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Marine Pollution Bulletin Oct 2018World production of plastic has dramatically increased from the 1950's and now it reaches approximately 311 million tons per year. The resulting accumulation of...
World production of plastic has dramatically increased from the 1950's and now it reaches approximately 311 million tons per year. The resulting accumulation of small plastic detritus less than 5 mm in size, termed "microplastics", has started threatening the life cycles of marine organisms. Here we show the first evidence that microplastics disturb the initiation of symbiotic relationships in anthozoan-algae symbiosis. We found in both the aposymbiotic sea-anemone Aiptasia sp. and the coral Favites chinensis that the infectivity of symbiotic algae into the host is severely suppressed by microspheres fed either directly or indirectly through microsphere-fed Artemia sp. Similar trends were seen when microplastics collected from commercial facewash were used instead of microspheres. Therefore, ongoing accumulation of microplastics in the ocean might disturb the healthy anthozoan-algae symbiotic relationships, which are cornerstones of the biologically enriched coral reef ecosystem.
Topics: Animals; Anthozoa; Artemia; Coral Reefs; Ecosystem; Ecotoxicology; Food Chain; Plastics; Sea Anemones; Symbiosis; Water Pollutants, Chemical
PubMed: 30301104
DOI: 10.1016/j.marpolbul.2018.07.016 -
The ISME Journal Nov 2019Coral reefs are threatened by global warming, which disrupts the symbiosis between corals and their photosynthetic symbionts (Symbiodiniaceae), leading to mass coral...
Coral reefs are threatened by global warming, which disrupts the symbiosis between corals and their photosynthetic symbionts (Symbiodiniaceae), leading to mass coral bleaching. Planktonic diazotrophs or dinitrogen (N)-fixing prokaryotes are abundant in coral lagoon waters and could be an alternative nutrient source for corals. Here we incubated untreated and bleached coral colonies of Stylophora pistillata with a N-pre-labelled natural plankton assemblage containing diazotrophs. N assimilation rates in Symbiodiniaceae cells and tissues of bleached corals were 5- and 30-fold higher, respectively, than those measured in untreated corals, demonstrating that corals incorporate more nitrogen derived from planktonic diazotrophs under bleaching conditions. Bleached corals also preferentially fed on Synechococcus, nitrogen-rich picophytoplanktonic cells, instead of Prochlorococcus and picoeukaryotes, which have a lower cellular nitrogen content. By providing an alternative source of bioavailable nitrogen, both the incorporation of nitrogen derived from planktonic diazotrophs and the ingestion of Synechococcus may have profound consequences for coral bleaching recovery, especially for the many coral reef ecosystems characterized by high abundance and activity of planktonic diazotrophs.
Topics: Animals; Anthozoa; Coral Reefs; Dinoflagellida; Ecosystem; Global Warming; Heterotrophic Processes; Photosynthesis; Symbiosis; Synechococcus
PubMed: 31249389
DOI: 10.1038/s41396-019-0456-2 -
Scientific Reports Feb 2020Corals and sponges harbor diverse microbial communities that are integral to the functioning of the host. While the taxonomic diversity of their microbiomes has been...
Corals and sponges harbor diverse microbial communities that are integral to the functioning of the host. While the taxonomic diversity of their microbiomes has been well-established for corals and sponges, their functional roles are less well-understood. It is unclear if the similarities of symbiosis in an invertebrate host would result in functionally similar microbiomes, or if differences in host phylogeny and environmentally driven microhabitats within each host would shape functionally distinct communities. Here we addressed this question, using metatranscriptomic and 16S rRNA gene profiling techniques to compare the microbiomes of two host organisms from different phyla. Our results indicate functional similarity in carbon, nitrogen, and sulfur assimilation, and aerobic nitrogen cycling. Additionally, there were few statistical differences in pathway coverage or abundance between the two hosts. For example, we observed higher coverage of phosphonate and siderophore metabolic pathways in the star coral, Montastraea cavernosa, while there was higher coverage of chloroalkane metabolism in the giant barrel sponge, Xestospongia muta. Higher abundance of genes associated with carbon fixation pathways was also observed in M. cavernosa, while in X. muta there was higher abundance of fatty acid metabolic pathways. Metagenomic predictions based on 16S rRNA gene profiling analysis were similar, and there was high correlation between the metatranscriptome and metagenome predictions for both hosts. Our results highlight several metabolic pathways that exhibit functional similarity in these coral and sponge microbiomes despite the taxonomic differences between the two microbiomes, as well as potential specialization of some microbially based metabolism within each host.
