The biogeography and distribution of megafauna at three California seamounts

Video recordings from Remotely Operated Vehicle (ROV) dives are used to describe the biogeography and distribution of megafauna communities found at three seamounts off central and southern California, USA. In total, 27 ROV dives were annotated in detail using the Monterey Bay Aquarium Research Institute\u27s (MBARI) Video Annotation Reference System (VARS). Video analysis yielded 136,716 biological observations. In all, 236 megafauna taxa are described from observations at these seamounts. Seamount bathymetry was analyzed to relate the observed faunal distribution to seamount slope, aspect, and bathymetric position index. Video transects, collected at Davidson Seamount in 2006 and at Pioneer Seamount in 2007, were analyzed to quantify species\u27 densities. Thirteen new species including sponges, corals, and echinoderms were observed and collected as part of this research; most of these are being or have been described by taxonomists. This study shows there is little or no endemism among invertebrate megafauna and demersal fishes identified at these seamounts. Results also indicate that many seamount organisms have specific depth distributions, and because of this, the depth of the seamount influences community composition. Additionally, proximity to the continental slope and seamount shape are important in determining community structure and organism distribution

Davidson Seamount Taxonomic Guide

Davidson Seamount is one of the largest seamounts in U.S. waters and the first to be characterized as a “seamount.” In 2002 and 2006, the Monterey Bay National Marine Sanctuary (MBNMS) led two multi-institutional expeditions to characterize the geology and natural history of Davidson Seamount. Results from these expeditions to Davidson Seamount are adding to the scientific knowledge of seamounts, including the discovery of new species. In November 2008, the MBNMS boundary was expanded to include the Davidson Seamount. In addition, a management plan for Davidson Seamount was created to develop resource protection, education, and research strategies for the area. The purpose of this taxonomic guide is to create an inventory of benthic and mid-water organisms observed at the Davidson Seamount to provide a baseline taxonomic characterization. At least 237 taxa were observed and are presented in this guide; including 15 new or undescribed species (8 sponges, 3 corals, 1 ctenophore, 1 nudibranch, 1 polychaete, 1 tunicate) recently or currently being described by taxonomic experts. This is the first taxonomic guide to Davidson Seamount, and is intended to be revised in the future as we learn more about the seamount and the organisms that live there. (PDF has 145 pages.

Endemicity, Biogeography, Composition, and Community Structure On a Northeast Pacific Seamount

The deep ocean greater than 1 km covers the majority of the earth's surface. Interspersed on the abyssal plains and continental slope are an estimated 14000 seamounts, topographic features extending 1000 m off the seafloor. A variety of hypotheses are posited that suggest the ecological, evolutionary, and oceanographic processes on seamounts differ from those governing the surrounding deep sea. The most prominent and oldest of these hypotheses, the seamount endemicity hypothesis (SMEH), states that seamounts possess a set of isolating mechanisms that produce highly endemic faunas. Here, we constructed a faunal inventory for Davidson Seamount, the first bathymetric feature to be characterized as a ‘seamount’, residing 120 km off the central California coast in approximately 3600 m of water (Fig 1). We find little support for the SMEH among megafauna of a Northeast Pacific seamount; instead, finding an assemblage of species that also occurs on adjacent continental margins. A large percentage of these species are also cosmopolitan with ranges extending over much of the Pacific Ocean Basin. Despite the similarity in composition between the seamount and non-seamount communities, we provide preliminary evidence that seamount communities may be structured differently and potentially serve as source of larvae for suboptimal, non-seamount habitats

The FathomNet2023 Competition Dataset

Ocean scientists have been collecting visual data to study marine organisms for decades. These images and videos are extremely valuable both for basic science and environmental monitoring tasks. There are tools for automatically processing these data, but none that are capable of handling the extreme variability in sample populations, image quality, and habitat characteristics that are common in visual sampling of the ocean. Such distribution shifts can occur over very short physical distances and in narrow time windows. Creating models that are able to recognize when an image or video sequence contains a new organism, an unusual collection of animals, or is otherwise out-of-sample is critical to fully leverage visual data in the ocean. The FathomNet2023 competition dataset presents a realistic scenario where the set of animals in the target data differs from the training data. The challenge is both to identify the organisms in a target image and assess whether it is out-of-sample.Comment: Competition was presented as part of the 10th Fine Grained Visual Categorization workshop at the 2023 Computer Vision and Pattern Recognition conference. 4 pages, 4 figure

