Pilar Ríos

Deep-sea sponge grounds of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland (Northwest Atlantic Ocean): Distribution and species composition

Abstract Distribution and species composition of deep-sea sponge grounds of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland are described based on Spanish/EU bottom trawl groundfish surveys between 40 and 1500 m depth. Four areas with large catches of sponges and at least 30 different species have been identified in the study area. Geodia barretti, Geodia macandrewii, Geodia phlegraei, Stryphnus ponderosus and Stelletta normani are the main structural sponges and constitute more than 94% of the total invertebrate biomass of these grounds. The temperature and salinity observed over these bottoms ranged between 3.38 and 3.84°C and between 34.85 and 34.90‰, respectively. The biomass of deep-water sponges per swept area was significantly higher on lightly or untrawled bottoms than in the grounds that are regularly fished. Data from trawl groundfish surveys cannot map the deep-sea sponge grounds to a precision less than the trawl distance of 1.5 nm. Nevertheless it has been used by the Northwest Atlantic Fisheries Organization (NAFO), along with additional Canadian data, to implement the 61/105 United Nations General Assembly Resolution in closing six areas to bottom fishing activities to protect the sponge grounds of the NAFO Regulatory Area.

Chemo-ecological studies on hexactinellid sponges from the Southern Ocean

Hexactinellids (glass sponges) are an understudied class with syncytial organization and poor procariotic associations, thought to lack defensive secondary metabolites. Poriferans, though, are outstanding sources of bioactive compounds; nonetheless, a growing suspicion suggests that many of these chemicals could be symbiont-derived. In Polar latitudes, sponges are readily invaded by diatoms, which could provide natural products. Hexactinellids are typical of deep waters; but in Antarctica, they dominate the upper shelf providing shelter and food supply to many opportunistic mesograzers and macroinvertebrates, which exert strong ecological pressures on them. Aiming to examine the incidence of defensive activities of hexactinellids against consumption, feeding experiments were conducted using their lipophilic fractions. Antarctic hexactinellid and demosponge extracts were tested against the asteroid Odontaster validus and the amphipod Cheirimedon femoratus as putative sympatric, omnivorous consumers. Hexactinellids yielded greater unpalatable activities towards the amphipod, while no apparent allocation of lipophilic defenses was noted. After chemical analyses on the lipophilic fractions from these Antarctic glass sponges, quite similar profiles were revealed, and no peculiar secondary metabolites, comparable to those characterizing other poriferans, were found. Instead, the lipidic compounds 5α(H)-cholestan-3-one and two glycoceramides were isolated for their particular outspread presence in our samples. The isolated compounds were further assessed in asteroid feeding assays, and their occurrence was evaluated for chemotaxonomical purposes in all the Antarctic samples as well as in glass sponges from other latitudes by NMR and MS. Characteristic sphingolipids are proposed as chemical markers in Hexactinellida, with possible contributions to the classification of this unsettled class.

The systematics of carnivorous sponges

Carnivorous sponges are characterized by their unique method of capturing mesoplanktonic prey coupled with the complete or partial reduction of the aquiferous system characteristic of the phylum Porifera. Current systematics place the vast majority of carnivorous sponges within Cladorhizidae, with certain species assigned to Guitarridae and Esperiopsidae. Morphological characters have not been able to show whether this classification is evolutionary accurate, and whether carnivory has evolved once or in several lineages. In the present paper we present the first comprehensive molecular phylogeny of the carnivorous sponges, interpret these results in conjunction with morphological characters, and propose a revised classification of the group. Molecular phylogenies were inferred using 18S rDNA and a combined dataset of partial 28S rDNA, COI and ALG11 sequences. The results recovered carnivorous sponges as a clade closely related to the families Mycalidae and Guitarridae, showing family Cladorhizidae to be monophyletic and also including carnivorous species currently placed in other families. The genus Lycopodina is resurrected for species currently placed in the paraphyletic subgenus Asbestopluma (Asbestopluma) featuring forceps spicules and lacking sigmas or sigmancistras. The genera Chondrocladia and Cladorhiza are found to be monophyletic. However, results indicate that the subgenus Chondrocladia is polyphyletic with respect to the subgenera Meliiderma and Symmetrocladia. Euchelipluma, formerly Guitarridae, is retained, but transferred to Cladorhizidae. The four known carnivorous species currently in Esperiopsis are transferred to Abyssocladia. Neocladia is a junior homonym and is here renamed Koltunicladia. Our results provide strong evidence in support of the hypothesis that carnivory in sponges has evolved only once. While spicule characters mostly reflect monophyletic groups at the generic level, differences between genera represent evolution within family Cladorhizidae rather than evolution of carnivory in separate lineages. Conflicting spicule characters can be reinterpreted to support the inclusion of all carnivorous sponges within Cladorhizidae, and a carnivorous habit should thus be considered the main diagnostic character in systematic classification.

