Sponge–seaweed associations in species of Ptilophora (Gelidiaceae, Rhodophyta)

Sponge–seaweed associations in the seaweed genus Ptilophora are poorly understood; therefore, 94 specimens, representing all 17 species of Ptilophora, were examined to detail this phenomenon. All but 2 Ptilophora species were shown to produce surface proliferations, with 13 species found to have sponge associations. Evidence for facultative sponge epiphytism was found with species–specific interactions being unlikely. Results show that surface proliferations are not induced by sponge epiphytes, as they often occur in the absence of sponge epiphytes, and vice versa. The significant number of proliferate thalli found with sponge epiphytes suggests that there is a likely relationship between the presence of surface proliferations and sponge infestation. Sponge epiphytes and Ptilophora species appeared structurally related in that the sponge probably exploits a niche habitat provided by the alga, for which surface proliferations might aid the sponge in bonding to the alga.     

Consistent Bacterial Community Structure Associated with the Surface of the Sponge Mycale adhaerens Bowerbank

As a crucial step in the identification of possible association between bacteria and sponges, we investigated if a unique bacterial population community was consistently associated with the surface of the sponge Mycale adhaerens, irrespective of environmental conditions. The composition of bacterial communities associated with the surface of sponges at three geographically distinctive sites in Hong Kong waters over four seasons was examined by analyzing terminal restriction fragment length polymorphism of the bacterial 16S rRNA genes. Statistical analysis indicated that bacterial communities on inanimate reference surfaces (polystyrene dishes deployed in the close vicinity of the sponge colonies for 7 days) had a relatively high degree of both site and seasonal specificities (R statistics of pairwise comparisons ∼1), which might be attributed to the differences in environmental conditions at different sites and seasons. On the contrary, the sponge-surface-associated bacterial communities from different sites and seasons were hardly distinguishable from each other (lowest R = −0.16) but were rather distinctive from the reference bacterial communities (R ∼ 1), suggesting a highly stable and distinctive bacteria–sponge association irrespective of the environmental conditions. The occurrence of some unique bacterial types in the sponge-surface-associated communities over space and time suggests that the associations are consistent and specific.     

Specificity of larval settlement of the Caribbean Orange Icing Sponge,Mycale laevis

The Caribbean sponge Mycale laevis is often found growing in close proximity to living scleractinian corals. This commonly observed sponge–coral association has been considered a mutualism, with the coral providing substratum for the sponge, and the sponge protecting the coral skeleton from boring organisms. We examined the specificity of sponge recruitment to live corals, expecting a positive and specific settlement response if a mutualism exists. Benthic surveys conducted off Key Largo, Florida, and Bocas del Toro, Panama, revealed that individuals of M. laevis grew on substrata that included dead coral and other species of sponges. Selectivity analysis indicated that at three of the four survey sites, M. laevis was not randomly distributed, but associated with live corals more frequently than expected from proportional coral cover. However, settlement assays demonstrated that larvae of M. laevis did not preferentially respond to the presence of live coral. We have previously demonstrated that adults of M. laevis are chemically undefended and readily eaten by spongivorous fishes unless protected by adjacent substrata such as live corals. In overfished areas, where spongivore density is low, the sponge is not selectively distributed near corals. Initial results of settlement experiments with different substrata suggested that larvae of M. laevis responded positively to the presence of the chemically defended sponge Amphimedon compressa, perhaps indicating an associational defense. Further experiments revealed that larvae were reacting to artificially high concentrations of exudates from cut surfaces of Am. compressa; settlement was not enhanced in response to healed pieces of Am. compressa. In addition, the larvae of M. laevis did not selectively respond to live coral or to chemically defended heterospecifics. These results indicate that the commonly observed proximity of M. laevis to live corals is not driven by larval settlement behavior, but instead by post‐settlement mortality due to predation.     

