| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
School of Biological Sciences, University of Liverpool, PO Box 147, Liverpool L69 7ZB, UK
Institute of Freshwater Ecology, Windermere Laboratory, The Ferry House, Far Sawrey, Ambleside, Cumbria LA22 0LP, UK
ABSTRACT
Prokaryote communities in post-glacial profundal freshwater sediments of Windermere, representing 10-12000 years of deposition, were examined for culturability, viability and community structure. The potential for active geochemical cycles was inferred from the presence of specific groups of bacteria. Direct count procedures revealed 1012 cells (g dry wt sediment)-1 in the surface sediments, which declined to approximately 109 cells (g dry wt sediment)-1 at 6 m depth of core (representing approximately 10000 years of deposition). The majority of the cells in the upper sediments were metabolically active when challenged with viability probes and responded to the direct viable count method. Below 250 cm, viability shown by 5-cyano-2,3-diotyl tetrazolium chloride (CTC) dye was not significantly different from the direct count; however, counts obtained with 5-carboxyfluorescein diacetate (CFDA) and the direct viable count both declined significantly from the direct count below 250 cm and 1 m, respectively. Culture was achieved from samples throughout the core, although the numbers of culturable bacteria decreased significantly with depth, from 107 c.f.u. (g dry wt sediment)-1 to 101-102 c.f.u. (g dry wt sediment)-1 below 3 m depth. Among culturable isolates, Gram-positives and Gram-negatives were found at all levels of the core, and spore-forming heterotrophs dominated. Although sulphate-reducing bacteria were not detected below 20 cm, isolates demonstrating denitrifying activity were detected at all depths. PCR performed on samples taken below 3 m (deposited more than 7000 years ago) using eubacterial and archaeal primers revealed sequences similar to those found in deep sediments of the Pacific Ocean and the presence of methanogenic archaea. These observations indicate that bacteria and archaea are capable of long-term persistence and activity in deep, aged freshwater sediments.
*Author for correspondence: Roger W. Pickup. Tel: +44 15394 42468/9. Fax: +44 15394 46914.
Present address: Institute for Arable Research, Rothamstead Research Station, Harpenden, Hertfordshire AL5 2JQ, UK.
Present address: Department of Fossil Fuels and Environmental Geochemistry, Drummond Building, University of Newcastle, Newcastle upon Tyne NE1 7RG, UK.
This article has been cited by other articles:
|
|
 |
|
  R. W. Pickup, G. Rhodes, T. J. Bull, S. Arnott, K. Sidi-Boumedine, M. Hurley, and J. Hermon-Taylor Mycobacterium avium subsp. paratuberculosis in Lake Catchments, in River Water Abstracted for Domestic Use, and in Effluent from Domestic Sewage Treatment Works: Diverse Opportunities for Environmental Cycling and Human Exposure. Appl. Envir. Microbiol., June 1, 2006; 72(6): 4067 - 4077. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. Pickup, G. Rhodes, S. Arnott, K. Sidi-Boumedine, T. J. Bull, A. Weightman, M. Hurley, and J. Hermon-Taylor Mycobacterium avium subsp. paratuberculosis in the Catchment Area and Water of the River Taff in South Wales, United Kingdom, and Its Potential Relationship to Clustering of Crohn's Disease Cases in the City of Cardiff Appl. Envir. Microbiol., April 1, 2005; 71(4): 2130 - 2139. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
