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Porifera are essential components of marine ecosystems, providing valuable ecological functions. Traditional approaches to estimating sponge growth and biomass are destructive and often not suitable for certain morphologies. The implementation of new innovative techniques and nondestructive methodologies have allowed for a more sustainable approach. In this study, a population of Sarcotragus foetidus Schmidt, 1982 (Demospongiae, Dictyoceratida, Irciinidae), thriving inside the Portofino Marine Protected Area, was monitored using Structure from Motion photogrammetry over a period of 6 years, from September 2017 to October 2023. Of the 20 initial individuals, only 12 were still in place during the last monitoring, indicating 40% mortality. Through photogrammetry, the overall volume change and biomass production were estimated to be 9.24 ± 5.47% year−1 and 29.52 ± 27.93 g DW year−1, respectively, indicating a general decreasing trend between 2021 and 2023. Signs of necrosis were observed in some individuals, potentially related to the high temperature occurring during summer 2022 and 2023. Considering the current climate crisis, long-term monitoring efforts must be made to better understand the dynamics of this species, and photogrammetry has the potential to be a versatile monitoring tool that will contribute to the standardization of methodologies for sponge growth studies. [ABSTRACT FROM AUTHOR]

The giant barrel sponge, Xestospongia muta, represents a dominant member of Caribbean reef communities. Recent microsatellite data have revealed the presence of two genetic clusters of X. muta in a monitored population on Conch Reef, Florida Keys, with a reduced abundance of one cluster among the largest individuals. Tracking changes to populations over time and their ecological significance requires rapid identification of each genetic cluster and subsequent studies of biological differences between clusters. Here, we show that single-gene barcoding detected the same intraspecific genetic variation within X. muta from Conch Reef as microsatellite data, with mitochondrial gene sequences (cytochrome c oxidase subunit I, I3-M11 partition) from 54 individuals corresponding to 4 known haplotypes within the two genetic clusters. Remarkably, mapping these haplotypes to barrel sponges worldwide revealed positioning on opposite ends of a global network, despite their sympatric occurrence. Further, we investigated whether differences in symbiotic microbial communities could be detected between the two clusters using next-generation (Illumina) sequencing of 16S rRNA gene amplicons. Both clusters exhibited highly diverse microbial communities, with 12,185 total OTUs spanning 38 bacterial and 3 archaeal phyla, but significant differences in microbial community structure (PERMANOVA; p < 0.001) and diversity (Shannon diversity index; p < 0.01) were detected between the two clusters. As sponges typically exhibit interspecific, but not intraspecific, variability in microbial communities, these findings within a sympatric population provide additional support for ecologically relevant cryptic species of X. muta. [ABSTRACT FROM AUTHOR]

Sponges are important ecological and functional components of coral reefs. Recently, a new hypothesis about the functional ecology of sponges in organic matter recycling pathways, the sponge‐loop hypothesis, in which dissolved and particulate organic matter is taken up by sponges and shunted to higher trophic levels as detritus, has been proposed and demonstrated for shallow (< 30 m) cryptic species. However, support for this hypothesis at mesophotic depths (∼ 30–150 m) is lacking. Here, we examined detritus production, a prerequisite of the sponge loop pathway, in a reciprocal transplant experiment, using Halisarca caerulea from water depths of 10 and 50 m. Detritus production was significantly lower in mesophotic sponges compared to shallow samples of H. caerulea. Additionally, detritus production rates in transplanted sponges moved in the direction of rates observed for resident conspecifics. The microbiome of these sponge populations was also significantly different between shallow and mesophotic depths, and the microbial communities of the transplanted sponges also shifted in the direction of their new depth in 10 d largely driven by changes in Oxyphotobacteria, Acidimicrobiia, Nitrososphaeria, Nitrospira, Deltaproteobacteria, and Dadabacteriia. This occurred in an environment where the availability of both dissolved and particulate trophic resources changed significantly across the shallow to mesophotic depth gradient where these sponge populations were found. These results suggest that changes in sponge detritus production are primarily driven by differential quality and quantity of trophic resources, as well as their utilization by the sponge host, and its microbiome, along the shallow to mesophotic depth gradient. [ABSTRACT FROM AUTHOR]

Endemic sponges (Demosponges, Lubomirskiidae) dominate the fauna of the littoral zone of Lake Baikal. These freshwater sponges live in symbiosis with diverse eukaryotes and prokaryotes, including chlorophyll-containing microalgae. Within the last 5 years, the incidence of sponge disease and mortality events in Lake Baikal has increased. The etiology and ecology of these events remain unknown, in part because of the lack of models to study sponge-microbe interactions. In this work, we tested the use of primmorph cell cultures of Lubomirskia baicalensis as a tool for investigating the microbiomes of sponges. We infected primmorphs, cultured in vitro, with samples from diseased sponges and observed, by microscopy, disease symptoms, including loss of green symbionts, associated with mass die-off events. Subsequent sequencing of 16S rRNA gene fragments revealed that the microbiome community of healthy sponge and primmorphs formed a group separate from the community of diseased sponges and infected primmorphs. This confirms the suitability of the primmorph cell culture as a model sponge system. We also discovered mass mortality of green symbionts (Chlorophyta) was associated with a shift in the microbial communities of sponges/primmorphs. Microbes in diseased sponges, and infected primmorphs, belonged mainly to the phyla Bacteroidetes and Proteobacteria and these families Flavobacteriaceae, Burkholderiaceae, and Moraxellaceae. Primmorphs cell culture may provide a model to study interactions between these bacteria and their host and elucidate the cause of mass mortality events. [ABSTRACT FROM AUTHOR]

Marine sponges host dense, diverse, and species-specific microbial communities around the globe; however, most of the current knowledge is restricted to species from tropical and temperate waters. Only recently, some studies have assessed the microbiome of a few Antarctic sponges; however, contrary to low mid-latitude sponges, the knowledge about temporal (stability) patterns in the bacterial communities of Antarctic sponges is absent. Here, we studied the temporal patterns of bacterial communities in the Antarctic sponges Mycale (Oxymycale) acerata , Isodictya sp., Hymeniacidon torquata , and Tedania (Tedaniopsis) wellsae that were tagged in situ and monitored during three austral summers over a 24-month period. By using amplicon sequencing of the bacterial 16S rRNA gene we found that the microbiome differed between species. In general, bacterial communities were dominated by gammaproteobacterial OTUs; however, M. acerata showed the most distinct pattern, being dominated by a single betaproteobacterial OTU. The analysis at OTU level (defined at 97% sequence similarity) showed a highly stable bacterial community through time, despite the abnormal seawater temperatures (reaching 3°C) and rates of temperature increase of 0.15°C day–1 recorded in austral summer 2017. Sponges were characterized by a small core bacterial community that accounted for a high percentage of the abundance. Overall, no consistent changes in core OTU abundance were recorded for all studied species, confirming a high temporal stability of the microbiome. In addition, predicted functional pathway profiles showed that the most abundant pathways among all sponges belonged mostly to metabolism pathway groups (e.g., amino acid, carbohydrate, energy, and nucleotide). The predicted functional pathway patterns differed among the four sponge species. However, no clear temporal differences were detected supporting what was found in terms of the relatively stable composition of the bacterial communities. [ABSTRACT FROM AUTHOR]

Tropical mesophotic reefs, which span the transition between shallow reefs and the bottom of the photic zone (30–150 m), are an understudied ecosystem. It has been proposed that sponge abundance increases with depth through 150 m on reefs throughout the Caribbean and perhaps globally (the "sponge increase hypothesis"). A recent review concluded that there was not sufficient evidence in the literature to support this hypothesis for the Caribbean and that further data quantifying changes in sponge abundance with depth on mesophotic reefs are needed. In this study, percentage cover of sponges, macroalgae, and hard corals was estimated using 1123 images taken by remotely operated vehicles on 58 dive tracks on mesophotic reefs off the coasts of Puerto Rico (to 180 m) and St. Thomas (US Virgin Islands; to 100 m), and on the Flower Garden Banks (Gulf of Mexico; to 100 m). Off Puerto Rico, sponge cover decreased with increasing depth below ~ 100 m, driven primarily by a decline in the cover of emergent (non-encrusting) sponge species. Sponge cover did not change with depth off St. Thomas or on the Flower Garden Banks and was an order of magnitude lower on the Flower Garden Banks. The data from these three locations did not support the sponge increase hypothesis. Mean cover of hard coral off Puerto Rico and St. Thomas was less than 8% between 20 and 80 m and negligible below these depths, but much higher (~ 15–30%) between 30 and 40 m on the Flower Garden Banks and negligible below these depths. Off Puerto Rico, cover of macroalgae decreased with depth in a manner similar to sponge cover, which may reflect a positive relationship between sponges and macroalgae in the lower mesophotic zone (> 100 m). Off St. Thomas and on the Flower Garden Banks, which were both shallower sites with more abundant macroalgae, sponge abundance was likely limited due to competition for space. Generalizations about patterns of sponge abundance across mesophotic depths await further studies, but our data suggest a depth-dependent relationship with macroalgal abundance. [ABSTRACT FROM AUTHOR]

