Vida després de la mort als ecosistemes marins

“És el meu últim viatge. Serà l’última vegada que torni a sentir la frescor de les seves aigüessobre la meva pell i l’aire gelat omplint els meus pulmons; d’això n’estic segura. Amb proufeines puc moure el meu cos de més de 30 tones de pes a través d’aquestes corrents marines,però ja no queda gaire. Cada vegada m’és més difícil propulsar-me a través d’aquest medi quem’ha vist néixer i on també trobaré la meva fi...

Ecología química en el bentos antártico

El estudio de las interacciones entre los organismos mediadas por sustancias químicas, lo que se denomina ecología química, nos da información sobre la biología de las especies implicadas, el funcionamiento de la comunidad en que viven y nos puede proporcionar además el conocimiento de nuevas sustancias que pueden ser útiles para el ser humano. En el marco de nuestros estudios sobre la ecología química de los invertebrados antárticos, en el proyecto ECOQUIM (2003-2006) se recolectaron numerosas muestras biológicas a partir de las cuales se obtuvieron extractos y sustancias naturales de invertebrados antárticos. En el proyecto ACTIQUIM (2007-actualidad), se ha evaluado el papel ecológico de estos extractos y sustancias naturales mediante experimentos de ecología química in situ (repelencia, defensa ante distintos tipos de macro y micro-depredadores, toxicidad, citotoxicidad y actividad antifouling) y también se ha analizado la actividad antitumoral de algunos compuestos obtenidos recientemente. Nuestros resultados demuestran, entre otras cuestiones, que las defensas químicas en los organismos antárticos son elevadas en las esponjas, los cnidarios, los tunicados, los briozoos, los equinodermos y los moluscos y que por lo tanto, estos grupos pueden ser una fuente rica en metabolitos secundarios con bioactividad, tanto a nivel ecológico como farmacológico

On the way to specificity ‐ Microbiome reflects sponge genetic cluster primarily in highly structured populations

Most animals, including sponges (Porifera), have species-specific microbiomes. Which genetic or environmental factors play major roles structuring the microbial community at the intraspecific level in sponges is, however, largely unknown. In this study, we tested whether geographic location or genetic structure of conspecific sponges influences their microbial assembly. For that, we used three sponge species with different rates of gene flow, and collected samples along their entire distribution range (two from the Mediterranean and one from the Southern Ocean) yielding a total of 393 samples. These three sponge species have been previously analysed by microsatellites or single nucleotide polymorphisms, and here we investigate their microbiomes by amplicon sequencing of the microbial 16S rRNA gene. The sponge Petrosia ficiformis, with highly isolated populations (low gene flow), showed a stronger influence of the host genetic distance on the microbial composition than the spatial distance. Host-specificity was therefore detected at the genotypic level, with individuals belonging to the same host genetic cluster harbouring more similar microbiomes than distant ones. On the contrary, the microbiome of Ircinia fasciculata and Dendrilla antarctica - both with weak population structure (high gene flow) - seemed influenced by location rather than by host genetic distance. Our results suggest that in sponge species with high population structure, the host genetic cluster influence the microbial community more than the geographic location

Gorgoniapolynoe caeciliae revisited: The discovery of new species and molecular connectivity in deep-sea commensal polynoids from the Central Atlantic

Gorgoniapolynoe caeciliae (Fauvel, 1913) is a deep-sea commensal polynoid that lives in association with several genera of octocorals from the order Alcyonacea. The species has been recorded in the Caribbean and in both Atlantic and Indian Ocean basins. The wide geographic range of G. caeciliae, coupled with it having multiple host coral species and the evolution of its taxonomic description, hints that it could potentially be a species complex. This study investigated the morphological and genetic differentiation in 82 specimens of G. cf. caeciliae, sampled from four seamounts in the Central Atlantic separated by thousands of kilometres. Our combined morphological and molecular analyses, including species delimitation models (ABGD and bPTP) using COI and a phylogenetic approach using four molecular markers (COI, 16S, 28S, and 18S), agreed in identifying three distinct species; two supported by morphological and molecular data and a third species, using molecular data only, from the Indian Ocean which had been previously identified as G. caeciliae. We formally describe a new species in the genus, Gorgoniapolynoe pseudocaecliae sp. nov., the most common taxa found in our study. Our morphological analyses of some members of the genus Gorgoniapolynoe revealed the presence of elytra with possible photocytes (bioluminescent cells) and conspicuous macropapillae with long cilia emerging from them, whose function is discussed here. Our demographic analysis using COI for two Gorgoniapolynoe sp. detected a high potential for dispersal for G. pseudocaecliae sp. nov., with sites approximately 3000 km apart being well connected. Unusually there was also no genetic differentiation across their bathymetric range of over 1500 m. All in all, our study highlights the importance of applying integrative taxonomy to poorly studied deep-sea species

