| 1. |
- Cranston, Alex, et al.
(author)
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A population specific mitochondrial intron from the sponge Phakellia robusta in the North-East Atlantic
- 2021
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In: Deep Sea Research Part I. - : Elsevier. - 0967-0637 .- 1879-0119. ; 172
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Journal article (peer-reviewed)abstract
- Self-splicing mitochondrial introns are a rarely reported phenomenon in animals, with a sparse and uneven distribution confined to some species of sponges, corals, placozoans, and a single species of annelid. Here, we describe a mitochondrial intron present only in some populations of Phakellia robusta, a sponge distributed across the North-east Atlantic deep-sea. The mitochondrial intron of P. robusta was detected in the position 387 of the COI gene and classified as a Group I intron of class IB. Interestingly, this intron was only detected in the shallower populations of P. robusta from Ireland to Norway, spanning 1000 km and was absent in deeper samples of the species. Such deeper populations have recently been proposed to be the result of hybridization between P. robusta and its congeneric Phakellia hirondellei. We propose that this past hybridization might be behind the absence of the intron in the specimens of P. robusta occurring at deep waters. Our analyses indicate that the intron detected in P. robusta might have a double origin (most likely fungi and other organism), as it has previously suggested for the sponge Stupenda singularis. BLAST searches produced matches with the homing endonuclease gene (HEG) nested within the S. singularis intron and this HEG belongs to the family of LAGLIDADG homing endonucleases (LHEs). The evolutionary relevance of the presence/absence of this intron for this species needs to be determined and potential adaptive advantages should not be ruled out.
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| 2. |
- Koutsouveli, Vasiliki, et al.
(author)
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Insights into the reproduction of some Antarctic dendroceratid, poecilosclerid, and haplosclerid demosponges
- 2018
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:2
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Journal article (peer-reviewed)abstract
- Sponges are a dominant element of the Antarctic benthic communities, posing both high species richness and large population densities. Despite their importance in Antarctic ecosystems, very little is known about their reproductive patterns and strategies. In our study, we surveyed the tissue of six different species for reproductive elements, namely, Dendrilla antarctica Topsent, 1905 (order Dendroceratida), Phorbas areolatus (Thiele, 1905), Kirkpatrickia variolosa (Kirkpatrick, 1907), and Isodictya kerguelenensis (Ridley & Dendy, 1886) (order Poecilosclerida), and Hemigellius pilosus (Kirkpatrick, 1907) and Haliclona penicillata (Topsent, 1908) (Haplosclerida). Samples of these six species containing various reproductive elements were collected in Deception Island and were processed for both light and transmission electron microscopy (TEM). Even though we were not able to monitor the entire reproductive cycle, due to time and meteorological conditions, we report important aspects of the reproduction of these species. This includes oocyte and embryo morphology and cell ultrastructure, follicular structures and nurse cell activity, as well as vitellogenesis. All species were brooding their embryos within their mesohyl. Both oocytes and embryos were registered in the majority of the studied species, and a single sperm cell being carried to an egg for fertilization was observed in H. penicillata. While the reproductive periods of all species coincided temporally, some of them seemed to rely on a single spawning event, this being suggested by the synchronic oogenesis and embryogenesis occurrence of D. antarctica, P. areolatus and I. kerguelenensis. In contrast, K. variolosa had an asynchronous embryo development, which suggests several larval release events. Our results suggest that differences in the reproductive strategies and morphological traits might succeed in the coexistence of these species at the same habitat avoiding the direct competition between them.
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| 3. |
- Plese, Bruna, et al.