Impact of an invasive alga (Womersleyella setacea) on sponge assemblages: compromising the viability of future populations

The effects of invasive species on native fauna are understudied, even though their consequences should be taken into consideration for the proper conservation and management of marine systems. Furthermore, bioinvasions may have greater consequences if they affect key structural species with slow dynamics such as marine sponges. We propose that reproductive output could be used as a potential early warning signal to detect possible future changes in population trends of long-lived species (i.e. sponges) as a result of biological invasions. The aim of this study was to investigate the effects of invasive algal (Womersleyella setacea) overgrowth on sponge reproduction by comparing the presence of reproductive elements (spermatic cysts, oocytes, embryos, and larvae) in sponges covered by a thick carpet of the invasive algae and in sponges dwelling in the same habitat but without the invasive algae. Three variables were calculated to assess the impact of the invasive alga on sponge reproduction: the reproductive effort, the proportion of individuals in reproduction, and the size of the reproductive structures. We studied eight sponge species representing the main components of the deep rocky reefs of the area. Our results showed that W. setacea had a strong negative effect on sponge reproduction in six out of eight sponge species studied, with lower and even nil reproductive structures on the sponges subjected to the algal overgrowth. Thus, considering that sexual reproduction is necessary for the persistence of most sponge populations, a significant and constant reduction of the reproductive effort may compromise their viability and affect future trends in these benthic systems.     

Induction of apoptosis by the marine sponge (Mycale) metabolites, mycalamide A and pateamine

The marine sponge metabolites mycalamide A (myca-lamide) and pateamine are extremely cytotoxic. While mycalamide has been shown to inhibit protein synthesis, the mechanism by which these compounds induce cell death is unknown. Using DNA laddering, Annexin-V staining, and morphological analysis, we demonstrate that both metabolites induce apoptosis in several different cell lines. Furthermore, both mycalamide and pateamine were more potent inducers of apoptosis in the 32D myeloid cell line after transformation with either the ras or bcr-abl oncogenes. This increased sensitivity was also observed in response to the protein synthesis inhibitors cycloheximide and puromycin, and cytosine--D-arabinofurano-side (Ara-C), an inducer of DNA damage. We propose, therefore, that in 32D cells where Ras signalling has been altered either by constitutive expression of oncogenic ras or by Bcr/abl-mediated perturbation of upstream signalling events, increased susceptibility to apoptosis by a range of stimuli is conferred.     

CERATODICTYON SPONGIOSUM (RHODOFHYTA), THE MACROALGAL PARTNER IN AN ALGA-SPONGE SYMBIOSIS,GROWN IN UNIALGAL CULTURE12

The marine alga Ceratodictyon spongiosum Zanardini, known only in nature in symbiotic association with a haplosclerid sponge, was isolated into unialgal culture for the first time. Protracted vegetative development took place in simple inorganic medium in the absence of the sponge. Cultured specimens transplanted into the field have not survived.     

Molecular detection of fungal communities in the Hawaiian marine sponges Suberites zeteki and Mycale armata

Symbiotic microbes play a variety of fundamental roles in the health and habitat ranges of their hosts. While prokaryotes in marine sponges have been broadly characterized, the diversity of sponge-inhabiting fungi has barely been explored using molecular approaches. Fungi are an important component of many marine and terrestrial ecosystems, and they may be an ecologically significant group in sponge-microbe interactions. This study tested the feasibility of using existing fungal primers for molecular analysis of sponge-associated fungal communities. None of the eight selected primer pairs yielded satisfactory results in fungal rRNA gene or internal transcribed spacer (ITS) clone library constructions. However, 3 of 10 denaturing gradient gel electrophoresis (DGGE) primer sets, which were designed to preferentially amplify fungal rRNA gene or ITS regions from terrestrial environmental samples, were successfully amplified from fungal targets in marine sponges. DGGE analysis indicated that fungal communities differ among different sponge species (Suberites zeteki and Mycale armata) and also vary between sponges and seawater. Sequence analysis of DGGE bands identified 23 and 21 fungal species from each of the two sponge species S. zeteki and M. armata, respectively. These species were representatives of 11 taxonomic orders and belonged to the phyla of Ascomycota (seven orders) and Basidiomycota (four orders). Five of these taxonomic orders (Malasseziales, Corticiales, Polyporales, Agaricales, and Dothideomycetes et Chaetothyriomcetes incertae sedis) have now been identified for the first time in marine sponges. Seven and six fungal species from S. zeteki and M. armata, respectively, are potentially new species because of their low sequence identity (< or =98%) with their references in GenBank. Phylogenetic analysis indicated sponge-derived sequences were clustered into "marine fungus clades" with those from other marine habitats. This is the first report of molecular analysis of fungal communities in marine sponges, adding depth and dimension to our understanding of sponge-associated microbial communities.     

