Search Results (527)

This study investigated the CaCO₃ spontaneous precipitation in the presence of soluble organic macromolecules (SOMs) extracted from the skeleton of Mediterranean colonial coral species, symbiotic Cladocora caespitosa (SOM-CCA) and asymbiotic Astroides calycularis (SOM-ACL). This approach was used as a model to explore biomineralization processes in marine organisms. The research was conducted in systems without or with the addition of Mg²⁺ (Mg/Ca molar ratio was 5:1) and/or SOMs (concentration range was 0.5–4 ppm). In the model system (system without Mg²⁺ or SOMs), only vaterite spherulites precipitated, while in the system with added Mg²⁺, only aragonite irregular aggregates were observed. Although the addition of SOMs did not influence the polymorphic composition of the CaCO₃ precipitates, it led to noticeable changes in induction time and morphology of CaCO₃ crystals, and these effects were stronger in the presence of SOM-ACL. By comparing systems containing both Mg²⁺ and SOM with the model system as well as with systems where Mg²⁺ or SOMs were added individually, the dominant role of Mg²⁺ in the aragonite formation was observed. However, the combined effect of Mg²⁺ and both SOMs enhanced the inhibition of CaCO₃ precipitation. This inhibitory effect was particularly enhanced in the system combining Mg²⁺ and SOM-ACL. Full article

The precipitation of minerals, in particular carbonates, is a widespread phenomenon in all ecosystems, where it assumes a high relevance both from a geological and biogeochemical standpoint. Most carbonate rocks are of biological origin and made in an aquatic environment. In particular, bioprecipitation of carbonates is believed to have started in the Mesoproterozoic Era, thanks to a process often driven by photosynthetic microorganisms. Nevertheless, an important contribution to carbonate precipitation is also due to the metabolic activity of heterotrophic bacteria, which is not restricted to specific taxonomic groups or to specific environments, making this process a ubiquitous phenomenon. In this framework, the relationship between carbonatogenic microorganisms and other living organisms assumes a particular interest. This study aims to isolate and identify the culturable heterotrophic bacterial component associated with the coenosarc of Corallium rubrum in order to evaluate the occurrence of strains able to precipitate carbonates. In particular, the study was focused on the identification and characterisation of bacterial strains isolated from a coral coenosarc showing a high carbonatogenic capacity under laboratory conditions. Samples of C. rubrum were taken in the coastal waters of three Italian regions. The concentration of the aerobic heterotrophic microflora colonising C. rubrum coenosarc samples spanned from 3 to 6∙10⁶ CFU/cm². This variation in microbial populations colonising the C. rubrum coenosarc, spanning over 6 orders of magnitude, is not mirrored by a corresponding variability in the colony morphotypes recorded, with the mean being 5.1 (±2.1 sd). Among these bacteria, the carbonatogenic predominant species was Staphylococcus equorum (93% of the isolates), whereas Staphylococcus xylosus and Shewanella sp. accounted only for 3% of isolates each. All these strains showed a remarkable capacity of precipitating calcium carbonate, in the form of calcite crystals organised radially as well crystalised spherulites (S. equorum) or coalescing spherulites (Shewanella sp.). S. xylosus only produced amorphous precipitates of calcium carbonate. All bacterial strains identified were positive both for the production of urease and carbon anhydrase in vitro at 30 °C. It seems that they potentially possess the major biochemical abilities conducive to Ca²⁺ precipitation, as they showed in vitro. In addition, all our carbonatogenic isolates were able to hydrolyse the phytic acid calcium salt and then were potentially able to induce precipitation of calcium phosphates also through such a mechanism. Full article

Recreational diving depends on healthy marine ecosystems, yet it can harm biodiversity through species displacement and habitat damage. Bombinhas, a biodiverse diving hotspot in southern Brazil, faces growing threats from human activity and climate change. This study assessed the ecological structure of Sepultura Beach (2018) for potential diving trails, comparing it with historical data from Porto Belo Island. Using visual censuses, transects, and photo-quadrats across six sampling campaigns, researchers documented 2419 organisms from five zoological groups, identifying 14 dominant species, including Haemulon aurolineatum and Diplodus argenteus. Cluster analysis revealed three ecological zones, with higher biodiversity at the site’s edges (Groups 1 and 3), but these areas also hosted endangered species like Epinephelus marginatus, complicating trail planning. A major concern was the widespread bleaching of the zoanthid Palythoa caribaeorum, a key ecosystem engineer, likely due to rising sea temperatures (+1.68 °C from 1961–2018) and declining chlorophyll-a levels post-2015. Comparisons with past data showed a 0.33 °C increase in species’ thermal preferences over 17 years, alongside lower trophic levels and greater ecological vulnerability, indicating tropicalization from the expanding Brazil Current. While Sepultura Beach’s biodiversity supports diving tourism, conservation efforts must address coral bleaching and endangered species protection. Long-term monitoring is crucial to track warming impacts, and adaptive management is needed for sustainable trail development. The study highlights the urgent need to balance ecotourism with climate resilience in subtropical marine ecosystems. Full article

