Coral Polyps Research Articles

The Trojan seahorse: citizen science pictures of a seahorse harbour insights into the distribution and behaviour of a long-overlooked polychaete worm.

Symbiotic marine invertebrates can be small, hidden or difficult to find, hampering the understanding of their distribution and ecological roles. Haplosyllis anthogorgicola is a polychaete inhabiting the gorgonian Anthogorgia bocki, where it lives in high densities within the host's coenenchyme and occupies burrows formed by host tissue near coral polyps. This study provides the first records of H. anthogorgicola since its description in 1956, from colonies of Anthogorgiidae in southern Japan. We observed that host gorgonians were also inhabited by the pygmy seahorse Hippocampus bargibanti, a popular species to observe and photograph among SCUBA divers. Therefore, we examined photographic records of H. bargibanti available on the citizen science website iNaturalist and screened for structures associated with infestation by H. anthogorgicola to gather information on this elusive species. Our analyses confirmed that this polychaete and/or similar species are widespread in the central Indo-Pacific region. In addition, we observed some polychaete behaviours, raising questions about the nature of the relationships between H. anthogorgicola, its gorgonian hosts and the pygmy seahorse. Our study demonstrates that citizen science can contribute to our knowledge not only on the distribution and behaviour of well known and charismatic species but also inadvertently on overlooked and neglected taxa.

Microscale sampling of the coral gastrovascular cavity reveals a gut-like microbial community

Animal guts contain numerous microbes, which are critical for nutrient assimilation and pathogen defence. While corals and other Cnidaria lack a true differentiated gut, they possess semi-enclosed gastrovascular cavities (GVCs), where vital processes such as digestion, reproduction and symbiotic exchanges take place. The microbiome harboured in GVCs is therefore likely key to holobiont fitness, but remains severely understudied due to challenges of working in these small compartments. Here, we developed minimally invasive methodologies to sample the GVC of coral polyps and characterise the microbial communities harboured within. We used glass capillaries, low dead volume microneedles, or nylon microswabs to sample the gastrovascular microbiome of individual polyps from six species of corals, then applied low-input DNA extraction to characterise the microbial communities from these microliter volume samples. Microsensor measurements of GVCs revealed anoxic or hypoxic micro-niches, which persist even under prolonged illumination with saturating irradiance. These niches harboured microbial communities enriched in putatively microaerophilic or facultatively anaerobic taxa, such as Epsilonproteobacteria. Some core taxa found in the GVC of Lobophyllia hemprichii from the Great Barrier Reef were also detected in conspecific colonies held in aquaria, indicating that these associations are unlikely to be transient. Our findings suggest that the coral GVC is chemically and microbiologically similar to the gut of higher Metazoa. Given the importance of gut microbiomes in mediating animal health, harnessing the coral “gut microbiome” may foster novel active interventions aimed at increasing the resilience of coral reefs to the climate crisis.

In Vivo Lifetime Imaging of the Internal O2 Dynamics in Corals with near-Infrared-Emitting Sensor Nanoparticles.

Mapping of O2 with luminescent sensors within intact animals is challenging due to attenuation of excitation and emission light caused by tissue absorption and scattering as well as interfering background fluorescence. Here we show the application of luminescent O2 sensor nanoparticles (∼50-70 nm) composed of the O2 indicator platinum(II) tetra(4-fluoro)phenyltetrabenzoporphyrin (PtTPTBPF) immobilized in poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA). We injected the sensor nanoparticles into the gastrovascular system of intact colony fractions of reef-building tropical corals that harbor photosynthetic microalgae in their tissues. The sensor nanoparticles are excited by red LED light (617 nm) and emit in the near-infrared (780 nm), which enhances the transmission of excitation and emission light through biological materials. This enabled us to map the internal O2 concentration via time-domain luminescence lifetime imaging through the outer tissue layers across several coral polyps in flowing seawater. After injection, nanoparticles dispersed within the coral tissue for several hours. While luminescence intensity imaging showed some local aggregation of sensor particles, lifetime imaging showed a more homogeneous O2 distribution across a larger area of the coral colony. Local stimulation of symbiont photosynthesis in corals induced oxygenation of illuminated tissue areas and formation of lateral O2 gradients toward surrounding respiring tissues, which were dissipated rapidly after the onset of darkness. Such measurements are key to improving our understanding of how corals regulate their internal chemical microenvironment and metabolic activity, and how they are affected by environmental stress such as ocean warming, acidification, and deoxygenation. Our experimental approach can also be adapted for in vivo O2 imaging in other natural systems such as biofilms, plant and animal tissues, as well as in organoids and other cell constructs, where imaging internal O2 conditions are relevant and challenging due to high optical density and background fluorescence.

