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Microplastics are ubiquitous contaminants in marine environments and organisms. Concerns about potential impacts on marine organisms are usually associated with uptake of microplastics, especially via ingestion. This study used environmentally relevant exposure conditions to investigate microplastic ingestion and depuration kinetics of the planktivorous damselfish, Pomacentrus amboinensis . Irregular shaped blue polypropylene (PP) particles (longest length 125–250 μm), and regular shaped blue polyester (PET) fibers (length 600–700 μm) were selected based on physical and chemical characteristics of microplastics commonly reported in the marine environment, including in coral reef ecosystems. Individual adult damselfish were exposed to a single dose of PP particles and PET fibers at concentrations reported for waters of the Great Barrier Reef (i.e., environmentally relevant concentrations, ERC), or future projected higher concentrations (10x ERC, 100x ERC). Measured microplastic concentrations were similar to their nominal values, confirming that PP particles and PET fibers were present at the desired concentrations and available for ingestion by individual damselfish. Throughout the 128-h depuration period, the 88 experimental fish were sampled 2, 4, 8, 16, 32, 64, and 128-h post microplastic exposure and their gastrointestinal tracts (GIT) analyzed for ingested microplastics. While damselfish ingested both experimental microplastics at all concentrations, body burden, and depuration rates of PET fibers were significantly larger and longer, respectively, compared to PP particles. For both microplastic types, exposure to higher concentrations led to an increase in body burden and lower depuration rates. These findings confirm ingestion of PP particles and PET fibers by P. amboinensis and demonstrate for the first time the influence of microplastic characteristics and concentrations on body burden and depuration rates. Finally, despite measures put in place to prevent contamination, extraneous microplastics were recovered from experimental fish, highlighting the challenge to completely eliminate contamination in microplastic exposure studies. These results are critical to inform and continuously improve protocols for future microplastics research, and to elucidate patterns of microplastic contamination and associated risks in marine organisms.

The corallivorous Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) has been linked with the widespread loss of scleractinian coral cover on Indo-Pacific reefs during periodic population outbreaks. Here, we re-examine CoTS consumption by coral reef fish species by using new DNA technologies to detect Pacific Crown-of-Thorns Starfish ( Acanthaster cf. solaris ) in fish faecal and gut content samples. CoTS DNA was detected in samples from 18 different coral reef fish species collected on reefs at various stages of CoTS outbreaks in the Great Barrier Reef Marine Park, nine of which had not been previously reported to feed on CoTS. A comprehensive set of negative and positive control samples confirmed that our collection, processing and analysis procedures were robust, although food web transfer of CoTS DNA cannot be ruled out for some fish species. Our results, combined with the (i) presence of CoTS spines in some samples, (ii) reported predation on CoTS gametes, larvae and settled individuals, and (iii) known diet information for fish species examined, strongly indicate that direct fish predation on CoTS may well be more common than is currently appreciated. We provide recommendations for specific management approaches to enhance predation on CoTS by coral reef fishes, and to support the mitigation of CoTS outbreaks and reverse declines in hard coral cover.

Wave energy shapes coral reef communities, yet its influence on early coral survival and growth remains poorly understood, limiting its use in reef restoration planning. This study investigated the survival and growth of three Acropora species deployed on seeding devices across a wave energy gradient at three reefs on the Great Barrier Reef. After 1.5-2 years, survival varied significantly within reefs, among sites, and among species, with highest average yield at Moore Reef ( A. millepora , 32% after 554 days) followed by Davies Reef ( A. hyacinthus , 24% after 527 days) and Heron Reef ( A. hyacinthus : 13% and A. cf. kenti : 23% after 834 days). However, no single environmental variable, including nominal wave energy, bottom stress, flow velocity, sedimentation or benthic community composition consistently predicted survival, and effects weakened over time. Coral size and survival varied more at the device level than across sites, indicating the importance of fine-scale spatial and transient factors. These findings underscore the limitations of broad-scale environmental models to guide restoration and highlight the need for flexible, site-specific strategies. While seeding devices show promise as a scalable restoration tool, their success depends on matching species to suitable microhabitats and monitoring local conditions over time to support long-term outcomes.

Seasonal variation in coral reef macroalgal size and condition is well documented, yet seasonal variability of herbivory on macroalgae by coral reef fishes is unknown. Herbivore feeding intensity was quantified monthly on an inner-shelf reef on the Great Barrier Reef, using Sargassum bioassays. Removal rates of transplants displayed high levels of variation with significantly higher rates of removal during the summer months. Differences in Sargassum plant size and condition suggest that the variability in herbivore feeding intensity is attributed primarily to the variation in the condition of the macroalgae, especially epiphyte loads. The dramatic changes in macroalgal removal reveal a considerable decrease in herbivore activity in the winter. This highlights the clear distinction between ‘summer' and ‘winter' months in terms of reef processes, emphasizing the high seasonal variation in macroalgal removal rates at different time of the year.