(author)
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Mitochondrial evolution in the Demospongiae (Porifera) : Phylogeny, divergence time, and genome biology
- 2021
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In: Molecular Phylogenetics and Evolution. - : Elsevier. - 1055-7903 .- 1095-9513. ; 155
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Journal article (peer-reviewed)abstract
- The sponge class Demospongiae is the most speciose and morphologically diverse in the phylum Porifera, and the species within it are vital components of a range of ecosystems worldwide. Despite their ubiquity, a number of recalcitrant problems still remain to be solved regarding their phylogenetic inter-relationships, the timing of their appearance, and their mitochondrial biology, the latter of which is only beginning to be investigated. Here we generated 14 new demosponge mitochondrial genomes which, alongside previously published mitochondrial resources, were used to address these issues. In addition to phylogenomic analysis, we have used syntenic data and analysis of coding regions to forge a framework for understanding the inter-relationships between Demospongiae sub-classes and orders. We have also leveraged our new resources to study the mitochondrial biology of these clades in terms of codon usage, optimisation and gene expression, to understand how these vital cellular components may have contributed to the success of the Porifera. Our results strongly support a sister relationship between Keratosa and (Verongimorpha + Heteroscleromorpha), contradicting previous studies using nuclear markers. Our study includes one species of Clionaida, and show for the first time support for a grouping of Suberitida+(Clionaida+(Tethyida + Poecilosclerida). The findings of our phylogenetic analyses are supported by in-depth examination of structural and coding-level evidence from our mitochondrial data. A time-calibrated phylogeny estimated the origin of Demospongiae in the Cambrian (similar to 529 Mya), and suggests that most demosponge order crown-groups emerged in the Mesozoic. This work therefore provides a robust basis for considering demosponge phylogenetic relationships, as well as essential mitochondrial data for understanding the biological basis for their success and diversity.
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| 4. |
- Rios, Pilar, et al.
(author)
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Aviles Canyon System : Increasing the benthic biodiversity knowledge
- 2022
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In: Estuarine, Coastal and Shelf Science. - : Elsevier. - 0272-7714 .- 1096-0015. ; 274
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Journal article (peer-reviewed)abstract
- Macro and megafauna were studied in the Avile acute accent s Canyon System (ACS), southern Bay of Biscay (Cantabrian Sea), during several oceanographic cruises carried out from 2009 to 2017. The biodiversity of ACS is summarized and its description is herein updated after sampling surveys of several programmes (ECOMARG, INDEMARES, SponGES, INTEMARES) conducted by the Spanish Institute of Oceanography (IEO).This study has updated previous knowledge in the canyon area from past national and international projects, their reports and publications as well as data collected in the context of regional projects designed to gain new insight into the diversity of marine invertebrates and fishes from the ACS. Samples were taken using a range of sampling gears (Rock dredge, Beam trawl, Trawl gear GOC-73, Suprabenthic sledge, Box corer and Remoted operated vehicle), from 55 to 2291 m in depth. A total of 1015 species were identified at the ACS: 98 Porifera, 153 Cnidaria, 14 Brachiopoda, 22 Bryozoa, 97 Mollusca, 151 Annelida, 315 Arthropoda, 74 Echinodermata and 91 Chordata. New records for the Bay of Biscay fauna include 13 Porifera species, 17 Cnidaria, 7 Mollusca, Arthopoda, 3 Echinodermata and 4 Chordata. Also the bathymetric range of some species has been extended. As a result of the research projects carried out in the area in the last fifteen years, important information is now available which suggests that the ACS houses a large number of species with a high ecological value, that represents a biodiversity hotspot in terms of the presence of sponge aggregations and coral reefs in certain regions, and that it sustains important fisheries due to the abundance of comercial species. Given the relevance of the species and habitats occurring in the ACS, there is a need to implement a conservation and management plan of the area in order to maintain habitats in good state of preservation.
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| 5. |
- Stewart, Eva C.D., et al.
