TY - JOUR

T1 - Adaptation of sympatric Achromatium spp. to different redox conditions as a mechanism for coexistence of functionally similar sulphur bacteria

AU - Gray, Neil D.

AU - Comaskey, Daria

AU - Miskin, Ian P.

AU - Pickup, Roger W.

AU - Suzuki, Keiko

AU - Head, Ian M.

PY - 2004/7/31

Y1 - 2004/7/31

N2 - Changes in the abundance of sympatric Achromatium spp. in response to the artificial manipulation of redox conditions in sediment microcosms was determined by fluorescence in situ hybridization (FISH). Adaptation to different redox conditions was shown to be one mechanism that supported the coexistence of functionally similar Achromatium spp. In sediment microcosms, in which the overlying water was oxygenated, Achromatium community size and composition remained unchanged over time. However, imposition of anoxic conditions induced changes in community structure. Anoxia caused a reduction in the relative abundance of Achromatium sp. RY8 (72 ± 4% to 49 ± 2%) and an increase in Achromatium sp. RY5 (19 ± 5% to 32 ± 3%) and a newly identified Achromatium sp., RYKS (14 ± 4% to 27 ± 2%). In anoxic microcosms supplemented with a single addition of nitrate at different initial concentrations the relative decline in Achromatium sp. RY8 was dependent on the initial nitrate concentration. In these experiments nitrate was rapidly removed. In contrast, when high levels of nitrate were maintained by periodic replacement of the overlying water with nitrate supplemented anoxic water, the composition of the Achromatium community remained stable over time. This suggested that all of the coexisting Achromatium spp. are obligate or facultative anaerobes, but, Achromatium sp. RY8 was more sensitive to sediment redox conditions than the other Achromatium species. Given the heterogeneous nature of sedimentary environments, redox-related niche differentiation may promote coexistence of sympatric Achromatium spp.

AB - Changes in the abundance of sympatric Achromatium spp. in response to the artificial manipulation of redox conditions in sediment microcosms was determined by fluorescence in situ hybridization (FISH). Adaptation to different redox conditions was shown to be one mechanism that supported the coexistence of functionally similar Achromatium spp. In sediment microcosms, in which the overlying water was oxygenated, Achromatium community size and composition remained unchanged over time. However, imposition of anoxic conditions induced changes in community structure. Anoxia caused a reduction in the relative abundance of Achromatium sp. RY8 (72 ± 4% to 49 ± 2%) and an increase in Achromatium sp. RY5 (19 ± 5% to 32 ± 3%) and a newly identified Achromatium sp., RYKS (14 ± 4% to 27 ± 2%). In anoxic microcosms supplemented with a single addition of nitrate at different initial concentrations the relative decline in Achromatium sp. RY8 was dependent on the initial nitrate concentration. In these experiments nitrate was rapidly removed. In contrast, when high levels of nitrate were maintained by periodic replacement of the overlying water with nitrate supplemented anoxic water, the composition of the Achromatium community remained stable over time. This suggested that all of the coexisting Achromatium spp. are obligate or facultative anaerobes, but, Achromatium sp. RY8 was more sensitive to sediment redox conditions than the other Achromatium species. Given the heterogeneous nature of sedimentary environments, redox-related niche differentiation may promote coexistence of sympatric Achromatium spp.

UR - http://www.scopus.com/inward/record.url?scp=3042701611&partnerID=8YFLogxK

U2 - 10.1111/j.1462-2920.2004.00607.x

DO - 10.1111/j.1462-2920.2004.00607.x

M3 - Journal article

C2 - 15186345

AN - SCOPUS:3042701611

VL - 6

SP - 669

EP - 677

JO - Environmental Microbiology

JF - Environmental Microbiology

SN - 1462-2912

IS - 7

ER -