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Instituto Español de OceanografíaVersión del editor0,000

El buceo en la Antártida

Any diving operation in cold waters requires careful preparation, but in addition, diving in Antarctica requires a series of additional precautions that must be taken into account to ensure the safety of diversCualquier operación de buceo en aguas frías requiere una cuidadosa preparación, pero además el buceo en la Antártida exige una serie de precauciones adicionales que se deben tener en cuenta para asegurar la seguridad de los buceadores

A new species of Isodictya (Porifera: Poecilosclerida) from the Southern Ocean

We discovered a new species of Porifera belonging to the genus Isodictya Bowerbank, 1864 during cruises aboard R/V Hesperides in Antarctica. Collected samples are mostly part of the surveys of the Spanish project BENTART whose main objective has been to study the benthic communities inhabiting sea bottoms of Livingston and Deception Island in the South Shetlands archipelago and the Antarctic Peninsula. Isodictya filiformis sp. nov., described here, is characterized by its fragile and thin morphology (very different from other known species in the area) and by having microxeas as additional microscleres. Three specimens were collected from Marguerite Bay, Low Island and Deception Island (Antarctic Peninsula) and one specimen at Peter I Island (Bellingshausen Sea). Its presence in Peter Island is quite relevant as this location is 390 km away from the nearest coast in the Bellingshausen Sea, an area that has scarcely been investigated in the past. However, results from the Bentart 03 Expedition seem to indicate that Peter I Island has a wide variety of benthic organisms, in contrast to the deep adjacent areas of Bellingshausen Sea. Apart from the morphological analyses, we place the new Isodictya species within its phylogenetic context using two nuclear markers (18S rDNA and 28S rDNA) and provide some information about the ecological preferences of the new speciesPostprint1,44

El Cachuchu, bayura y biodiversidá nel monte submarín d’Asturies

Academia de la Llingua AsturianaEn prens

Unique spicules may confound species differentiation: Taxonomy and biogeography of Melonanchora Carter, 1874 and two new related genera (Myxillidae: Poecilosclerida) from the Okhotsk Sea

Sponges are amongst the most difficult benthic taxa to properly identify, which has led to a prevalence of cryptic species in several sponge genera, especially in those with simple skeletons. This is particularly true for sponges living in remote or hardly accessible environments, such as the deep-sea, as the inaccessibility of their habitat and the lack of accurate descriptions usually leads to misclassifications. However, species can also remain hidden even when they belong to genera that have particularly characteristic features. In these cases, researchers inevitably pay attention to these peculiar features, sometimes disregarding small differences in the other “typical” spicules. The genus Melonanchora Carter, 1874, is among those well suited for a revision, as their representatives possess a unique type of spicule (spherancorae). After a thorough review of the material available for this genus from several institutions, four new species of Melonanchora, M. tumultuosa sp. nov., M. insulsa sp. nov., M. intermedia sp. nov. and M. maeli sp. nov. are formally described from different localities across the Atlanto-Mediterranean region. Additionally, all Melonanchora from the Okhotsk Sea and nearby areas are reassigned to other genera; Melonanchora kobjakovae is transferred to Myxilla (Burtonanchora) while two new genera, Hanstoreia gen. nov. and Arhythmata gen. nov. are created to accommodate Melonanchora globogilva and Melonanchora tetradedritifera, respectively. Hanstoreia gen. nov. is closest to Melonanchora, whereas Arhythmata gen. nov., is closer to Stelodoryx, which is most likely polyphyletic and in need of revision.publishedVersio

Increasing knowledge of biodiversity on the Orphan Seamount: a new species of Tedania (Tedaniopsis) Dendy, 1924