Geology of the Alarcon Rise, Southern Gulf of California

Meter‐scale AUV bathymetric mapping and ROV sampling of the entire 47 km‐long Alarcon Rise between the Pescadero and Tamayo transforms show that the shallowest inflated portion of the segment hosts all four active hydrothermal vent fields and the youngest, hottest, and highest effusion rate lava flows. This shallowest inflated part is located ∼1/3 of the way between the Tamayo and Pescadero transforms and is paved by a 16 km2 channelized flow that erupted from 9 km of en echelon fissures and is larger than historic flows on the East Pacific Rise or on the Gorda and Juan de Fuca Ridges. Starting ∼5 km south of the Pescadero transform, 6.5 km of the Alarcon Rise is characterized by faulted ridges and domes of fractionated lavas ranging from basaltic andesite to rhyolite with up to 77.3 wt % SiO2. These are the first known rhyolites from the submarine global mid‐ocean ridge system. Silicic lavas range from \u3e11.7 ka, to as young as 1.1 ka. A basalt‐to‐basaltic andesite sequence and an andesite‐to‐dacite‐to‐rhyolite sequence are consistent with crystal fractionation but some intermediate basaltic andesite and andesite formed by mixing basalt with dacite or rhyolite. Magmatism occurred along the bounding Tamayo and Pescadero transforms as extensive channelized flows. The flows erupted from ring faults surrounding uplifted sediment hills inferred to overlie sills. The transforms are transtensional to accommodate magma migration from the adjacent Alarcon Rise

Geology of the Alarcon Rise, Southern Gulf of California

Abstract Meter-scale AUV bathymetric mapping and ROV sampling of the entire 47 km-long Alarcon Rise between the Pescadero and Tamayo transforms show that the shallowest inflated portion of the segment hosts all four active hydrothermal vent fields and the youngest, hottest, and highest effusion rate lava flows. This shallowest inflated part is located ~1/3 of the way between the Tamayo and Pescadero transforms and is paved by a 16 km2 channelized flow that erupted from 9 km of en echelon fissures and is larger than historic flows on the East Pacific Rise or on the Gorda and Juan de Fuca Ridges. Starting ~5 km south of the Pescadero transform, 6.5 km of the Alarcon Rise is characterized by faulted ridges and domes of fractionated lavas ranging from basaltic andesite to rhyolite with up to 77.3 wt % SiO2. These are the first known rhyolites from the submarine global mid-ocean ridge system. Silicic lavas range from \u3e11.7 ka, to as young as 1.1 ka. A basalt-to-basaltic andesite sequence and an andesite-to-dacite-to-rhyolite sequence are consistent with crystal fractionation but some intermediate basaltic andesite and andesite formed by mixing basalt with dacite or rhyolite. Magmatism occurred along the bounding Tamayo and Pescadero transforms as extensive channelized flows. The flows erupted from ring faults surrounding uplifted sediment hills inferred to overlie sills. The transforms are transtensional to accommodate magma migration from the adjacent Alarcon Rise. Plain Language Summary This study combines 1 m resolution bathymetry collected using an autonomous underwater vehicle, with chemical compositions of precisely located lava samples and ages of lava flows determined from short sediment cores collected using a remotely operated vehicle. The objective was to determine the history of an entire 47 km long segment of the global mid-ocean ridge system. The ridge segment studied is named the Alarcon Rise and is located at the mouth of the Gulf of California. The Rise is bounded to the north and south by strike-slip faults that offset the Rise from adjacent segments of the spreading ridge system. Such faults are usually thought to be parallel to the direction of seafloor spreading, but these have an oblique component to their movement that makes space for magma to be injected along the faults where it uplifts hills of sediment and sometimes erupts. Most lavas erupted along midocean ridges are basalts, but some highly unusual silica-rich lavas were identified by their rough surface texture and sampled. These lavas include the most silica-rich ones found along the entire global submarine mid-ocean ridge system. They formed, not by melting of nearby continental crust, but from common basalt by extreme amounts of crystallization of minerals, leaving a small volume of remaining high-silica magma. The complete mapping and closely spaced sampling along the Rise show that old ideas indicating a central point of magma delivery from the underlying mantle for each ridge segment followed by shallow transport of the magmas along the ridge are supported by the central distribution of (1) hydrothermally active sites, (2) the youngest, hottest, most fluid lava flows, and (3) the most voluminous lava flows that accumulate to form the shallowest portion of the ridge segment. The study shows how magmas are transported at shallow depths along the ridge and even around the corners in the adjacent faults