Possible sink of missing ocean plastic: Accumulation patterns in reef-building corals in the Gulf of Thailand

Individual coral polyps contain three distinct components—the surface mucus layer, tissue, and skeleton; each component may exhibit varying extent of microplastic (MP) accumulation and serve as a short- or long-term repository for these pollutants. However, the literature on MP accumulation in wild corals, particularly with respect to the different components, is limited. In this study, we investigated the adhesion and accumulation of MPs in four coral species, including both large (Lobophyllia sp. and Platygyra sinensis) and small (Pocillopora cf. damicornis and Porites lutea) polyp corals collected from Si Chang Island in the upper Gulf of Thailand. The results revealed that MP accumulation varied significantly among the four coral species and their components. Specifically, P. cf. damicornis exhibited the highest degree of accumulation (2.28 ± 0.34 particles g−1 w.w.) [Tukey's honestly significant difference (HSD) test, p < 0.05], particularly in their skeleton (52.63 %) and with a notable presence of high-density MPs (Fisher's extract test, p < 0.05). The most common MP morphotype was fragment, accounting for 75.29 % of the total MPs found in the coral. Notably, the majority of MPs were black, white, or blue, accounting for 36.20 %, 15.52 %, and 11.49 % of the samples, respectively. The predominant size range of MP particles was 101–200 μm. Nylon, polyacetylene, and polyethylene terephthalate (PET) were the prevalent polymer types, accounting for 20.11 %, 14.37 %, and 9.77 % of the identified samples, respectively. In the large polyp corals, while MP shapes, colors, and sizes exhibited consistent patterns, remarkable differences were noted in the polymer types across the three components. The findings of this study improve the understanding of MP accumulation and its fate in coral reef ecosystems, underscoring the need for further investigation into MP-accumulation patterns in reef-building corals worldwide.

Growth and Survival Rate of Pocillopora spp. Fragments on Coral Tree and Coral Table Media in Semut Kecil Island, Anambas Islands

Graphical Abstract Highlight Research Pocillopora spp. coral fragments have been identified and analyzed. Growth of new coral polyp tissue on skeletal media and substrate. The presence of coral bleaching was caused by sedimentation and algal growth that covered the fragments. The effectiveness of the media for transplantation. Abstract Pulau Semut Kecil, Anambas Islands, are located within the coral reef triangle, as one of the largest Marine Protected Areas (MPAs) in Indonesia. Coral reefs possess significant functional attributes within ecosystems, and their condition is progressively deteriorating due to anthropogenic activities. This situation necessitates restoration endeavors, primarily through coral transplantation methodologies. The methods involved the introduction or relocation of donor corals into substrates such as tree transplantation media and tables, exhibiting high success rates. This study was conducted to determine the growth and survival rate of Pocillopora spp. The direct survey approach was used and the different coral transplanting media were statistically analyzed with the ANOVA test and SPSS software. The results of the growth of coral fragments Pocillopora spp. Reported coral tree media and table with an average value of 0.55 cm/month and 0.15 cm/month. The survival rate of Pocillopora spp. coral fragments in tree media and table was 97.3% and 87.0%. The media for dropping coral trees and table did not affect the growth and survival rate. This coral transplantation method can facilitate for the restoration of degraded ecosystem and ecological succession.

