Coral Siderastrea Stellata Research Articles

Microbiota of healthy and bleached corals of the species Siderastrea stellata in response to river influx and seasonality in Brazilian northeast.

Although coral bleaching is increasing worldwide due to warming oceans exacerbated by climate change, there has been a growing recognition that local stressors may play an additional role. Important stressors include the physicochemical and microbiological influences that are related to river runoff. Here, we investigated the microbiota associated to mucus and tissue of endemic coral Siderastrea stellata, collected from Brazilian northeast coral reefs of Barra de Santo Antônio (subject to river runoff) and Maragogi (minimal river runoff) during both the rainy and dry seasons. We sequenced the V4 region of 16S rDNA and used multiple R packages to process raw data and performed statistical analysis to reveal the microbial community structure composition and functional predictions. Major dissimilarities between microbial communities were related to seasonality, while healthy and bleached specimens were mainly associated with the enrichment of several less abundant taxa involved in specific metabolic functions, mainly related to the nitrogen cycle. We were not able to observe the dominance of groups that has been previously associated with bleachings, such as Vibrionaceae or Burkholderiaceae. The influx of freshwater appears to increase the homogeneity between individuals in Barra de Santo Antonio, especially during the rainy season. By contrast, we observed an increased homogeneity between samples in Maragogi during the dry season. Understanding the dynamics of the coral microbiota and how bleaching appears in response to specific environmental variables, in addition to determining the conditions that lead to a more robust coral microbiota, is essential for choosing the most appropriate area and conservation methods, for example.

CORAL DISEASES IN NORTHEASTERN BRAZILIAN REEFS

In the last decade, corals from northeastern Brazil have experienced bleaching events linked to thermal anomalies, the consequences of which have been the appearance of disease outbreaks affecting different species. As a way to explain and monitoring diseases progression and other characteristics regarding the identification in the field for coral diseases, this article aimed to demonstrate the particularities that follows each diseases symptom. This study presents the results of an assessment of the presence of coral diseases on six coastal reefs in northeastern Brazil, including marine protected areas. After 300 hours of visual censuses, a total of 875 colonies were observed; of these, 114 colonies had some disease, representing 13.02% of the colonies analyzed. Five diseases/syndromes were recorded in four host coral species: white syndrome, white plague, red band, dark spots, and white band. This is the first record of white band on the Brazilian coast. The massive coral Siderastrea stellata showed colonies with all registered diseases, which arouses great concern for conservation of the Brazilian coast.

SCREENING OF BACILLUS SP. ISOLATED FROM CORAL SIDERASTREA STELLATA FOR ANTIMICROBIAL ACTIVITY AGAINST ENTEROPATHOGENIC STRAINS OF SALMONELLA AND ESCHERICHIA COLI / SCREENING DE BACILLUS SP. ISOLADOS DO CORAL SIDERASTREA STELLATA PARA ATIVIDADE ANTIMICROBIANA CONTRA LINHAGENS ENTEROPATOGÊNICAS DE SALMONELLA E ESCHERICHIA COLI

Siderastrea stellata is a coral endemic to Brazilian waters and is widely distributed throughout the coast of Bahia state. Exposure of the coral to pathogens stimulates the production of important enzymes by associated symbiont microorganisms. Besides being natural sources of bioactive compounds, these microorganisms possess characteristics that help them survive under extreme conditions. Sixty-eight bacterial strains isolated from the S. stellata coral were analyzed for antimicrobial activity against ten pathogenic bacteria. The cultivation of marine isolates was carried out in liquid or solid seawater. Eight isolates produced antimicrobial compounds against at least two of the ten pathogenic bacteria tested. When isolates were grown in Mueller-Hinton broth, a distinct biocidal spectrum was observed, indicating that the culture medium directly influences the production of antimicrobial compounds. Through molecular characterization of activity-positive isolates, they were identified as belonging to the genus Bacillus . The bioactive compounds produced by the Bacillus stratosphericus SS85 and SS69 strains were stable after storage time for three months. This is the first paper reporting on the antimicrobial activity of microorganisms isolated from coral Siderastrea stellata .