Phenotypic variability in the Caribbean Orange Icing sponge Mycale laevis (Demospongiae: Poecilosclerida)

Sponge species may present several morphotypes, but sponges that are morphologically similar can be separate species. We investigated morphological variation in Mycale laevis, a common Caribbean reef sponge. Four morphotypes of M. laevis have been observed (1) orange, semi-cryptic, (2) orange, massive, (3) white, semi-cryptic, and (4) white, massive. Samples of M. laevis were collected from Key Largo, Florida, the Bahamas Islands, and Bocas del Toro, Panama. Fragments of the 18S and 28S rRNA ribosomal genes were sequenced and subjected to phylogentic analyses together with sequences obtained for 11 other Mycale species and additional sequences retrieved from GenBank. Phylogenetic analyses confirmed that the genus Mycale is monophyletic within the Order Poecilosclerida, although the subgenus Aegogropila is polyphyletic and the subgenus Mycale is paraphyletic. All 4 morphotypes formed a monophyletic group within Mycale, and no genetic differences were observed among them. Spicule lengths did not differ among the 4 morphotypes, but the dominant megasclere in samples collected from Florida and the Bahamas was the strongyle, while those from Panama had subtylostyles. Our data suggest that the 4 morphotypes constitute a single species, but further studies would be necessary to determine whether skeletal variability is due to phentotypic or genotypic plasticity.     

The diversity of relationships between Antarctic sponges and diatoms: the case of Mycale acerata Kirkpatrick, 1907 (Porifera,Demospongiae)

The diatom assemblage associated with the Antarctic sponge Mycale acerata was studied through an analysis of the diatom frustule and pigment concentrations in both the sponge ectosome and choanosome. Sponges were sampled weekly from November 2001 to February 2002 at Terra Nova Bay, Antarctica, at a depth of 25–35 m. The most abundant diatoms were Porannulus contentus, Fragilariopsis curta, Thalassiosira cf. gracilis, T. perpusilla and Plagiotropis sp. High abundances of P. contentus were found on the sponge ectosome up to the beginning of November, before the ice melted, while later frustules were incorporated inside, indicating that P. contentus lives epibiontically on M. acerata and represents a potential food source for the sponge. The presence of other diatom species was mainly related to the summer phytoplankton bloom. The sponge incorporates diatoms from the water column and utilises them as a food source, accumulating frustules inside the choanosome. The lack of planktonic diatom frustules at the beginning of the summer indicates that they are expelled or dissolved during the cold season.     

Haramonas pauciplastida sp. nov. (Raphidophyceae, Heterokontophyta) and phylogenetic analyses of Haramonas species using small subunit ribosomal RNA gene sequences

A new species of the Raphidophyceae, Haramonas pauciplastida sp. nov. from Canada is described. The genus Haramonas has been described based on the type species Haramonas dimorpha and currently only two species are known. This new alga belongs to the genus because it possesses a tubular invagination at the posterior end of the cell, producing a large amount of mucilage and generating both motile and non-motile phases in its life cycle. The chloroplast color of H. pauciplastida is yellowish green, and is similar to that of Haramonas viridis Horiguchi et Hoppenrath . However, this alga differs from the other species of the genus in that it possesses fewer chloroplasts, which are rarely overlapping. The ultrastructual study shows differences between these two species in the number of thylakoids in the lamella, the presence of a scattered pyrenoid matrix, and the position of the plastoglobuli. The phylogenetic analyses of the small subunit ribosomal RNA gene from the Haramonas species reveal that three species can be distinguished genetically from each other and they form a robust clade in the Raphidophyceae. This result supports the notion that the characteristic features of Haramonas are synapomorphies. This is the first report of molecular data from the Haramonas species.     