A possible archaic precursor of the octocoral structural plan from the Ordovician of Estonia

AbstractA new species and genus of colonial coral, Lindaphylon solovjevi, from the Upper Ordovician of Estonia is described in detail. The colony has a zonation similar to the zonation structure of the mesogleal skeleton of octocorals, since it consists of a narrow axis and a surrounding wide cortex of small calcite sclerites and a system of large solenia. Corallites present 12 sclerosepta in a wide shallow cup. A new family Lindaphylonidae and an order Lyndaphylonaceae are based on these features, and a new order placed in the subphylum Anthozoa as incertae sedis. A comparative study of skeleton formation and mesenteric apparatus symmetry in different groups of coral polyps is considered in detail.

Parabens, bisphenols, and triclosan in coral polyps, algae, and sediments from sanya, China: Occurrence, profiles, and environmental implications

Parabens, bisphenols (BPs), and triclosan (TCS) are common environmental phenols widely applied in industrial products, pharmaceuticals, and personal care products. They are endocrine disruptors and pervade the natural environment, causing significant detrimental impacts on ecosystems, including marine habitats. Therefore, in this study, 40 samples comprising coral polyps, algae, and sediments were collected from Sanya, Hainan Province, China, in which the presence and compositional profiles of parabens, BPs, and TCS were examined to identify their fate in the oceans. The results unveiled the ubiquitous occurrence of at least one paraben or bisphenol in all samples, with TCS detected in over 80% of cases. Notably, coral samples contained the most contaminants (median concentration: 9.42 ng/g dry weight-dw), followed by sediment samples (5.95 ng/g dw) and algal samples (3.58 ng/g dw). Attributed to their broadest application, methylparaben (MeP) and propylparaben (PrP) emerged as the primary paraben constituents. MeP displayed the highest median concentration in coral samples (4.42 ng/g dw), probably related to its high-water solubility and the filtration mechanism employed by the coral polyps during seawater intake. Intriguingly, bisphenol P (BPP) superseded bisphenol A (BPA) as the dominant bisphenol, especially in the algal samples, probably owing to the lipophilic character of BPP and the enhanced biodegradability of BPA within aquatic environments. The highest concentration of TCS (3.44 ng/g dw) was found in the sediment samples, associated with its long half-life in the sediments. Furthermore, the correlation between multiple parabens and TCS implies their co-use to augment antimicrobial efficacy. Future research should prioritize the examination of these phenols in diverse marine environmental media. Corresponding toxicological experiments should be conducted to visualize their transport dynamics, degradation byproducts, and toxicity to marine biota to gain insights into the risks they pose to the marine ecosystem.

Genome and tissue-specific transcriptomes of the large-polyp coral, Fimbriaphyllia (Euphyllia) ancora: a recipe for a coral polyp

Coral polyps are composed of four tissues; however, their characteristics are largely unexplored. Here we report biological characteristics of tentacles (Te), mesenterial filaments (Me), body wall (Bo), and mouth with pharynx (MP), using comparative genomic, morpho-histological, and transcriptomic analyses of the large-polyp coral, Fimbriaphyllia ancora. A draft F. ancora genome assembly of 434 Mbp was created. Morpho-histological and transcriptomic characterization of the four tissues showed that they have distinct differences in structure, primary cellular composition, and transcriptional profiles. Tissue-specific, highly expressed genes (HEGs) of Te are related to biological defense, predation, and coral-algal symbiosis. Me expresses multiple digestive enzymes, whereas Bo expresses innate immunity and biomineralization-related molecules. Many receptors for neuropeptides and neurotransmitters are expressed in MP. This dataset and new insights into tissue functions will facilitate a deeper understanding of symbiotic biology, immunology, biomineralization, digestive biology, and neurobiology in corals.

Microbiome heterogeneity in tissues of the coral, Fimbriaphyllia (Euphyllia) ancora.

Coral microbiomes differ in the mucus, soft tissue and skeleton of a coral colony, but whether variations exist in different tissues of a single polyp is unknown. In the stony coral, Fimbriaphyllia ancora, we identified 8,994 amplicon sequencing variants (ASVs) in functionally differentiated polyp tissues, i.e., tentacles, body wall, mouth and pharynx, mesenterial filaments, and gonads (testes and ovaries), with a large proportion of ASVs specific to individual tissues. However, shared ASVs comprised the majority of microbiomes from all tissues in terms of relative abundance. No tissue-specific ASVs were found, except in testes, for which there were only two samples. At the generic level, Endozoicomonas was significantly less abundant in the body wall, where calicoblastic cells reside. On the other hand, several bacterial taxa presented significantly higher abundances in the mouth. Interestingly, although without statistical confirmation, gonadal tissues showed lower ASV richness and relatively high abundances of Endozoicomonas (in ovaries) and Pseudomonas (in testes). These findings provide evidence for microbiome heterogeneity between tissues within coral polyps, suggesting a promising field for future studies of functional interactions between corals and their bacterial symbionts.

