Two <Emphasis Type="Italic">Pione</Emphasis> species (Hadromerida,Clionaidae) from the Red Sea: a taxonomical challenge

Boring sponges of the genus Pione (Hadromerida, Clionaidae) are easily recognizable due to their spiculation. However, species identification is challenging, as the potentially diagnostic morphological character states of different species often overlap. For this reason, this group of species is frequently referred to as the ‘Pione vastifica complex’, after the most well-studied species of the genus. Boring-sponge samples were collected in the Red Sea and identified as P. cf. lampa and P. cf. vastifica, respectively. So far, these two species names have usually been considered as valid, although some authors suggested them to be synonymous. Morphological analyses were performed on spicules and micro-erosion patterns by means of both light and scanning electron microscopy. Two apparent morphotypes can be distinguished, mainly by the growth form, but statistical analysis does not support a clear separation in two species. In addition, a DNA barcoding approach using sequences of CO1 has not identified any nucleotide sequence differences. These data support the hypothesis that P. cf. lampa and P. cf. vastifica from the Red Sea are conspecific.     

Assessment of the relative contribution of asexual propagation in a population of the coral-excavating sponge Cliona delitrix from the Bahamas

Cliona delitrix is a very destructive coral-excavating sponge in Caribbean coral reef systems, particularly for Montastraea species. Little is known about how these excavating sponges propagate across coral reefs. In this study a hypothesis was tested that coral breakage caused by the bioeroding activity facilitates the asexual propagation of this sponge and in turn favors the spread of the most aggressive sponge genotypes. An allozyme analysis, involving 12 loci systems of 52 sponge individuals from a total of 13 Montastraea heads, found that no two sponges possessed identical multi-locus genotypes. Contrary to the pattern expected for fragmenting species, the incidence of clonality and asexual propagation at the population level was minimal. The lack of correlation between genetic and physical distances for the studied sponges also suggests that population maintenance appears to derive from larval dispersal, with a spatial range of dispersal larger than the average distance between the coral heads (10–10² m).     

Population structure and dispersal of the coral‐excavating sponge Cliona delitrix

Some excavating sponges of the genus Cliona compete with live reef corals, often killing and bioeroding entire colonies. Important aspects affecting distribution of these species, such as dispersal capability and population structure, remain largely unknown. Thus, the aim of this study was to determine levels of genetic connectivity and dispersal of Cliona delitrix across the Greater Caribbean (Caribbean Sea, Bahamas and Florida), to understand current patterns and possible future trends in their distribution and effects on coral reefs. Using ten species‐specific microsatellite markers, we found high levels of genetic differentiation between six genetically distinct populations: one in the Atlantic (Florida‐Bahamas), one specific to Florida and four in the South Caribbean Sea. In Florida, two independent breeding populations are likely separated by depth. Gene flow and ecological dispersal occur among other populations in the Florida reef tract, and between some Florida locations and the Bahamas. Similarly, gene flow occurs between populations in the South Caribbean Sea, but appears restricted between the Caribbean Sea and the Atlantic (Florida‐Bahamas). Dispersal of C. delitrix was farther than expected for a marine sponge and favoured in areas where currents are strong enough to transport sponge eggs or larvae over longer distances. Our results support the influence of ocean current patterns on genetic connectivity, and constitute a baseline to monitor future C. delitrix trends under climate change.     

Reproductive cycle of the coral-excavating sponge Thoosa mismalolli (Clionaidae) from Mexican Pacific coral reefs

Abstract. Individuals of the recently described demosponge Thoosa mismalolli are common on Mexican Pacific coral reefs, excavating burrows in living corals and in other calcareous substrata. To better understand the propagative abilities of this sponge, we conducted a histological study over an 18-month period (May 2007–November 2008) to identify sexual and asexual reproductive structures. Members of the species are viviparous and hermaphroditic, with various developmental stages of oocytes, spermatic cysts, and embryos co-occurring in the mesohyl for most of the year. This nearly continuous reproductive activity intensified during the warm season. Fertilization was internal, and embryos developed inside the parental sponge to produce an unciliated hoplitomella larva, characterized by a peculiar siliceous skeleton. In addition to the sexually generated larvae, adults of T. mismalolli formed gemmules for asexual reproduction. Gemmules occurred within the mesohyl during all months of the year, but were most abundant in the coldest months. This combination of sexual and asexual processes enables individuals of T. mismalolli to reproduce almost continuously. This strategy may facilitate both long-term persistence within reefs and effective dispersal between distant reefs.     