Histopatological effects of bleaching and disease on the coral Siderastrea stellata from coastal reefs of Brazil

ABSTRACT Histological analysis of bleached samples of Siderastrea stellata Verrill, 1868, with white plague disease and with alteration in the color pattern, revealed drastic tissue and cellular disturbances, such as lysis of the external epithelium, hyperplasia of gastrodermis, apoptosis of epithelial cells and zooxanthellae, and degradation of mesenteric filaments and reproductive cells. Fungal hyphae, diatoms, and cyanobacteria were present in diseased samples and colonies with alteration in the color pattern. Furthermore, bleached and diseased samples showed significant reductions in the number of zooxanthellae per 100 µm2 of gastrodermis and significant reductions in the diameters and volumes of stage V oocytes. We found that bleaching events, diseases, and colonies with alteration in the color pattern promoted degradation of reproductive cells, resulting in the consequent interruption of the reproduction of the coral S. stellata, which is one of the most common Brazilian coral species. The implications of these indirect effects of bleaching, disease, and changes in coral color patterns in the population dynamics of Brazilian reefs are discussed.

Coral recovery after a burial event: insights on coral resilience in a marginal reef

Scleractinian reef-building corals can lose their endosymbiotic photosynthetic dinoflagelates (Symbiodiniaceae) and bleach in response to drastic changes in environmental conditions, such as extreme temperature fluctuations and burial events. As bleaching episodes are becoming more frequent and intense worldwide, post-bleaching recovery is critical for coral resilience. We report an in situ experiment in which a previously monitored colony of the coral Siderastrea stellata was found detached, overturned, buried, and bleached (95% of its surface). We reattached the coral to the reef and documented its recovery during 6 months by quantifying its surface area and health condition using 3D models derived from structure-from-motion photogametry of videos obtained in the field. The coral showed the first signs of recovery from a bright-white bleached state within 2 days and fully recovered to a healthy-like state in roughly 1 month, demonstrating that the endosymbiotic algal community recovered fast. Understanding the mechanisms of this fast recovery in marginal reefs in which post-bleaching mortality of dominant reef-building corals like S. stellata is relatively low (< 10%) may provide insights on how reef-building corals will cope with future climate change.

Outlook of fosmid library from metagenomic of the symbionts associated with coral Siderastrea stellata: structural and functional screening for metabolic and antimicrobial activity

Microorganisms colonize the corals and produce compounds with interesting biological properties for biotechnology. The aim of the present study was to search for biocompounds with industrial potential through the cloning metagenomic DNA of symbionts the coral S. stellata in fosmid vector. The metagenomic library was analyzed using functional screening and sequencing via the Illumina MiSeq. Of the 3648 clones, eight were identified as proteolytic and six as amylolytic. The proteolytic clone, P07H3, also exhibited antimicrobial activity against S. aureus, S Enterica PT11, S Enterica PT4 and S Typhi. No clones were positive for lipase/esterase. Beta-lactamase was a single subsystem identified by Rapid Annotation using Subsystem Technology (RAST) through fosmid sequencing of clone P07H3. However, there were identifications of enzymes that participate in metabolic processes such as polysaccharide catabolism, oxidation-reduction, signal transduction and phosphorylation. When the hypothetical proteins were re-analyzed they exhibited a defined functional domain. All the identified open reading frames (ORFs) had low identity with proteins deposited in BLASTp. The sequencing shows that most of the genomic fragments of clone P07H3 possibly consist of new proteins. The Proteobacteria phylum had the greatest predominance among the analyzed fragments. This is the first report on the prospection of amylases, proteases and antimicrobials of coral S. stellata samples. The analyzes of this study help to improve the knowledge about the metabolic diversity of S. stellata still little explored and viable in the future study of the identified compounds.

Thermal stress and tropical reefs: mass coral bleaching in a stable temperature environment?

This study reports on the deepest records (~ 24 m depth) of coral bleaching in a naturally temperature-stable environment (> 26 °C with an intra-annual variability of ~ 2 °C), which was recorded during a mass bleaching event in the locally dominant, massive scleractinian coral Siderastrea stellata in equatorial waters of Brazil (SW Atlantic). An inter-annual analysis (2002–2017) indicated that this bleaching event was related to anomalies in sea surface temperature (SST) that led to the warmest year (2010) in this century (1 to 1.7 °C above average). Such anomalies caused heat stress (28.5–29.5 °C) in this equatorial environment that resulted in a bleaching event. Our results suggest that the increase in SST, low turbidity, and weak winds may have acted together to affect these stress-tolerant corals in marginal reefs. The equatorial coastline of Brazil is characterized by low intra-annual and inter-annual variations in SST, which suggests that the S. stellata corals here may be acclimatized to these stable conditions and, consequently, have a lower bleaching threshold because of lower historical heat stress.