Upper Triassic (Norian) hypercalcified sponges from the Musandam Peninsula (United Arab Emirates and Oman)

Supercalcified sponges, including sphinctozoans, inozoans, chaetetids, spongiomorphids, occurring in Upper Triassic (Norian-Rhaetian) shallow-marine limestones of Musandam Mountains in United Arab Emirates (UAE), are described. The following taxa were determined: sphinctozoans: Hajarispongia osmani Senowbari-Daryan and Yancey, Nevadathalamia arabica n. sp., Nevadathalamia conica n. sp., Fanthalamia milahaensis n. sp., Iranothalamia incrustans (Boiko), Cinnabaria regularis n. sp.; inozoans: Cavsonella triassica n. sp., Molengraaffia regularis Vinassa de Regny, Peronidella? sp., Circopora cf. caucasica Moiseev, Circopora? sp.; spongiomorphids: Spongiomorpha sp.; chaetetids: Lovcenipora chaetetiformis Vinassa de Regny, Lovcenipora musandamensis n. sp., Lovcenipora sp., chaetetid sponge gen. et sp. indet. The most abundant sponge in the studied material is Nevadathalamia arabica n. sp. The described sponge association of the Arabian shelf (Musandam Mountains) shows close affinity to the sponge association known from age-equivalent terranes in the Panthalassa Ocean (Sonora Mountains in Mexico; Pilot Mountains in Nevada, USA), but is remarkably different from sponge associations in carbonates bordering the Tethys. This difference goes along with the biogeography of wallowaconchid bivalves and is most likely attributed to climatic, palaeogeographic or oceanographic factors.     

Copepods of the genus Asterocheres (Copepoda: Siphonostomatoida) feeding on sponges: behavioral and ecological traits

Abstract. Four copepod species of the genus Asterocheres (A. echinicola, A. latus, A. suberitis and A. complexus ) are recorded for the first time as associated with Mediterranean sponges of the classes Calcarea and Demospongiae (orders Dictyoceratida, Dendroceratida, and Poecilosclerida). Individuals of A. suberitis are described for the first time as inhabiting sponges other than Suberites domuncula . The copepods seemed to use their trunk to suck the material (cuticles or excreted cells) produced at the sponge periphery (ectosome), which indicates that their feeding habits are similar to those observed in species of the same genus that feed on exfoliated tissues of echinoderms. In the laboratory, copepods fed on young sponges (rhagons) of the species Crambe crambe, Cacospongia mollior , and Dysidea avara without reducing the rhagon biomass. In contrast, rhagons of the species Haliclona sp., Hymedesmia spp., and Phorbas tenacior were consumed and their biomass reduced. This may be because the latter group does not produce external proteinaceous material. Copepod offspring were continuously released (∼6 nauplii every 48 h) and the larval stages were capable of limited swimming. We found significantly more copepods over the surface of the sponges than inside them. Copepod abundance was positively correlated with the sponge surface area while not with the sponge biomass. These results indicate that the copepods live preferentially over the sponge surface and that their abundance is surface-area dependent. The behavioral traits described here indicate that the interactions between asterocherid species and sponges are worthy of future study.     

Studies on inoculation of aerial algae. I. Semi-mass culture and quantification of algal color of Klebsormidium flaccidum (Ulotrichales, Chlorophyceae) sprayed on to concrete board

This paper describes methods of semi-mass culture and the quantification of algal color sprayed on a concrete board of the alga Klebsormidium flaccidum (Küitzing) S. Mattox et Blackwell. The alga was cultured in 100 L tanks normally used for hatching brine shrimp, with aeration from the deepest parts of the slanting sides. Initially mean algal density increased rapidly and attained 9.1 times the original density after 4 weeks. Subsequently, increase of the algal density was slow, and the density became 16.1 times the original level after 8 weeks. The alga cultured in this study was sprayed on to a concrete board using an agricultural sprayer. The relationship between the algal density on the board and its color, expressed as L*a*b* color space, was quantified. The chromaticity was maximum as the algal density on the board was about 5 g/m², and the color was most vivid. When the algal density was more than 20 g/m², both the lightness and chromaticity changed slightly, and the color became dark green.     