Sponge diversity has been reported to decrease from well-preserved to polluted environments, but whether diversity and intra-species variation of their associated microbiomes also change as function of environmental quality remains unknown. Our study aimed to assess whether microbiome composition and structure are related to the proliferation of some sponges and not others under degraded conditions. We characterized the most frequent sponges and their associated bacteria in two close areas (impacted and well-preserved) of Nha Trang Bay (Indo-Pacific). Sponge assemblages were richer and more diverse in the well-preserved reefs, but more abundant (individuals/m. transect) in the impacted environments, where two species (Clathria reinwardti and Amphimedon paraviridis) dominated. Sponge microbiomes from the polluted zones had, in general, lower bacterial diversity and core size and consequently, higher intra-species dispersion than microbiomes of sponges from the well-preserved environments. Microbial communities reflect the reduction of diversity and richness shown by their host sponges. In this sense, sponges with less complex and more variable microbiomes proliferate under degraded environmental conditions, following the ecological paradigm that negatively correlates community diversity and environmental degradation. Thereby, the diversity and structure of sponge microbiomes might indirectly determine the presence and proliferation of sponge species in certain habitats. [ABSTRACT FROM AUTHOR]

Sponges are major components of benthic ecosystems, particularly on Caribbean reefs, where their importance in carbon cycling and ecosystem function is only beginning to be understood. There is a recurring statement in the literature, herein called the "sponge increase hypothesis," asserting that the biomass and diversity of sponges increase with depth on Caribbean reefs through the mesophotic zone (to 150 m). We reviewed evidence for the sponge increase hypothesis, beginning with electronically searchable contributions to the literature, then working backward in time through the bibliographies of more recent citations. We found 17 studies that report one or more metrics associated with sponge abundance or diversity as a function of depth through all or part of the mesophotic zone. None of these studies reported data on either overall sponge biomass or diversity as a function of reef surface area. Among abundance metrics, including cover and density, patterns as a function of depth were disparate across sites and locations. We conclude that there is no evidence to support the sponge increase hypothesis for Caribbean mesophotic reefs and suggest that patterns of sponge abundance as a function of depth are likely to vary for a number of reasons, including substratum type, slope, and orientation. General theories of sponge abundance and diversity as a function of depth await more sophisticated survey studies that employ standardized methods for relating sponge biomass and diversity to reef surface area. [ABSTRACT FROM AUTHOR]

Abstract Sponges harbor a great diversity of symbiotic microorganisms. However, environmental stresses can affect this partnership and influence the health and abundance of the host sponges. In Bolinao, Pangasinan, Philippines, chronic input of organic materials from mariculture activities contributes to a eutrophic coastal environment. To understand how these conditions might affect sponge-microbial partnerships, transplantation experiments were conducted with the marine sponge Gelliodes obtusa. High-throughput sequencing of 16S rRNA revealed that the associated microbial community of the sponges did not exhibit significant shifts after six weeks of transplantation at a eutrophic fish farm site compared to sponges grown at a coral reef or a seagrass area. However, sponges at the fish farm revealed higher abundance of the amoA gene, suggesting that microbiome members are responsive to increased ammonium levels at the site. The stable association between G. obtusa and its microbiome indicates that the sponge holobiont can withstand eutrophication pressure from mariculture. Highlights • G. obtusa hosts a diverse community of microorganisms dominated by Proteobacteria. • Transplantation to eutrophic conditions did not cause significant changes in sponge microbiome structure. • Sponges from eutrophic site showed higher abundance of the ammonia oxidation gene marker. [ABSTRACT FROM AUTHOR]

Abstract Watershed-based pollution is a common form of coral reef degradation. Affected reefs are often highly turbid, where light-limitation confines the distribution of photosynthetic benthic taxa and the capacity for photoacclimation is important for survival. We investigated low light photoacclimation in a Symbiodinium- hosting bioeroding sponge using in situ PAM fluorometry. Cliona aff. viridis was artificially shaded (70 & 95% ambient light reduction) on a low turbidity Indonesian reef for 25 days, with a subsequent 14-day recovery period. Significant changes in rETR max , and qP, and a non-significant but observable decline in E k, demonstrated that C. aff. viridis is able to photoacclimate to conditions of extreme light reduction and recover within a relatively short period of time. The sponge is therefore unlikely to be light limited on even the most turbid reefs. However, other aspects of watershed-pollution such as sedimentation may still limit their distribution in affected coastal waters. Highlights • Photoacclimation of Symbiodinium- containing clionaid sponges investigated. • Cliona aff. viridis was capable of photoacclimating to extreme light reduction. • Cliona aff. viridis survived and recovered from 25 days of near darkness. • Cliona aff. viridis is unlikely to be light-limited on turbid coral reefs. [ABSTRACT FROM AUTHOR]

Abstract: Anthropogenic stressors are impacting ecological systems across the world. Of particular concern are the recent rapid changes occurring in coral reef systems. With ongoing degradation from both local and global stressors, future reefs are likely to function differently from current coral‐dominated ecosystems. Determining key attributes of future reef states is critical to reliably predict outcomes for ecosystem service provision. Here we explore the impacts of changing sponge dominance on coral reefs. Qualitative modelling of reef futures suggests that changing sponge dominance due to increased sponge abundance will have different outcomes for other trophic levels compared with increased sponge dominance as a result of declining coral abundance. By exploring uncertainty in the model outcomes we identify the need to (1) quantify changes in carbon flow through sponges, (2) determine the importance of food limitation for sponges, (3) assess the ubiquity of the recently described “sponge loop,” (4) determine the competitive relationships between sponges and other benthic taxa, particularly algae, and (5) understand how changing dominance of other organisms alters trophic pathways and energy flows through ecosystems. Addressing these knowledge gaps will facilitate development of more complex models that assess functional attributes of sponge‐dominated reef ecosystems. [ABSTRACT FROM AUTHOR]

To comprehend the state of the art of sponge reproduction science (SRS), we quantified and analyzed the trends in SRS in the last decade, aiming to answer three questions: (i) Were there fewer SRS works presented during the last sponge conference? (ii) Did the number of SRS publications decline in the last decade? (iii) Does the number of abstracts at sponge conferences influence overall SRS publications? In addition, we checked whether the SRS community has answered Ereskovsky's 'five important questions', enabling us to advance SRS enough to be considered as a fourth period of this scientific field. We found that SRS was less represented at the last sponge conference, despite an increase in the number of publications during the last decade. Moreover, the number of abstracts presented at sponge conferences contributed to a small portion (25%) of the published works in this area during the last decade. In addition, we found that two of the five Ereskovsky's questions are still mostly not answered. Thus, we conclude that SRS is healthy and advancing steadily, especially in some subareas (e.g. developmental biology and life history). There are still much to advance, but this is still a strong field of biological science research. [ABSTRACT FROM AUTHOR]