Microcystins production and antibacterial activity of cyanobacterial strains of Synechocystis, Synechococcus and Romeria isolated from water and coral reef organisms of Brazilian coast

Cyanobacteria are widely distributed in terrestrial, freshwater and marine environments, and over the past decades have been recognized as a powerful source of bioactive compounds. In this study, some cyanobacterial strains were isolated from samples of seawater, brackish water and tissue of reef benthic invertebrates (zoanthid Protopalythoa variabilis, the sponges Cynachrella sp. and Haliclona sp., the coral Siderastrea stellata, and ascidians), collected at the states of Paraiba and Rio Grande do Norte (Northeast of Brazil), during the period between July 2010 and February 2014. After standard isolation methods, the cultivation of the strains was carried out in acclimatized culture chamber (25 °C) under constant aeration, for 15 days at 12-hour photoperiod, using Conway and BG11 media made with filtered seawater. After ethanolic and methanolic extracts, the strains were analysed for the microcystin production by the ELISA technique and for the antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa by the agar well diffusion method. The detection of the mcy B gene, one of the genes related to the microcystin synthesis, was done by the Polymerase Chain Reaction (PCR) technique. The majority of the eighteen cyanobacterial strains belonged to Synechococcaceae Family. The genera of Synechocystis, Synechococcus and Romeria were represented by ten, six and two strains, respectively. The production of microcystins was observed in five strains belonging to the genus Synechocystis . The presence of mcy B gene was detected in 12 strains of cyanobacteria: Synechocystis (three strains), Synechococcus (six strains) and Romeria (two strains). Only one strain ( Synechocystis aquatilis ) showed both the microcystin production and the mcy B gene presence. The antibacterial activity was observed for one strain of Romeria gracilis , one strain of Synechocystis aquatilis and two strains of Synechococcus sp. The ethanolic extracts of R. gracilis strain and two Synechococcus spp. strains inhibited the growth of P. aeruginosa . Among methanolic extracts of cyanobacteria, only one strain of S. aquatilis showed activity against S. aureus, and one R. gracilis strain against P. aeruginosa . Some cyanobacterial strains studied were positive for the microcystin production and antibacterial activity against pathogenic bacteria S. aureus and P. aeuruginosa , and may be further explored for additional biotechnological applications.

Microcystins production and antibacterial activity of cyanobacterial strains of Synechocystis, Synechococcus and Romeria isolated from water and coral reef organisms of Brazilian coast

Cyanobacteria are widely distributed in terrestrial, freshwater and marine environments, and over the past decades have been recognized as a powerful source of bioactive compounds. In this study, some cyanobacterial strains were isolated from samples of seawater, brackish water and tissue of reef benthic invertebrates (zoanthid Protopalythoa variabilis, the sponges Cynachrella sp. and Haliclona sp., the coral Siderastrea stellata, and ascidians), collected at the states of Paraíba and Rio Grande do Norte (Northeast of Brazil), during the period between July 2010 and February 2014. After standard isolation methods, the cultivation of the strains was carried out in acclimatized culture chamber (25 °C) under constant aeration, for 15 days at 12-hour photoperiod, using Conway and BG11 media made with filtered seawater. After ethanolic and methanolic extracts, the strains were analysed for the microcystin production by the ELISA technique and for the antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa by the agar well diffusion method. The detection of the mcyB gene, one of the genes related to the microcystin synthesis, was done by the Polymerase Chain Reaction (PCR) technique. The majority of the eighteen cyanobacterial strains belonged to Synechococcaceae Family. The genera of Synechocystis, Synechococcus and Romeria were represented by ten, six and two strains, respectively. The production of microcystins was observed in five strains belonging to the genus Synechocystis. The presence of mcyB gene was detected in 12 strains of cyanobacteria: Synechocystis (three strains), Synechococcus (six strains) and Romeria (two strains). Only one strain (Synechocystis aquatilis) showed both the microcystin production and the mcyB gene presence. The antibacterial activity was observed for one strain of Romeria gracilis, one strain of Synechocystis aquatilis and two strains of Synechococcus sp. The ethanolic extracts of R. gracilis strain and two Synechococcus spp. strains inhibited the growth of P. aeruginosa. Among methanolic extracts of cyanobacteria, only one strain of S. aquatilis showed activity against S. aureus, and one R. gracilis strain against P. aeruginosa. Some cyanobacterial strains studied were positive for the microcystin production and antibacterial activity against pathogenic bacteria S. aureus and P. aeuruginosa, and may be further explored for additional biotechnological applications.