The effects of cadmium and mercury on gemmule formation and gemmosclere morphology in Ephydatia fluviatilis (Porifera : Spongillidae)

A laboratory study of the effects of cadmium and mercury on the freshwater sponge, Ephydatia fluviatilis, was conducted. Sponge cuttings were exposed to concentrations of cadmium or mercury which ranged from 1.000 to 0.001 ppm for one month. The responses exhibited by the specimens resulted in four groups characterized as follows: sponge colony survived and produced gemmules with normal gemmoscleres; sponge colony survived and produced gemmules with malformed gemmoscleres; sponge colony survived but did not gemmulate; sponge colony died. A direct discriminant functions analysis of the four sponge groups, metal concentrations and other chemical data established a highly significant correlation between increasing metal concentrations and amount of damage to the sponge.     

Survival of the gemmules of Anheteromeyenia ryderi (Potts) following aerial exposure during winter in New England

Gemmules of Anheteromeyenia ryderi survived 24 h exposure to air temperatures as low as –20 °C under laboratory conditions. Drying the gemmules of A. ryderi at 5 °C under laboratory conditions resulted in a reduced viability and a slower germination rate following rehydration compared with undried control gemmules. Only 25% of the gemmules germinated after drying for one month. Up to 25% of the gemmules of A. ryderi that were tested survived aerial exposure from early November to early April when a pond in Connecticut inhabited by this sponge was drained. During this period air temperatures dropped to as low as –16 °C. Continued aerial exposure of the gemmules during the summer resulted in nearly complete gemmule mortality.     

Siphonodictyal B1 from a Marine Sponge Increases Intracellular Calcium Levels Comparable to the Ca2+-ATPase (SERCA) Inhibitor Thapsigargin

Siphonodictyal B1 is a sesquiterpene-hydroquinone isolated from the Caribbean coral reef bioeroding sponge Siphonodictyon coralliphagum. Siphonodictyal B1 increased intracellular calcium levels in neuroendocrine cells (PC12) in the presence and absence of extracellular calcium using Fura-2 as a calcium-sensitive dye. The calcium rise was comparable in amplitude and timing to the application of the sarco-endoplasmic reticulum calcium-ATPase (SERCA) inhibitor thapsigargin from the terrestrial plant Thapsia garganica. The effects of thapsigargin and siphonodictyal B1 on intracellular calcium levels were not distinguishable in pharmacological experiments conducted with caffeine, ryanodine, muscarine, and thapsigargin in calcium-free and calcium-containing buffer, although thapsigargin was effective at lower concentrations. Thapsigargin is a sesquiterpene-lactone and has no structural similarities to siphonodictyal B1. We conclude that thapsigargin and siphonodictyal B1 share SERCAs as cellular targets. Siphonodictyal B1 may be involved in the process of bioeroding the calcium carbonate endoskeleton of the scleractinian corals attacked by S. coralliphagum.     

Genetic assessment of connectivity in the common reef sponge, Callyspongia vaginalis (Demospongiae: Haplosclerida) reveals high population structure along the Florida reef tract

The genetic population structure of the common branching vase sponge, Callyspongia vaginalis, was determined along the entire length (465 km) of the Florida reef system from Palm Beach to the Dry Tortugas based on sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene. Populations of C. vaginalis were highly structured (overall Φ_ST = 0.33), in some cases over distances as small as tens of kilometers. However, nonsignificant pairwise Φ_ST values were also found between a few relatively distant sampling sites suggesting that some long distance larval dispersal may occur via ocean currents or transport in sponge fragments along continuous, shallow coastlines. Indeed, sufficient gene flow appears to occur along the Florida reef tract to obscure a signal of isolation by distance, but not to homogenize COI haplotype frequencies. The strong genetic differentiation among most of the sampling locations suggests that recruitment in this species is largely local source-driven, pointing to the importance of further elucidating general connectivity patterns along the Florida reef tract to guide the spatial scale of management efforts.     