Chemical Interactions in Antarctic Marine Benthic Ecosystems

Antarctic marine ecosystems are immersed in an isolated, relatively constant environment where the organisms inhabiting their benthos are mainly sessile suspension feeders. For these reasons, physical and chemical biotic interactions play an essential role in structuring these marine benthic communities (Dayton et al., 1974; Orejas et al., 2000). These interactions may include diverse strategies to avoid predation (e.g. Iken et al., 2002), competition for space or food (e.g. Bowden et al., 2006) and avoiding fouling (e.g. Rittschof, 2001; Peters et al., 2010). For instance, in the marine benthos, one of the most extended effective strategies among sessile soft-bodied organisms is chemical defense, mediated by several bioactive natural products mostly considered secondary metabolites (e.g. Paul et al., 2011). The study of the “chemical network” (chemical ecology interactions) structuring the communities provides information about the ecology and biology of the involved species, the function and the structure of the community and, simultaneously, it may lead to the discovery of new compounds useful to humans for their pharmacological potential (e.g. Avila, 1995; Bhakuni, 1998; Munro et al., 1999; Faulkner, 2000; Lebar et al., 2007; Avila et al., 2008). In the last three decades, the study of marine chemical ecology has experienced great progress, thanks to the new technological advances for collecting and studying marine samples, and the possibility of identification of molecules with smaller amounts of compounds (e.g. Paul et al., 2006, 2011; Blunt et al., 2011)

Genetic diversity, connectivity and gene flow along the distribution of the emblematic Atlanto-Mediterranean sponge Petrosia ficiformis (Haplosclerida, Demospongiae)

Background: Knowledge about the distribution of the genetic variation of marine species is fundamental to address species conservation and management strategies, especially in scenarios with mass mortalities. In the Mediterranean Sea, Petrosia ficiformis is one of the species most affected by temperature-related diseases. Our study aimed to assess its genetic structure, connectivity, and bottleneck signatures to understand its evolutionary history and to provide information to help design conservation strategies of sessile marine invertebrates. Results: We genotyped 280 individuals from 19 locations across the entire distribution range of P. ficiformis in the Atlanto-Mediterranean region at 10 microsatellite loci. High levels of inbreeding were detected in most locations (especially in the Macaronesia and the Western Mediterranean) and bottleneck signatures were only detected in Mediterranean populations, although not coinciding entirely with those with reported die-offs. We detected strong significant population differentiation, with the Atlantic populations being the most genetically isolated, and show that six clusters explained the genetic structure along the distribution range of this sponge. Although we detected a pattern of isolation by distance in P. ficiformis when all locations were analyzed together, stratified Mantel tests revealed that other factors could be playing a more prominent role than isolation by distance. Indeed, we detected a strong effect of oceanographic barriers impeding the gene flow among certain areas, the strongest one being the Almeria-Oran front, hampering gene flow between the Atlantic Ocean and the Mediterranean Sea. Finally, migration and genetic diversity distribution analyses suggest a Mediterranean origin for the species. Conclusions: In our study Petrosia ficiformis showed extreme levels of inbreeding and population differentiation, which could all be linked to the poor swimming abilities of the larva. However, the observed moderate migration patterns are highly difficult to reconcile with such poor larval dispersal, and suggest that, although unlikely, dispersal may also be achieved in the gamete phase. Overall, because of the high genetic diversity in the Eastern Mediterranean and frequent mass mortalities in the Western Mediterranean, we suggest that conservation efforts should be carried out specifically in those areas of the Mediterranean to safeguard the genetic diversity of the species

Insights into the reproduction of some Antarctic dendroceratid, poecilosclerid, and haplosclerid demosponges

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

From the Idea of a basic income to the political movement in Europe

Volume: 71Start Page: 289End Page: 30

Spatial and seasonal biodiversity variation in a large Mediterranean lagoon using environmental DNA metabarcoding through sponge tissue collection