The brown tube sponge Agelas tubulata (cf. Agelas conifera) is an abundant and long-lived sponge on Caribbean reefs. Recently, a disease-like condition, Agelas wasting syndrome (AWS), was described from A. tubulata in the Florida Keys, where prevalence of the syndrome increased from 7 to 35% of the sponge population between 2010 and 2015. In this study, we characterized the prokaryotic symbiont community of A. tubulata for the first time from individuals collected within the same monitoring plots where AWS was described. We also sampled tissue from A. tubulata exhibiting symptoms of AWS to determine its effect on the diversity and structure of prokaryotic symbiont communities. Bacteria from the phyla Chloroflexi and Proteobacteria, particularly the class Gammaproteobacteria, dominated the sponge microbiome in tissue samples of both healthy sponges and those exhibiting AWS. Prokaryotic community structure differed significantly between the diseased and healthy sponge samples, with greater variability among communities in diseased samples compared to healthy samples. These differences in prokaryotic community structure included a shift in relative abundance of the dominant, ammonia-oxidizing (Thaumarchaeota) symbionts present in diseased and healthy sponge samples. Further research is required to determine the functional consequences of this shift in microbial community structure and the causal relationship of dysbiosis and sponge disease in A. tubulata. [ABSTRACT FROM AUTHOR]

Deep-sea sponge grounds are relatively understudied ecosystems that may provide key habitats for a large number of fish and invertebrates including commercial species. Glass sponge grounds have been discovered from the tropics to polar regions but there are only a few places with high densities of dictyonine sponges. Dictyonine glass sponges have a fused skeleton, which stays intact when they die and in some areas the accumulation of successive generations of sponges leads to the formation of reefs. In 2010 and 2016, we surveyed an area near Grays Canyon in Washington, USA, where dense aggregations of glass sponges and potential sponge reefs were discovered in 2007. Our primary aims were to make a preliminary assessment of whether the glass sponges form reefs at this location, characterize the sponge assemblage present at this site and examine associations between the sponges and commercially important species. Multibeam mapping and sub-bottom profiling indicate that the glass sponges at this site do not form reefs and are mostly attached to hard substrates. Analysis of photographs collected by an autonomous underwater vehicle and samples collected by a remotely operated vehicle guided by telepresence revealed the presence of two abundant dictyonine sponge species at this site, Heterochone calyx and Aphrocallistes vastus (mean densities = 1.43 ± 0.057 per 10 m 2 , max = 24 per 10 m 2 ). We also observed a large number of non-reef-building glass sponges and various demosponges including a potentially new species in the genus Acarnus . A diverse fish assemblage was recorded at this site including eight species of rockfish. Rockfish abundance was positively related to sponge abundance. Spot prawns ( Pandalus platyceros) were also abundant and were strongly associated with sponges. Despite not finding sponge reefs, this is an ecologically significant area. Further research is necessary to determine the environmental factors that give rise to the abundance of large dictyonine sponges at this location and also to determine if other similar sponge grounds exist along the west coast of the United States. [ABSTRACT FROM AUTHOR]

Cuban coral reefs have been called the "crown jewels of the Caribbean Sea," but there are few comparative data to validate this claim. Here, we provide an overview of Cuban coral reefs based on surveys carried out between 2010 and 2016 on seven of the main Cuban coral reef systems: Havana, Artemisa, Los Colorados, Punta Francés, Los Canarreos Archipelago, Península Ancón, and Jardines de la Reina. Ecological indicators were evaluated for each of these areas at the community level. Results suggest differences among benthic communities (corals, sponges, and gorgonians) that are most evident for reefs that develop near highly urbanized areas, such as Havana, than for those far from the coast and less accessible. Offshore reefs along the south-central coast at Jardines de la Reina and Península Ancón exhibited high coral density and diversity. Acropora cervicornis (Lamarck, 1816) and the Orbicella complex corals were uncommon, possibly indicating losses prior to our study due to coral diseases or competition with macroalgae. Siderastrea siderea (Ellis and Solander, 1786) was the most consistently-abundant species at all reef sites. The ecological condition at Jardines de la Reina and Península Ancón is comparatively healthy. Our study supports claims that some Cuban coral reef systems are probably among the best preserved in the Caribbean basin, but other highly impacted areas exhibit many of the degradation patterns that are common to the rest of the Caribbean region. Strong conservation strategies are required with regard to subsistence fisheries and pollution at highly-impacted reefs to stop further degradation, and reefs that appear healthy need protection to avoid degradation and maintain resilience. [ABSTRACT FROM AUTHOR]

Competition for resources, which often results in resource tradeoffs, is intense among sessile benthic organisms. In this investigation, we tested the tradeoffs between the primary and secondary functions by studying the influence of spatial competitor Zoanthus sansibaricus on the reproductive outcome of the sponge Cinachyrella cf. cavernosa. Field studies were carried out at a rocky intertidal beach at Anjuna, Goa, India, from October 2013 to September 2015. C. cf. cavernosa reproduces asexually via ‘budding’ that comprises three stages (Stage I–III) with distinctive morphological and skeletal characteristics. The budding frequency was positively regulated by temperature of the rock pool water and negatively by the substrate cover of Z. sansibaricus. In the absence of the spatial competitor Z. sansibaricus, there was a significant increase in budding frequency (10–30%), bud count per sponge (45–60%), bud settlement probability (60–80%) and physiological activity (RNA/DNA ratio) of buds (10–35%). Over-expression (75–80%) of heat shock protein 70 (stress response) was observed in the sponge during the competitive interaction. This investigation shows that spatial competition adversely affects asexual reproduction of C. cf. cavernosa, and it supports the earlier observations of tradeoffs between the primary and secondary functions. [ABSTRACT FROM AUTHOR]

The freshwater sponge collections of the National Museum of Natural History of Madrid were examined and the presence of Eunapius carteri (Bowerbank, 1863) in the Iberian Peninsula was rediscovered. An approach to its ecology is also presented. This species is not currently considered within the Iberian and Western European fauna. Therefore, its rediscovery changes the conception of this species' biogeographical distribution in Europe linked to its ecology. [ABSTRACT FROM AUTHOR]

A Mississippian hexactinellid sponge from the western Argentina improves the extremely poor late Paleozoic sponge records from Gondwana. The sponge is included in the subfamily Thysanodictyinae of family Dictyospongiidae. The new genus and species Minitaspongia parvis is erected, and its well-preserved spicular structure is described in detail representing the first approximation of the spicule assemblage in Thysanodictyinae. The skeleton is clathrate, three-dimensional with at least two ranks of rectangular openings. This first report of this subfamily outside North America represents the best-known hexactinellid and the first dictyosponge record from the Carboniferous of Gondwana. Unlike the occurrences of Thysanodictyinae in North America, with thick skeletons linked to high-energy shallow water settings, Minitaspongia occurs in low-energy water siliciclastic settings related to a cold climate and glacimarine deposits. Accordingly, the complex wall structure of this sponge should not be invoked as a necessary adaptation to high energy and shallow water settings. [ABSTRACT FROM AUTHOR]

Sponges and their associated microbial communities have sparked much interest in recent decades due on the abundant production of chemically diverse metabolites that in nature serve as functional compounds required by the marine sponge host. These compounds were found to carry therapeutic importance for medicinal applications. In the presented study, 123 bacterial isolates from the culture collection of the Australian Institute of Marine Science (AIMS) previously isolated from two different sponge species, namely Candidaspongia flabellata and Rhopaloeides odorabile, originating from different locations on the Great Barrier Reef in Queensland, Australia, were thus studied for their bioactivity. The symbiotic bacterial isolates were first identified using 16S rRNA gene analysis and they were found to belong to five different dominating classes of Domain Bacteria, namely Alphaproteobacteria, Gammaproteobacteria, Flavobacteria, Bacilli and Actinobacteria. Following their taxonomical categorization, the isolates were screened for their antimicrobial activity against human pathogenic microbial reference strains: Escherichia coli (ATCC­ BAA-196™), E. coli (ATCC® 13706™), E. coli (ATCC® 25922™), Klebsiella pneumoniae (ATCC® BAA-1705™), Enterococcus faecalis (ATCC® 51575™), Bacillus subtilis (ATCC® 19659™), Staphylococcus aureus (ATCC® 29247™), Candida albicans (ATCC® 10231™) and Aspergillus niger (ATCC® 16888™). Over 50% of the isolates displayed antimicrobial activity against one or more of the reference strains tested. The subset of these bioactive bacterial isolates was further investigated to identify their biosynthetic genes such as polyketide synthase (PKS) type I and non-ribosomal peptide synthetase (NRPS) genes. This was done using polymerase chain reaction (PCR) with degenerate primers that have been previously used to amplify PKS-I and NRPS genes. These specific genes have been reported to be possibly involved in bacterial secondary metabolite production. In 47% of the bacterial isolates investigated, the PKS and NRPS genes were located. Some of the bacterial isolates were found to possess both gene types, which agrees with the previous reported biosynthetic ability of certain sponge-symbiotic bacteria such as the Actinobacteria or Gammaproteobacteria to produce secondary metabolites with antimicrobial activity. All these reported activities further confirm that sponge-symbiotic bacteria hold significant bioactivity with medicinal and biotechnological importance. [ABSTRACT FROM AUTHOR]

