Demosponges from the sublittoral and shallow-circalittoral (lt;24m depth) Antarctic Peninsula with a description of four new species and notes on br />in situ identification characteristics.

Specimens were collected by SCUBA diving from 22 sites along the Antarctic Peninsula, spanning latitudes from Diomedea Island (62°12.185'S) to Jenny Island (67°43.325'S). The aims of the survey were to record the sponge biodiversity of the sublittoral and shallow-circalittoral and to provide information on in situ identification features. In total 24 sponge species were recorded, ranging from 0 to 12 species per site. The most widespread species were Dendrilla antarctica (10 sites), Sphaerotylus antarcticus (11 sites); and Mycale (Oxymycale) acerata (13 sites). Four species new to science were discovered and are described here: Megaciella cardenasi sp. nov., Crella (Crella) hennequinae sp. nov., Hymedesmia (Hymedesmia) noramaloneae sp. nov., Clathria (Clathria) priestleyae sp. nov. Suberites topsenti (Burton, 1929) is reassigned to Hemimycale topsenti (Burton, 1929) comb. nov. General habitat notes are provided for the survey sites, many of which were previously unsurveyed.

Hexactinellida (Porifera) from the Drake Passage (Southern Ocean) with a description of three new species.

The Drake Passage has over 20 seamounts and ridges but it is notorious for large waves, fierce storms and strong currents that make benthic sampling difficult and therefore infrequent. Seamounts often have diverse sponge communities and may have high levels of endemism. Hexactinellida from Sars Seamount, an area in which the sponges had not previously been studied, and the Shackleton fracture zone were collected on a research cruise by the Nathaniel B Palmer in the Drake Passage, Southern Ocean. In total, from all cruise stations, 103 specimens of Hexactinellida were collected, however many appeared to be fragments of dead specimens and could not be identified due to missing microscleres. From Sars Seamount 127 sponge specimens were taken and from the Shackleton Fracture Zone 76 sponge specimens were taken; of these 36 and 16 respectively were Hexactinellida. From these two areas three new species of Hexactinellida are described: Doconesthes robinsoni sp. nov., Sympagella walleri sp. nov. and Caulophacus palmeri sp. nov and new records were made of Aulocalyx irregularis and Rossella antarctica.

Effects of two decades of rising sea surface temperatures on sublittoral macrobenthos communities in Northern Ireland, UK.

We examined whether two decades of rising sea surface temperatures have resulted in significant changes in the benthic community and frequency of occurrence of Northern and Southern species in three areas of Northern Ireland, using visual census data collected by SCUBA surveys undertaken during two periods: pre-1986 and post-2006. We found little evidence to suggest that rising sea surface temperatures have contributed to the changes in benthic assemblage structure between the pre-1986 and post-2006 surveys. However, there were slight but not significant declines in extreme Northern species at Rathlin Island, and increases in the mean number and frequency of occurrence of extreme Southern species in all three areas. There were also substantial declines in the spatial presence of 7 extreme Northern species and notable increases in distribution of 19 extreme Southern species. In contrast, there were no clear trends in the intermediate to Northern and intermediate to Southern species. These results suggest that rising sea surface temperatures have had significant impacts on the occurrence of rarer marine invertebrate species at the edges of their biogeographic range however the trends differed between areas in Northern Ireland.