Topics: Animals; Anthozoa; Bacteria; Biodiversity; Host-Pathogen Interactions; Metabolic Networks and Pathways; Metagenome; Microbiota; Phylogeny; Porifera; RNA, Ribosomal, 16S; Symbiosis
PubMed: 32047192
DOI: 10.1038/s41598-020-59320-9 -
Current Biology : CB Jun 2021Coral reefs are the epitome of species diversity, yet the number of described scleractinian coral species, the framework-builders of coral reefs, remains moderate by...
Coral reefs are the epitome of species diversity, yet the number of described scleractinian coral species, the framework-builders of coral reefs, remains moderate by comparison. DNA sequencing studies are rapidly challenging this notion by exposing a wealth of undescribed diversity, but the evolutionary and ecological significance of this diversity remains largely unclear. Here, we present an annotated genome for one of the most ubiquitous corals in the Indo-Pacific (Pachyseris speciosa) and uncover, through a comprehensive genomic and phenotypic assessment, that it comprises morphologically indistinguishable but ecologically divergent lineages. Demographic modeling based on whole-genome resequencing indicated that morphological crypsis (across micro- and macromorphological traits) was due to ancient morphological stasis rather than recent divergence. Although the lineages occur sympatrically across shallow and mesophotic habitats, extensive genotyping using a rapid molecular assay revealed differentiation of their ecological distributions. Leveraging "common garden" conditions facilitated by the overlapping distributions, we assessed physiological and quantitative skeletal traits and demonstrated concurrent phenotypic differentiation. Lastly, spawning observations of genotyped colonies highlighted the potential role of temporal reproductive isolation in the limited admixture, with consistent genomic signatures in genes related to morphogenesis and reproduction. Overall, our findings demonstrate the presence of ecologically and phenotypically divergent coral species without substantial morphological differentiation and provide new leads into the potential mechanisms facilitating such divergence. More broadly, they indicate that our current taxonomic framework for reef-building corals may be scratching the surface of the ecologically relevant diversity on coral reefs, consequently limiting our ability to protect or restore this diversity effectively.
Topics: Animals; Anthozoa; Biodiversity; Coral Reefs; Morphogenesis; Reproduction; Tropical Climate
PubMed: 33811819
DOI: 10.1016/j.cub.2021.03.028 -
Environmental Microbiology Reports Aug 2020Reef-building corals live in a mutualistic relationship with photosynthetic algae (family Symbiodiniaceae) that usually provide most of the energy required by the coral... (Comparative Study)
Comparative Study
Reef-building corals live in a mutualistic relationship with photosynthetic algae (family Symbiodiniaceae) that usually provide most of the energy required by the coral host. This relationship is sensitive to temperature stress; as little as a 1°C increase often leads to the collapse of the association. This sensitivity has led to an interest in the potential of more stress-tolerant algae to supplement or substitute for the normal Symbiodiniaceae mutualists. In this respect, the apicomplexan-like microalga Chromera is of particular interest due to its greater temperature tolerance. We generated a de novo transcriptome for a Chromera strain isolated from a GBR coral ('GBR Chromera') and compared with those of the reference strain of Chromera ('Sydney Chromera'), and to those of Symbiodiniaceae (Fugacium kawagutii, Cladocopium goreaui and Breviolum minutum), as well as the apicomplexan parasite, Plasmodium falciparum. In contrast to the high sequence divergence amongst representatives of different genera within the family Symbiodiniaceae, the two Chromera strains featured low sequence divergence at orthologous genes, implying that they are likely to be conspecifics. Although KEGG categories provide few criteria by which true coral mutualists might be identified, they do supply a molecular rationalization that explains the ecological dominance of Cladocopium spp. amongst Indo-Pacific reef corals. The presence of HSP20 genes may contribute to the high thermal tolerance of Chromera.