A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian mission HUD2010-029 and the British RRS Discovery Cruise DY081, on the Orphan Seamount near the Orphan Knoll, northwest Atlantic, between 2999.88 and 3450.4 m depth. Orphan Knoll is an isolated, drowned continental fragment 550 km northeast Newfoundland in the Labrador Sea. This region is biologically rich and complex and in 2007, the regional fisheries management organization operating in the area regulated that no vessel shall engage in bottom-contact fishing activities until reviewed in 2020 with a review slated at the end of this year. Members of the genus Tedania are uncommon in the temperate northern hemisphere with only six species known previously: Tedania (Tedania) anhelans; Tedania (Tedania) pilarriosae; Tedania (Tedania) suctoria; Tedania (Tedania) urgorrii; Tedania (Tedaniopsis) gurjanovae; and Tedania (Tedaniopsis) phacellina. The particular features of the new sponge we describe are the very peculiar external morphology which is tree-like with dichotomous branching—a morphology not previously described in this subgenus; and the combination of spicules found: long styles, the typical tornotes of the subgenus and two sizes of onychaetes. Additional information is provided on other species of Tedaniopsis described from the Atlantic Ocean. Based on the characteristics reported, we propose a new species, Tedania (Tedaniopsis) rappi sp. nov. in honor of Prof. Hans Tore Rapp (1972–2020), University of Bergen, Norway, a renowned sponge taxonomist and coordinator of the Horizon 2020 SponGES project. The holotype of T. (T.) phacellina Topsent, 1912 from the Azores, the only other northern Atlantic species in the subgenus Tedaniopsis, was reviewed for comparison.Postprin

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)

High resolution spatial distribution for the hexactinellid sponges Asconema setubalense and Pheronema carpenteri in the Central Cantabrian Sea

In the present work we focus on the distribution of two species of sponges. One of these is Asconema setubalense, a sponge found in rocky substrate that was sampled with a photogrammetric vehicle through georeferenced images. The other is Pheronema carpenteri, which inhabits soft bottoms and was sampled by beam trawl. For the spatial distribution modeling of both sponges, the geomorphological variables of depth, slope, broad and fine scale bathymetric position index (BPI), aspect, and types of bottoms were used, all with a resolution of 32 m. Additionally, layers of silicates and currents near the bottom were extracted from Copernicus Marine Environment Monitoring Service (CMEMS), with a resolution of 4 and 9 km, respectively. Due to the low resolution of the layers, it was considered necessary to validate their use by model comparison, where those that included these variables turned out to be more explanatory than the others. The models were developed in a complex continental break of the Central Cantabrian Sea, which comprises several submarine canyons and a seamount (Le Danois Bank). On the one hand, a very high resolution (32 m) spatial distribution model based on A. setubalense presence was developed using the MaxEnt maximum entropy model. On the other, depending on the availability of density data, generalized additive models (GAMs) were developed for P. carpenteri distribution, although in this case the sampler only allowed a maximum resolution of almost 1 Km. For the A. setubalense, the variables that best explained their distribution were ground types and depth, and for P. carpenteri, silicates, slope, northness, and eastward seawater velocity. The final model scores obtained were an AUC of 0.98 for the MaxEnt model, and an R squared of 0.87 for the GAM model.Postprin

In-situ growth rate assessment of hexactinellid sponge Asconema setubalense using 3D photogrammetric reconstruction

We describe the first application of a non-invasive and novel approach to estimate the growth rate of Asconema setubalense (Porifera, Hexactinellida) through the use of 3D photogrammetric methodology. Structure-from-Motion techniques (SfM) were applied to videos acquired with the Politolana ROTV in the El Cachucho Marine Protected Area (MPA) (Cantabrian Sea) on three different dates (2014, 2017, and 2019) over six years. With these data, a multi-temporal study was conducted within the framework of MPA monitoring. A complete 3D reconstruction of the deep-sea floor was achieved with Pix4D Mapper Pro software for each date. Having 3D point clouds of the study area enabled a series of measurements that were impossible to obtain in 2D images. In 3D space, the sizes (height, diameter, cup-perimeter, and cup-surface area) of several A. setubalense specimens were measured each year. The annual growth rates recorded ranged from zero (“no growth”) for a large size specimen, to an average of 2.2 cm year�����1 in cup-diameter, and 2.5 cm year�����1 in height for developing specimens. Von Bertalanffy growth parameters were estimated. Taking into account the size indicators used in this study and based on the von Bertalanffy growth model, this sponge reaches 95% maximum size at 98 years of age. During the MPA monitoring program, a high number of specimens disappeared. This raised suspicions of a phenomenon affecting the survival of this species in the area. This type of image-based methodology does not cause damage or alterations to benthic communities and should be employed in vulnerable ecosystem studies and MPA monitoring. Keywords: underwater photogrammetry, Asconema setubalense, Marine ProtectedPostprin

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