New and noteworthy publications in deep-sea science for the week of January 7, 2013.
Deep Sea Research Part 1: Oceanographic Research Papers: Discovery of a new hydrothermal vent based on an underwater, high-resolution geophysical survey
A new hydrothermal vent site in the Southern Mariana Trough has been discovered using acoustic and magnetic surveys conducted by the Japan Agency for Marine–Earth Science and Technology’s (JAMSTEC) autonomous underwater vehicle (AUV) Urashima. The high-resolution magnetic survey, part of near-bottom geophysical mapping around a previously known hydrothermal vent site, the Pika site, during YK09-08 cruise in June-July 2009, found that a clear magnetization low extends ~500 m north from the Pika site. Acoustic signals, suggesting hydrothermal plumes, and 10 m-scale chimney-like topographic highs were detected within this low magnetization zone by a 120 kHz side-scan sonar and a 400 kHz multibeam echo sounder. In order to confirm the seafloor sources of the geophysical signals, seafloor observations were carried out using the deep-sea manned submersible Shinkai 6500 during the YK 10-10 cruise in August 2010. These discovered a new hydrothermal vent site (12°55.30′N, 143°38.89′E; at a depth of 2922 m), which we have named the Urashima site. This hydrothermal vent site covers an area of approximately 300 m x 300 m and consists of black and clear smoker chimneys, brownish-colored shimmering chimneys, and inactive chimneys. All of the fluids sampled from the Urashima and Pika sites have chlorinity greater than local ambient seawater, suggesting subseafloor phase separation or leaching from rocks in the hydrothermal reaction zone. End-member compositions of the Urashima and Pika fluids suggest that fluids from two different sources feed the two sites, even though are located on the same knoll and separated by only ~500 m. We demonstrate that investigations on hydrothermal vent sites located in close proximity to one another can provide important insights into subseafloor hydrothermal fluid flow, and also that, while such hydrothermal sites are difficult to detect by conventional plume survey methods, high-resolution underwater geophysical surveys provide an effective means.
A new species of the squat lobster genus Munidopsis is described from Nukuhou Seamount, North Island, New Zealand. The new species is allied to members of the “Galathodes group” within Munidopsis that share a flattened, distally trifid rostrum, an unarmed carapace surface (apart from paired epigastric spines in some species), unarmed abdominal tergites and absence of pereopodal epipods. The new species is readily separated from these species by the combination of unarmed lateral carapace margins posterior to the anterolateral spine, absence of epigastric spines, and prominently spinose extensor margins of the pereopod 2–4 meri. Fourteen species of Munidopsis are now recorded from New Zealand; a key to the New Zealand species is provided.
And, of course: First Stills of the Giant Squid filmed in its natural habitat.