Functional screening for cellulolytic activity in a metagenomic fosmid library of microorganisms associated with coral.

Cellulases are enzymes that degrade cellulosic materials. Cellulose is the most abundant renewable carbon resource on Earth, and cellulases are used in various industrial sectors. Although cellulases are obtained from a variety of sources, this is the first description of cellulolytic activity isolated from a coral metagenomic library. A metagenomic fosmid library of microorganisms associated with the coral Siderastrea stellata, comprising 3552 clones, was screened for cellulolytic activity; this allows access to non-cultivable microorganisms by exploiting the full biotechnological potential. Clones were grown on LB agar plates supplemented with 0.5% carboxymethylcellulose and cellulase positive clones revealed by staining with Congo red. Using this approach, six positive clones with cellulolytic activity were identified. The enzymatic index (EI) of the positive clones was calculated by the ratio between the hydrolysis zone diameter and colony diameter. All positive clones had an EI greater than 1.5. Digestion of the DNA isolated from the six positive clones, using the HindIII restriction endonuclease, revealed different restriction patterns in each clone, indicating that the DNA of each clone is different. There is a growing interest for new cellulolytic enzymes in various industry sectors. Here, we present the initial selection of potential clones for cellulose degradation that could be targets for future studies of enzymatic characterization.

A test of herbivory-mediated coral–algae interaction on a Brazilian reef during a bleaching event

Many ecosystem services and functions provided by coral reefs have been compromised worldwide because of its conservation status. Despite such evidence, no published studies address herbivory-mediated competitive interactions between corals and algae in Brazilian reefs. The reciprocal effects of the interaction between the endemic massive coral Siderastrea stellata and filamentous algae in the presence and absence of herbivory typically found in coastal reefs of Brazil were tested during a bleaching event. To manipulate herbivory, five coral colonies were caged, five left uncaged, and partial cages were placed around five more colonies to test for a cage artifact. In order to assess the competitive interaction, three treatments were applied within each herbivory plot. Coral–algae contact zones either had algae removed, coral tissue removed or both left untouched. During the five month experiment, all 15 colonies bleached because of natural causes and coral tissue did not grow in any of the replicates. Coral mortality was not significantly affected by any experimental factor. On the other hand, algal growth was negatively affected by herbivorous fishes, mainly parrot fishes and damselfishes, but direct contact with S. stellata tissue did not have any effect on filamentous algae. Considering that S. stellata is one of the most common corals in tide pools and reef tops in Brazil, it is very likely that the bleaching event weakened coral polyps and filamentous algae became the major competitor. In conclusion, the coral S. stellata did not offer any resistance to algae overgrowth that was only controlled by herbivory. In case bleaching events alter coral–algae competitive interaction outcomes, herbivory provides a window of opportunity for corals to recover after the disturbance.

Zonación vertical del macrobentos de sustratos sólidos del estuario del río Massangana, Bahía de Suape, Pernambuco, Brasil