Myelodysplastic syndromes (MDS) with mutated SF3B1 gene present features including a favourable outcome distinct from MDS with mutations in other splicing factor genes SRSF2 or U2AF1 . Molecular bases of these divergences are poorly understood. Here we find that SF3B1 -mutated MDS show reduced R-loop formation predominating in gene bodies associated with intron retention reduction, not found in U2AF1 - or SRSF2 -mutated MDS. Compared to erythroblasts from SRSF2- or U2AF1 -mutated patients, SF3B1 -mutated erythroblasts exhibit augmented DNA synthesis, accelerated replication forks, and single-stranded DNA exposure upon differentiation. Importantly, histone deacetylase inhibition using vorinostat restores R-loop formation, slows down DNA replication forks and improves SF3B1 -mutated erythroblast differentiation. In conclusion, loss of R-loops with associated DNA replication stress represents a hallmark of SF3B1 -mutated MDS ineffective erythropoiesis, which could be used as a therapeutic target. Here the authors find that erythroblasts of myelodysplastic syndromes with SF3B1 mutation leading to inefficient erythropoiesis show DNA replication stress with accelerated forks and reduced R-loops. Restoring R-loops by a histone deacetylase inhibitor rescues erythroid differentiation.

The dynamic nature of coral reefs offers a rare opportunity to examine the response of ecosystems to disruption due to climate change. In 1998, the Great Barrier Reef experienced widespread coral bleaching and mortality. As a result, cryptobenthic fish assemblages underwent a dramatic phase-shift. Thirteen years, and up to 96 fish generations later, the cryptobenthic fish assemblage has not returned to its pre-bleach configuration. This is despite coral abundances returning to, or exceeding, pre-bleach values. The post-bleach fish assemblage exhibits no evidence of recovery. If these short-lived fish species are a model for their longer-lived counterparts, they suggest that (1) the full effects of the 1998 bleaching event on long-lived fish populations have yet to be seen, (2) it may take decades, or more, before recovery or regeneration of these long-lived species will begin, and (3) fish assemblages may not recover to their previous composition despite the return of corals.

The majority of coral reef goby species are short-lived, with some highly abundant species living less than 100 d. To understand the role and consequences of this extreme life history in shaping coral reef fish populations, we quantitatively documented the structure of small reef fish populations over a 26-month period (>14 short-lived fish generations) at an inshore reef on the Great Barrier Reef, Australia. Most species with life spans >1 yr, such as pomacentrids, exhibited a peak in recruitment during the austral summer, driving seasonal changes in the small fish community composition. In contrast, there were no clear changes in goby community composition, despite the abundance of short-lived, high turnover species. Species of Eviota , the most abundant gobiid genus observed, showed remarkably similar demographic profiles year-round, with consistent densities of adults as well as recently recruited juveniles. Our results demonstrate ongoing recruitment of these small cryptic fishes, which appears to compensate for an exceptionally short life span on the reef. Our results suggest that gobiid populations are able to overcome demographic limitations, and by maintaining reproduction, larval survival and recruitment throughout the year, they may avoid population bottlenecks. These findings also underline the potential trophodynamic importance of these small species; because of this constant turnover, Eviota species and other short-lived fishes may be particularly valuable contributors to the flow of energy on coral reefs, underpinning the year-round trophic structure.

Despite the widely accepted importance of fish herbivory on coral reefs, few studies have considered the temporal variability in the nature of algal–herbivore interactions. We therefore quantified monthly feeding intensity onSargassumsp. bioassays for 12 mo with remote underwater video cameras deployed to identify the herbivores responsible for macroalgal removal on an inshore island of the Great Barrier Reef, Australia. Significantly higher removal rates were observed during the summer months whereas winter months were characterized by 4 times lower removal rates. However, rather than being simply changes in the feeding activity of a single species, this temporal pattern in herbivory also incorporated changes in the species responsible for the removal ofSargassum. Video analyses revealed that, of the 43 herbivore species recorded from the bay, only 3 played a significant role inSargassumremoval:Kyphosus vaigiensis,Naso unicornisandScarus rivulatus.K. vaigiensis, a rudderfish, was primarily responsible for the removal ofSargassumduring the summer months (83% of the total recorded bites; 85 553 bites). There was almost no feeding activity onSargassumbyK. vaigiensisduring the winter months (82 bites). However, there was a reciprocal increase in feeding intensity onSargassumby parrotfishes in the winter months, particularlyS. rivulatus(71 bites during summer versus 2884 bites in winter). This temporal variability in herbivore functional roles suggests that functional redundancy on reefs may be less than previously assumed in that the feeding activities of fishes may be both spatially and temporally constrained.

The emergence of next‐generation sequencing techniques has led to the genetic characterization of numerous congenital erythroid disorders, emphasizing crucial pathways in both normal and pathological erythropoiesis. In this study, whole exome sequencing of a single patient with atypical congenital pure red cell aplasia revealed a mutation in the CDAN1 gene, typically associated with congenital dyserythropoietic anemia type 1 (CDAI), together with a previously unreported mutation in the MMS22L gene. Combined mms22l and cdan1 haploinsufficiency results in severe anemia in a zebrafish model. In human erythroid progenitors, loss of MMS22L leads to proliferation and differentiation arrest associated with activation of the p53 pathway and global epigenetic alterations, showing that MMS22L plays an indispensable role in erythropoiesis. Furthermore, MMS22L and CDAN1 are involved in the same protein complex whose nuclear import is mediated by the importin 4 (IPO4) protein, and MMS22L nuclear import is impaired in CDAI patients due to a defective interaction between CDAN1 and IPO4. Overall, through the genetic description of a single case characterized by digenic inheritance, we identified MMS22L as a novel key factor in erythropoiesis and brought new insights into normal erythropoiesis regulation and CDAI pathophysiology.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.