The modeled distribution of corals and sponges surrounding the Salas y Gómez and Nazca ridges with implications for high seas conservation

The Salas y Gómez and Nazca ridges are two adjacent seamount chains off the west coast of South America that collectively contain more than 110 seamounts. The ridges support an exceptionally rich diversity of benthic and pelagic communities, with the highest level of endemism found in any marine environment. Despite some historical fishing in the region, the seamounts are relatively pristine and represent an excellent conservation opportunity to protect a global biodiversity hotspot before it is degraded. One obstacle to effective spatial management of the ridges is the scarcity of direct observations in deeper waters throughout the region and an accompanying understanding of the distribution of key taxa. Species distribution models are increasingly used tools to quantify the distributions of species in data-poor environments. Here, we focused on modeling the distribution of demosponges, glass sponges, and stony corals, three foundation taxa that support large assemblages of associated fauna through the creation of complex habitat structures. Models were constructed at a 1 km2 resolution using presence and pseudoabsence data, dissolved oxygen, nitrate, phosphate, silicate, aragonite saturation state, and several measures of seafloor topography. Highly suitable habitat for each taxa was predicted to occur throughout the Salas y Gómez and Nazca ridges, with the most suitable habitat occurring in small patches on large terrain features such as seamounts, guyots, ridges, and escarpments. Determining the spatial distribution of these three taxa is a critical first step towards supporting the improved spatial management of the region. While the total area of highly suitable habitat was small, our results showed that nearly all of the seamounts in this region provide suitable habitats for deep-water corals and sponges and should therefore be protected from exploitation using the best available conservation measures.

Rossellid glass sponges (Porifera, Hexactinellida) from New Zealand waters, with description of one new genus and six new species

New Zealand’s surrounding deep waters have become known as a diversity hotspot for glass sponges (Porifera: Hexactinellida) in recent years, and description and collection efforts are continuing. Here we report on eight rossellids (Hexasterophora: Lyssacinosida: Rossellidae) collected during the 2017 RV Sonne cruise SO254 by ROV Kiel 6000 as part of Project PoribacNewZ of the University of Oldenburg, Germany. The material includes six species new to science, two of which are assigned to a so far undescribed genus; we further re-describe two previously known species. The known extant rossellid diversity from the New Zealand region is thus almost doubled, from nine species in five genera to 17 species in eight genera. The specimens described here are only a small fraction of hexactinellids collected on cruise SO254. Unfortunately, the first author passed away while working on this collection, only being able to complete the nine descriptions reported here. The paper concludes with an obituary to him, the world-leading expert on glass sponge taxonomy who will be greatly missed.

Hexactinellida from the Perth Canyon, Eastern Indian Ocean, with descriptions of five new species

Glass sponges (Class Hexactinellida) are described from the Perth Canyon in the eastern Indian Ocean, resulting in 10 genera being recorded, including 11 species, five of which are new to science. In addition, the study resulted in two new records for Australia, Pheronema raphanus and Monorhaphis chuni, and one new record for the Indian Ocean, Walteria flemmingi. A second species of Calyptorete is described over 90 years after the genus was first established with a single species. A significant difference was noted between the condition of sponges collected on the RV Falkor, which used an ROV, and the earlier RV Southern Surveyor expedition, which used sleds and trawls. The ROV collected specimens were in excellent condition, while those from the sleds and trawls tended to be damaged or fragmented.

Skeletons of Glass Sponges as a Substrate for Creating Functional Composite Organosilicon Materials

The article describes a method of creating a three-dimensional organosilicon composite material based on the glass sponge spicules through a combination of soft etching and controlled mechanical action, non-destroying spicules. When in an alkaline medium, the material of the spicules’ outer concentric layers is dissolved and silica passes into solution. After 20 to 30 days in alkaline medium, the silica is in excess and precipitates on organic components, forming a network of 300–500-nm thick organosilicon trabeculae, by which the spicules are fused into a single structure. The resulting composite material contains a mineral component of silica and an organic component. The results indicate that the natural organosilicon material can be reformed as a result of self-assembly into three-dimensional or flat structures.