AME 64:51-67 (2011)  -  DOI: https://doi.org/10.3354/ame01509

ABSTRACT: Using a combination of clone library and DGGE analyses, we assessed the diversity of coastal planktonic ciliates from the oligotrich and choreotrich clades across environmental gradients in Long Island Sound, USA. We sampled fresh and saline, as well as stratified and well-mixed, waters and found that these ciliate assemblages consist of a few common haplotypes and numerous rare haplotypes. Rarefaction estimates of total richness indicated that our survey did not cover the full diversity of the samples, suggesting that there may be many more haplotypes present in the Sound than predicted by previous microscopic surveys. We also found that haplotype richness varied on small spatial scales (<1 km) and that differences in community composition among samples are not readily attributable to commonly measured environmental factors. This result suggests that the ­driving forces behind these differences are more complex than the abiotic measures captured here. In common with other studies, we found that most of the haplotypes we observed had not been ­identified previously and posted on public genetic databases.

KEY WORDS: Oligotrichia · Choreotrichia · Coastal ciliate · Long Island Sound · Haplotype diversity · Microbial assemblage