Comparison of free-living and particle-associated bacterial communities in a coastal Lagoon
- 234 Downloads
We analyzed, by terminal restriction fragment length polymorphisms (T-RFLPs) of PCR-amplified 16S rDNA, microbial diversity in water collected during the dry and wet seasons in a human-impacted coastal lagoon. Water samples were fractionated by prefiltration to differentiate particle-associated and free-living microbes. From a sample collected during the dry season, prefiltration removed 23 to 44% of bacteria, as assessed by direct counts and MPN, and 99% of phytoplankton, as assessed by chlorophyll a. Restriction with RsaI yielded fewer peaks than restriction with HhaI. Diversity indices calculated from T-RFLPs were higher in the lagoon than adjoining coastal waters and higher in the particle-associated than the free-living fraction. In the dry season, peaks found only in bulk and particle-associated T-RFLPs were consistent with plastid and cyanobacterial ribotypes. These peaks matched those observed in the sequence of a clone generated from the bulk fraction with plastid and cyanobacterial specific primers. This clone appeared related to plastids found in the diatom genus Skeletonema. Principal component analysis of T-RFLPs suggested that the difference between the free-living and particle-associated fractions in the dry season was less than temporal variability in this lagoon and that these fractions varied significantly only in the wet season. This fractionation of microbial populations into particle-associated and free-living guilds during the wet season, when water residence time in the lagoon is relatively low, suggests an external source of particle-associated bacteria such as erosion of upland soils by runoff.
Unable to display preview. Download preview PDF.
- 3.Atlas RM, Bartha R (1993) Microbial Ecology: Fundamentals and Applications, 3rd ed. Benjamin/Cummings, Redwood City, CAGoogle Scholar
- 13.Delong EF, Franks DG, Alldredge AL (1993) Phylogenetic diversity of aggregate-attached vs free-living marine bacterial assemblages. Limnol Oceanogr 38:924–934Google Scholar
- 22.Knap AH, Michaels AF, Dow RL, Johnson RJ, Gundersen K, Sorensen JC, Close AR, Howse FA, Hammer M, Bates N, Doyle A, Waterhouse T (1993) BATS Method Manual Version 3. U.S. Joint Global Ocean Flux Study Planning and Coordination Office, Woods Hole, MAGoogle Scholar
- 25.Langenheder S, Jurgens K (2001) Regulation of bacterial biomass and community structure by metazoan and protozoan predation. Limnol Oceanogr 46:121–134Google Scholar
- 30.Moeseneder MM, Arrieta JM, Muyzer G, Winter C, Herndl GJ (1999) Optimization of terminal-restriction fragment length polymorphism analysis for complex marine bacterioplankton communities and comparison with denaturing gradient gel electrophoresis. Appl Environ Microbiol 65:3518–3525PubMedGoogle Scholar
- 31.Moeseneder MM, Winter C, Herndl GJ (2001) Horizontal and vertical complexity of attached and free-living bacteria of the eastern Mediterranean Sea, determined by 16S rDNA and 16S rRNA fingerprints. Limnol Oceanogr 46:95–107Google Scholar
- 43.Urbach E, Vergin KL, Young L, Morse A, Larson GL, Giovannoni SJ (2001) Unusual bacterioplankton community structure in ultra-oligotrophic Crater Lake. Limnol Oceanogr 46:557–572Google Scholar
- 46.Zhou JZ, Davey ME, Figueras JB, Rivkina E, Gilichinsky D, Tiedje JM (1997) Phylogenetic diversity of a bacterial community determined from Siberian tundra soil DNA. Microbiology (UK) 143:3913–3919Google Scholar