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Microbial diversity in Baltic Sea sediments

Edlund, Anna (2007). Microbial diversity in Baltic Sea sediments. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2007:26
ISBN 91-576-7325-1
[Doctoral thesis]

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This thesis focuses on microbial community structures and their functions in Baltic Sea sediments. First we investigated the distribution of archaea and bacteria in Baltic Sea sediments along a eutrophication gradient. Community profile analysis of 16S rRNA genes using terminal restriction length polymorphism (T-RFLP) indicated that archaeal and bacterial communities were spatially heterogeneous. By employing statistical ordination methods we observed that archaea and bacteria were structured and impacted differently by environmental parameters that were significantly linked to eutrophication. In a separate study, we analyzed bacterial communities at a different site in the Baltic Sea that was heavily contaminated with polyaromatic hydrocarbons (PAHs) and several other pollutants. Sediment samples were collected before and after remediation by dredging in two consecutive years. A polyphasic experimental approach was used to assess growing bacteria and degradation genes in the sediments. The bacterial communities were significantly different before and after dredging of the sediment. Several isolates collected from contaminated sediments showed an intrinsic capacity for degradation of phenanthrene (a PAH model compound). Quantititative real-time PCR was used to monitor the abundance of degradation genes in sediment microcosms spiked with phenanthrene. Although both xylE and phnAc genes increased in abundance in the microcosms, the isolates only carried phnAc genes. Isolates with closest 16S rRNA gene sequence matches to Exigobacterium oxidotolerans, a Pseudomonas sp. and a Gammaproteobacterium were identified by all approaches used as growing bacteria that are capable of phenanthrene degradation. These isolates were assigned species and strain designations as follows: Exiguobacterium oxidotolerans AE3, Pseudomonas fluorescens AE1 and Pseudomonas migulae AE2. We also identified and studied the distribution of actively growing bacteria along red-ox profiles in Baltic Sea sediments. Community structures were found to be significantly different at different red-ox depths. Also, according to multivariate statistical ordination analysis organic carbon, nitrogen, and red-ox potential were crucial parameters for structuring the bacterial communities on a vertical scale. Novel lineages of bacteria were obtained by sequencing 16S rRNA genes from different red-ox depths and sampling stations indicating that bacterial diversity in Baltic Sea sediments is largely unexplored.

Authors/Creators:Edlund, Anna
Title:Microbial diversity in Baltic Sea sediments
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2007
Number of Pages:36
ALLI. Edlund, A., Soule, T., Sjöling, S. & Jansson, J. K. 2006. Microbial community structure in polluted Baltic Sea sediments. Environmental Microbiology, 8, 223-232. II. Edlund, A. & Jansson, J. K. 2006. Changes in active bacterial communities before and after dredging of highly polluted Baltic Sea sediments. Applied and Environmental Microbiology, 72, 6800-6807. III. Edlund, A. & Jansson. J. K. 2006. Identification of metabolically active phenanthrene degrading bacteria in polluted Baltic Sea sediments. Manuscript. IV. Edlund, A., Hårdeman, F., Jansson. J. K. & Sjöling, S. Active bacterial population structures along vertical red-ox gradients in Baltic Sea sediment. Manuscript.
Place of Publication:Uppsala
ISBN for printed version:91-576-7325-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:sediment, eutrophication, aromatic hydrocarbons, oxidoreductions, rflp, microorganisms, bacteria, pcr, baltic sea
Keywords:Baltic Sea sediment, eutrophication, polyaromatic hydrocarbon (PAH), red-ox, terminal-restriction fragment length polymorphism (T-RFLP), bromodeoxyuridine (BrdU), Exioguobacterium, phenanthrene
Permanent URL:
ID Code:1396
Department:(NL, NJ) > Dept. of Microbiology (until 161231)
Deposited By: Anna Edlund
Deposited On:18 Apr 2007 00:00
Metadata Last Modified:02 Dec 2014 10:11

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