Characterization and comparison of prokaryotic epiphytes associated with three east African seagrasses
2007 (English)In: Journal of Phycology, ISSN 0022-3646, Vol. 43, no 4, 768-779 p.Article in journal (Refereed) Published
Prokaryotic epiphytes on leaves of three seagrass species, Thalassodendron ciliatum, Thalassia hemprichii, and Cymodocea rotundata, from two Kenyan coastal sites, Nyali (a high-nutrient site) and Vipingo (a low-nutrient site), were characterized genetically and morphol. Denaturing gradient gel electrophoresis (DGGE) and clone libraries of PCR-amplified 16S rRNA gene fragments were used to study prokaryotes assocd. with these seagrasses. In general, the epiphytic coverage was greater in the high-nutrient site, while the microbial diversity was linked to seagrass species rather than the study sites. Cytophaga-Flavobacteria-Bacteroides (CFB) were assocd. with T. ciliatum and T. hemprichii mainly in the nutrient-poor site, while a-, b-, and g-proteobacteria were assocd. with all three species at the two study sites. Some bacteria phylotypes were closely related to sequences of microorganisms previously recovered from wastewaters or other contaminated sources, indicating the influx of land-based wastes into these coastal lagoon ecosystems. The abundance of potential nitrogen (N2)-fixing cyanobacteria on C. rotundata, particularly in the low-nutrient site, suggested that this assocn. may have been acquired to meet N demands. Unicellular cyanobacteria were dominant and assocd. with C. rotundata and T. hemprichii (with those on T. hemprichii being closely related to cyanobacterial symbiotic species), while T. ciliatum was almost devoid of cyanobacterial assocns. at the same site (Nyali), which suggests specificity in the cyanobacteria-seagrass assocns. The abundance of prokaryotic epiphytes was considered to be linked to water depth and tidal exposure.
Place, publisher, year, edition, pages
2007. Vol. 43, no 4, 768-779 p.
IdentifiersURN: urn:nbn:se:su:diva-11005ISI: 000248544800015OAI: oai:DiVA.org:su-11005DiVA: diva2:177524