AME 45:247-254 (2006)  -  doi:10.3354/ame045247

Seasonal changes and diversity of aerobic anoxygenic phototrophs in the Baltic Sea

Michal Masín1,2, Agnieszka Zdun3, Joanna Ston-Egiert3, Monika Nausch4, Matthias Labrenz4, Vladimíra Moulisová2, Michal Koblízek1,2,*

1Institute of Physical Biology, Zámek 136, 373 33 Nové Hrady, Czech Republic
2Department of Autotrophic Microorganisms, Institute of Microbiology CAS, Opatovicky mlyn, 379 81 Trebon, Czech Republic
3Institute of Oceanology PAN, Powstanców Warszawy 55, 81-712 Sopot, Poland
4Institut für Ostseeforschung, Warnemünde, Seestrasse 15, 18119 Rostock-Warnemünde, Germany
*Corresponding author. Email:

ABSTRACT: The community of aerobic anoxygenic phototrophs was investigated in the Baltic Sea using infrared epifluorescence microscopy from September 2004 to October 2005. The majority of these bacteriochlorophyll-containing organisms exhibited a specific sickle-shaped morphology, with rods or other morphotypes observed only occasionally. Aerobic anoxygenic phototrophs were observed mostly from April to September (1 to 12% of total prokaryotes), peaking in May 2005 at a concentration of up to 0.38 × 106 cells ml–1. This peak was associated with the later phase of the spring bloom. In the later months, the amount of phototrophic bacteria gradually declined until the beginning of the fall mixing, and remained low from November to March, contributing only 0 to 2% of total prokaryotes. A novel technique combining fluorescent in situ hybridization (FISH) and infrared epifluorescence microscopy indicated that the Baltic aerobic anoxygenic phototrophs were mostly Gammaproteobacteria, with a smaller fraction of Alphaproteobacteria.

KEY WORDS: Aerobic photosynthetic bacteria · Bacteriochlorophyll a · Photoheterotrophy ·Epifluorescence microscopy

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