Relative Contribution of Viral Lysis and Grazing to Bacterial Mortality in Tropical Coastal Waters of Peninsular Malaysia

• Autores: Lee Choon Weng, Chui Wei Bong
• Localización: Bulletin of Marine Science, ISSN 0007-4977, Vol. 88, Nº. 1, 2012, págs. 1-14
• Idioma: inglés
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• Resumen

  • We investigated the relative importance of viral lysis and heterotrophic nanoflagellate (HNF) grazing in bacterial mortality as part of a study to understand the microbial loop functioning in tropical waters of Straits of Malacca and South China Sea above the Sunda Shelf. Bacterial abundance ranged from 0.8 × 106 to 2.9 × 106 cells ml-1 and bacterial production ranged from 0.7 × 105 to 4.2 × 105 cells ml-1 hr-1. HNF and viral abundance ranged from 0.6 × 103 to 10.1 × 103 cells ml-1 and 0.3 × 107 to 1.4 × 107 virus particles ml-1, respectively. HNF grazing rates were from 1.1 × 104 to 16.8 × 104 cells ml-1 hr-1, whereas viral lysis rates ranged from 0.7 × 104 to 3.9 × 104 cells ml-1 hr-1. There was predator-prey coupling across the stations with both viral lysis and HNF grazing rates significantly correlated with bacterial production. HNF grazing accounted for 26.1% ± 14.6 of bacterial production, whereas viral lysis was 9.0% ± 3.5 of bacterial production. Bacterial mortality by both HNF and viruses averaged 35.5% ± 13.9, and was outpaced by bacterial production. Other loss factors, such as grazing by ciliates, sedimentation, benthic filter feeders, autolysis, or predatory bacteria, could be important.