(author)
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Biodiversity, biogeography, and connectivity of polychaetes in the world's largest marine minerals exploration frontier
- 2023
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In: Diversity and Distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 29:6, s. 727-47
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Journal article (peer-reviewed)abstract
- Aim: The abyssal Clarion-Clipperton Zone (CCZ), Pacific Ocean, is an area of commercial importance owing to the growing interest in mining high-grade polymetallic nodules at the seafloor for battery metals. Research into the spatial patterns of faunal diversity, composition, and population connectivity is needed to better understand the ecological impacts of potential resource extraction. Here, a DNA taxonomy approach is used to investigate regional-scale patterns of taxonomic and phylogenetic alpha and beta diversity, and genetic connectivity, of the dominant macrofaunal group (annelids) across a 6 million km2 region of the abyssal seafloor. Location: The abyssal seafloor (3932–5055 m depth) of the Clarion-Clipperton Zone, equatorial Pacific Ocean. Methods: We used a combination of new and published barcode data to study 1866 polychaete specimens using molecular species delimitation. Both phylogenetic and taxonomic alpha and beta diversity metrics were used to analyse spatial patterns of biodiversity. Connectivity analyses were based on haplotype distributions for a subset of the studied taxa. Results: DNA taxonomy identified 291–314 polychaete species from the COI and 16S datasets respectively. Taxonomic and phylogenetic beta diversity between sites were relatively high and mostly explained by lineage turnover. Over half of pairwise comparisons were more phylogenetically distinct than expected based on their taxonomic diversity. Connectivity analyses in abundant, broadly distributed taxa suggest an absence of genetic structuring driven by geographical location. Main Conclusions: Species diversity in abyssal Pacific polychaetes is high relative to other deep-sea regions. Results suggest that environmental filtering, where the environment selects against certain species, may play a significant role in regulating spatial patterns of biodiversity in the CCZ. A core group of widespread species have diverse haplotypes but are well connected over broad distances. Our data suggest that the high environmental and faunal heterogeneity of the CCZ should be considered in future policy decisions.
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| 6. |
- Taboada, Sergi, et al.
(author)
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Genetic diversity, gene flow and hybridization in fan-shaped sponges (Phakellia spp.) in the North-East Atlantic deep sea
- 2022
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In: Deep Sea Research Part I. - : Elsevier. - 0967-0637 .- 1879-0119. ; 181
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Journal article (peer-reviewed)abstract
- Deep-sea North Atlantic sponge grounds are crucial components of the marine fauna providing a key role in ecosystem functioning. To properly develop effective conservation and management plans, it is crucial to understand the genetic diversity, molecular connectivity patterns and turnover at the population level of the species involved. Here we present the study of two congeneric sponges, Phakellia robusta and Phakellia hirondellei, using multiple sources of evidence. Our phylogenetic study using a fragment of COI placed these two species as sister. Haplotype network analysis using COI revealed no genetic structure for P. hirondellei in samples from the Cantabrian Sea (<100 km). Contrastingly, P. robusta showed a clear genetic structure separating deep-water samples from the Cantabrian Sea and the Hatton-Rockall Basin, from samples from shallower waters from Kerry Head Reefs, NW of Orkney, and Norway. ddRADseq-derived SNPs for P. robusta also segregated samples by bathymetry rather than by geographical distances, and detected a predominant northwards migration for shallow-water specimens connecting sites separated ca. 2,000 km, probably thanks to prevalent oceanographic currents. Importantly, our analysis using SNPs combining the datasets of the two species revealed the presence of potential hybrids, which was corroborated by morphological (spicule) and microbial (16S amplicon sequencing) analyses. Our data suggest that hybridization between these two species occurred at least two times in the past. We discuss the importance of using next-generation techniques to unveil hybridization and the implications of our results for conservation.
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| 7. |
- Taboada, Sergi, et al.
(author)
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Insights into the symbiotic relationship between scale worms and carnivorous sponges (Cladorhizidae, Chondrocladia)
- 2020
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In: Deep Sea Research Part I. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0967-0637 .- 1879-0119. ; 156
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Journal article (peer-reviewed)abstract
- Symbiotic associations between polynoid scale worms and other marine invertebrates are common, but sometimes poorly understood. Compounding this problem is the fact that polynoid systematics is largely unresolved. Here, we transfer the species originally described as Nemidia antillicola chondrocladiae Fauvel (1943), and currently synonymized with Neopolynoe acanellae (Verrill, 1881), to the species Neopolynoe chondrocladiae n. comb. This species is characterized by living in association with the carnivorous sponges Chondrocladia robertballnrdi Cristobo, Rios, Pomponi & Xavier, 2015 and Chondrocladia virgata Thompson, 1873. The existence of specialized chaetae in N. chondrocladiae n. comb. and the occurrence of open galleries in the sponge, derived from a gradual overgrowth of the sponge to accommodate the worm, suggest an obligate symbiotic relationship between worm and sponge. The presence of a gravid female with relatively small oocytes (maximum diameter 56.94 +/- 14.89 mu m) suggests that N. chondrocladiae n. comb. is a gonochoristic broadcaster with a planktotrophic larva, a means of reproduction that would maximize the chances of this species finding new suitable hosts to colonize. We also provide a phylogenetic placement, using four genetic markers (18S, 28S, 16S and COI), for N. chondrocladiae n. comb. and N. acanellae, which confirms they are two different species. In addition, we also report here the occurrence of another deep-water polynoid species in association with the carnivorous sponge Chondrocladia vertical= Topsent, 1920, from the Gulf of Mexico, and place it in a phylogeny.