Deep-sea coral and sponge ecosystems are widespread throughout most of Alaska's marine waters, and are associated with many different species of fishes and invertebrates. These ecosystems are vulnerable to the effects of commercial fishing activities and climate change. We compared four commonly used species distribution models (general linear models, generalized additive models, boosted regression trees and random forest models) and an ensemble model to predict the presence or absence and abundance of six groups of benthic invertebrate taxa in the Gulf of Alaska. All four model types performed adequately on training data for predicting presence and absence, with regression forest models having the best overall performance measured by the area under the receiver-operating-curve (AUC). The models also performed well on the test data for presence and absence with average AUCs ranging from 0.66 to 0.82. For the test data, ensemble models performed the best. For abundance data, there was an obvious demarcation in performance between the two regression-based methods (general linear models and generalized additive models), and the tree-based models. The boosted regression tree and random forest models out-performed the other models by a wide margin on both the training and testing data. However, there was a significant drop-off in performance for all models of invertebrate abundance (~50%) when moving from the training data to the testing data. Ensemble model performance was between the tree-based and regression-based methods. The maps of predictions from the models for both presence and abundance agreed very well across model types, with an increase in variability in predictions for the abundance data. We conclude that where data conforms well to the modeled distribution (such as the presence-absence data and binomial distribution in this study), the four types of models will provide similar results, although the regression-type models may be more consistent with biological theory. For data with highly zero-inflated distributions and non-normal distributions such as the abundance data from this study, the tree-based methods performed better. Ensemble models that averaged predictions across the four model types, performed better than the GLM or GAM models but slightly poorer than the tree-based methods, suggesting ensemble models might be more robust to overfitting than tree methods, while mitigating some of the disadvantages in predictive performance of regression methods. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated that sponge-eating fishes alter the community of sponges on coral reefs across the Caribbean. Sponge species that lack chemical defenses but grow or reproduce faster than defended species are more abundant on reefs where sponge-eating fishes have been removed by overfishing. Does predator-removal have an effect on the distribution of sponges at smaller spatial scales? We conducted transect surveys of sponge species that are palatable to sponge predators in proximity to refuge organisms that are chemically or physically defended (fire coral, gorgonians, hard corals) on the heavily overfished reefs of Bocas del Toro, Panama, and a reef in the Florida Keys where sponge-eating fishes are abundant. In Panama, palatable sponge species were not distributed in close association with refuge organisms, while in the Florida Keys, palatable sponge species were strongly associated with refuge organisms. The presence of fish predators alters the meter-scale pattern of sponge distribution, and defense by association enhances biodiversity by allowing palatable sponges to persist on reefs where sponge-eating fishes are abundant. [ABSTRACT FROM AUTHOR]

Summary The Late Ordovician (Hirnantian, approximately 445 million years ago) extinction event was among the largest known, with 85% species loss [ 1 ]. Post-extinction survival faunas are invariably low diversity, especially benthic communities [ 2 ], but ecological structure was restored relatively rapidly [ 1 ]. This pattern, however, reflects organisms with robust skeletons, as only one exceptionally preserved Hirnantian fossil biota was previously known [ 3, 4 ]; in particular, almost no Hirnantian sponges have been recorded. Our study reveals an extraordinarily diverse, sponge-dominated community thriving immediately after the Hirnantian extinction in Zhejiang, South China. Several contemporaneous sites preserve a total diversity of over 75 sponge species, many with preserved soft tissues, in pronounced contrast to normal survival and early recovery faunas. This diversity is unprecedented for any Hirnantian fossil group, and the fauna provides a unique window into a post-extinction ecosystem. The sponges are often large and structurally complex and represent numerous different lineages that survived the extinction. Layers with abundant sponge remains were deposited after other mass extinctions [ 5, 6 ], suggesting a general pattern of sponge abundance during collapse of Phanerozoic marine ecosystems. It is possible that the conditions of ecological collapse increase the particulate food sources for sponges, while they themselves are relatively unaffected by the crises. Furthermore, the abundance of sponges in the Hirnantian sequence of South China may have aided post-extinction ecosystem recovery by stabilizing the sediment surface, allowing sessile suspension feeders such as brachiopods, corals, and bryozoans to recover rapidly. [ABSTRACT FROM AUTHOR]

The antipredatory chemical ecology of Caribbean reef sponges has been well studied, with two distinct ecological strategies described: chemically defended species use secondary metabolites to deter fish predators, while palatable species lack chemical defenses, but grow, reproduce, or recruit fast enough to persist despite predation. While most palatable sponge species are consistently undefended from fish predators in laboratory feeding assays, there are some species that exhibit individual inter- and intra-site variation ranging from palatable to defended. The objective of this study was to better document the extent of chemical defense variability for 7 of these species over a wider geographic range and to test the dual hypotheses that variably defended sponge species would be (1) more palatable, and (2) exhibit greater variability in chemical defenses from reefs without sponge predators than from reefs where predators are abundant. Laboratory feeding assays using the bluehead wrasse confirmed intraspecific variability of chemical defenses for Clathria virgultosa , Cribrochalina vasculum , Desmapsamma anchorata , Dragmacidon reticulata , Iotrochota birotulata , Niphates digitalis , and Xestospongia muta for sites across the Caribbean. Surprisingly, logistic regression models relating levels of sponge chemical defense to a site-specific index of spongivorous fish abundance offered little support for the hypothesis that predator abundance alters palatability for any of these variably defended sponge species. The presence of symbiotic zoanthids in the tissue of I. birotulata and N. digitalis did not alter palatability. While the selective effect of predation has segregated most species of Caribbean reef sponges into chemically defended and undefended categories, this study concludes that the situation is more complex for variably defended sponge species, and suggests that automimicry is a possible explanation for this alternative strategy. [ABSTRACT FROM AUTHOR]

A siliceous sponge fauna, consisting of more than 900 specimens, is described from an early Lutetian tuffite horizon in the Chiampo Valley, Lessini Mountains, north-eastern Italy. Thirty-two taxa (15 Hexactinellida, 17 Demospongiae) are determined and illustrated, belonging to 24 genera, two of which are new (Rigoniagen. nov. andCoronispongiagen. nov.). Among these, 10 new species are proposed:Stauractinella eocenicasp. nov.,Rigonia plicatagen. et sp. nov.,Hexactinella clampensissp. nov.,Camerospongia visentinaesp. nov.,C. tuberculatasp. nov.,Toulminia italicasp. nov.,Coronispongia confossagen. et sp. nov.,Cavispongia scarpaisp. nov.,Corallistes multiosculatasp. nov. andBolidium bertiisp. nov. Of the genera identified at Chiampo, 14 range back to the Cretaceous, three to the Jurassic and one to the Triassic, while six are still extant. The studied fauna shows affinities with sponges from the Eocene of Spain and the Cretaceous of Germany. The sponge fossils are uncompressed and bodily preserved, but the original siliceous skeleton is dissolved and substituted by calcite. Delicate attachments can be nevertheless documented: some sponges attached to a hard substrate by encrustation, while others were anchored on soft sediments by root-like structures. The presence of different modes of attachment suggests heterogeneous substrate conditions. Small, possibly young, sponges are recorded too. The sponge fauna is essentially autochthonous and lived in the middle-outer part of a carbonate ramp, where it formed clusters. This study extends the geographical and stratigraphical range of many sponge taxa, includingCamerospongia,Toulminia,OzotrachelusandBolidium, previously documented only from the Cretaceous. The Recent calcified demosponge genusAstrosclerais reported here in the Cenozoic for the first time, having been reported previously in the Triassic only. Additionally, this study documents the second worldwide occurrence of the Recent sphinctozoan genusVaceletiain the Palaeogene, formerly recorded exclusively in Australia. http://zoobank.org/urn:lsid:zoobank.org:pub:B3466955-8E20-429A-89BE-42BAEB4002E8 [ABSTRACT FROM PUBLISHER]