Tubastraea coccinea and T. tagusensis, commonly known as sun corals, are two species of stony corals (Scleractinia, Dendrophylliidae) native to the Indo-Pacific region (T. coccinea) and the Galapagos Islands (T. tagusensis), respectively. They are considered highly invasive species, particularly in the Western Atlantic Ocean, due to high adaptability to various ecological conditions and notable resilience. Given their demonstrated invasiveness, it is important to delve into their physiology and the molecular bases supporting their resilience. However, to date, only a few molecular tools are available for the study of these organisms. The primary objective of the present study was the development of an efficient RNA extraction protocol for Tubastraea coccinea and T.a tagusensis samples collected off Ilha Grande Bay, Rio de Janeiro (Brazil). The quantity of isolated RNA was evaluated using NanoDrop, while its purity and quality were determined by evaluating the A260/A280 and A260/230 ratios. Subsequently, based on genes known for T. coccinea, two housekeeping genes and seven stress response-related genes were isolated and characterized, for the first time for both species, using a molecular approach. An interactomic analysis was also conducted, which revealed functional interactions among these genes. This study represents the first report on gene networks in Tubastraea spp., opening new perspectives for understanding the chemical ecology and the cellular mechanisms underlying the invasiveness of these species. The results obtained will be useful for ecological conservation purposes, contributing to the formulation of strategies to limit their further expansion. Full article

Remote reefs offer insights into natural coral dynamics, influenced by regional environmental factors and climate change fluctuations. Clipperton Atoll is the eastern tropical Pacific’s most isolated reef, where coral reef growth and life strategies have been poorly studied so far. Recognizing the coral species’ growth response might help understand ecological dynamics and the impacts of anthropogenic stressors on coastal reefs. The present study evaluates annual coral growth parameters of the most abundant coral reef-building species, Porites australiensis, Porites arnaudi, Porites lutea, and Porites lobata. The results showed that during 2015–2019, corals exhibited the lowest annual linear extension (0.65 ± 0.29 cm yr⁻¹), skeletal density (1.14 ± 0.32 g cm⁻³), and calcification rates (0.78 ± 0.44 g cm⁻² yr⁻¹) for the genera along the Pacific. Differences in growth patterns among species were observed, with Porites lutea and Porites lobata showing a higher radial extension, developing massive-hemispherical morphologies, and acting as structural stabilizers; meanwhile, P. arnaudi and P. australiensis exhibited more skeletal compaction but also with a high plasticity on their morphologies, contributing to benthic heterogeneity. These differences are particularly important as each species fulfills different ecological functions within the reef, contributing to the ecosystem balance and enhancing the relevance of the massive species in the physical structure of remote reef systems, such as Clipperton Atoll. Full article

Microplastics are pervasive in marine ecosystems and have been shown to affect a range of marine organisms, including corals. These particles can develop biofilms, facilitating the transport of pollutants and pathogenic microorganisms. Although the effects of primary microplastics on adult corals have been extensively studied, little is known about the impacts of secondary microplastics on early life stages. This study investigated (1) the effects of different abundances of secondary microplastics on the early development of Orbicella faveolata; (2) the influence of fibers and fragments on the larval settlement of Acropora palmata; and (3) the effects of the microplastic size, abundance, and biofilm presence on the settlement of Favia fragum. For O. faveolata, fertilization, embryogenesis, and settlement were all impaired by fragments, with embryonic development showing a 25.9% reduction in viability. Larval development was unaffected, but post-settlement survival declined by 35.8% with exposure to fibers and fragments. For A. palmata, settlement was reduced by fragments, while for F. fragum, only 2–4 mm fragments significantly decreased settlement rates. This study contributes to the knowledge of the effect of microplastics on the early development of corals, providing valuable information to improve strategies to control microplastic pollution. Full article