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| 8. |
- Taboada, Sergi, et al.
(author)
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Long distance dispersal and oceanographic fronts shape the connectivity of the keystone sponge Phakellia ventilabrum in the deep northeast Atlantic
- 2023
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In: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 10
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Journal article (peer-reviewed)abstract
- Little is known about dispersal in deep-sea ecosystems, especially for sponges, which are abundant ecosystem engineers. Understanding patterns of gene flow in deep-sea sponges is essential, especially in areas where rising pressure from anthropogenic activities makes difficult to combine management and conservation. Here, we combined population genomics and oceanographic modelling to understand how Northeast Atlantic populations (Cantabrian Sea to Norway) of the deep-sea sponge Phakellia ventilabrum are connected. The analysis comprised ddRADseq derived SNP datasets of 166 individuals collected from 57 sampling stations from 17 different areas, including two Marine Protected Areas, one Special Area of Conservation and other areas with different levels of protection. The 4,017 neutral SNPs used indicated high connectivity and panmixis amongst the majority of areas (Ireland to Norway), spanning ca. 2,500-km at depths of 99-900 m. This was likely due to the presence of strong ocean currents allowing long-distance larval transport, as supported by our migration analysis and by 3D particle tracking modelling. On the contrary, the Cantabrian Sea and Roscoff (France) samples, the southernmost areas in our study, appeared disconnected from the remaining areas, probably due to prevailing current circulation patterns and topographic features, which might be acting as barriers for gene flow. Despite this major genetic break, our results suggest that all protected areas studied are well-connected with each other. Interestingly, analysis of SNPs under selection replicated results obtained for neutral SNPs. The relatively low genetic diversity observed along the study area, though, highlights the potential fragility of this species to changing climates, which might compromise resilience to future threats.
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| 9. |
- Taboada, Sergi, et al.
(author)
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Mitochondrial genome and polymorphic microsatellite markers from the abyssal sponge Plenaster craigi Lim & Wiklund, 2017: tools for understanding the impact of deep-sea mining
- 2018
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In: Marine Biodiversity. - : Springer Science and Business Media LLC. - 1867-1616 .- 1867-1624. ; 48:1, s. 621-630
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Journal article (peer-reviewed)abstract
- © 2017, The Author(s). The abyssal demosponge Plenaster craigi is endemic to the Clarion - Clipperton Zone (CCZ) in the NE Pacific, a region with abundant seafloor polymetallic nodules and of potential interest for mining. Plenaster craigi encrusts on these nodules and is an abundant component of the ecosystem. To assess the impact of mining operations, it is crucial to understand the genetics of this species, because its genetic diversity and connectivity across the area may be representative of other nodule-encrusting invertebrate epifauna. Here we describe and characterize 14 polymorphic microsatellite markers from this keystone species using Illumina MiSeq, tested for 75 individuals from three different areas across the CCZ, including an Area of Particular Environmental Interest (APEI-6) and two areas within the adjacent UK1 mining exploration area. The number of alleles per locus ranged from 3 to 30 (13.33 average alleles for all loci across areas). Observed and expected heterozygosity ranged from 0.909–0.048 and from 0.954–0.255, respectively. Several loci displayed significant deviation from the Hardy-Weinberg equilibrium, which appears to be common in other sponge studies. The microsatellite loci described here will be used to assess the genetic structure and connectivity on populations of the sponge across the CCZ, which will be invaluable for monitoring the impact of mining operations on its habitat. Also, we provide the annotated mitochondrial genome of P. craigi, compare its arrangement with other closely related species, and discuss the phylogenetic framework for the sponge after Maximum Likelihood and Bayesian Inference analyses using nucleotide and amino acid sequences data sets separately.
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