Figure 1.
In hospite net photosynthesis-irradiance (P-E) curves from four Caribbean gorgonian species.
(A) P-E curves per cm2 of gorgonian branches and, (B) P-E curves per Symbiodinium cell. Solid lines represent the average fitted values for Pterogorgia anceps (n = 9), Eunicea tourneforti (n = 8), Pseudoplexaura porosa (n = 6), and Pseudoplexaura wagenaari (n = 6). Dotted lines represent ± standard error. The photosynthetic rate at 1800 µmol quanta was used as a proxy for the maximum photosynthetic rate.
Table 1.
Photosynthesis-irradiance (P-E) curve parameters for gorgonian species.
Table 2.
Photosynthesis-irradiance (P-E) curve parameters for isolated Symbiodinium.
Figure 2.
Symbiodinium parameters in four Caribbean gorgonian species.
(A) Cell densities and, (B) Concentration of chlorophylls a (circles) and c2 (squares) per Symbiodinium cell. Points represent sample means ± standard error. Gorgonian species that do not share a letter are significantly different from each other in either density or chlorophyll a per cell (α = 0.05, see Figure 1 for full species names and sample sizes). See Table 3 for significant differences in chlorophyll c2 per cell.
Table 3.
Photosynthetic characteristics of Symbiodinium in four Caribbean gorgonian species.
Figure 3.
Estimated absorbance spectra, De (A), and Chlorophyll a specific absorption, a*chl a (B) in four Caribbean gorgonian species.
Pterogorgia anceps (red line; n = 9), Eunicea tourneforti (green line; n = 8), Pseudoplexaura porosa (blue line; n = 6), and Pseudoplexaura wagenaari (purple line; n = 6). Lines in (A) represent average De spectra for each species. The equation for the line in (B) is y = 0.7586*(x−0.8976).
Figure 4.
A maximum likelihood phylogenetic tree based on microsatellite flanking regions of B1 Symbiodinium.
The phylogeny includes B1 Symbiodinium from the four gorgonian species in this study (highlighted in gray), from other gorgonian corals [47], from scleractinian and hydrozoan corals [36], as well as Symbiodinium minutum from Aiptasia, a sea anemone [47]. Branch tips are labeled with host species and sample sizes when n>1. Gorgonian and scleractinian coral species are shown in black and red, respectively, and the other cnidarians are shown in blue. B1 lineages described by Finney et al. [36] are listed besides the host taxa. Numbers above the branches are the posterior probability above the maximum likelihood consensus support for each group. B1 Symbiodinium from 16 of 19 gorgonian colonies sampled clustered in a phylogenetic group with high posterior probability (top gray box). Three gorgonian colonies were placed outside of this clade (bottom gray box) and were most closely related to Symbiodinium isolated from Pseudoplexaura porosa from Florida (indicated with (+1)) and cultured Symbiodinium from Gorgonia ventalina [47] indicated with *. (#) indicates a group recovered in the maximum likelihood tree, but not the Bayesian phylogenetic tree.