Sponge borehole size as a relative measure of bioerosion and paleoproductivity

Bioerosion intensity has been proposed as a measure of paleoproductivity in fossil reefs, but it is difficult to measure directly because fossil corals are often incomplete and because it is difticult to infer the length of time a given coral was exposed to bioeroding organisms. Both nutrient availability and taphonomic factors can affect bioerosion intensity as measured in dead corals. Here, we examine these two effects separately using data from previous studies on bioerosion in modern and fossil corals. Size of individual sponge borings accurately reflects total bioerosion in modern massive and branching corals on the Great Barrier Reef. Total bioerosion in both massive and branching corals decreases outward across the continental shelf, paralleling trends in nutrient availability. Size of individual Cliothosa hancocki borings decreases across the shelf in branching Acropora but not in massive Porites. Fossil sponge borings Entobia convoluta and Uniglobites glomerata in massive corals from Oligocene and Miocene reefs in Puerto Rico are smallest in Oligocene shelf-edge reefs, intermediate in Oligocene patch reefs, and largest in Miocene patch reefs. Both facies-related influence, represented by Oligocene shelf-edge reefs vs. Oligocene patch reefs, and nutrient-related influence, represented by Oligocene vs. Miocene patch reefs, were reflected in the size of sponge boreholes. Size of sponge borings also varies among species of host corals, apparently in relation to skeletal architecture. Borehole size is inversely correlated with skeletal density as measured by the relative proportion of skeleton and pore space in transverse thin section. There is a weak positive correlation between borehole size and corallite diameter. These findings contradict reported positive correlations between total bioerosion and bulk density in modern corals. Borehole size appears accurately to reflect intensity of total internal bioerosion in fossil corals. Facies-controlled taphonomic overprints and influence of skeletal differences between coral species limit the use of sponge borehole size to a rough indicator of paleoproductivity in fossil coral reef environments.     

Pyrosequencing reveals sponge specific bacterial communities in marine sponges of Red Sea,Saudi Arabia

Bacterial communities of marine sponges are believed to be an important partner for host survival but remain poorly studied. Sponges show difference in richness and abundance of microbial population inhabiting them. Three marine sponges belonging to the species of Pione vastifica, Siphonochalina siphonella and Suberea mollis were collected from Red sea in Jeddah and were investigated using high throughput sequencing. Highly diverse communities containing 105 OTUs were identified in S. mollis host. Only 61 and 43 OTUs were found in P. vastifica and S. siphonella respectively. We identified 10 different bacterial phyla and 31 genera using 27,356 sequences. Most of the OTUs belong to phylum Proteobacteria (29%–99%) comprising of Gammaproteobacteria, Alphaproteobacteria, and Deltaproteobacteria where later two were only detected in HMA sponge, S. mollis. A number of 16S rRNA sequences (25%) were not identified to phylum level and may be novel taxa. Richness of bacterial community and Shannon, Simpson diversity revealed that sponge S. mollis harbors high diversity compared to other two LMA sponges. Dominance of Proteobacteria in sponges may indicate an ecological significance of this phylum in the Red sea sponges. These differences in bacterial composition may be due to difference in location site or host responses to environmental conditions. To the best of our knowledge, the microbial communities of these sponges have never been studied before and this is first attempt to unravel bacterial diversity using PCR-based 454-pyrosequencing method.     

Distribution and ecology of freshwater sponges in Connecticut

A survey of Connecticut lakes and rivers revealed the presence of 7 species of freshwater sponge: Spongilla lacustris, Ephydatia muelleri, Eunapius fragilis, Anheteromeyenia ryderi, A. argyrosperma, Corvomeyenia carolinensis, and Corvospongilla novaeterrae in order of decreasing frequency of occurrence. Corvomeyenia carolinensis has not been reported previously beyond its type locality in South Carolina. In addition, microscleres of Spongilla lacustris, Anheteromeyenia-like megascleres, Ephydatia muelleri-like megascleres, and smooth megascleres (amphioxeas), which could not be assigned to a particular species, were found in surface sediments from lake cores. Spongilla lacustris inhabiting small rivers produced brown, thick-capsuled gemmules during the summer and yellow, thin-capsuled gemmules during the fall. The thick-capsuled gemmules, but not the thin-capsuled gemmules, are tolerant of desiccation; and populations of Spongilla lacustris and Ephydatia muelleri survived severe drying of their habitats during the summer.     

Effects of eutrophication on bioeroding sponge communities with the description of new West Indian sponges, Cliona spp. (Porifera: Hadromerida: Clionidae)

Abstract. Pieces of coral rubble ( Porites porites ), collected from across 3 fringing reefs that lie along a eutrophication gradient, were examined for the presence of clionid sponges. A similarity analysis of species composition showed that reef zone had less effect on clionid community composition than did other factors affecting the reefs as a whole. Except on the back reef, the Zones, distances, and depths within the reefs had no significant influence on the number of clionid invasions. Reef comparisons demonstrated that clionid abundance increased with increasing eutrophication. Clionids were found in 41% of the pieces collected from the most eutrophic site vs. 24% from the least eutrophic. Because clionids are the principal bio-eroders of coral reefs, any increase in their abundance will likely result in greater bioerosion rates. The mean abundance of Type 3 corals (in which fragmentation is the primary mode of propagation) is positively related to the frequency of boring sponge invasion. suggesting that increased bioerosion may be partly responsible for community shifts toward Type 3 corals in polluted waters. Cliona cf. vastifica , found for the first time in Barbados, flourishes on the most eutrophic reef and may become an important bioeroder under the highly eutrophic conditions that have begun to plague West Indian reefs. Two new species of Cliona (Porifera: Hadro-merida: Clionidae) are described.     