Aim To test whether phylogeographical barriers in the brooding sponge Callyspongia vaginalis match breaks previously identified in the Caribbean. We also compared patterns of subdivision in the sponge to those of three of its commensals, the broadcast spawning brittle star Ophiothrix suensonii and the brooding amphipods Leucothoe ashleyae and L. kensleyi, and tested whether any shared breaks arose simultaneously. Location Florida, Bahamas and the Caribbean. Methods Subdivision of C. vaginalis populations was inferred from one mitochondrial ( COI) and six nuclear loci using clustering analyses. We identified phylogeographical breaks in the sponge and its invertebrate commensals by determining geographical patterns of genetic variation and tested simultaneous population divergence across barriers shared among taxa using hierarchical approximate Bayesian computation. Results Sponge populations were partitioned into western and eastern groups across the Caribbean, with hierarchical subdivision within regions. The sponge and its commensals shared barriers across their ranges despite differences in dispersal strategy: C. vaginalis, L. ashleyae and O. suensonii populations in Central America were isolated from the remainder of the Caribbean, and all four taxa shared a break between Florida and the Bahamas, although simultaneous population divergence could not be inferred with statistical certainty. Our results also suggest cryptic speciation within C. vaginalis. Main conclusions Phylogeographical patterns in C. vaginalis largely matched barriers previously identified at the Florida Straits, Mona Passage and Bay of Honduras in other Caribbean taxa. Oceanographic features such as deep water between locations, strong currents, and eddies are likely mechanisms responsible for these breaks. [ABSTRACT FROM AUTHOR]

Sponges form a significant component of the diversity of the Tremadocian (Early Ordovician) Fezouata Biota in the Anti-Atlas of Morocco, but are distributed intermittently and have so far received only limited attention. New material reveals a high diversity of undescribed taxa (a total of at least 27 species), including numerous representatives of protomonaxonid groups such as the Leptomitidae, Piraniidae and “Choiidae”. Some of these taxa show unusually complex skeletal architecture, and represent derived variations of their lineages relative to those in the Cambrian Burgess Shale-type faunas, although most species are assignable to described families. Reticulosan sponges are rare in the Fezouata Biota, and usually fragmentary. The palaeoecology of the sponge fauna is unusual, with most species known only from single sites (frequently single bedding planes), but are often abundant where they occur. It is very rare for two species of sponge to be found on the same slab, or at precisely the same horizon. With some species of protomonaxonid, particular bedding planes are crowded with individuals of species that are rarely, if ever, found isolated. Only two species ( Pirania auraeum Botting, 2007 and an undescribed hazeliid) are found at numerous levels, and these are not known from crowded assemblages; this may relate to differences in reproductive strategy. The dense, usually monospecific populations can best be explained through repeated colonisation events in a frequently hostile environment, rather than representing a range of different stable communities. [ABSTRACT FROM AUTHOR]

Bioerosion is a critical process on coral reefs, influencing reef structural integrity and complexity and generating significant amounts of sediment. Excavating sponges are important bioeroders, especially in the Caribbean where sponges dominate macroborer communities. However, the contribution of bioeroding sponge communities to total bioerosion on coral reefs is not well understood; census surveys are rarely employed by monitoring agencies, and there is little data on the erosion rates of different species. Here, we investigated bioerosion by two Caribbean sponge species with different growth forms ( Siphonodictyon brevitubulatum-α-form and Cliona tenuis-β-form). We also described new approaches to estimating bioerosion by sponge communities. By categorising the growth form of different species, we applied newly developed bioerosion rates, along with a previously published rate for C. delitrix, to census surveys and use these to estimate bioerosion by sponge communities on Grand Cayman reefs. Results indicate distinct habitat preferences for the two most abundant sponge species, C. tenuis and C. caribbaea. Mean sponge bioerosion across eight sites was 0.1 kg CaCO m yr. Visible cover by α-growth-form excavating sponges caused a disproportionately high level of bioerosion in comparison with cover by β-growth-form species. Therefore, it is important to consider growth forms and excavation strategies when assessing bioerosion by sponge communities. Our present level of understanding of bioerosion by sponge species is limited, and more research is clearly required. However, the approaches described here can generate instant, meaningful results on sponge abundance and bioerosion and would complement many current benthic monitoring regimes. Furthermore, they create a framework for the provision of data, which is relevant to both coral reef management and to developing our understanding of how bioeroding sponge populations influence reef structure and carbonate budgets. [ABSTRACT FROM AUTHOR]

An inventory of the sponge fauna from the Singapore Strait to the Taiwan Strait along the western coastline of the South China Sea was compiled from published and grey literature from the following regions: Singapore, peninsular Malaysia, Thailand, Cambodia, Vietnam, southern China and Taiwan. This study provides a partial update to the "Checklist of sponges (Porifera) of the South China Sea region" published 15 years ago. A total of 388 sponge species belonging to 24 orders, 78 families and 158 genera are listed, with the following regional species diversities: Singapore (130); east coast of peninsular Malaysia (25); Gulf of Thailand (90); Vietnam (141); southern China (138); and Taiwan (64). A total of 12 new species and over 200 new records were added to the Porifera inventory of the South China Sea since 2001. Of the 388 species, only 16 species (4%) are widespread. They are: Aaptos suberitoides, Acanthella cavernosa, Biemna fortis, Cinachyrella australiensis, Clathria (Thalysias) reinwardti, Coelocarteria singaporensis, Echinodictyum asperum, Hyrtios erectus, Haliclona (Gellius) cymaeformis, Iotrochota baculifera, I. purpurea, Mycale (Zygomycale) parishii, Neopetrosia exigua, Oceanapia sagittaria, Spheciospongia vagabunda, Xestospongia testudinaria. Only X. testudinaria, M. (Zygomycale) parishii and C. australiensis are present along the entire coastline from Singapore Strait to Taiwan Strait. Distinct sponge faunal assemblages occur between the equator and 25°N along the western coastline of the South China Sea. [ABSTRACT FROM AUTHOR]

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In healthy sponges, microbes have been shown to account for up to 40 % of tissues. The majority of these are thought to originate from survivors evading digestion and immune responses of the sponge and growing and residing in the microenvironments of the mesophyll. Although a large percentage of these microbes are likely commensals, they may also include potentially pathogenic agents, which under specific conditions, such as temperature stress, may cause disease. Here we report a novel disease (sponge necrosis syndrome) that is severely affecting populations of the sponge Callyspongia ( Euplacella) aff biru. Both ITS fungal and 16S rDNA bacterial diversities were assessed in healthy and diseased individuals, highlighting six potential primary causal agents for this new disease: two bacteria, a Rhodobacteraceae sp. and a cyanobacterium, Hormoscilla spongeliae (formally identified as Oscillatoria spongeliae), and four fungi, a Ascomycota sp., a Pleosporales sp., a Rhabdocline sp., and a Clasosporium sp. Furthermore, histological analysis showed the dominance of fungal hyphae rather than bacteria throughout the disease lesion, which was absent or rare in healthy tissues. Inoculation trails showed that only a combination of one bacterium and one fungus could replicate the disease, fulfilling Henle-Koch's postulates and showing that this sponge disease is caused by a poly-microbial consortium. [ABSTRACT FROM AUTHOR]