Allelopathy in the tropical alga Lobophora variegata (Phaeophyceae): mechanistic basis for a phase shift on mesophotic coral reefs?

Macroalgal phase shifts on Caribbean reefs have been reported with increasing frequency, and recent reports of these changes on mesophotic coral reefs have raised questions regarding the mechanistic processes behind algal population expansions to deeper depths. The brown alga Lobophora variegata is a dominant species on many shallow and deep coral reefs of the Caribbean and Pacific, and it increased in percent cover (>50%) up to 61 m on Bahamian reefs following the invasion of the lionfish Pterois volitans. We examined the physiological and ecological constraints contributing to the spread of Lobophora on Bahamian reefs across a mesophotic depth gradient from 30 to 61 m, pre‐ and post‐lionfish invasion. Results indicate that there were no physiological limitations to the depth distribution of Lobophora within this range prior to the lionfish invasion. Herbivory by acanthurids and scarids in algal recruitment plots at mesophotic depths was higher prior to the lionfish invasion, and Lobophora chemical defenses were ineffective against an omnivorous fish species. In contrast, Lobophora exhibited significant allelopathic activity against the coral Montastraea cavernosa and the sponge Agelas clathrodes in laboratory assays. These data indicate that when lionfish predation on herbivorous fish released Lobophora from grazing pressure at depth, Lobophora expanded its benthic cover to a depth of 61 m, where it replaced the dominant coral and sponge species. Our results suggest that this chemically defended alga may out‐compete these species in situ, and that mesophotic reefs may be further impacted in the near future as Lobophora continues to expand to its compensation point.     

Grammephora peyssonnelioides gen. et sp. nov. (Rhodophyta, Rhodymeniaceae) from the Solomon Islands, South Pacific

A new genus and species of red alga in the Rhodymeniaceae, Grammephora peyssonnelioides, is described from both shallow and deepwater habitats in the Solomon Islands, South Pacific. The new genus and species is characterized by prostrate overlapping lobes with a strongly cartilaginous flexible texture, distinct surface linear markings perpendicular to the growing margins, and a compact three to four celled medulla of relatively small refractive cells. Tetrasporangia are elongate and decussately divided, and occur in large scattered dorsal surface sori. Cystocarps are prominent and conical, on the dorsal surface of the blade, with a network of nutritive filaments and basal nutritive tissue around the suspended, centrally located carposporophyte, with all gonimoblast initials becoming carposporangia. The columnar fusion cell is uniquely crowned by a ring of discoid cells of nonalgal origin.     

Protein-mediated adhesion of the dissimilatory Fe(III)-reducing bacterium Shewanella alga BrY to hydrous ferric oxide.

The rate and extent of bacterial Fe(III) mineral reduction are governed by molecular-scale interactions between the bacterial cell surface and the mineral surface. These interactions are poorly understood. This study examined the role of surface proteins in the adhesion of Shewanella alga BrY to hydrous ferric oxide (HFO). Enzymatic degradation of cell surface polysaccharides had no effect on cell adhesion to HFO. The proteolytic enzymes Streptomyces griseus protease and chymotrypsin inhibited the adhesion of S. alga BrY cells to HFO through catalytic degradation of surface proteins. Trypsin inhibited S. alga BrY adhesion solely through surface-coating effects. Protease and chymotrypsin also mediated desorption of adhered S. alga BrY cells from HFO while trypsin did not mediate cell desorption. Protease removed a single peptide band that represented a protein with an apparent molecular mass of 50 kDa. Chymotrypsin removed two peptide bands that represented proteins with apparent molecular masses of 60 and 31 kDa. These proteins represent putative HFO adhesion molecules. S. alga BrY adhesion was inhibited by up to 46% when cells were cultured at sub-MICs of chloramphenicol, suggesting that protein synthesis is necessary for adhesion. Proteins extracted from the surface of S. alga BrY cells inhibited adhesion to HFO by up to 41%. A number of these proteins bound specifically to HFO, suggesting that a complex system of surface proteins mediates S. alga BrY adhesion to HFO.     

