Single-cell vs. bulk activity properties of coastal bacterioplankton over an annual cycle in a temperate ecosystem

• Published in: FEMS microbiology ecology Vol. 67; no. 1; pp. 43 - 56
• Main Authors: ANXELU, Xosé, MORAN, G, CALVO-DIAZ, Alejandra
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 2009; Blackwell Publishing Ltd; Blackwell; Oxford University Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Atlantic; Atlantic Ocean; Bacteria; Bacteria - cytology; Bacteria - growth & development; Bacteria - metabolism; bacterial activity; Bacterial Physiological Phenomena; Bacterioplankton; Biological and medical sciences; Chlorophyll; Climate; coastal; Coastal waters; Communities; Ecology; Ecosystem; Flow cytometry; Fundamental and applied biological sciences. Psychology; General aspects; Growth rate; Heterotrophic Processes; Incorporation; Leucine; Leucine - metabolism; Marine; Microbial ecology; Microbiology; Nucleic acids; Plankton - cytology; Plankton - growth & development; Plankton - metabolism; Properties (attributes); seasonal variations; Seawater - microbiology; single-cell properties; Spain; Synecology; Tritium - metabolism; Atlantic Ocean; Spain; Spain Coasts; single-cell properties; seasonal variations; Atlantic; bacterioplankton; bacterial activity; coastal; Cycle; Coastal zone; Infection; Marine environment; Aquatic environment; Bacterioplankton; Plankton; Seasonal variation; Ecosystem; Bacteriosis; Isolated cell; Bacteria
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1111/j.1574-6941.2008.00601.x

The connections between single-cell activity properties of heterotrophic planktonic bacteria and whole community metabolism are still poorly understood. Here, we show flow cytometry single-cell analysis of membrane-intact (live), high nucleic acid (HNA) content and actively respiring (CTC+) bacteria with samples collected monthly during 2006 in northern Spain coastal waters. Bulk activity was assessed by measuring ³H-Leucine incorporation and specific growth rates. Consistently, different single-cell relative abundances were found, with 60-100% for live, 30-84% for HNA and 0.2-12% for CTC+ cells. Leucine incorporation rates (2-153 pmol L⁻¹ h⁻¹), specific growth rates (0.01-0.29 day⁻¹) and the total and relative abundances of the three single-cell groups showed marked seasonal patterns. Distinct depth distributions during summer stratification and different relations with temperature, chlorophyll and bacterial biovolume suggest the existence of different controlling factors on each single-cell property. Pooled leucine incorporation rates were similarly correlated with the abundance of all physiological groups, while specific growth rates were only substantially explained by the percentage of CTC+ cells. However, the ability to reduce CTC proved notably better than the other two single-cell properties at predicting bacterial bulk rates within seasons, suggesting a tight linkage between bacterial individual respiration and biomass production at the community level.