Cliona vermifera is one of the most abundant excavating sponges in Mexican coral reefs, and represents a potential threat to their health. It appears to have limited dispersal potential, but, paradoxically, it is widespread over much of the 2000 km of Mexican Pacific waters, suggesting mechanisms of long-distance dissemination. Despite its ecological importance, nothing is known about its patterns of genetic structure and connectivity in space and time. In this study, we assess levels of genetic structure and test the hypothesis of limited dispersal and isolation by distance among coral reef systems in the Mexican Pacific. Genetic diversity levels were consistently low in DNA sequences from two mitochondrial genes and one nuclear gene; however, they revealed strong and significant genetic differentiation throughout the study region. Patterns of genetic differentiation from the slow-evolving mitochondrial, but not the nuclear, genes were geographic scale dependent. We found higher mitochondrial genetic similarity among localities at 10-100s km than at larger scales (100-1000s km). However, all samples were genetically differentiated at the nuclear locus, which is inconsistent with frequent long-distance dispersal. Significant isolation by distance is consistent with life history traits shared by boring sponges: a short larval period and larval philopatric behavior. The patterns of genetic differentiation in C. vermifera concur with those found in other sympatric coral species, and suggest the influence of community-wide ecological and genetic mechanisms on the genetic makeup of coral reef species in the Mexican Pacific. Fixed genetic differences suggest that the southern population of Oaxaca may be experiencing incipient speciation. [ABSTRACT FROM AUTHOR]

Certain biodiversity patterns on coral reefs are generally consistent but we still lack fundamental insight into how assemblages vary across spatially heterogeneous reef systems. We compared fish, coral, and sponge assemblages across a symmetrical physiographical gradient (windward forereef, lagoon patch reef, leeward forereef) of the Glover's Reef atoll, Belize. Species richness of fishes and corals was highest in the deep habitat (15 m) on the windward forereef. Sponges were diverse and abundant on both deep windward and leeward forereefs but not on the exposed shallow (5 m) windward forereef. Fish and benthic assemblages were relatively distinct in each reef zone, with the lagoon patch reef communities consisting of a combination of leeward and windward species. Nevertheless, there were no clear patterns in community similarity matrices of fish and benthic assemblages, suggesting that overall coral and sponge assemblages had weak or no direct association with patterns in fish assemblages. A closer examination of fish trophic groups indicated that planktivores and predators were predictably associated with depth, whereas herbivores were associated with shallow protected reefs. None was specifically associated with spatial location along the atoll gradient. These patterns of diversity distribution are important for identifying spatial conservation priorities. A Marine Protected Area ( MPA) at Glover's Reef encompasses substantial windward forereef and patch reef habitats. A much lesser extent of protection is afforded the leeward forereef that supports faunal assemblages that are unique and productive, if not as diverse as the windward forereef. Isolated coral atolls can serve as ideal systems to study spatial heterogeneity and biodiversity patterns, but more experimental studies are needed to reveal the mechanistic processes underlying these patterns. [ABSTRACT FROM AUTHOR]

One popular concept used to explain the high biodiversity of some ecosystems is the Janzen-Connell hypothesis, which states that the distribution of conspecifics is controlled by species-specific pathogens or predators that are attracted to adults or to their reproductive output. The distribution of the affected species would then display a distinct pattern, with survivorship increasing at greater distance from the conspecific adult (negative density dependence), leaving a vacant area around the adult where other species can survive. The giant barrel sponge, Xestospongia muta, is an abundant and long-lived sponge on Caribbean coral reefs that is actively grazed by sponge-eating fishes and is susceptible to disease. We tested the Janzen-Connell hypothesis on barrel sponges on Conch Reef, Florida, by examining their distribution as a function of size using spatial point pattern analyses. Clark and Evans tests and a series of Ripley's K function analyses revealed no consistent distribution pattern, with most analyses resulting in a random pattern of sponge distribution. While predation by sponge-eating fishes has recently been discovered to structure sponge communities on reefs across the Caribbean, these top-down effects do not translate to spatial distributions of X. muta that support Janzen-Connell predictions. [ABSTRACT FROM AUTHOR]

Deep-water sponges are considered ecosystem engineers, and the presence of large aggregations of these organisms, commonly referred to as sponge grounds, is associated with enhanced biodiversity and abundance of epibenthic fauna compared to non-sponge habitat. However, the degree and magnitude to which the presence of these sponge grounds elicits large changes in composition of the associated megafaunal community remains unknown. Here we identify the external drivers of epibenthic megafaunal community composition and explore the patterns and magnitude of compositional change in the megafaunal community within the sponge grounds of the Sackville Spur, northwest Atlantic. Epibenthic megafauna were quantified from five image transects collected on the Sackville Spur in 2009 between 1080 and 1723 m depth. Using Gradient Forest Modelling we found that the abundance of structure-forming sponges was the most important variable for predicting compositional patterns in the Sackville Spur megafaunal community, followed by depth, range in bottom current speed, in situ salinity, and longitude. Along the gradient in structure-forming sponge abundance, the largest turnover in megafaunal community composition occurred when the sponges reached 15 individuals m −2 . Examination of the regional hydrographic conditions suggests that the dense sponge grounds of the Sackville Spur are associated with a warm, salty water mass that occurs between ~1300 and 1800 m. [ABSTRACT FROM AUTHOR]

In the present study, we assessed the composition of Bacteria in four biotopes namely sediment, seawater and two sponge species (Stylissa massa and Xestospongia testudinaria) at four different reef sites in a coral reef ecosystem in West Java, Indonesia. In addition to this, we used a predictive metagenomic approach to estimate to what extent nitrogen metabolic pathways differed among bacterial communities from different biotopes. We observed marked differences in bacterial composition of the most abundant bacterial phyla, classes and orders among sponge species, water and sediment. Proteobacteria were by far the most abundant phylum in terms of both sequences and Operational Taxonomic Units (OTUs). Predicted counts for genes associated with the nitrogen metabolism suggested that several genes involved in the nitrogen cycle were enriched in sponge samples, including nosZ, nifD, nirK, norB and nrfA genes. Our data show that a combined barcoded pyrosequencing and predictive metagenomic approach can provide novel insights into the potential ecological functions of the microbial communities. Not only is this approach useful for our understanding of the vast microbial diversity found in sponges but also to understand the potential response of microbial communities to environmental change. [ABSTRACT FROM AUTHOR]

Changes in habitat-forming organisms can have complex consequences for associated species. Sessile epibenthic glass 'plate' sponges (Porifera: Hexactinellida) are conspicuous inhabitants of soft-sediment abyssal areas and their siliceous spicules create persistent spicule patches on the seafloor. Sponge spicule patch density, spatial dispersion, and percent cover were examined over a seven-year period (2006-2013) using remotely operated vehicle videos from Station M in the abyssal northeast Pacific (50˚00N, 123˚00W, ~4,000 m depth). There was an apparent large increase in newly dead plate sponges in February 2007 compared with December 2006, with this trend continuing through June 2007 (mean 0.03 % cover increasing to 0.33 %). A second increase in mean percent cover of dead plate sponges occurred from May 2011 (0.24 %) through June 2012 (0.60 %). Among the 28 megafaunal taxa occurring in association with the patches, the distributions of three taxa [two sponge taxa (Porifera) and brittle stars (Ophiuroidea)] suggested selectivity for the sponge spicule patches. The community structure of visible megafauna within sponge spicule patches was different when compared with that outside the patches suggesting that the sponges, after death, provide preferred habitat patches for certain benthic megafauna. These findings indicate that sponge spicule patches contribute to habitat heterogeneity in space and time. [ABSTRACT FROM AUTHOR]

Marine sponges harbor diverse microbial communities, encompassing not only three domains of life including Bacteria, Archaea and eukaryotes, but also many different phyla within Bacteria. This diversity implies a rich source for biodiscovery of new natural products. Here, we review recent progress in our understanding of this genetic diversity, its retrieval via culture and genomic approaches, and its implications for chemical diversity and other biotechnology applications of sponge microorganisms and their genes. [ABSTRACT FROM AUTHOR]

The presence and association of fungi with sessile marine animals such as coral and sponges has been well established, yet information on the extent of diversity of the associated fungi is still in its infancy. Culture ? aswell as metagenomic ? and transcriptomicbased analyses have shown that fungal presence in association with these animals can be dynamic and can include ?core? residents as well as shifts in fungal communities. Evidence for detrimental and beneficial interactions between fungi and their marine hosts is accumulating and current challenges include the elucidation of the chemical and cellular crosstalk between fungi and their associates within the holobionts. The ecological function of fungi in association with sessile marine animals is complex and is founded on a combination of factors such as fungal origin, host health, environmental conditions and the presence of other resident or invasive microorganisms in the host. Based on evidence from the much more studied terrestrial systems, the evaluation of marine animal? fungal symbioses under varying environmental conditions may well prove to be critical in predicting ecosystem response to global change, including effects on the health of sessile marine animals. [ABSTRACT FROM AUTHOR]