Ecosystem monitoring is a fundamental tool to avert biodiversity loss, gathering valuable information that can be used to develop conservation policies, evaluating management outcomes, and guiding science-based decision-making. The Mar Menor costal lagoon (South-East of Spain) has experienced episodes of eutrophication due to intensive agriculture and other human activities, causing mass mortalities of marine fauna. In this scenario, biodiversity monitoring is crucial to evaluate the status of fauna and flora and take appropriate measures. Here, our main objective was to assess faunal composition and its spatial and temporal structure associated with the pillars used to support the built recreational well-being facilities along the Mar Menor. We capitalised on the many sea sponges that settle on these structures by collecting tissue samples for subsequent extraction of filtered environmental DNA (i.e. ‘natural sampler DNA’, nsDNA) in northern and southern areas of the lagoon, both in spring and summer. We metabarcoded all samples at the cytochrome oxidase subunit I gene (COI), and reliably identified 76 taxa belonging to nine different phyla, with annelids, poriferans, molluscs and cnidarians being the richest groups. We detected emblematic species of threatened status, such as pipefishes (genus Syngnathus) and the piddock clam, Pholas dactylus, and others known to become invasive, such as the ascidians Styela canopus and Botrylloides niger, the barnacle Amphibalanus amphitrite, and the polychaetes Branchiomma bairdi and Branchiomma boholense. The use of common and widely distributed sponges as natural eDNA samplers allowed us to characterise both spatial and temporal diversity, further emphasizing the importance of this low-cost approach to monitoring biological communities in shallow coastal ecosystems.APR acknowledges funding from “Monitoring and predictive analysis of the ecological state evolution of the Mar Menor lagoon ecosystem and prevention of impacts 2020-2022 and 2023” financed by the General Directorate of the Mar Menor of the Region of Murcia that also have contributed to the contracts of BMC and MVR. AR acknowledges funding from the SponBIODIV project (granted to AR and ST), a 2021-2022 BiodivProtect joint call for research proposals, under the Biodiversa+ Partnership co-funded by the European Commission, and with the funding organisations ‘Fundación Biodiversidad’ and FORMAS, the grant NE/T007028/1 from the UK Natural Environment Research Council (to SM and AR), an intramural grant from CSIC (PIE-202030E006) to AR, and three grants from the Spanish Ministry of Science and Innovation (RYC2018-024247-I, PID2019-105769GB-I00, and CNS2023-144571) in the framework of MCIN/AEI/10.13039/50110001103 and EI “FSE invierte en tu futuro”, to AR. ST received funding from the grants PID2020-117115GA-100 and by CNS2023-144572 funded by MCIN/AEI/10.13039/501100011033 and by the Ramón y Cajal grant RYC2021-03152-I, funded by the MCIN/AEI/10.13039/501100011033 and the European Union «NextGenerationEU/PRTR».N

Implications of population connectivity studies for the design of marine protected areas in the deep sea: An example of a demosponge from the Clarion-Clipperton Zone

The abyssal demosponge Plenaster craigi inhabits the Clarion‐Clipperton Zone (CCZ) in the northeast Pacific, a region with abundant seafloor polymetallic nodules with potential mining interest. Since P. craigi is a very abundant encrusting sponge on nodules, understanding its genetic diversity and connectivity could provide important insights into extinction risks and design of marine protected areas. Our main aim was to assess the effectiveness of the Area of Particular Environmental Interest 6 (APEI‐6) as a potential genetic reservoir for three adjacent mining exploration contract areas (UK‐1A, UK‐1B and OMS‐1A). As in many other sponges, COI showed extremely low variability even for samples ~900 km apart. Conversely, the 168 individuals of P. craigi, genotyped for 11 microsatellite markers, provided strong genetic structure at large geographical scales not explained by isolation by distance (IBD). Interestingly, we detected molecular affinities between samples from APEI‐6 and UK‐1A, despite being separated ~800 km. Although our migration analysis inferred very little progeny dispersal of individuals between areas, the major differentiation of OMS‐1A from the other areas might be explained by the occurrence of predominantly northeasterly transport predicted by the HYCOM hydrodynamic model. Our study suggests that although APEI‐6 does serve a conservation role, with species connectivity to the exploration areas, it is on its own inadequate as a propagule source for P. craigi for the entire eastern portion of the CCZ. Our new data suggest that an APEI located to the east and/or the south of the UK‐1, OMS‐1, BGR, TOML and NORI areas would be highly valuable