Coral Shoals Detection from Optical Satellite Imagery Using Deep Belief Network Algorithm: A Case Study for the Xisha Islands, South China Sea

Coral islands and reefs are formed by the cementation of the remains of shallow water reef-building coral polyps and other reef dwelling organisms in tropical oceans. They can be divided into coral islands, coral sandbanks, coral reefs, and coral shoals, of which, Coral shoals are located below the depth datum and are not exposed even at low tide, and sometimes are distributed at water depths exceeding 30 m. Satellite images with wide spatial–temporal coverage have played a crucial role in coral island and reef monitoring, and remote sensing data with multiple platforms, sensors, and spatial and spectral resolutions are employed. However, the accurate detection of coral shoals remains challenging mainly due to the depth effect, that is, coral shoals, especially deeper ones, have very similar spectral characteristics to the sea in optical images. Here, an optical remote sensing detection method is proposed to rapidly and accurately detect the coral shoals using a deep belief network (DBN) from optical satellite imagery. The median filter is used to filter the DBN classification results, and the appropriate filtering window is selected according to the spatial resolution of the optical images. The proposed method demonstrated outstanding performance by validating and comparing the detection results of the Yinli Shoal. Moreover, the expected results are obtained by applying this method to other coral shoals in the Xisha Islands, including the Binmei Shoal, Beibianlang, Zhanhan Shoal, Shanhudong Shoal, and Yongnan Shoal. This detection method is expected to provide the coral shoals’ information rapidly once optical satellite images are available and cloud cover and tropical cyclones are satisfactory. The further integration of the detection results of coral shoals with water depth and other information can effectively ensure the safe navigation of ships.

Coral Polyp and Spine Dual‐Inspired Gradient Hierarchical Architecture for Ultrahigh‐Rate and Long‐Life Sodium Storage

AbstractSodium‐ion batteries (SIBs) are promising alternatives to lithium‐ion batteries with similar working principles, cell structures, and material systems. However, attaining long‐term stability and high‐capacity performance of SIBs at ultrahigh rates remains a significant challenge due to the large ionic radius and slow kinetic behavior of Na+. Herein, a novel robust anode with a dual‐biomimetic gradient hierarchical architecture is proposed and provide a simple strategy to fabricate this sulfur‐doped mesoporous carbon concave hollow sphere/Ti3C2Tx MXene (SCMX) anode. In addition, Cu2S nanoparticles are in situ embedded into the SCMX architecture by electrochemical induction during the cycling process to act as active sites, which enhances the rate performance and cycling stability. Relying on its hybrid architecture and in situ formed Cu2S, this SCMX anode can achieve high ion accessibility, rich active sites, rapid charge transfer, and favorable structure stability, as disclosed by in/ex situ characterizations. As a result, it exhibits high reversible capacity (745.6 mAh g−1 at 0.2 A g−1), ultrahigh‐rate capability (380.5 mAh g−1 at 50.0 A g−1), and long cycling stability (98.2% capacity retention after 10 000 cycles at 80.0 A g−1). This work is anticipated to accelerate the development of high‐performance SIBs and offer distinctive inspiration for the design of electrode structures/systems.