Topics: Alveolata; Animals; Anthozoa; Coral Reefs; Dinoflagellida; Photosynthesis; Symbiosis; Transcriptome
PubMed: 32452166
DOI: 10.1111/1758-2229.12859 -
Journal of Invertebrate Pathology Jun 2020Diseases in marine invertebrate corals have been reported worldwide and have been associated with infection by various microbial pathogens that cause massive mortality.... (Review)
Review
Diseases in marine invertebrate corals have been reported worldwide and have been associated with infection by various microbial pathogens that cause massive mortality. Several bacterial species, especially Vibrio species but also members of the cyanobacteria, fungi, viruses, and protists, are described as important pathogens associated with coral disease and mortality. The present work provides an updated overview of main diseases and implicated microbial species affecting corals in Indian reefs. Further study on pathogen diversity, classification, spread and environmental factors on pathogen-host interactions may contribute a better understanding of the coral diseases.
Topics: Animals; Anthozoa; Aquatic Organisms; Coral Reefs; Host-Pathogen Interactions; India
PubMed: 32272136
DOI: 10.1016/j.jip.2020.107373 -
Scientific Reports May 2018The blue coral, Heliopora coerulea, is a reef-building octocoral that prefers shallow water and exhibits optimal growth at a temperature close to that which causes...
The blue coral, Heliopora coerulea, is a reef-building octocoral that prefers shallow water and exhibits optimal growth at a temperature close to that which causes bleaching in scleractinian corals. To better understand the molecular mechanisms underlying its biology and ecology, we generated a reference transcriptome for H. coerulea using next-generation sequencing. Metatranscriptome assembly yielded 90,817 sequences of which 71% (64,610) could be annotated by comparison to public databases. The assembly included transcript sequences from both the coral host and its symbionts, which are related to the thermotolerant C3-Gulf ITS2 type Symbiodinium. Analysis of the blue coral transcriptome revealed enrichment of genes involved in stress response, including heat-shock proteins and antioxidants, as well as genes participating in signal transduction and stimulus response. Furthermore, the blue coral possesses homologs of biomineralization genes found in other corals and may use a biomineralization strategy similar to that of scleractinians to build its massive aragonite skeleton. These findings thus offer insights into the ecology of H. coerulea and suggest gene networks that may govern its interactions with its environment.
Topics: Animals; Anthozoa; Coral Reefs; Gene Expression Profiling; Minerals; Molecular Sequence Annotation; Sequence Analysis, RNA
PubMed: 29849113
DOI: 10.1038/s41598-018-26718-5 -
Journal of the Royal Society, Interface May 2015Scleractinian corals are a major source of biogenic calcium carbonate, yet the relationship between their skeletal microstructure and mechanical properties has been... (Comparative Study)
Comparative Study
Scleractinian corals are a major source of biogenic calcium carbonate, yet the relationship between their skeletal microstructure and mechanical properties has been scarcely studied. In this work, the skeletons of two coral species:solitary Balanophyllia europaea and colonial Stylophora pistillata, were investigated by nanoindentation. The hardness HIT and Young's modulus E(IT) were determined from the analysis of several load-depth data on two perpendicular sections of the skeletons: longitudinal (parallel to the main growth axis) and transverse. Within the experimental and statistical uncertainty,the average values of the mechanical parameters are independent on the section's orientation. The hydration state of the skeletons did not affect the mechanical properties. The measured values, EIT in the 76-77 GPa range, and H(IT) in the 4.9–5.1 GPa range, are close to the ones expected for polycrystalline pure aragonite. Notably, a small difference in H(IT) is observed between the species. Different from corals, single-crystal aragonite and the nacreous layer of the seashell Atrina rigida exhibit clearly orientation-dependent mechanical properties. The homogeneous and isotropic mechanical behaviour of the coral skeletons at the microscale is correlated with the microstructure,observed by electron microscopy and atomic force microscopy, and with the X-ray diffraction patterns of the longitudinal and transverse sections.