Ecological studies have rarely been performed at the community level across a large biogeographic region. Sponges are now the primary habitat-forming organisms on Caribbean coral reefs. Recent species-level investigations have demonstrated that predatory fishes (angelfishes and some parrotfishes) differentially graze sponges that lack chemical defenses, while co-occurring, palatable species heal, grow, reproduce, or recruit at faster rates than defended species. Our prediction, based on resource allocation theory, was that predator removal would result in a greater proportion of palatable species in the sponge community on overfished reefs. We tested this prediction by performing surveys of sponge and fish community composition on reefs having different levels of fishing intensity across the Caribbean. A total of 109 sponge species was recorded from 69 sites, with the 10 most common species comprising 51.0% of sponge cover (3.6-7.7% per species). Nonmetric multidimensional scaling indicated that the species composition of sponge communities depended more on the abundance of sponge-eating fishes than geographic location. Across all sites, multiple-regression analyses revealed that spongivore abundance explained 32.8% of the variation in the proportion of palatable sponges, but when data were limited to geographically adjacent locations with strongly contrasting levels of fishing pressure (Cayman Islands and Jamaica; Curaçao, Bonaire, and Martinique), the adjusted R² values were much higher (76.5% and 94.6%, respectively). Overfishing of Caribbean coral reefs, particularly by fish trapping, removes sponge predators and is likely to result in greater competition for space between fastergrowing palatable sponges and endangered reef-building corals. [ABSTRACT FROM AUTHOR]

Aim Estuaries are common focal points for industry and development, but often little is known of their biology or ecology, particularly for sessile taxa. We sought to examine how size and opening regime of shallow saline coastal lakes altered patterns of diversity and abundance for a suite of epifaunal invertebrates. We also sought to determine how these patterns were affected by the degree of lake modification by humans. Location We sampled 10 coastal barrier lakes of a range of sizes, opening regimes and degrees of modification in south-eastern Australia. Methods We quantified the diversity and abundance of sponges and ascidians in transects and undertook timed searches for these fauna at multiple locations within each coastal lake; placing the data in a hypothesis testing framework. Results Eighteen species of sponge, most of which appear to be new to science, and six species of ascidian were found among the 10 lakes we examined. All sponges and most ascidians were extremely patchily distributed among the lakes. Few species were widespread, with most restricted to one or two lakes. Diversity was largest in lakes mostly open to the sea and large in size. Diversity and abundance were smaller in highly modified lakes. Main Conclusions We suggest that sponge assemblages in these lakes consist of a combination of species largely restricted in distribution to lakes, and marine species that are at their limits of distribution. In contrast, ascidian assemblages were dominated by species that were more widespread. Conservation of biodiversity in these systems will rely heavily on effective management, which will in turn rely on a sound scientific understanding of natural processes; this will require the management of water quality through protection of catchments. The control of opening regimes should consider the ecological consequences rather than being purely based on ad hoc and reactive management. [ABSTRACT FROM AUTHOR]

Coral reefs across the world are under threat from a range of stressors, and while there has been considerable focus on the impacts of these stressors on corals, far less is known about their effect on other reef organisms. The 1997–8 El-Niño Southern Oscillation (ENSO) had notable and severe impacts on coral reefs worldwide, but not all reef organisms were negatively impacted by this large-scale event. Here we describe how the sponge fauna at Bahia, Brazil was influenced by the 1997–8 ENSO event. Sponge assemblages from three contrasting reef habitats (reef tops, walls and shallow banks) at four sites were assessed annually from 1995 to 2011. The within-habitat sponge diversity did not vary significantly across the study period; however, there was a significant increase in density in all habitats. Multivariate analyses revealed no significant difference in sponge assemblage composition (ANOSIM) between pre- and post-ENSO years for any of the habitats, suggesting that neither the 1997–8 nor any subsequent smaller ENSO events have had any measurable impact on the reef sponge assemblage. Importantly, this is in marked contrast to the results previously reported for a suite of other taxa (including corals, echinoderms, bryozoans, and ascidians), which all suffered mass mortalities as a result of the ENSO event. Our results suggest that of all reef taxa, sponges have the potential to be resilient to large-scale thermal stress events and we hypothesize that sponges might be less affected by projected increases in sea surface temperature compared to other major groups of reef organisms. [ABSTRACT FROM AUTHOR]

The life-history traits of long-lived benthic littoral invertebrates remain poorly understood. In this study, we analysed patterns of growth in three abundant sublittoral sponges from the western Mediterranean Sea, chosen for their close phylogenetic relatedness, sympatric distribution, and contrasting amounts of photosymbionts: high in Ircinia fasciculata, lower in I. variabilis, and absent in I. oros. Sponge area, perimeter, number of oscula, and epibiont abundance were quantified from in situ digital images taken monthly for 1.5 years and volumetric growth rates were calculated from empirical area-volume relationships. Volumetric growth rates were different among species and coherent with the photosymbiont abundance: high in I. fasciculata (40.03 ± 4.81 % year, mean ± SE), low in I. variabilis (5.65 ± 6.11 % year), and almost nil in I. oros (−0.04 ± 3.02 % year). Furthermore, a marked seasonality was observed in the first two species, with greater growth during the warm season. The high growth rates of I. fasciculata were likely fuelled by symbiont-derived photosynthates and required to compete in the well-lit, algal-dominated habitats this species prefers. In contrast, I. variabilis and I. oros tended to dwell in shaded habitats, where competition from slow-growing invertebrates is intense, and featured lower growth rates. The flattened morphology and lower circularity of I. variabilis indicates a capacity for adaptation to any space that is freed, while I. oros had less oscula and was more massive and circular, suggesting a strategy of passive occupation and minimisation of biological interactions. The results show that even congeneric species living sympatrically can achieve important biomass using different growth and substrate occupation strategies. [ABSTRACT FROM AUTHOR]

The vital roles that sponges play in marine habitats are well-known. However, sponges inhabiting freshwaters have been largely ignored despite having widespread distributions and often high local abundances. We used natural abundance stable isotope signatures of carbon and nitrogen ( δC and δN) to infer the primary food source of the cosmopolitan freshwater sponge Spongilla lacustris. Our results suggest that S. lacustris feed largely on pelagic resources and may therefore link pelagic and benthic food webs. A facultative association between S. lacustris and endosymbiotic green algae caused S. lacustris to have significantly depleted carbon and nitrogen signatures that may reflect carbon and nitrogen exchange between sponges and their symbiotic algae. Isotopic data from specialist sponge consumers demonstrated that sponges hosting zoochlorellae were the major component of the diet of the spongillafly Climacia areolaris and the sponge-eating caddisfly Ceraclea resurgens suggesting that the symbiosis between freshwater sponges and algae is important to sponge predator trophic ecology. Our results help define the role of sponges in freshwater ecosystems and shed new light on the evolution and ecological consequences of a complex tri-trophic symbiosis involving freshwater sponges, zoochlorellae, and spongivorous insects. [ABSTRACT FROM AUTHOR]

The interactions between sponges and red macroalgae have been widely documented in tropical and subtropical environments worldwide, and many of them have been documented as mutualistic associations. Sponges, however, have also been frequently described as part of the associated fauna of rhodolith habitats (aggregations of free-living non-geniculated coralline macroalgae). Nonetheless, the types of interaction they establish as well as the role of sponges in these habitats remain unknown. In this study, the associations between sponges and rhodoliths were investigated in an estuarine ecosystem of the Mexican Pacific based on qualitative and quantitative data. A total of 13 sponge species were identified in five newly discovered rhodolith beds dominated by the non-geniculate coralline macroalga Lithophyllum margaritae. The sponge assemblages were strongly restricted to rhodolith habitats. The best predictor of sponge abundance (from 5.1 to 51.7 ind m) and species richness (from 2.6 to 6.1 sponge species m) was the rhodolith density rather than other population descriptors assessed (e.g., average size, branch density and sphericity). The identified sponges included a variety of forms: massive (46 %), encrusting (23 %), excavating (15 %), cushion-shape (8 %) and digitate (8 %). Moreover, more than 50 % of sponge species recorded (mainly massive and encrusting forms) were frequently found overgrowing and binding rhodoliths. Halichondria cf. semitubulosa and Mycale cecilia were the most common binding agents; these species bind an average of 3.1 and 6.6 rhodoliths per sponge individual, respectively. These findings reveal the importance of rhodoliths as habitat forming species, since these seaweed beds notably increased the substrate complexity in soft bottom environments. In addition, the relatively high abundance of sponges and their capability to bind rhodoliths suggest that these associated organisms could have an important contribution to rhodolith bed stability. [ABSTRACT FROM AUTHOR]