The extensive development of the turf-forming red alga Womersleyella setacea (Hollenberg) R. E. Norris (Rhodophyta,Ceramiales) in the Bay of Boka Kotorska,Montenegro (southern Adriatic Sea)

Abstract

In August 2003, dense turfs formed by the filamentous red alga Womersleyella setacea (Hollenberg) R. E. Norris were found in the open part of the Bay of Boka Kotorska, on the shore of Montenegro (southern Adriatic Sea). The habitat and morphology of the alga are described and the impact of the massive development of this species on the structure of the algal communities is discussed.     

Observations on a new species of Symphyonemopsis Tiwari & Mitra,viz. S. Pantii n. sp. (Cyanophyta,Stigonematales)

The paper describes the morphology and reproduction of a new species of Symphyonemopsis viz. S. pantii n. sp. isolated from enrichment cultures of a soil sample collected from the campus of Sangeet Samiti, Allahabad (India). Thalli grow as dark blue-green, small, wooly patches on soil surface but as cushion-like growths on agar plates. It has a prostrate and erect system. The latter bears secondary branches of almost equal breadth. It possesses both false and true branches. Usually true branches are reverse V-shaped. The alga shows formation of hormocysts and akinetes. In old cultures usually the main filament becomes multiseriate. The crescent-shaped stages of hormocysts are also present here. Cells of the present alga are constricted at the cross-walls On comparison it was found to come close to Symphyonemopsis katniensis Tiwari et Mitra but differs in certain fundamental characters. It is, therefore, described as a new species viz. S. pantii n. sp. (Cyanophyta, Stigonematales, Mastigocladaceae).     

Unionicola (Pentatax) billieaehonore n. sp. a sponge-associated Hydracarina (Acari: Unionicolidae) from New Zealand

Abstract

Records of sponge-associated Hydracarina from the Southern Hemisphere are uncommon. Unionicola (Pentatax) billieaehonore n. sp. has been found in association with the freshwater sponge Ephydatia kakahuensis in Lake Rotoiti (North Island) and Lake Taupo in New Zealand. Differences in palpal characteristics and in setal patterns of the epimera distinguish this species from the holotype of Unionicola longiseta Walter 1915 which was reported from New Zealand by Schröder (1935).     

Role of Hydrophobicity in Adhesion of the Dissimilatory Fe(III)-Reducing Bacterium Shewanella alga to Amorphous Fe(III) Oxide

The mechanisms by which the dissimilatory Fe(III)-reducing bacterium Shewanella alga adheres to amorphous Fe(III) oxide were examined through comparative analysis of S. alga BrY and an adhesion-deficient strain of this species, S. alga RAD20. Approximately 100% of S. alga BrY cells typically adhered to amorphous Fe(III) oxide, while less than 50% of S. alga RAD20 cells adhered. Bulk chemical analysis, isoelectric point analysis, and cell surface analysis by time-of-flight secondary-ion mass spectrometry and electron spectroscopy for chemical analysis demonstrated that the surfaces of S. alga BrY cells were predominantly protein but that the surfaces of S. alga RAD20 cells were predominantly exopolysaccharide. Physicochemical analyses and hydrophobic interaction assays demonstrated that S. alga BrY cells were more hydrophobic than S. alga RAD20 cells. This study represents the first quantitative analysis of the adhesion of a dissimilatory Fe(III)-reducing bacterium to amorphous Fe(III) oxide, and the results collectively suggest that hydrophobic interactions are a factor in controlling the adhesion of this bacterium to amorphous Fe(III) oxide. Despite having a reduced ability to adhere, S. alga RAD20 reduced Fe(III) oxide at a rate identical to that of S. alga BrY. This result contrasts with results of previous studies by demonstrating that irreversible cell adhesion is not requisite for microbial reduction of amorphous Fe(III) oxide. These results suggest that the interaction between dissimilatory Fe(III)-reducing bacteria and amorphous Fe(III) oxide is more complex than previously believed.