Single-polyp metabolomics for coral health assessment

Coral reef ecosystems supported by environmentally sensitive reef-building corals face serious threats from human activities. Our understanding of these reef threats is hampered by the lack of sufficiently sensitive coral environmental impact assessment systems. In this study, we established a platform for metabolomic analysis at the single-coral-polyp level using state-of-the-art mass spectrometry (probe electrospray ionization/tandem mass spectrometry; PESI/MS/MS) capable of fine-scale analysis. We analyzed the impact of the organic UV filter, benzophenone (BP), which has a negative impact on corals. We also analyzed ammonium and nitrate samples, which affect the environmental sensitivity of coral-zooxanthella (Symbiodiniaceae) holobionts, to provide new insights into coral biology with a focus on metabolites. The method established in this study breaks new ground by combining PESI/MS/MS with a technique for coral polyps that can control the presence or absence of zooxanthellae in corals, enabling functions of zooxanthellae to be assessed on a polyp-by-polyp basis for the first time. This system will clarify biological mechanisms of corals and will become an important model system for environmental impact assessment using marine organisms.

Analysis of the Rate and Nutrient Content of Sediment in The Coral Transplantation Installation Vertical Method on Samalona Island, Makassar City

Samalona Island is a small island that administratively belongs to the inner zone of the Spermonde Islands region with low live coral cover. One effort to improve coral conditions is to carry out vertical transplantation, but hydro-oceanographic conditions are thought to be an inhibiting factor, including sediment. The research carried out aims to determine the suitability of oceanographic parameters, estimate sediment rates, and determine the phosphate and nitrate in sediments. The research method used a field experiment method by taking water and sediment samples and installing sediment traps for 15 days. The parameters measured in situ are temperature, pH, current speed, salinity, and dissolved oxygen, while the ex-situ test is the dry weight of sediment, TSS, nitrate, and phosphate concentrations. Data analysis uses descriptive statistics and is categorized according to the evaluation instrument used. The research results show that the values for temperature, pH, current speed, salinity, and dissolved oxygen meet the standard criteria for coral-based on PP 21/2022. The sediment rate during the research period was 0,003 – 0,015 gr/cm2/day, so it was categorized as having the potential damage to corals with a mild to severe impact level. The nitrate concentration in sediment ranges from 0,19 – 0,25 ppm while phosphate ranges from 0,35 – 0,72 ppm, so it can be said to be waters with a medium trophic level (mesotrophic). The current speeds and sediment rates potentially accelerate nutrient concentrations and cause sediment resuspension, thereby closing coral polyps, especially on corals closest to the substrate where vertical coral transplant installations are installed.

2bRAD reveals fine-scale genetic structuring among populations within the Mediterranean zoanthid Parazoanthus axinellae (Schmidt, 1862)

The zoanthid Parazoanthus axinellae (Schmidt, 1862) is a widespread coral species in the Mediterranean coralligenous assemblages where two morphotypes are found: Slender and Stocky, differing in size, color, and preferred substrate. Due to these marked differences, Slender and Stocky morphotypes were hypothesized to be two species. Here, we used 2bRAD to obtain genome‐wide genotyped single nucleotide polymorphisms (SNPs) to investigate the genetic differentiation between Slender and Stocky morphs, as well as their population structure. A total of 101 specimens of P. axinellae were sampled and genotyped from eight locations along the Italian coastline. In four locations, samples of the two morphotypes were collected in sympatry. 2bRAD genome-wide SNPs were used to assess the genetic divergence between the two morphotypes (1319 SNPs), and population connectivity patterns within Slender (1926 SNPs) and Stocky (1871 SNPs) morphotypes. Marked and consistent differentiation was detected between Slender and Stocky morphotypes. The widely distributed Slender morphotype showed higher population mixing patterns, while populations of the Stocky morphotype exhibited a stronger genetic structure at a regional scale. The strong genetic differentiation observed between P. axinellae Slender and Stocky morphotypes provides additional evidence that these morphs could be attributed to different species, although further morphological and ecological studies are required to validate this hypothesis. Our study highlights the importance of resolving phylogenetic and taxonomic disparities within taxonomically problematic groups, such as the P. axinellae species complex, when performing genetic connectivity studies for management and conservation purposes.Graphical Schematic overview of the main genetic structuring patterns observed in this study. Coral polyps were colored to intuitively associate the reader to Parazoanthus axinellae morphotypes, with orange tones being attributed to the Stocky morphotype, and yellow tones to the Slender morphotype. Bidirectional arrows represent gene flow between coral individuals, with the number and thickness of arrows corresponding to the intensity of gene flow rates. The red dashed line represents the potential reproductive isolation between Slender and Stocky morphs

