen demand, and primary production, but low nutrient concentration 4) Cyanobacteria, a minor group that occupied 4.58% of the total bacterioplankton, was higher in abundance in low temperatures 5) The Cytophaga-Flavobacter group was higher in abundance in nutrient rich conditions including high concentrations of dissolved organic carbon and inorganic nutrients this group also demonstrated a time-lag of declined in abundance following summer phytoplankton blooms 6) Community-level changes in 16S-based diversity and metagenomic profiles are best explained by seasonal patterns. In the absence of predator pressure, the pron