Bryozoan Myriapora Truncata Research Articles

Assessing the erect bryozoan Myriapora truncata (Pallas, 1766) as indicator of recreational diving impact on coralligenous reef communities

Recreational diving effects on Mediterranean benthic communities have been scarcely studied to date. In this study, we evaluate the recreational diving impact on the Mediterranean bryozoan Myriapora truncata. Eight localities with different diving rates and protection levels were sampled before and after summer, the season of maximum presence of divers in the region. A photographic sampling technique was used, which made possible to increase the number of replicates. In each sample: number; mean, maximum and total area; total and mean perimeter and exposure; and aggregation levels of M. truncata colonies were measured by image treatment software. ANOVA, MDS and PERMANOVA were the statistical techniques used to detect and evaluate the effects of the five factors considered (time, protection, impact, locality and site) on M. truncata colonies. The number, area and perimeter of colonies significantly decreased after summer at localities with high presence of divers; whereas hidden colonies went through a positive increase comparing with exposed colonies. Our results evidence M. truncata as a good indicator species for recreational diving impact on coralligenous reef communities. The monitoring of a combination of representative parameters of this species could play an important role on the management of diving areas.

Structural and geochemical alterations in the Mg calcite bryozoan Myriapora truncata under elevated seawater pCO2 simulating ocean acidification

The possible effects of ocean acidification on the calcareous skeleton of the Mediterranean bryozoan Myriapora truncata (Pallas, 1766) were studied by transplanting live and dead colonies into an area of natural volcanic CO2 vents at Ischia (Gulf of Naples, Tyrrhenian Sea), Italy. Morphology and geochemistry were compared between colonies from normal (mean pH = 8.07, min. pH 7.95), below-normal (mean pH 7.66, min. pH 7.32) and acidic (mean pH 7.43, min. pH 6.83) conditions after colonies had been exposed in situ for 45 and 128 days. Both distal (juvenile) and proximal (adult) parts of the branches were investigated. Skeletons of live colonies in acidic pH site after 45 days of exposure were less corroded than those of dead colonies, suggesting that the organic tissues enveloping the skeleton play a protective role. Colonies remained alive at the below-normal and acidic pH sites during the 45-day experiment but corrosion was very striking after 128 days, with colonies from the acidic site showing significant loss of skeleton. Compared to the control, these colonies also had lower levels of Mg (mean 8 versus 9.5 wt% Mg) within their skeletons. Electron microprobe mapping showed Mg to be higher in the outer layers of the skeletal walls in colonies from the normal pH site. Corrosion of outer layers of the walls probably explains the lower Mg level found in colonies exposed to acidic conditions. As solubility of calcite increases with Mg content, the enrichment of Mg in outer layers of the skeleton should enhance the vulnerability of Myriapora truncata to dissolution. These findings raise concerns over the survival of bryozoans with Mg calcite skeletons in the face of predicted decreases in oceanic pH levels.

Effects of ocean acidification and high temperatures on the bryozoan Myriapora truncata at natural CO2 vents

AbstractThere are serious concerns that ocean acidification will combine with the effects of global warming to cause major shifts in marine ecosystems, but there is a lack of field data on the combined ecological effects of these changes due to the difficulty of creating large‐scale, long‐term exposures to elevated CO2 and temperature. Here we report the first coastal transplant experiment designed to investigate the effects of naturally acidified seawater on the rates of net calcification and dissolution of the branched calcitic bryozoan Myriapora truncata (Pallas, 1766). Colonies were transplanted to normal (pH 8.1), high (mean pH 7.66, minimum value 7.33) and extremely high CO2 conditions (mean pH 7.43, minimum value 6.83) at gas vents off Ischia Island (Tyrrhenian Sea, Italy). The net calcification rates of live colonies and the dissolution rates of dead colonies were estimated by weighing after 45 days (May–June 2008) and after 128 days (July–October) to examine the hypothesis that high CO2 levels affect bryozoan growth and survival differently during moderate and warm water conditions. In the first observation period, seawater temperatures ranged from 19 to 24 °C; dead M. truncata colonies dissolved at high CO2 levels (pH 7.66), whereas live specimens maintained the same net calcification rate as those growing at normal pH. In extremely high CO2 conditions (mean pH 7.43), the live bryozoans calcified significantly less than those at normal pH. Therefore, established colonies of M. truncata seem well able to withstand the levels of ocean acidification predicted in the next 200 years, possibly because the soft tissues protect the skeleton from an external decrease in pH. However, during the second period of observation a prolonged period of high seawater temperatures (25–28 °C) halted calcification both in controls and at high CO2, and all transplants died when high temperatures were combined with extremely high CO2 levels. Clearly, attempts to predict the future response of organisms to ocean acidification need to consider the effects of concurrent changes such as the Mediterranean trend for increased summer temperatures in surface waters. Although M. truncata was resilient to short‐term exposure to high levels of ocean acidification at normal temperatures, our field transplants showed that its ability to calcify at higher temperatures was compromised, adding it to the growing list of species now potentially threatened by global warming.