High abundance of Trochospongilla horrida (Porifera, Spongillidae) in the Rhine (Germany) 1992–1995

Trochospongilla horrida (Porifera, Spongillidae) was the dominant freshwater sponge in the Rhine between Karlsruhe and Bonn between 1992 and 1995 are reported. It showed an annual life cycle, with an inactive phase during winter. The life cycle was controlled by temperature. Gemmules were produced in high numbers, and played a significant role as resting bodies. Their role as distribution units was negligible because they were tightly fixed to the substratum. Trochospongilla horrida preferred relatively stable habitats, not affected by fluctuations in water level; it was restricted to habitats with a slightly alkaline pH. Laboratory experiments showed a delayed germination of the gemmules, which explains why the highest abundance of the species occured considerably after the first hatching colonies.     

Composition and community structure of the coralline algal reefs from Atol das Rocas, South Atlantic, Brazil

 Coralline-algal frameworks from Atol das Rocas reefs were sampled along windward and leeward transects, and multivariate statistical analysis was used to investigate the composition and community structure of the encrusting community. The following components of the reefs were identified in slabbed and polished reef blocks sampled along each transect: encrusting coralline algae dominated by Porolithon cf. pachydermum, vermetid gastropods, Homotrema rubrum, acervulinid foraminiferans, molluscs, corals, polychaete tubes, clionid sponge borings, polychaete/sipunculid borings, cemented sediments, and growth cavities. Q-mode cluster analysis correctly classified 78% of all windward samples and 69% of all leeward samples, and R-mode separated reef components adapted to high wave energy environments from those adapted to low wave energy. Separate classification and ordination of samples from each transect indicate that seriation breakdown occurs in the windward reef between 25 and 45 m from the reef front. In the leeward reef between 75 and 90 m from the leeward reef front, seriation breakdown was not found to be significant. These results confirm that seriation (zonation) is best developed in the windward reef, as has been documented in coral-dominated reefs. Accepted: 28 February 2000     

Fragment generation, survival, and attachment of Dictyota spp. at Conch Reef in the Florida Keys, USA

During the past decade, the relative abundance of the brown macroalgae Dictyota spp. has been high in the Florida Keys. Recent studies have shown that members of this genus successfully reproduce via vegetative fragmentation. To investigate the importance of fragmentation on the reef community, this study examined: (1) the degree of epiphytism on benthic organisms, (2) the rate of fragment production through fish foraging activities, (3) the likelihood of fragment entanglement, and (4) the fragment attachment and success rate. It was found that reef fish contributed substantially to the fragment pool; furthermore, most fish-produced fragments produced rhizoids and attached to sand grains within 24 h in the field. Fragments of Dictyota spp. most commonly became entangled around and then attached themselves to the green alga Halimeda tuna, and other Dictyota spp. These results suggest that vegetative fragmentation of Dictyota spp. plays an important role in the changing community structure on the Florida Keys reef tract.     

中国新记录穗芽水葱的分类学研究

该文报道了发现于浙江省景宁畲族自治县山地沼泽中的莎草科水葱属一中国新记录种———穗芽水葱(Schoenoplectus gemmifer C. Sato, T. Maeda ＆ Uchino)。该种外形与水毛花相似,但其秆质地较柔软,小穗较短,花柱2,具无性繁殖的穗芽。染色体数目为2n ＝78±2(水毛花的染色体数目为2n ＝44)。文献记载穗芽水葱特产于日本,并被列为日本稀有物种。该种在景宁的发现,对研究中国—日本植物区系具有重要学术价值。     

Cytological and cytochemical investigations of development from dormant gemmules of the marine sponge,Haliclona loosanoffi

Vernalized gemmules of the marine sponge Haliclona loosanoffi were cultured at 20°C, fixed at 24-hour intervals (0–11 days), and processed for light microscopy by using a variety of absorption and fluorescent staining methods. The cytochemistry and morphology of development were compared to the well-studied developmental patterns of freshwater sponges and to the patterns described in the marine sponge Suberites domuncula. The precocious development of H. loosanoffi gemmules involves early morphogenesis occurring within the unhatched gemmule, as opposed to the patterns in freshwater sponges, where most development occurs after the gemmule hatches. Definitive sponge tissue surrounding a single osculum is present 9 days after release from dormancy.