Large-scale mortality of marine invertebrates is a major global concern for ocean ecosystems and many sessile, reef-building animals, such as sponges and corals, are experiencing significant declines through temperature-induced disease and bleaching. The health and survival of marine invertebrates is often dependent on intimate symbiotic associations with complex microbial communities, yet we have a very limited understanding of the detailed biology and ecology of both the host and the symbiont community in response to environmental stressors, such as elevated seawater temperatures. Here, we use the ecologically important sponge Rhopaloeides odorabile as a model to explore the changes in symbiosis during the development of temperature-induced necrosis. Expression profiling of the sponge host was examined in conjunction with the phylogenetic and functional structure and the expression profile of the symbiont community. Elevated temperature causes an immediate stress response in both the host and symbiont community, including reduced expression of functions that mediate their partnership. Disruption to nutritional interdependence and molecular interactions during early heat stress further destabilizes the holobiont, ultimately leading to the loss of archetypal sponge symbionts and the introduction of new microorganisms that have functional and expression profiles consistent with a scavenging lifestyle, a lack virulence functions and a high growth rate. Previous models have postulated various mechanisms of mortality and disease in marine invertebrates. Our study suggests that interruption of symbiotic interactions is a major determinant for mortality in marine sessile invertebrates. High symbiont specialization and low functional redundancy, thus make these holobionts extremely vulnerable to environmental perturbations, including climate change. [ABSTRACT FROM AUTHOR]

Warmer, more acidic water resulting from greenhouse gas emissions could influence ecosystem processes like bioerosion of calcifying organisms. Based on summer-maxima values (temperature = 26 °C; pH = 8.1) at a collection site in New York (40°56″ N, 72°30″ W), explants of the boring sponge Cliona celata Grant, were grown for 133 days on scallop shells in seawater ranging from current values to one scenario predicted for the year 2100 ( T = 31 °C; pH = 7.8). High water temperature had little effect on sponge growth, survival, or boring rates. Lower pH slightly reduced sponge survival, while greatly influencing shell boring. At pH = 7.8, sponges bored twice the number of papillar holes and removed two times more shell weight than at pH = 8.1. Greater erosion resulted in weaker scallop shells. This study suggests that lower seawater pH may increase boring rates of C. celata in shellfish, with potentially severe implications for wild and farmed shellfish populations. [ABSTRACT FROM AUTHOR]

Marine sponges are well known for their associations with highly diverse, yet very specific and often highly similar microbiota. The aim of this study was to identify potential bacterial sub-populations in relation to sponge phylogeny and sampling sites and to define the core bacterial community. 16S ribosomal RNA gene amplicon pyrosequencing was applied to 32 sponge species from eight locations around the world's oceans, thereby generating 2567 operational taxonomic units (OTUs at the 97% sequence similarity level) in total and up to 364 different OTUs per sponge species. The taxonomic richness detected in this study comprised 25 bacterial phyla with Proteobacteria, Chloroflexi and Poribacteria being most diverse in sponges. Among these phyla were nine candidate phyla, six of them found for the first time in sponges. Similarity comparison of bacterial communities revealed no correlation with host phylogeny but a tropical sub-population in that tropical sponges have more similar bacterial communities to each other than to subtropical sponges. A minimal core bacterial community consisting of very few OTUs (97%, 95% and 90%) was found. These microbes have a global distribution and are probably acquired via environmental transmission. In contrast, a large species-specific bacterial community was detected, which is represented by OTUs present in only a single sponge species. The species-specific bacterial community is probably mainly vertically transmitted. It is proposed that different sponges contain different bacterial species, however, these bacteria are still closely related to each other explaining the observed similarity of bacterial communities in sponges in this and previous studies. This global analysis represents the most comprehensive study of bacterial symbionts in sponges to date and provides novel insights into the complex structure of these unique associations. [ABSTRACT FROM AUTHOR]

Abstract: Aquaculture of the bath sponge Coscinoderma matthewsi relies on collection of seed stock from the wild. This study investigated the potential of larval culture as a sustainable source of seed stock by quantifying reproduction, larval metamorphosis, and juvenile survival and growth of C. matthewsi. The accuracy of using surface area (2-dimensional) measurements as a proxy for juvenile growth was also assessed against volumetric (3-dimensional) data. Coscinoderma matthewsi is gonochoric and releases parenchymellae larvae over several weeks, corresponding with increasing sea surface temperatures, over the Austral summer (26.6°C in November and 29.1°C in January). Sexual maturity is size dependent and smaller individuals (1267.78cm3 ±405.66) were non-reproductive. There were no size differences between males and females and both sexes occur in equal proportions. Male reproductive output (ROI) (4.33%±0.75) was higher than females (1.62%±0.15). Larval metamorphic success was 98.0%±2 after 72h post-release. Juvenile survival over seven months was independent of settlement density and ranged between 18% and 30%. Using surface area underestimated growth of juvenile sponges by approximately half in comparison to volume estimates. This study demonstrates larval culture as a sustainable source of seed stock to support large scale aquaculture operations. [Copyright &y& Elsevier]

Sponges constitute an abundant and functionally important component of coral reef systems. Given their demonstrated resistance to environmental stress, it might be expected that the role of sponges in reef systems under modern regimes of frequent and severe disturbance may become even more substantial. Disturbances have recently reshaped the community structure of many Caribbean coral reefs shifting them towards a state of persistent low coral cover and often a dominance of macroalgae. Using competition and growth rates recorded from Glover's Atoll in Belize, we parameterise a mathematical model used to simulate the three-way competition between sponges, macroalgae and coral. We use the model to determine the range of parameters in which each of the three species might be expected to dominate. Emergent properties arise from our simple model of this complex system, and these include a special case in which heightened competitive ability of macroalgae versus coral may counter-intuitively prove to be advantageous to the persistence of corals. Importantly, we show that even under scenarios whereby sponges fail to invade the system, inclusion of this third antagonist can qualitatively affect the likelihood of alternative stable states – generally in favour of macroalgal dominance. The interplay between multi-species competition and predation is complex, but our efforts highlight a key process that has, until now, remained unexplored: the extent to which sponges dissipate algal grazing pressure by providing generalist fish with an alternative food source. We highlight the necessity of identifying the extent by which this process takes place in tropical systems in order to improve projections of alternative stable states for Caribbean coral reefs. [Copyright &y& Elsevier]

Mass mortality events are increasing dramatically in all coastal marine environments. Determining the underlying causes of mass mortality events has proven difficult in the past because of the lack of prior quantitative data on populations and environmental variables. Four-year surveys of two shallow-water sponge species, Ircinia fasciculata and Sarcotragus spinosulum, were carried out in the western Mediterranean Sea. These surveys provided evidence of two severe sponge dieoffs (total mortality ranging from 80 to 95% of specimens) occurring in the summers of 2008 and 2009. These events primarily affected I. fasciculata, which hosts both phototrophic and heterotrophic microsymbionts, while they did not affect S. spinosulum, which harbors only heterotrophic bacteria. We observed a significant positive correlation between the percentage of injured I. fasciculata specimens and exposure time to elevated temperature conditions in all populations, suggesting a key role of temperature in triggering mortality events. A comparative ultrastructural study of injured and healthy I. fasciculata specimens showed that cyanobacteria disappeared from injured specimens, which suggests that cyanobacterial decay could be involved in I. fasciculata mortality. A laboratory experiment confirmed that the cyanobacteria harbored by I. fasciculata displayed a significant reduction in photosynthetic efficiency in the highest temperature treatment. The sponge disease reported here led to a severe decrease in the abundance of the surveyed populations. It represents one of the most dramatic mass mortality events to date in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]