Symbiodinium spp. in colonies of eastern Pacific Pocillopora spp. are highly stable despite the prevalence of low-abundance background populations

Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

“…However, the observed shift between sampling points from domin ance of Symbiodinium C15n in winter to C15p in summer was unexpected. Whilst seasonality of Symbiodinium communities has been observed before in Acropora palifera (Chen et al 2005), most corals exhibit stable Symbiodinium associations over time (Thornhill et al 2006, McGinley et al 2012. However, this seasonality effect was limited to shallow water, where environmental variability was highest, which has previously been proposed as an explanation for more heterogeneous Symbiodinium communities at shallow sites relative to deep sites (Thornhill et al 2006).…”

“…In several coral species in the Great Barrier Reef, the prevalence of Symbiodinium from clade C at offshore locations converge to the prevalence of Symbiodinium from clade D with increasing coastal influence (Ulstrup & van Oppen 2003). Comparable changes of Symbiodinium communities in response to season are less common (Chen et al 2005); studies that monitored several coral species over 5 yr demonstrated that most hostSymbiodinium combinations are stable over time (Thornhill et al 2006), although background shuffling (McGinley et al 2012), and shifting dominance between co-occurring types within the same Symbiodinium community does occur (Ulstrup et al 2008). Taken together, flexible association with Symbiodinium types along environmental gradients is an important factor that broadens a coral's distribution range (Rodriguez-Lanetty et al 2001, Bongaerts et al 2010.…”

Conservation of Symbiodinium spp. clade in the coral Pocillopora damicornis during the 2014 mass-bleaching event

“…For example, in eastern Pacific populations of Pocillopora spp., less than 3% of surveyed colonies changed their symbionts from thermally-sensitive clade C to thermally tolerant clade D (McGinley et al, 2012), while some genera would undergo full shifts following prolonged elevated thermal exposure (Silverstein, Cunning, & Baker, 2015). However, for Pocillopora spp, conflicting results also exist; Pocillopora colonies that recruited more thermally tolerant symbionts, or in which the dominant clade was thermo-tolerant, were observed to be more abundant and more resilient in the mass bleaching events (Glynn et al 2001;Baker et al 2005).…”

“…Some Symbiodinium clades are predominantly associated with certain species of corals, and some coral species show no shuffling of clades even after bleaching (Cunning, Glynn, & Baker, 2013;Glynn et al, 2001;LaJeunesse et al, 2010;McGinley et al, 2012;Stat et al, 2008).…”

“…The genera Pocillopora, Pavona, Porites, Gardineroseris, and Psammocora are known to have high fidelity to certain clades of symbionts without shuffling (Glynn, Maté, Baker, & Calderón, 2001;McGinley et al, 2012). For example, in eastern Pacific populations of Pocillopora spp., less than 3% of surveyed colonies changed their symbionts from thermally-sensitive clade C to thermally tolerant clade D (McGinley et al, 2012), while some genera would undergo full shifts following prolonged elevated thermal exposure (Silverstein, Cunning, & Baker, 2015).…”