Epibiotic Vibrio Luminous Bacteria Isolated from Some Hydrozoa and Bryozoa Species

Luminous bacteria are isolated from both Hydrozoa and Bryozoa with chitinous structures on their surfaces. All the specimens of the examined hydroid species (Aglaophenia kirchenpaueri, Aglaophenia octodonta, Aglaophenia tubiformis, Halopteris diaphana, Plumularia setacea, Ventromma halecioides), observed under blue light excitation, showed a clear fluorescence on the external side of the perisarc (chitinous exoskeleton) around hydrocladia. In the bryozoan Myriapora truncata, luminous bacteria are present on the chitinous opercula. All the isolated luminous bacteria were identified on the basis of both phenotypic and genotypic analysis. The isolates from A. tubiformis and H. diaphana were unambiguously assigned to the species Vibrio fischeri. In contrast, the isolates from the other hydroids, phenotypically assigned to the species Vibrio harveyi, were then split into two distinct species by phylogenetic analysis of 16S rRNA gene sequences and DNA-DNA hybridization experiments. Scanning electron microscopy analysis and results of culture-based and culture-independent approaches enabled us to establish that luminous vibrios represent major constituents of the bacterial community inhabiting the A. octodonta surface suggesting that the interactions between luminous bacteria and the examined hydrozoan and bryozoan species are highly specific. These interactions might have epidemiological as well as ecological implications because of the opportunistic pathogenicity of luminous Vibrio species for marine organisms and the wide-distribution of the hydrozoan and bryozoan functioning as carriers.

Morphology of the larva and ancestrula of Myriapora truncata (Bryozoa, Cheilostomatida)

During an essay to rear in aquarium some colonies of the Mediterranean erect bryozoan Myriapora truncata (Gymnolaemata, Cheilostomatida, Ascophorina, Myriaporidae) it was possible to study its larval and ancestrular morphology by scanning electron microscope (SEM) and by light microscope. The different phases of metamorphosis, giving origin to the preancestrula and the ancestrula, were also investigated. The larva of M. truncata is short‐lived, lecithotrophic, and of the coronate type, with expanded corona and small pallial sinus (AEO/ps type, according to Zimmer & Woollacott; VB type, according to d'Hondt). Its morphology, life and metamorphosis appear very similar to those of other well described cheilostome larvae (Neocheilostomida sensu d'Hondt). But, unlike in the other known species of this group, the ancestrula derived from metamorphosis is an ‘ancestrular twin’, in which two zooids simultaneously develop; these can form in two possible reciprocal orientations (same—ipsolateral—or opposite—contralateral—in the direction of growth).

The Mediterranean bryozoan Myriapora truncata (): a potential indicator of (palaeo-) environmental conditions

Fossil and Recent specimens of the Mediterranean bryozoan Myriapora truncata show considerable intra- and intercolonial differences in branch diameter and zooid size. Statistically significant variability occurs within colonies, between colonies within sites, and between sampled sites, while the presence of intracolonial variability clearly shows that branch diameter is largely controlled by environmental parameters. The three structural traits measured (branch diameter, zooid size and zooid depth) do not correlate, thus indicating a disconnection between the controls on overall zooid size and branch diameter. Possible environmental parameters that may have an influence on morphology are temperature, food supply or current energy. Whereas current energy has an effect on the colony branching pattern (branch spacing), there are indications that temperature may be the main, but not the only, parameter controlling zooid size, and it is suggested that food supply largely determines the branch diameter in M. truncata. However, the identification of the decisive factors and quantification of the relationships between environmental and morphological change is beyond the scope of this study. The results nevertheless show that, if the control factors of morphological variability can be ascertained in Recent M. truncata, this species may prove to be an indicator of environmental conditions and their change at different spatial and temporal scales in Cenozoic to Recent Mediterranean habitats.

Myriaporones 1−4, Cytotoxic Metabolites from the Mediterranean Bryozoan Myriapora truncata

Four novel polyketide-derived metabolites, myriaporones 1, 2, 3, and 4, have been isolated from the Mediterranean bryozoan Myriapora truncata. Their structures and stereochemistry have been assigned from the analysis of spectroscopic data. The inseparable equilibrium mixture of myriaporones 3 and 4 showed 88% inhibition of L1210 murine leukemia cells at 0.2 microg/mL.

Synthesis of 24-ethylcholesta-7, 22E-diene-3β, 5β-triol — A natural trihydroxysteroid from the bryozoan Myriapora truncata

24-Ethylcholesta-7, 22E-diene-3β,5α,6β-triol — a natural trihydroxysteroid from the bryozoanMyriapora truncata — has been synthesized from stigmasterol.

3β,5α,6β-Trihydroxysterols from the Mediterranean Bryozoan Myriapora truncata

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT3β,5α,6β-Trihydroxysterols from the Mediterranean Bryozoan Myriapora truncataFrancesco Cafieri, Ernesto Fattorusso, Margherita Gavagnin, and Ciro SantacroceCite this: J. Nat. Prod. 1985, 48, 6, 944–947Publication Date (Print):November 1, 1985Publication History Published online1 July 2004Published inissue 1 November 1985https://doi.org/10.1021/np50042a010RIGHTS & PERMISSIONSArticle Views325Altmetric-Citations39LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (297 KB) Get e-Alerts Get e-Alerts