The outbreak of Drupella snails and its catastrophic effects on coral reefs: a comprehensive review

The recurring outbreaks of Drupella snails are a significant threat to coral reef ecosystems on a global scale. However, research on Drupella snails is currently very fragmentary. This article explores the ecological impacts and mitigation methods of Drupella snails and its outbreaks, and draws the following main conclusions. 1) Drupella snails inhabit the tropical oceans of the Indo-Pacific, utilizing their specialized radula to feed on coral polyps, and they predominantly spawn during summer, attaching egg capsules onto coral skeletons. 2) An outbreak of Drupella snails is defined by a density of &amp;gt; 2 ind/m2, but large aggregations alone do not necessarily indicate an outbreak. 3) The damage of coral reef ecosystem is the primary cause of Drupella snail outbreaks, with the hypotheses of “terrestrial nutrient input” and “overfishing of predator” being widely accepted but not fully explaining all outbreak events. 4) Countering Drupella snail outbreaks involves improving the health of coral reef ecosystems, protected areas, biological control and manual removal, though manual removal is the most direct and effective in short-term. 5) The understanding of the physiological and ecological characteristics of Drupella snails is inadequate at present, with larval development and population ecology being areas of particular under-investigation. 6) Studies of Drupella snail outbreaks have focused mainly on mid-outbreak stages, with little attention to early warnings beforehand or adverse outcomes afterwards. Despite significant challenges, addressing knowledge gaps in the biology of Drupella snails is crucial to determine the true causes of their outbreaks and identify corresponding solutions.

The Physical and Mechanical Properties of Coral Sand

Coral sand interacts with a variety of particles and species in tropical marine habitats due to its special characteristics. particular emphasizes the benefits of using contemporary mathematical technologies to examine the characteristics and behavior of coral sand for engineering applications. Coral sand's composition and creation processes influence its distinctive qualities. Coral sand is mostly made up of the skeletal remains of tiny coral polyps and has a white or off-white appearance due to its high calcium carbonate content. Particularly in the area of geotechnical engineering, the interaction of coral sand particles is of great importance. Particle form, size distribution, and interparticle forces are a few examples of the variables that affect how coral sand behaves as a granular material. Investigations on its geotechnical characteristics, such as its shear strength, permeability, and compressibility, are the main focus of current research. To learn more about the engineering behavior of coral sand, researchers are examining field monitoring approaches and laboratory testing procedures. Additionally, research aims to comprehend how biological activity, cementation, and particle form affect coral sand's mechanical characteristics. In the coral sand study, the benefit of contemporary computation technologies is remarkable. Advanced computer methods, in combination with numerical modeling and simulation approaches, provide precise forecasting of coral sand behavior under various loading and climatic conditions. Engineers may use these technologies to examine foundation design issues, determine the stability of coastal buildings, and create methods for controlling coastal erosion. The study of coral sand and its characteristics has important ramifications for geotechnical engineering. The capacity to assess and construct engineering structures in coral sand settings is improved by the application of contemporary computation technologies.

A coral-associated actinobacterium mitigates coral bleaching under heat stress

BackgroundThe positive effects of exposing corals to microorganisms have been reported though how the benefits are conferred are poorly understood. Here, we isolated an actinobacterial strain (SCSIO 13291) from Pocillopora damicornis with capabilities to synthesize antioxidants, vitamins, and antibacterial and antiviral compounds supported with phenotypic and/or genomic evidence. Strain SCSIO 13291 was labeled with 5 (and − 6)-carboxytetramethylrhodamine, succinimidyl ester and the labeled cell suspension directly inoculated onto the coral polyp tissues when nubbins were under thermal stress in a mesocosm experiment. We then visualized the labelled bacterial cells and analyzed the coral physiological, transcriptome and microbiome to elucidate the effect this strain conferred on the coral holobiont under thermal stress.ResultsSubsequent microscopic observations confirmed the presence of the bacterium attached to the coral polyps. Addition of the SCSIO 13291 strain reduced signs of bleaching in the corals subjected to heat stress. At the same time, alterations in gene expression, which were involved in reactive oxygen species and light damage mitigation, attenuated apoptosis and exocytosis in addition to metabolite utilization, were observed in the coral host and Symbiodiniaceae populations. In addition, the coral associated bacterial community altered with a more stable ecological network for samples inoculated with the bacterial strain.ConclusionsOur results provide insights into the benefits of a putative actinobacterial probiotic strain that mitigate coral bleaching signs. This study suggests that the inoculation of bacteria can potentially directly benefit the coral holobiont through conferring metabolic activities or through indirect mechanisms of suppling additional nutrient sources.

