Last species standing: loss of Pocilloporidae corals associated with coastal urbanization in a tropical city state

Poquita-Du, Rosa Celia; Quek, Zheng Bin Randolph; Jain, Sudhanshi S.; Schmidt‐Roach, Sebastian; Tun, Karenne; Heery, Eliza C.; Chou, Loke Ming; Todd, Peter A.; Huang, Danwei

doi:10.1007/s12526-019-00939-x

Cited by 37 publications

(22 citation statements)

References 114 publications

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“…Studies also suggest that the genus is a possible indicator of marginal reef environments and that its members tend to be more prevalent on reefs with higher levels of environmental disturbance (Chen et al 2003;Stat and Gates 2011). The close proximity of coral reefs in Singapore to a large urban population and Singapore's role as a major maritime shipping and petrochemical processing hub (Chou 2006;Heery et al 2018) likely create stresses and disturbances that are not present in other regions (Poquita-Du et al 2019). On the one hand, subclades D1b and D2 are not associated with P. lutea outside of Singapore possibly because they have been excluded by other endosymbionts better adapted to less stressful environments.…”

Section: Discussionmentioning

confidence: 99%

Endosymbiont diversity and community structure in Porites lutea from Southeast Asia are driven by a suite of environmental variables

et al. 2020

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Many corals depend upon the highly specialised and intricate relationship they form with Symbiodiniaceae algal symbionts. Porites lutea is a massive reef-building coral found throughout Southeast Asia that hosts these endosymbionts obligately. Yet despite the prevalence and importance of P. lutea as one of the most dominant corals here, its associated Symbiodiniaceae communities have not been precisely characterised. In this study, we used high-throughput DNA amplicon sequencing of the nuclear internal transcribed spacer 2 (ITS2) to characterise the diversity, community structure and biogeographic distribution of Symbiodiniaceae in P. lutea throughout Singapore and Peninsular Malaysia. Consistent with previous studies, we found that Cladocopium was the most dominant genus among all samples, and Cladocopium C15 was the most dominant type (or subclade) with 100% occurrence in all samples from every study site. Results also revealed numerous Symbiodiniaceae types associated with P. lutea that were previously undetected in Southeast Asia. Endosymbiont diversity and community variation are driven by a combination of site-specific mean monthly cloud cover and variance in monthly sea surface temperature. This study contributes baseline data toward understanding differences in Symbiodiniaceae assemblages hosted by P. lutea, shedding light on how they might be indicative of particular environmental conditions and coral responses.Electronic supplementary material The online version of this article (https://doi.

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Section: Discussionmentioning

confidence: 99%

Endosymbiont diversity and community structure in Porites lutea from Southeast Asia are driven by a suite of environmental variables

et al. 2020

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“…Owing to its weedy life-history strategy (Darling et al, 2012), it is believed to allocate more energy toward growth than survival responses to environmental changes (Pinzon et al, 2014). The genus Pocillopora was previously categorized as one of the most susceptible to thermal stress (Loya et al, 2001;McClanahan et al, 2004), however, recent observations during coral bleaching events in Singapore identify Pocillopora as one of the least affected genera (Guest et al, 2012;Chou et al, 2016;Poquita-Du et al, 2019). A total of eight adult colonies (called genotypes hereafter) of P. acuta (∼25 cm maximum diameter) were collected from three reef sites (∼4 m depth) in Singapore's southern islands ( Table 1).…”

Section: Study Species and Sampling Sitesmentioning

confidence: 99%

Short Term Exposure to Heat and Sediment Triggers Changes in Coral Gene Expression and Photo-Physiological Performance