Mapping marine habitats is fundamental for biodiversity conservation and ecosystem-based management in oceanic regions under increasing anthropogenic and climatic pressures. In the context of global initiatives—such as marine protected area expansion and international agreements—habitat mapping has become mandatory for regional and global conservation policies. It provides spatial data to delineate essential habitats, support connectivity analyses, and assess pressures, enabling ecosystem-based marine spatial planning aligned with EU directives (2008/56/EC; 2014/89/EU). Beyond biodiversity, macrophytes, rhodolith beds, and coral reefs deliver key ecosystem services—carbon sequestration, coastal protection, nursery functions, and fisheries support—essential to local socioeconomies. This systematic review (PRISMA guidelines) examined 69 peer-reviewed studies across Central-Eastern Atlantic archipelagos (Macaronesia: the Azores, Madeira, the Canaries, and Cabo Verde) and the Mid-Atlantic Ridge. We identified knowledge gaps, methodological trends, and key challenges, emphasizing the integration of cartographic, ecological, and technological approaches. Although methodologies diversified over time, the lack of survey standardization, limited ground truthing, and heterogeneous datasets constrained the production of high-resolution bionomic maps. Regional disparities persist in technology access and habitat coverage. The Azores showed the highest species richness (393), dominated by acoustic mapping in corals. Madeira was most advanced in the remote mapping of rhodoliths; the Canaries focused on shallow macrophytes with direct mapping; and Cabo Verde remains underrepresented. Harmonized protocols and regional cooperation are needed to improve data interoperability and predictive modeling. Full article

Fungi are the most poorly described kingdom of Eukarya. Fundamental questions about their species diversity, their distributions, and their biotic interactions remain largely unanswered, despite fungi playing important roles in the ecology and biogeochemistry of terrestrial ecosystems. To assess some of these data gaps, we intensively surveyed club and coral fungi in a temperate Australian forest in the Upper Lane Cove Valley, Sydney, Australia, over a period of two years. Specimens identified as Clavulinopsis, Ramaria, or Ramariopsis based on morphology were then assigned to operational taxonomic units (OTUs) using the criterion of 97% identity across the entire rDNA internal transcribed spacer (ITS) region. Based on this criterion and ITS-based phylogenies, we identified 80 OTUs in these genera of club and coral fungi within the survey area. Of these OTUs, only 11.25% could be assigned a species name based on BLASTn matches to full-length ITS sequences, suggesting that almost 90% of OTUs were novel taxa, or are yet to be represented in DNA databases. Specimens that were morphologically similar to well-known Northern Hemisphere species were shown to be distinct upon DNA sequencing. Accumulation curves suggest that our surveys only recovered about half of the species in the target genera, and seven times the effort would be required to sample to exhaustion. In summary, even in a small area of less than 100 km², there is evidence for multiple undescribed, cryptic, and undiscovered species. This highlights the fundamental work that remains to be completed in fungal taxonomy and biology. Full article

Climate change and anthropogenic stressors are accelerating coral reef degradation, prompting urgent restoration strategies. This study evaluates the performance of two coral nursery types, floating mid-water nurseries (FNs) and bottom-attached table nurseries (TNs), at two contrasting reef environments in Mauritius: the degraded, high sedimentation site of Flic-en-Flac (FEF) and the more pristine Pointe aux Feuilles (PAF). Coral fragments from Millepora sp., Acropora muricata, Acropora selago, and Pocillopora damicornis were monitored over three years for survivorship, growth, and linear extension rate (LER). Survivorship exceeded 88% in all cases, with Millepora sp. in PAF–TN achieving the highest rate (99.8%) and P. damicornis in FEF–FN the lowest (88%). Growth was greatest at PAF–TN, where Millepora sp. reached a mean length of 27.25 cm and LER of 9.66 mm y⁻¹. In contrast, the same species in FEF–TN averaged only 3.64 cm in length and 3.44 mm y⁻¹ in LER. Environmental conditions including higher turbidity, nitrate, and phosphate at FEF, and higher phytoplankton density at PAF significantly influenced coral performance. We propose a site-specific nursery selection framework, including FNs for high-sediment areas and TNs for protected and biodiverse sites, to support more effective coral farming outcomes in island restoration programs. Full article