Management Strategies to Limit the Impact of Bottom Trawling on VMEs in the High Seas of the SW Atlantic

For the past nine years, the issue of protecting biodiversity in the deep sea in areas beyond national jurisdiction – the high seas (HS) – has been widely debated by the United Nations General Assembly (UNGA) and in other international fora. The UNGA adopted a series of resolutions, beginning with Resolution 59/25 in 2004, which called on high seas fishing nations and regional fisheries management organisations (RFMOs) to take urgent action to protect vulnerable marine ecosystems (VMEs) from destructive fishing practices in areas beyond national jurisdiction (Rogers & Gianni, 2010; UNGA, 2004). In December 2006 the UNGA adopted resolution 61/105 on Sustainable Fisheries, calling on flag states, RFMOs and arrangements to immediately act for the sustainable management of fish stocks and to protect VMEs from destructive fishing practices (Portela et al., 2010; UNGA, 2007). In 2009, the UNGA adopted Resolution 64/72 reaffirming the 2006 resolution and made it clear that the measures called for in Resolution 61/105 should be implemented, consistent with the 2009 FAO International Guidelines for the Management of Deep-Sea Fisheries in the High Seas (FAO Deepwater Guidelines), by flag states and RFMOs. Resolution 64/72 placed particular emphasis on conducting impact assessments of bottom fisheries on the high seas (UNGA, 2009: Paras 119–120).

A new species of Phorbas (Porifera: Poecilosclerida) from the Bellingshausen Sea, Antarctica

Phorbas is a common genus with cosmopolitan distribution. A new species of sponge, Phorbas megasigma sp. nov. (Porifera: Poecilosclerida: Hymedesmiidae) is described from material collected during the third Spanish expedition on the study of the Antarctic benthos, ‘Bentart 03’. Phorbas megasigma is closely related to P. nexus but differs in the possession of arcuate chelae and very big sigmata as microscleres.

A new species of Biemna (Porifera: Poecilosclerida) from Antarctica : Biemna strongylota

A new species of Biemna, Biemna strongylota sp. nov. is described from Antarctica. The new species is compared to other Antarctic species of Biemna, B. chilensis and B. macrorhaphis from which it differs in that it possesses strongyle megascleres, instead of styles, and of the microsclere complement which includes microxeas, raphides and two categories of sigmata.

Antarctic Porifera database from the Spanish benthic expeditions.

Abstract The information about the sponges in this dataset is derived from the samples collected during five Spanish Antarctic expeditions: Bentart 94, Bentart 95, Gebrap 96, Ciemar 99/00 and Bentart 2003. Samples were collected in the Antarctic Peninsula and Bellingshausen Sea at depths ranging from 4 to 2044 m using various sampling gears. The Antarctic Porifera database from the Spanish benthic expeditions is unique as it provides information for an under-explored region of the Southern Ocean (Bellingshausen Sea). It fills an information gap on Antarctic deep-sea sponges, for which there were previously very few data. This phylum is an important part of the Antarctic biota and plays a key role in the structure of the Antarctic marine benthic community due to its considerable diversity and predominance in different areas. It is often a dominant component of Southern Ocean benthic communities. The quality of the data was controlled very thoroughly with GPS systems onboard the R/V Hesperides and by checking the data against the World Porifera Database (which is part of the World Register of Marine Species, WoRMS). The data are therefore fit for completing checklists, inclusion in biodiversity pattern analysis and niche modelling. The authors can be contacted if any additional information is needed before carrying out detailed biodiversity or biogeographic studies. The dataset currently contains 767 occurrence data items that have been checked for systematic reliability. This database is not yet complete and the collection is growing. Specimens are stored in the author’s collection at the Spanish Institute of Oceanography (IEO) in the city of Gijón (Spain). The data are available in GBIF.

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.

Integrative systematics of clathrinid sponges: morphological, reproductive and phylogenetic characterisation of a new species of Leucetta from Antarctica (Porifera, Calcarea, Calcinea) with notes on the occurrence of flagellated sperm

Abstract. Our study reports on the occurrence of a new species of Leucetta (Calcinea, Calcarea) from the Southern Ocean, Leucetta giribeti, sp. nov., collected in the shallow waters (15 m depth) of Deception Island, South Shetland Islands. This new taxon is described based on a combination of morphological and molecular data, including the description of oocytes, embryos, larvae and sperm found in the choanosome. While female reproductive elements showed great similarities with those of other calcineans, sperm is reported here for the first time in the whole Calcinea subclass. Sperm cells are flagellated and possess a typical spermatic mid-piece, which is usually observed in cnidarians. In our phylogenetic analyses, we recovered Leucetta giribeti, sp. nov. as sister species of a clade formed by species of the genera Leucetta, Pericharax and Leucettusa. Although the clade in which Leucetta giribeti, sp. nov. is placed is supported by molecular and morphological features, we cannot propose a new genus due to uncertainties regarding the type species of the genus, Leucetta primigenia Haeckel, 1872. Our study reinforces the relevance of integrative approaches in the description of new taxa and contributes to resolving the poorly known reproductive patterns of Antarctic sponge species.