et al. 2019

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Corals, together with their endosymbiotic Symbiodiniaceae, are known to exhibit a suite of mechanisms for survival under stressful conditions. However, exactly how the host animal responds to varying environmental conditions remains unclear. In this study, we tested two relevant environmental factors that can have deleterious effects on corals: heat and sediment. We examined among-genotype responses of Pocillopora acuta to these factors with RNA-Seq in concert with widely-used tools for assessing the physiological conditions of corals. Heat and sediment treatments were applied in a 2 × 2 crossed experimental design: (1) ∼30 • C without sediment (control, "C"), (2) ∼30 • C with sediment (sediment-only, "S"), (3) ∼32 • C without sediment (heat-only, "H"), (4) ∼32 • C with sediment (heat + sediment, "H+S") over four consecutive days (3-h daily exposure) in ex situ aquarium conditions. A clear differentiation in gene expression patterns was observed in corals exposed to heat alone and to heat with sediment, relative to the control treatment. Few transcripts (∼3) were found to be differentially expressed for corals exposed to sediment only. The greater impact of heat was supported by photophysiological measurements that showed significant effects on maximum quantum yield and average symbiont density among genotypes of P. acuta. The combined effect of heat and sediment caused a greater reduction in average symbiont density than the effect of sediment alone. Furthermore, "H+S" disrupted the ability of corals to maintain processes involving assembly and disassembly of cilium which suggests a synergistic effect between the two factors. We also found that host-specific genes which were expressed differentially may not be related to their interactions with algal symbionts. Rather, these genes are involved in a variety of biological functions including, but not limited to, cilium biogenesis and degradation, cilia motility, innate and adaptive immune responses, cell adhesion and bone mineralization, and processes involved in the cell

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“…In Singapore, the genus Micromussa and in particular M. amakusensis have not been documented from historical or contemporary records (Huang et al 2009;Guest et al 2016;Wong et al 2018;Chow et al 2019), so our discovery represents the southern-most record of this species in the South China Sea region (Huang et al 2015). The present finding is remarkable given that species losses have occurred over the last five decades as a consequence of coastal urbanisation in Singapore (Hoeksema and Koh 2009;Poquita-Du et al 2019b). Growth rates of encrusting lobophyllids have rarely been reported in the literature (Madin et al 2016).…”

Section: Discussionmentioning

confidence: 60%

“…These discoveries have wide-ranging impacts, even for the evaluation of species conservation status (see Agapow et al 2004;Mace 2004;Ely et al 2017). For example, a recent investigation of the identity of Pocillopora colonies in Singapore has shown that P. acuta is the only pocilloporid species remaining on its reefs following the historical loss of four species driven by habitat loss, coastal urbanisation and coral bleaching (Poquita-Du et al 2019b). Due to the rapidly changing environment impacting corals locally and worldwide (Pandolfi et al 2003;Hughes et al 2014Hughes et al , 2017, the distribution of coral taxa ought to be assessed continually, particularly for those that have been revised taxonomically.…”

Section: Introductionmentioning

confidence: 99%

New genus and species record of reef coral Micromussa amakusensis in the southern South China Sea

Jain

Nguyen

et al. 2019

Mar Biodivers Rec

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Background: Recent taxonomic revisions of zooxanthellate scleractinian coral taxa have inevitably resulted in confusion regarding the geographic ranges of even the most well-studied species. For example, the recorded distribution ranges of Stylophora pistillata and Pocillopora damicornis, two of the most intensely researched experimental subjects, have been restricted dramatically due to confounding cryptic species. Micromussa is an Indo-Pacific genus that has been revised recently. The revision incorporated five new members and led to substantial range restriction of its type species and only initial member M. amakusensis to Japan and the Coral Triangle. Here, we report the presence of Micromussa amakusensis in Singapore using phylogenetic methods. Results: A total of seven M. amakusensis colonies were recorded via SCUBA surveys at four coral reef sites south of mainland Singapore, including two artificial seawall sites. Colonies were found encrusting on dead coral skeletons or bare rocky substrate between 2 and 5 m in depth. Morphological examination and phylogenetic analyses support the identity of these colonies as M. amakusensis, but the phylogeny reconstruction also shows that they form relatively distinct branches with unexpected lineage diversity. Conclusions: Our results and verified geographic records of M. amakusensis illustrate that, outside the type locality in Japan, the species can also be found widely in the South China Sea. Moreover, our discovery provides a new genus and species record in Singapore and represents the southern-most occurrence of the species in the Indo-Pacific. Despite the extensive survey efforts in Singapore over the last three decades, taxonomic studies integrating morphological and molecular methods remain instrumental in quantifying the actual coral species diversity.

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Last species standing: loss of Pocilloporidae corals associated with coastal urbanization in a tropical city state

Cited by 37 publications

References 114 publications

Endosymbiont diversity and community structure in Porites lutea from Southeast Asia are driven by a suite of environmental variables

Endosymbiont diversity and community structure in Porites lutea from Southeast Asia are driven by a suite of environmental variables

Short Term Exposure to Heat and Sediment Triggers Changes in Coral Gene Expression and Photo-Physiological Performance

New genus and species record of reef coral Micromussa amakusensis in the southern South China Sea

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