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Limitation of bacterial growth by dissolved organic matter and iron in the Southern ocean.
Church, M J; Hutchins, D A; Ducklow, H W.
Afiliação
  • Church MJ; School of Marine Science, The College of William and Mary, Gloucester Point, Virginia 23062-1346, USA. mattc@vims.edu
Appl Environ Microbiol ; 66(2): 455-66, 2000 Feb.
Article em En | MEDLINE | ID: mdl-10653704
ABSTRACT
The importance of resource limitation in controlling bacterial growth in the high-nutrient, low-chlorophyll (HNLC) region of the Southern Ocean was experimentally determined during February and March 1998. Organic- and inorganic-nutrient enrichment experiments were performed between 42 degrees S and 55 degrees S along 141 degrees E. Bacterial abundance, mean cell volume, and [(3)H]thymidine and [(3)H]leucine incorporation were measured during 4- to 5-day incubations. Bacterial biomass, production, and rates of growth all responded to organic enrichments in three of the four experiments. These results indicate that bacterial growth was constrained primarily by the availability of dissolved organic matter. Bacterial growth in the subtropical front, subantarctic zone, and subantarctic front responded most favorably to additions of dissolved free amino acids or glucose plus ammonium. Bacterial growth in these regions may be limited by input of both organic matter and reduced nitrogen. Unlike similar experimental results in other HNLC regions (subarctic and equatorial Pacific), growth stimulation of bacteria in the Southern Ocean resulted in significant biomass accumulation, apparently by stimulating bacterial growth in excess of removal processes. Bacterial growth was relatively unchanged by additions of iron alone; however, additions of glucose plus iron resulted in substantial increases in rates of bacterial growth and biomass accumulation. These results imply that bacterial growth efficiency and nitrogen utilization may be partly constrained by iron availability in the HNLC Southern Ocean.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Compostos Orgânicos / Água do Mar / Bactérias / Ferro País/Região como assunto: Oceania Idioma: En Revista: Appl Environ Microbiol Ano de publicação: 2000 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Compostos Orgânicos / Água do Mar / Bactérias / Ferro País/Região como assunto: Oceania Idioma: En Revista: Appl Environ Microbiol Ano de publicação: 2000 Tipo de documento: Article País de afiliação: Estados Unidos