Compositional analysis of bacterial communities in seawater, sediment, and sponges in the Misool coral reef system, Indonesia

Sponge species have been deemed high microbial abundance (HMA) or low microbial abundance (LMA) based on the composition and abundance of their microbial symbionts. In the present study, we evaluated the richness and composition of bacterial communities associated with one HMA sponge (Xestospongia testudinaria; Demospongiae: Haplosclerida: Petrosiidae), one LMA sponge (Stylissa carteri; Demospongiae: Scopalinida - Scopalinidae), and one sponge with a hitherto unknown microbial community (Aaptos suberitoides; Demospongiae: Suberitida: Suberitidae) inhabiting the Misool coral reef system in the West Papua province of Indonesia. The bacterial communities of these sponge species were also compared with seawater and sediment bacterial communities from the same coastal coral reef habitat. Using a 16S rRNA gene barcoded pyrosequencing approach, we showed that the most abundant phylum overall was Proteobacteria. The biotope (sponge species, sediment or seawater) explained almost 84% of the variation in bacterial composition with highly significant differences in composition among biotopes and a clear separation between bacterial communities from seawater and S. carteri; X. testudinaria and A. suberitoides and sediment. The Chloroflexi classes SAR202 and Anaerolineae were most abundant in A. suberitoides and X. testudinaria and both of these species shared several OTUs that were largely absent in the remaining biotopes. This suggests that A. suberitoides is a HMA sponge. Although similar, the bacterial communities of S. carteri and seawater were compositionally distinct. These results confirm compositional differences between sponge and non-sponge biotopes and between HMA and LMA sponges.publishe

The sponge microbiome within the greater coral reef microbial metacommunity

Much recent marine microbial research has focused on sponges, but very little is known about how the sponge microbiome fits in the greater coral reef microbial metacommunity. Here, we present an extensive survey of the prokaryote communities of a wide range of biotopes from Indo-Pacific coral reef environments. We find a large variation in operational taxonomic unit (OTU) richness, with algae, chitons, stony corals and sea cucumbers housing the most diverse prokaryote communities. These biotopes share a higher percentage and number of OTUs with sediment and are particularly enriched in members of the phylum Planctomycetes. Despite having lower OTU richness, sponges share the greatest percentage (>90%) of OTUs with >100 sequences with the environment (sediment and/or seawater) although there is considerable variation among sponge species. Our results, furthermore, highlight that prokaryote microorganisms are shared among multiple coral reef biotopes, and that, although compositionally distinct, the sponge prokaryote community does not appear to be as sponge-specific as previously thought.publishe

More Evidence that Depressive Symptoms Predict Mortality in COPD Patients: Is Type D Personality an Alternative Explanation?

The present study attempted to replicate our previous finding that depressive symptoms are a risk factor for mortality in stable chronic obstructive pulmonary disease (COPD), but in a different population with a different measure of depressive symptoms. We further investigated whether type D personality is associated with mortality in patients with COPD and whether it explains any relationship observed between depressive symptoms and mortality. In 122 COPD patients, mean age 60.8 +/- 10.3 years, 52% female, and mean forced expiratory volume in 1 s (FEV(1)) 41.1 +/- 17.6%pred, we assessed body mass index, post bronchodilator FEV(1), exercise capacity, depressive symptoms with the Hospital Anxiety and Depression Scale, and type D with the Type D Scale. In the 7 years follow-up, 48 (39%) deaths occurred. The median survival time was 5.3 years. Depressive symptoms (hazard ratio = 1.07, 95% confidence intervals = 1.00-1.14) were an independent risk factor for mortality. Type D was not associated with mortality. We can rule out type D as an explanation for the relationship between depressive symptoms and mortality observed in this sample. However, ambiguity remains as to the interpretation of the value of depressive symptoms in predicting death

In Situ Oxygen Dynamics in Coral-Algal Interactions

Background: Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. Methods/Findings: We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300-400 μM during the day. At night, the interface was hypoxic (~70 μM) in coral-turf interactions and close to anoxic (~2 μM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. Conclusions/Significance: Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental conditions in studies on coral stress. © 2012 Wangpraseurt et al

Assessment of variation in bacterial composition among microhabitats in a mangrove environment using DGGE fingerprints and barcoded pyrosequencing

Here, we use DGGE fingerprinting and barcoded pyrosequencing data, at six cut-off levels (85-100%), of all bacteria, Alphaproteobacteria and Betaproteobacteria to assess composition in the rhizosphere of nursery plants and nursery-raised transplants, native plants and bulk sediment in a mangrove habitat. When comparing compositional data based on DGGE fingerprinting and barcoded pyrosequencing at different cut-off levels, all revealed highly significant differences in composition among microhabitats. Procrustes superimposition revealed that ordination results using cut-off levels from 85-100% and DGGE fingerprint data were highly congruent with the standard 97% cut-off level. The various approaches revealed a primary gradient in composition from nursery to mangrove samples. The affinity between the nursery and transplants was greatest when using Betaproteobacteria followed by Alphaproteobacteria data. There was a distinct secondary gradient in composition from transplants to bulk sediment with native plants intermediate, which was most prevalent using all bacteria at intermediate cut-off levels (92-97%). Our results show that PCR-DGGE provides a robust and cost effective exploratory approach and is effective in distinguishing among a priori defined groups.This study was funded by the Deutsche Forschungsgemeinschaft SM59/4-1 and 4-2 (www.dfg.de/en/index.jsp), FAPERJ-Brazil (www.faperj.br), Centre for Environmental and Marine Studies (CESAM, Portugal) (www.cesam.ua.pt), Foundation for Science and Technology (FCT, Portugal) PTDC/AAC-CLI/107916/2008 (http://alfa.fct.mctes.pt) and the European Regional Development Fund (ERDF) through COMPETE- (FCOMP-01-0124-FEDER-008657). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.publishe

Partial mortality in corals overgrown by the sponge Terpios hoshinota at Tioman Island, Peninsular Malaysia (South China Sea)

No abstract is available for this articl

Partial mortality in corals overgrown by the sponge Terpios hoshinota at Tioman Island, Peninsular Malaysia (South China Sea)

No abstract is available for this articl

Partial mortality in corals overgrown by the sponge Terpios hoshinota at Tioman Island, Peninsular Malaysia (South China Sea)

No abstract is available for this articl

Variability in the spatial association patterns of sponge assemblages in response to environmental heterogeneity

Previous work on tropical sponge assemblages has provided strong evidence that sponges coexist on coral reefs through a diversity of positive and negative associations; however, the majority of this work has focused on Caribbean coral reefs. Here, we investigate the intra-phyletic spatial associations between the 20 most abundant sponge species at two sites experiencing different environmental regimes in the Wakatobi National Marine Park, Indonesia. We used a Monte Carlo simulation approach to compare the number of spatial associations between each species pair to that expected if species distribution patterns were non-associative (i.e. random). We found that sponges were predominately randomly distributed at the high coral cover site, whereas most sponges were negatively associated with other sponges at the sedimented, low coral cover site. We also found differences between distribution patterns for specific species at the two sites; a number of species that showed a random distribution pattern at the high coral cover site had negative association patterns at the low coral cover site. Our research supports recent ecological studies suggesting that interactions between species are unlikely to be homogenously distributed, as we found that some sponge species interactions differed depending on the environmental regimes in which they were found; this suggests that species interactions may be spatially variable. Finally, our results contrast with studies from elsewhere, as the sponge assemblages at these two sites in the Wakatobi appear to be dominated by negative associations and random distribution patterns rather than widespread competition