Search Results (8)

To date, only a few microbial community studies of cold seeps at the South China Sea (SCS) have been reported. The cold seep dominated by tubeworms was discovered at South Yungan East Ridge (SYER) offshore southwestern Taiwan by miniROV. The tubeworms were identified and proposed as Paraescarpia formosa sp. nov. through morphological and phylogenetic analyses. The endosymbionts in the trunk of P. formosa analyzed by a 16S rRNA gene clone library represented only one phylotype, which belonged to the family Sedimenticolaceae in Gammaproteobacteria. In addition, the archaeal and bacterial communities in the habitat of tubeworm P. formosa were investigated by using high-phylogenetic-resolution full-length 16S rRNA gene amplicon sequencing. The results showed that anerobic methane-oxidizing archaea (ANME)-1b was most abundant and ANME-2ab was minor in a consortia of the anerobic oxidation of methane (AOM). The known sulfate-reducing bacteria (SRB) partners in AOM consortia, such as SEEP-SRB1, -SRB2, and -SRB4, Desulfococcus and Desulfobulbus, occurred in a small population (0–5.7%) at the SYER cold seep, and it was suggested that ANME-1b and ANME-2ab might be coupled with multiple SRB in AOM consortia. Besides AOM consortia, various methanogenic archaea, including Bathyarchaeota (Subgroup-8), Methanocellales, Methanomicrobiales, Methanosarcinales, Methanofastidiosales and Methanomassiliicoccales, were identified, and sulfur-oxidizing bacteria Sulfurovum and Sulfurimonas in phylum Epsilonbacteraeota were dominant. This study revealed the first investigation of microbiota in and around tubeworm P. formosa discovered at the SYER cold seep offshore southwestern Taiwan. We could gain insights into the chemosynthetic communities in the deep sea, especially regarding the cold seep ecosystems at the SCS. Full article

Spirorbinae, a ubiquitous group of marine calcareous tubeworms with a small body size as adults, have a fascinating diversity of brooding modes that form the basis for their taxonomic division into six tribes (traditionally subfamilies): in-tube incubation, with varying degrees of attachment to adult structures (four tribes), and external incubation in a modified radiole (opercular brood chambers; two tribes). We investigated the evolutionary transitions among these brooding modes. Phylogenetic reconstruction with molecular (28s and 18s rDNA) and morphological data (83 characters) among 36 taxa (32 ingroup spirorbins; 4 filogranin outgroups) of the combined data set, using maximum parsimony, maximum likelihood, and Bayesian analyses, inferred Spirorbinae to be monophyletic, with strong support for the monophyly for five tribes (Circeini, Januini, Romanchellini, Paralaeospirini and Spirorbini), but non-monophyly for Pileolariini. However, deeper relationships among some tribes remain unresolved. Neomicrorbis was found to be the sistergroup to all other Spirorbinae. Alternative coding strategies for assessing the ancestral state reconstruction for the reproductive mode allowed for a range of conclusions as to the evolution of tube and opercular brooding in Spirorbinae. Two of the transformations suggest that opercular brooding may be ancestral for Spirorbinae, and the tube-incubating tribes may have been derived independently from opercular-brooding ancestors. Full article

There is a controversy involved in the models of the formation of serpulid tube microstructures, which either have been formed in similar ways to molluscan structures or in an alternative, unique serpulid way. A scanning electron microscope (SEM) study of the tube microstructure of Crucigera zygophora has been performed. A new serpulid tube microstructure, an aggregative SIOP, has been discovered in C. zygophora, herein termed ASIOP. During the first phase of crystallization, the sparsely located nuclei of the ASIOP structure formed, and in the second phase of crystal growth, the nucleation of spherultic sectors took place on the surface of preformed nuclei. The ASIOP structure differs from SIOP by more sparsely located crystallisation centres (nuclei) and the slower formation (i.e., crystallisation) of basic units. The formation of the ASIOP structure cannot be fully explained by the classical carbonate slurry model. Future comparative studies should show whether molluscan crossed spindle-like structures and serpulid SIOP structures are structural analogues. Full article