Characteristic and histological evidence of microplastic in scleractinian corals of Java Sea

Coral reefs are threatened by emerging microplastic pollution but only a few studies are available regarding the extent of contamination in coral reef systems in situ. For this research, we collected samples from the seawater, sediments, and coral colonies of the Panjang Island cluster and the Karimunjawa Archipelago, Java Sea. Microplastics were detected in all sample types. Based on a Mann–Whitney test (p < 0.05), there is a significant difference in microplastic abundance between areas subjected to different levels of human activity. Corals showed the highest concentration of microplastics, with fragments being the most dominant type. No significant difference in microplastic abundance was found among the different polyp sizes (Mann–Whitney test, p > 0.05) or among different species (Kruskal–Wallis test, p > 0.05). All coral samples contained fragment and fiber microplastics in their polyps, consisting of Polyethylene terephthalate (PET), silicone-based plastic, polysulfoxide, and Polyvinyl alcohol (PVA) polymer. Here, we provide the first evidence of microplastics inside corals, observed using a histological method. The types of microplastic detected in the histological sections were similar to those extracted from the coral polyps. Tourism and fishing activity both play a role in governing the distribution, abundance, and diversity of microplastics in coral reef systems.

Cosplay as a Novel Method for Outreach in Ocean Science

We present our experience using cosplay to engage attendees on the topic of microplastics pollution at the world’s largest Comic-Con convention, held annually in San Diego, California, USA. Cosplay is an activity that has gained popularity in the last two decades. Cosplayers wear costumes and fashion accessories, usually representing specific characters from comic books, manga, anime, or superhero franchises. Cosplayer conventions are often large events. For example, Comic-Con International has &gt; 150,000 attendees over a several-day period, and provides a large platform for outreach. Our costumes and accessories were a mix of science (coral polyp costume; microplastics sampling device ‘sword’), and fantasy (Amphitrite costume; with bracelets and hair made with plastic debris). We found that the novelty factor of our costumes and accessories, not part of the traditional cosplay pantheon of characters, was a captivating way to engage convention attendees. During a 6-hour period in the Exhibit Hall, we dispersed 240 flyers with information on the problem of microplastics pollution and our laboratory’s efforts to develop sensing solutions. Engagement lasted 1–8 minutes in length, with 1–9 attendees at a time. All attendees we engaged took the proffered flyer after the interaction. With a low barrier to entry, and ability to reach large numbers of people, we propose cosplay as a novel method for marine education and outreach. Cosplay can be used by student groups, non-governmental organizations, university researchers, and citizen scientists to educate the public about pressing problems facing the oceans and the proposed solutions.

Single-polyp metabolomics reveals biochemical structuring of the coral holobiont at multiple scales

All biology happens in space, and spatial structuring plays an important role in mediating biological processes at all scales from cells to ecosystems. However, the metabolomic structuring of the coral holobiont has yet to be fully explored. Here, we present a method to detect high-quality metabolomic data from individual coral polyps and apply this method to study the patterning of biochemicals across multiple spatial (~1 mm - ~100 m) and organizational scales (polyp to population). The data show a strong signature for individual coral colonies, a weaker signature of branches within colonies, and variation at the polyp level related to the polyps’ location along a branch. Mapping metabolites to either the coral or algal components of the holobiont reveals that polyp-level variation along the length of a branch was largely driven by molecules associated with the cnidarian host as opposed to the algal symbiont, predominantly putative sulfur-containing metabolites. This work yields insights on the spatial structuring of biochemicals in the coral holobiont, which is critical for design, analysis, and interpretation of studies on coral reef biochemistry.