Geology of the Alarcon Rise, Southern Gulf of California

Meter‐scale AUV bathymetric mapping and ROV sampling of the entire 47 km‐long Alarcon Rise between the Pescadero and Tamayo transforms show that the shallowest inflated portion of the segment hosts all four active hydrothermal vent fields and the youngest, hottest, and highest effusion rate lava flows. This shallowest inflated part is located ∼1/3 of the way between the Tamayo and Pescadero transforms and is paved by a 16 km2 channelized flow that erupted from 9 km of en echelon fissures and is larger than historic flows on the East Pacific Rise or on the Gorda and Juan de Fuca Ridges. Starting ∼5 km south of the Pescadero transform, 6.5 km of the Alarcon Rise is characterized by faulted ridges and domes of fractionated lavas ranging from basaltic andesite to rhyolite with up to 77.3 wt % SiO2. These are the first known rhyolites from the submarine global mid‐ocean ridge system. Silicic lavas range from \u3e11.7 ka, to as young as 1.1 ka. A basalt‐to‐basaltic andesite sequence and an andesite‐to‐dacite‐to‐rhyolite sequence are consistent with crystal fractionation but some intermediate basaltic andesite and andesite formed by mixing basalt with dacite or rhyolite. Magmatism occurred along the bounding Tamayo and Pescadero transforms as extensive channelized flows. The flows erupted from ring faults surrounding uplifted sediment hills inferred to overlie sills. The transforms are transtensional to accommodate magma migration from the adjacent Alarcon Rise

Figure 1. Collection locality maps. A in Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores, including one new genus and three new species

Figure 1. Collection locality maps. A, tropical Atlantic localities for Sthenaster and Gilbertaster caribaea; B, North-east Pacific localities for Evoplosoma spp. nov.Published as part of <i>Mah, Christopher, Nizinski, Martha & Lundsten, Lonny, 2010, Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores, including one new genus and three new species, pp. 266-301 in Zoological Journal of the Linnean Society 160 (2)</i> on page 268, DOI: 10.1111/j.1096-3642.2010.00638.x, <a href="http://zenodo.org/record/10114738">http://zenodo.org/record/10114738</a&gt

Figure 10. Hippasteria phrygiana USNM E46606.A in Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores, including one new genus and three new species

Figure 10. Hippasteria phrygiana USNM E46606.A, abactinal view; B, actinal view; C, lateral view; D, H. phrygiana USNM 5235. Actinal surface showing bivalve pedicellariae; E, Hippasteria californica USNM E10413. Abactinal plates internal view; F, H. californica USNM 33354 abactinal surface pedicellariae; G, USNM E10413. Lateral view showing marginal plate series. Scale bars: A–C, G = 5 mm; D, E = 2 mm; F = 1 mm.Published as part of <i>Mah, Christopher, Nizinski, Martha & Lundsten, Lonny, 2010, Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores, including one new genus and three new species, pp. 266-301 in Zoological Journal of the Linnean Society 160 (2)</i> on page 290, DOI: 10.1111/j.1096-3642.2010.00638.x, <a href="http://zenodo.org/record/10114738">http://zenodo.org/record/10114738</a&gt