Xyloplax is a genus of three species of sea stars previously found only on sunken wood in the deep ocean. Their circular and petaloid bodies, which lend them their common name “sea daisy”, and their presumed exclusive diet of wood make them an unusual and rare element of deep-sea ecosystems. We describe here the fourth species of Xyloplax from the eastern Pacific Ocean, Xyloplax princealberti n. sp., which ranges from offshore Canada to the Gulf of California (Mexico) and Costa Rica. Though sampled geographically close to another described species of Xyloplax from the northeastern Pacific, X. janetae, this new species is unique morphologically and according to available DNA data. The short abactinal spines are the most obvious feature that distinguishes X. princealberti n. sp. from other Xyloplax. The minimum distance for mitochondrial cytochrome c oxidase subunit I from Xyloplax princealberti n. sp. to the only other available Xyloplax, X. janetae, was 13.5%. We also describe Ridgeia vestimentiferan tubeworm bushes from active hydrothermal vents as a new Xyloplax habitat, the first record of a non-wood substrate, and a new reproductive strategy, simultaneous hermaphroditism, for this genus. We generated the first mitochondrial genome for a member of Xyloplax and analyzed it with other available asteroid data using nucleotide-coding or amino acid (for protein-coding genes) plus nucleotide coding (for rRNA genes). The nucleotide-coding results place Xylopax as part of the clade Velatida, consistent with a previous phylogenomic analysis that included Xyloplax princealberti n. sp. (as Xyloplax sp.), though the placement of Velatida within Asteroidea differed. The amino acid plus nucleotide coding recovered Velatida to be a grade with X. princealberti n. sp. as sister group to all other Asteroidea. Full article

An increase in population along the Indian River Lagoon has led to eutrophication, a decline in water quality, and overall degradation. The Living Docks program is a citizen–science initiative started at the Florida Institute of Technology for lagoon restoration. Public and private docks are volunteered to become Living Docks, where oyster mats are attached to dock pilings to provide a natural substrate for benthic organism growth. The community development on the oyster mats boosts water filtration to improve overall water quality and combat anthropogenic effects on the lagoon. The purpose of this project was to model benthic settlement and recruitment of prominent organisms on the Living Dock oyster mats at four research sites with specific environmental factors (e.g., temperature, salinity, turbidity, and pH). Beta regression models for recruitment and settlement were created for five of the more dominant organisms observed: oyster, barnacle, sponge, tubeworm, and encrusting bryozoan. The results of the modeling indicated that the settlement was influenced by pH, salinity, dock location, and turbidity, while recruitment was influenced by pH, salinity, dock location, and immersion time. This project provides insight into how lagoon conditions surrounding the Living Docks impact benthic growth and can aid in IRL restoration. Full article

Biochemistry of bioluminescence of the marine parchment tubeworm Chaetopterus has been in research focus for over a century; however, the results obtained by various groups contradict each other. Here, we report the isolation and structural elucidation of three compounds from Chaetomorpha linum algae, which demonstrate bioluminescence activity with Chaetopterus luciferase in the presence of Fe²⁺ ions. These compounds are derivatives of polyunsaturated fatty acid peroxides. We have also obtained their structural analogues and demonstrated their activity in the bioluminescence reaction, thus confirming the broad substrate specificity of the luciferase. Full article

Aragonite plays an important role in the biomineralization of serpulid polychaetes. Aragonitic structures are present in a wide range of serpulid species, but they mostly belong to one clade. Aragonitic structures are present in a wide range of marine environments, including the deep ocean. Aragonitic tube microstructures were studied using a scanning electron microscope. X-ray powder diffraction was used to identify the aragonite. Aragonite is used to build five different types of microstructures in serpulid tubes. The most common aragonitic irregularly oriented prismatic structure (AIOP) is also, evolutionarily, the most primitive. Some aragonitic microstructures, such as the spherulitic prismatic (SPHP) structure, have likely evolved from the AIOP structure. Aragonitic microstructures in serpulids are far less numerous than calcitic microstructures, and they lack the complexity of advanced calcitic microstructures. The reason why aragonitic microstructures have remained less evolvable than calcitic microstructures is currently unknown, considering their fit with the current aragonite sea conditions (Paleogene–recent). Full article

Biofouling is problematic for the shipping industry and can lead to functional and financial setbacks. One possible means of biofouling prevention is the use of ultraviolet-C (UVC) light. Previous studies have investigated UVC with marine coatings, but the synergistic effect with color and surface material, specifically reflectance, has yet to be determined. This study comprised three parts: UVC and color (red vs. white), UVC and reflectance (stainless steel vs. polycarbonate), and UVC and exposure intervals (weekly intervals and 10 min intervals). There was no variance in the biofouling communities for colored surfaces when exposed to 254 nm UVC. Reflectance studies demonstrated that the surface material plays a role in biofouling settlement. Stainless steel panels had significantly greater macrofouling settlement than polycarbonate, specifically among encrusting bryozoan, tubeworms, and tunicate communities. Panels of both surface materials exposed to indirect UVC significantly differed from controls and those exposed directly to UVC. Exposure intervals were also found to reduce biofouling settlement especially with long frequent intervals (i.e., 10 min/day). UVC can be utilized on various colored surfaces and different surface types, but the effectiveness in preventing biofouling is ultimately determined by the duration and frequency of UVC exposure. Full article