El área estuarina del río Massangana (Pernambuco, Brasil) está sujeta a diversas intervenciones antropomórficas resultantes de las actividades del Complejo Industrial y Portuario de Suape, que pueden afectar las comunidades bióticas. Con esa perspectiva, este estudio tuvo como finalidad verificar la composición de la macrofauna bentónica de los sustratos sólidos, en su gradiente de distribución vertical, que sirva de referencia para futuros monitoreos biológicos relacionados a los cambios que pueden ocurrir en el complejo portuario. Se colectaron los invertebrados presentes en un área de 519 m² y su distribución en los sustratos biogénicos y abiogénicos es mostrada en el siguiente trabajo. Fueron encontradas 79 especies presentes principalmente en los mangles y distribuidas en tres zonas del intermareal: Chthamaletum, delimitando el supralitoral, "zona balanoide", conteniendo cirripedios y ostras, en la región intermareal media, y el Bostrychietum, en la región inferior. Esta distribución coincidió en forma general, con el patrón brasileño e internacional de distribución vertical de los invertebrados de manglares. La presencia de sustrato rocoso y la alta salinidad posibilitó la aparición de 28 especies, incluyendo el coral Siderastrea stellata en un área estuarina. La ampliación de la distribución en el litoral brasileño del bivalvo Isognomon alatus, del cirripedio Amphibalanus reticulatus y de los briozoos Biflustra savartii, Bowerbankia gracilis y Conopeum reticulum fue justificada por la proximidad con el Puerto de Suape, facilitada por el transporte pasivo en las embarcaciones. La distribución esparcida de los organismos incrustantes en los sustratos y la ausencia de animales característicos de este ecosistema, como los mejillones, muestran señales de que el ambiente ya sufre algún estrés, resultado de las diversas intervenciones antropomórficas que están aconteciendo.

Zooxanthellae genotypes in the coral Siderastrea stellata from coastal reefs in northeastern Brazil

Siderastrea stellata is a common scleractinian coral that inhabits shallow reefs off the coast of Brazil. This species is considered to be very resistant to temperature and salinity variations and water turbidity, demonstrating great ecological plasticity and adaptability to environmental changes. Samples of S. stellata were taken from the Cabo Branco coastal reefs near João Pessoa, Brazil, every month for two years and analyzed using PCR and Restriction Fragment Length Polymorphisms of SSU rDNA techniques. The data indicated that during the study period S. stellata hosted only one SSU rDNA genotype of Symbiodinium with the RFLP pattern of clade C. The presence of clade C zooxanthellae in S. stellata in northeastern Brazilian reefs shows the wide geographical distribution of this clade, and it may aid bleaching recovery in S. stellata. Furthermore, the association of S. stellata with a zooxanthellae clade considered to be one of most resistant to bleaching may help to explain the high ecological plasticity of this scleractinian species, its capacity to reverse bleaching, and its high resistance and resilience to environmental disturbances.

Colony size-frequency distributions among different populations of the scleractinan coral Siderastrea stellata in Southwestern Atlantic: implications for life history patterns

Colony size-frequency distributions of reef corals may be used to infer growth potential and population responses upon environmental changes. The present paper compares the size structure of colonies of Siderastrea stellata Verrill, 1868,among 11 sites, six of them distributed along a gradient of sediment deposition in Abrolhos, Bahia, Brazil (18º S). Results indicated that the population structure is likely to be influenced by local conditions, rather than large scale factors, such as latitude. The 11 distributions, however, showed higher frequencies of small size classes. Class 1 (up to 2.5 cm diameter) was always present and the frequency of colonies from size class 3 (10 cm diameter) tended to decrease in all sites. Comparison among the six Abrolhos sites showed that S. stellata has advantages at sites with intermediate sedimentation, where colonies attain larger sizes, probably, reflecting a higher survivorship over time. The present study showed that, despite the influence of environmental conditions on parameters of the populations such as size of colony, the life history strategy of S. stellata reflects a local adaptation that allows its development and survivorship in shallow waters and horizontal substrates, sites characterized by high mortality rates.

Distribution of Benthic Communities on the Tropical Rocky Subtidal of Armação dos Búzios, Southeastern Brazil

Abstract. Few studies have described the spatial patterns of rocky sublittoral benthic communities in Brazil, where these habitats are almost exclusively located on the southeast and south coastline. The fauna and flora were analyzed using a quadrat method, and the species abundance and distribution were determined along transects down to the bottom sand plain on 10 rocky shores at Armação dos Búzios, Brazil. The 16 most common species accounted for around 97% of the benthos coverage and included cnidarians, algae, poriferans, and echinoderms. Cnidarians and algae were the most important groups, with abundance ranging from 13–66% and 27–68%, respectively. The species distribution indicated a clear depth zonation pattern. The algal community dominated the shallowest depths in sites more exposed to waves and steeper substrate slope, whereas the cnidarian community, divided into the zoanthidean Palythoa caribaeorum and the coral Siderastrea stellata, was more abundant from intermediate to greater (4 m) depths. Different community patterns were found between sites, demonstrating that different spatially discrete factors may be acting on each rocky shore.