Figure 1.
Rarefaction analysis of bacterial SSU rRNA gene sequences.
This analysis represents data subsampled at 3,662 sequences per sample. Samples with OTU richness greater than 130 are listed by name.
Table 1.
Observed OTUs (97% similarity grouped) and diversity indices from 3,662 sequences for the different sample categories (data for normal animals only).
Figure 2.
Similarity analysis of whale skin-bacteria.
(A) Clustering dendogram, and (B) nonmetric multidimensional scaling analysis of 97% similarity grouped OTUs of bacterial communities associated with whale skin sampled from different populations and locations, and seawater.
Table 2.
PERMANOVA analysis of the effect of geographic area, metabolic state, age class, sex and sample type on the 97% OTU grouped bacterial SSU rDNA data from humpback skin (GOM = Gulf of Maine).
Figure 3.
Taxonomic composition whale skin-bacteria.
The 97% similarity grouped OTU bacterial communities were associated with humpback whale skin sampled from different populations and locations. Graphs represent total composition (A), and abundances of skin-bacterial sequences specifically belonging to the Tenacibaculum and Psychrobacter lineages (B). Each bar graph represents the relative abundance of each major taxonomic group, and sums to 100%.
Table 3.
Abundances of whale skin-bacterial sequences corresponding to the Tenacibaculum and Psychrobacter genera.
Table 4.
Results of SIMPER analysis describing 97% similarity grouped OTUs contributing to the differences between the whales with anabolic and catabolic metabolisms (>1% contribution only).
Figure 4.
Abundances of Tenacibaculum and Psychrobacter-affiliated sequences.
Presence of skin-bacterial OTUs (97% similarity grouped) classified as Tenacibaculum (A) and Psychrobacter (B), in relation to the geographic region of the whales.
Figure 5.
Phylogenetic relationship of Tenacibaculum-affiliated sequences.
Represented SSU rRNA gene sequences include Tenacibaculum-affiliated sequences recovered from whale skin, cultivated Tenacibaculum isolates, and relatives within the Tenacibaculum lineage. Red sequences are short-reads from this study and blue are full-length sequences from a previous study on humpback whale skin [8]. The scale bar corresponds to 0.10 substitutions per nucleotide position, and only bootstrap values >70 are listed. Sequences from Caldilinea aerophila (AB067647), Roseiflexus castenholzii (CP000804) and Actinomyces oris (GQ421308), were used to form the outgroup. Full accession numbers for the dolphin respiratory-bacteria sequences are available in [35].
Figure 6.
Oligotyping analysis of major humpback skin-bacterial groups.
MDS analysis of the healthy animals from four regional groups based on Tenacibaculum (A) and Psychrobacter (B) oligotypes. Centroid and shape of each ellipse is defined by the distribution and standard deviation of points in the defined regional groups.
Table 5.
PERMANOVA analysis of the effect of geographic area, age, sex and sample type on Tenacibaculum and Psychrobacter spp. populations determined by oligotyping.
Figure 7.
Phylogenetic relationship of Psychrobacter-affiliated sequences.
Represented SSU rRNA gene sequences include Psychrobacter-affiliated sequences recovered from whale-skin, cultivated Psychrobacter isolates, and relatives within the Gammaproteobacteria. Red colored sequences are short-reads from this study, and blue full-length sequences are from a previous study [8]. The scale bar corresponds to 0.10 substitutions per nucleotide position, and only bootstrap values >70 are listed. Sequences from Hymenobacter soli (AB251884), Salegentibacter flavus (AY682200) and Ureaplasma urealyticum were used to form the outgroup.
Figure 8.
Scanning electron micrographs of whale skin-bacteria.
Overview (A, C, E, G) and detailed (B, D, F, H) scanning electron micrographs of the surface of humpback whale skin from individuals CCS2010-100 (A, B), CCS2010-99 (C,D), CCS2010-96 (E,F) and CCS2010-98 (G,H). Diatoms, and microbes residing on these cells, were present on the surfaces of CCS2010-100 (I) and CCS2010-97 (J). Arrows indicate possible unique microbial cell morphotypes.
Table 6.
Comparison of skin-bacteria among normal, health-compromised and dead humpback whales, (n/a) indicates not applicable.