Phototropic sulfur and sulfate-reducing bacteria in the chemocline of meromictic Lake Cadagno, Switzerland

Tonolla, Mauro; Peduzzi, Sandro; Demarta, Antonella; Peduzzi, Raffaele; Hahn, Dittmar

doi:10.4081/jlimnol.2004.161

Cited by 45 publications

(45 citation statements)

References 67 publications

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“…Measurements of physicochemical parameters confirmed earlier reports (16,21,22), showing steep vertical gradients of nutrients and oxygen within the pycnocline and a shift in redox potential between 10-and 11-m depth, indicating anoxic, reducing conditions in the hypolimnion (Fig. 1).…”

Section: Resultssupporting

confidence: 72%

“…The anoxic, lower layer is stagnant and enriched in phosphate and ammonium. At the chemocline between these 2 layers, sharp gradients appear in depth profiles of these nutrients and in those of oxygen, sulfate, sulfide, and light (14,16).…”

mentioning

confidence: 99%

“…The seasonal variations of this assemblage have been studied intensively in the past 10 years (15)(16)(17) and make this lake an attractive test system for investigating the activities of single cells. These anaerobic phototrophs, which use light energy to oxidize sulfide and other reduced sulfur compounds, are commonly found in seasonally or permanently stratified lakes, anoxic ponds or sediments.…”

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confidence: 99%

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A single-cell view on the ecophysiology of anaerobic phototrophic bacteria

Musat

Halm

Winterholler

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Quantitative information on the ecophysiology of individual microorganisms is generally limited because it is difficult to assign specific metabolic activities to identified single cells. Here, we develop and apply a method, Halogen In Situ HybridizationSecondary Ion Mass Spectroscopy (HISH-SIMS), and show that it allows simultaneous phylogenetic identification and quantitation of metabolic activities of single microbial cells in the environment. Using HISH-SIMS, individual cells of the anaerobic, phototropic bacteria Chromatium okenii, Lamprocystis purpurea, and Chlorobium clathratiforme inhabiting the oligotrophic, meromictic Lake Cadagno were analyzed with respect to H 13 CO3 ؊ and 15 NH4 ؉ assimilation. Metabolic rates were found to vary greatly between individual cells of the same species, showing that microbial populations in the environment are heterogeneous, being comprised of physiologically distinct individuals. Furthermore, C. okenii, the least abundant species representing Ϸ0.3% of the total cell number, contributed more than 40% of the total uptake of ammonium and 70% of the total uptake of carbon in the system, thereby emphasizing that numerically inconspicuous microbes can play a significant role in the nitrogen and carbon cycles in the environment. By introducing this quantification method for the ecophysiological roles of individual cells, our study opens a variety of possibilities of research in environmental microbiology, especially by increasing the ability to examine the ecophysiological roles of individual cells, including those of less abundant and less active microbes, and by the capacity to track not only nitrogen and carbon but also phosphorus, sulfur, and other biological element flows within microbial communities.anaerobic phototrophs ͉ nanoSIMS

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Section: Resultssupporting

confidence: 72%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A single-cell view on the ecophysiology of anaerobic phototrophic bacteria

Musat

Halm

Winterholler

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

391

421

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“…The observations for the initial 8 years essentially reflect those from many studies performed during the last century that describe purple sulfur bacteria as the typical and characteristic bacterial group in the chemocline of Lake Cadagno (see references 25 and 33 for reviews). As in this study, the most abundant populations were found to belong to the genus Lamprocystis (31,33,34). In contrast to Thiocystis, all populations of the genus Lamprocystis form aggregates with up to 900 cells in the chemocline of Lake Cadagno (31,34).…”

Section: Resultsmentioning

confidence: 76%

“…5 g KH 2 (10). The medium was reduced with 0.3 g liter Ϫ1 Na 2 S · 9H 2 O (1.10 mM final concentration) and adjusted to a pH around 7.2 or 6.8 for Chromatiaceae (33) and Chlorobiaceae (23), respectively. Media were prepared in a 2-liter bottle with an N 2 /CO 2 (80%/20%) gas phase according to Widdel and Bak (36).…”

Section: Methodsmentioning

confidence: 99%

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland

Tonolla

Peduzzi

Hahn

2005

Appl Environ Microbiol

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Population analyses in water samples obtained from the chemocline of crenogenic, meromictic Lake Cadagno, Switzerland, in October for the years 1994 to 2003 were studied using in situ hybridization with specific probes. During this 10-year period, large shifts in abundance between purple and green sulfur bacteria and among different populations were obtained. Purple sulfur bacteria were the numerically most prominent phototrophic sulfur bacteria in samples obtained from 1994 to 2001, when they represented between 70 and 95% of the phototrophic sulfur bacteria. All populations of purple sulfur bacteria showed large fluctuations in time with populations belonging to the genus Lamprocystis being numerically much more important than those of the genera Chromatium and Thiocystis. Green sulfur bacteria were initially represented by Chlorobium phaeobacteroides but were replaced by Chlorobium clathratiforme by the end of the study. C. clathratiforme was the only green sulfur bacterium detected during the last 2 years of the analysis, when a shift in dominance from purple sulfur bacteria to green sulfur bacteria was observed in the chemocline. At this time, numbers of purple sulfur bacteria had decreased and those of green sulfur bacteria increased by about 1 order of magnitude and C. clathratiforme represented about 95% of the phototrophic sulfur bacteria. This major change in community structure in the chemocline was accompanied by changes in profiles of turbidity and photosynthetically available radiation, as well as for sulfide concentrations and light intensity. Overall, these findings suggest that a disruption of the chemocline in 2000 may have altered environmental niches and populations in subsequent years.Lake Cadagno is a crenogenic meromictic lake located in the catchment area of a dolomite vein rich in gypsum in the Piora valley in the southern Alps of Switzerland (46°33ЈN, 8°43ЈE). This lake is characterized by a compact chemocline with high concentrations of sulfate; steep gradients of oxygen, sulfide, and light; and a turbidity maximum that correlates to large numbers of bacteria (up to 10 7 cells ml Ϫ1 ) (5, 21, 31). Molecular methods such as 16S rRNA gene clone library analysis and subsequent in situ hybridization with specific fluorescent probes identified the most abundant bacteria in the chemocline as large-and small-celled purple sulfur bacteria. These accounted for up to 35% of all bacteria (34) and consisted of Chromatium okenii as the only representative of the largecelled purple sulfur bacteria and of four populations related to the genus Lamprocystis that represented the small-celled purple sulfur bacteria (31). Small-celled purple sulfur bacteria were most abundant with two populations accounting for 40 to 80% of the purple sulfur bacteria depending on the season (31). These populations, designated D and F, were not represented by a cultured relative, whereas the remaining populations were identified as Lamprocystis purpurea and Lamprocystis roseopersicina. L. purpurea and L. roseopersicina wer...

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