Topics: Animal Shells; Animals; Anisotropy; Anthozoa; Elastic Modulus; Hardness; Models, Biological; Porosity; Species Specificity; Stress, Mechanical
PubMed: 25977958
DOI: 10.1098/rsif.2015.0168 -
Current Biology : CB Nov 2018Sustaining ecological functions as biodiversity changes will be a major challenge in the 21st century [1]. However, our understanding of the relationship between...
Sustaining ecological functions as biodiversity changes will be a major challenge in the 21st century [1]. However, our understanding of the relationship between biodiversity and ecosystem function is still emerging on tropical coral reefs [2], where reef-building corals form highly productive assemblages [3, 4] and species respond in different ways to their neighbors [5] and their environment (e.g., water flow) [6]. Experimental coral communities were assembled to quantify the performance of coral colonies with and without neighbors and in the presence of conspecifics versus heterospecifics. Under higher flow, we identified a positive effect of coral species richness on primary productivity (gross and net photosynthesis) indicated by a 53% increase in productivity in multispecies assemblages (2-4 species) relative to monocultures. Productivity in monocultures was predicted by surface areas associated with different species morphologies. In contrast, multispecies assemblages maintained high levels of productivity even in the absence of the most productive species, reflecting non-additive effects of species richness on community functioning. Assemblage performances were regulated by positive and negative interactions between colonies, with many colonies performing better among heterospecific neighbors than in isolation (facilitation). Facilitation occurred primarily among flow-sensitive taxa with simple morphologies and did not occur under lower flow, suggesting that modifications to flow microclimates by corals generated beneficial, interspecific interactions. Our results show that competition and facilitation among neighbors may be important mechanisms regulating coral assemblage productivity in variable environments. Furthermore, shifts in the diversity and identity of neighbors can impair these interactions, with potentially widespread consequences for coral community functioning.
Topics: Animals; Anthozoa; Biodiversity; Ecosystem; Environment; Population Dynamics
PubMed: 30393039
DOI: 10.1016/j.cub.2018.09.025 -
Scientific Reports Oct 2018As the world's oceans are currently threatened by anthropogenic pollution and climate change, coral breeding has become an important conservation method, since it can...
As the world's oceans are currently threatened by anthropogenic pollution and climate change, coral breeding has become an important conservation method, since it can limit marine organisms' exposure to sub-optimal environment conditions. However, the aquarium environment is inherently different from the ocean, and this could manifest in physiological changes in the reared organisms, particularly with respect to their reproduction. Therefore, the aim of this study was to observe and compare the ultrastructure of the oocytes from wild Oxypora lacera and Echinopora gemmacea with the oocytes from cultured corals using transmission electron microscope. The oocytes from Wild O. lacera and E. gemmacea were larger than cultured ones, though their microvillus layers were significantly thiner. Internally, lipid granule areas and yolk material density in the oocytes of wild O. lacera and E. gemmacea were ~25% lower than in their cultured counterparts. Food availability and the presence and availability of symbiotic dinoflagellates (genus Symbiodinium) may have played a role in driving these lipid-based differences, in particular, as cultured corals had limited potential for heterotrophic feeding. These data will aid in future coral husbandry efforts.
Topics: Animals; Anthozoa; Endangered Species; Oocytes
PubMed: 30310130
DOI: 10.1038/s41598-018-33341-x