Coral restoration is essential for recovering depleted populations and reef ecological functions. However, its effect on enhancing fish assemblages remains understudied. This study investigated the integration of 3D-printed and natural Staghorn coral (Acropora cervicornis) out-planting to assess their role in enhancing benthic spatial complexity and attracting fish communities. Conducted between 2021 and 2023 at Culebra Island, Puerto Rico, we employed a before-after-control-impact (BACI) design to test four treatments: natural A. cervicornis, 3D-printed corals, mixed stands of 3D-printed and natural corals, and non-restored controls. Fish assemblages were monitored through stationary counts. Results showed that integrating 3D-printed and natural corals enhanced fish assemblages and their ecological functions. Significant temporal changes in fish community structure and biodiversity metrics were observed, influenced by treatment and location. Herbivore abundance and biomass increased over time, especially in live coral and 3D-printed plots. Reefs with higher rugosity exhibited greater Scarid abundance and biomass post-restoration. Piscivore abundance also rose significantly over time, notably at Tampico site. Fishery-targeted species density and biomass increased, particularly in areas with live and 3D-printed coral out-plants. Fish assemblages became more complex and diverse post-restoration, especially at Tampico, which supported greater habitat complexity. Before restoration, fish assemblages showed a disturbed status, with biomass k-dominance curves above abundance curves. Post-out-planting, this trend reversed. Control sites showed no significant changes. The study demonstrates that restoring fast-growing branching corals, alongside 3D-printed structures, leads to rapid increases in abundance and biomass of key fishery species, suggesting its potential role promoting faster ecosystem recovery and enhanced coral demographic performance. Full article

A quantitative literature review of restoration techniques and supporting management strategies used throughout the Caribbean and Western Atlantic from 1998 through 2024 was compiled using references from the Web of Science to highlight those with potential for reef replenishment. From 93 sources listed, 74 publications were relevant and categorized into subtopics based on the most prevalent restoration techniques. Roughly half the studies focused on three general topics: the benefits of restoring Acropora species, studies utilizing micro-fragmentation and fragment nurseries, and outplanting techniques. Other subtopics, each with at least three references, included optimizing substrates and artificial reefs, enhancing larval recruitment, emphasizing the role of herbivory, improving management practices, and addressing the impacts of tourism and community engagement. The information from the references was compiled to determine the overlap among categories and the ways in which techniques and management strategies might be applied simultaneously to enhance restoration outcomes. Additionally, sources were analyzed according to time and location of publication to better visualize the emergence of this area of research and restoration efforts. An increase in publications was observed from 2014 to 2024, associated with the rise in major events impacting coral reefs. The major locations for published research were the Florida reef tract and Puerto Rico, though restoration studies were also reported from the Bahamas and sites around the Caribbean. Criteria to assess the success of techniques included coral survival, recruitment, coral coverage, habitat structure and complexity, and biomass of marine life, including fish and invertebrates that inhabited a restored reef. Most restoration efforts utilized either fragmentation or assisted sexual breeding, followed by cultivation in nurseries or labs. Outplanting success depended on fragment size, attachment style, and site selection, with less-intrusive techniques and intermediate planting densities promoting survival. Tools like GAO maps can guide site selection based on herbivore presence and algal coverage. Monitoring is critical to ensuring coral survival, especially after the first year of outplanting, while community involvement can foster public engagement in reef conservation. Full article

Coral-reef fishes in the South China Sea play a crucial role in sustaining ecosystem stability and delivering essential ecological functions. However, widespread coral degradation has led to habitat loss, intensifying environmental stress on reef-associated fish communities. To better understand their current status and guide conservation efforts, this study conducted a comprehensive, trait-based assessment of coral-reef fish diversity across 19 reef sites in the South China Sea, spanning nearshore (Sanya, Hainan) and offshore (Xisha and Nansha Islands) systems. Significant spatial differences were observed in species composition, functional trait structure, and responses to environmental disturbance. Offshore reefs, particularly in the Nansha Islands, exhibited the highest species richness, trophic complexity, and functional diversity, while nearshore reefs showed simplified community structure dominated by small, sedentary species with high microhabitat dependence. Coral cover was only weakly correlated with fish diversity and failed to reflect functional trait complexity, highlighting the limitation of relying on structural indicators alone. Using community-weighted trait metrics, PCA, and indicator species analysis, this study established a tri-principle framework for identifying priority conservation species based on ecological function, rarity, and vulnerability. Key functional species—including Chlorurus sordidus, Siganus fuscescens, and Cephalopholis urodeta—were identified, along with representative conservation sites such as Meiji Reef, Lingyang Reef, and Luhuitou. These findings underscore the need to integrate species-level and functional diversity into coral reef monitoring and management. The proposed framework provides a science-based foundation for prioritizing species and habitats, enhancing the resilience of reef ecosystems under the dual threats of climate change and anthropogenic pressure. Full article

Marine biodiversity is of critical importance to global ecosystems. The Indo-Pacific Convergence Zone (IPCZ), a global marine biodiversity hotspot, faces escalating threats from human activities and climate change. This underscores the pressing need to develop effective conservation strategies for marine biodiversity in the IPCZ. This study integrates spatial analysis of ecological sensitivity (coral reefs, mangroves, and seagrass) and anthropogenic pressures (shipping/fishing intensity) to identify biodiversity hotspots and conservation gaps. Using datasets from UNEP-WCMC, OBIS, and Global Fishing Watch, we applied GIS-based multi-criteria evaluation to 5408 grid cells (0.5° resolution) across the IPCZ. Results revealed that 14.7% of the study area constitutes biodiversity hotspots, primarily in coastal Philippines, Indonesia’s Lesser Sunda Islands, and northern Australia. However, only 6% of the IPCZ is currently protected, with merely 13.88% of hotspots overlapping existing marine protected areas (MPAs). Anthropogenic pressure hotspots (e.g., Malacca Strait) showed limited spatial overlap with biodiversity hotspots, suggesting species displacement from high-disturbance zones. Priority conservation areas were delineated by balancing ecological significance and economic activity conflicts. We propose targeted strategies, including buffer zones, seasonal no-take areas, and green shipping technologies, to reconcile conservation with sustainable development. This framework provides actionable insights for enhancing MPA networks in biogeographic transition zones. Full article

An atypical surface shape was observed in encrusting coral colonies of Montipora millepora. Initial assumptions on their origin focused on the presence of epibiotic intermediate habitat formers, such as coral-dwelling and -boring organisms. However, further investigations revealed their origin to also be substrate shape-related, prompted by overgrowing other foundation species. The unusual bumps stemmed from encrusting over specimens of the coral Alveopora japonica, and the forked, tube-like structures over holdfasts of the brown alga Ecklonia cava. Spatial distribution patterns and interspecific competition are briefly reviewed. Potential effects of morphological changes for Montipora species identification, as well as implications of altered topography in general, are mentioned. Full article

Precious corals from the Corallidae family (Corallium, Hemicorallium, and Pleurocorallium genera) are well known in the high-end jewelry industry due to their colorful and durable axial skeleton. They exist in various colors from white to pink to dark red. One highly appreciated shade is the light pink color, the so-called ‘angel skin’. This color is most often associated with Pleurocorallium elatius and Pleurocorallium secundum, species listed in CITES Appendix III. However, this has been based on an assumption of their visual similarity and has never been underpinned by detailed morphologic or genetic data. In this study, we present the analysis of an ‘angel skin’ coral necklace of exceptional size and homogeneous color and quality. Visual observation and Raman spectroscopy confirmed that the necklace consists of genuine, untreated precious coral material. Following minimally destructive sampling, respectively, drilling 2.2, 2.4, and 2.4 milligrams of material from the existing drill-holes, three randomly selected beads from the necklace were subject to a routine genetic identification assay, which is based on sequencing a short, taxonomically informative mitochondrial region. This genetic analysis identified the coral material as not from P. elatius or P. secundum but from another Pleurocorallium species. We subsequently sequenced additional mitochondrial DNA fragments from one ‘angel skin’ coral bead and compared them against a well-represented, curated reference data set of Pleurocorallium, including the first-ever sequencing of Pleurocorallium gotoense, Pleurocorallium johnsoni, Pleurocorallium cf. pusillum, and Pleurocorallium uchidai. We concluded that the analyzed material of the ‘angel skin’ coral necklace belongs to the Pleurocorallium norfolkicum species complex but is not identical to any hitherto analyzed and published Pleurocorallium specimens. A comparison with further taxonomically unidentified precious coral colony fragments identified a single sample fished in Vietnam to be completely identical to the ‘angel skin’ coral bead in the studied DNA regions. Thus, by the analysis of a high-end jewel, we discovered a species new to the jewelry trade and potentially also unknown to science. This implies that the currently considered list of species present in the precious coral trade is incomplete. Full article