Annotated record of the detailed examination of Mn deposits from the LUSIAD Expedition stations

The cores and dredges described in this report were taken on the LUSIAD Expedition from May 1962 until August 1963 by the Scripps Institution of Oceanography from both the R/V Argo and the R/V Horizon. A total of 310 cores and dredges were recovered and are available at Scripps for sampling and study.

Annotated record of the detailed examination of Mn deposits recovered from dredges and cores from VEMA 17 Expedition stations

The cores and dredges described in this report were taken during the Vema 17 Expedition from December 1960 until October 1961 by the Lamont Geological Observatory, Columbia University from the R/V Vema. An approximate total of 210 cores, dredges and camera stations were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

Nematode absolute densities and genus counts from four stations near the Antarctic Peninsula, collected with a multicorer device during POLARSTERN cruise ANT-XXIX/3 in January-March 2013

Marine free-living nematode communities were studied at similar depths (~500m) at two sides of the Antarctic Peninsula, characterised by different environmental and oceanographic conditions. At the Weddell Sea side, benthic communities are influenced by cold deep-water formation and seasonal sea-ice conditions, whereas the Drake Passage side experiences milder oceanic conditions and strong dynamics of the Antarctic Circumpolar Current. Surface primary productivity contrasted with observed benthic pigment patterns and varied according to the area studied: chlorophyll a concentrations (as a proxy for primary production) were high in the Weddell Sea sediments, but low in the surface waters above; this pattern was reversed in the Drake Passage. Differences between areas were largely mirrored by the nematode communities: nematode densities peaked in Weddell stations and showed deeper vertical occurrence in the sediment, associated with deeper penetration of chlorophyll a. Generic composition did not differ markedly between both areas, but rather showed distinct community shifts with depth in the sediment.

Annotated record of the detailed examination of Mn deposits from ARA Islas Orcadas Cruise 15 core stations

The purpose of this volume, the tenth in a series of similar publications (Goodell, 1964, 1965, 1968; Frakes 1971, 1973 ; Cassidy et al., 1977), is to continue a presentation to the research community of sediment core descriptions and attendant data of cored and otherwise obtained sediments retrieved in waters of the Southern Ocean aboard the research vessel, ARA Islas Orcadas (formerly, USNS Eltanin), as a part of the circumpolar survey begun by Eltanin in 1962 (see issue of Antarctic Journal of the United States, Vol. 8, No. 3, 1973). The data presented herein are concerned with the results of coring activities aboard cruise 1578 of Islas Orcadas, the fourth marine geology coring cruise of this vessel under the terms of the present United States-Argentine agreement. The core descriptions are organised as follows: 1) a brief summary of the coring objectives of the cruise, together with a discussion of core recovery; 2) a table and map of station location data for materials retrieved; 3) a table of tentative age-dates for each piston core; 4) an explanation of the laboratory procedures and descriptive criteria used in the description of the sediments, and 5) lithologic descriptions of the piston and trigger cores, and the piston and trigger core bag samples.

(Table 6) Number of specimens of Polymastiidae and Suberitidae spp. found in ANDEEP I and II stations, POLARSTERN cruises ANT-XIX/4 and ANT-XXII/3

The Antarctic deep-water fauna of Polymastiidae and Suberitidae is revised using recently collected material from the Weddell Sea. The former family appeared to be more abundant and diverse than the latter family in the studied area. Seven species within five polymastiid genera and three species within three suberitid genera are described. Relatively high sponge abundance at two stations deeper than 4700 m was mainly constituted by a polymastiid species Radiella ant- arctica sp. nov. Previously, representatives of Radiella have never been found in the Antarctic. An eurybathic species, Polymastia invaginata , well known from the Antarctic and subantarctic, appeared to be especially abundant at less than 1000 m depth. Another eurybathic polymastiid species, Tentorium cf. semisuberites , known for its bipolar distribution, was the third abundant species at the depths between 1000-2600 m, with the highest density found at the deeper stations. Tentorium papillatum , endemic of the Southern Hemisphere, was registered only at a depth of about 1000 m. Other spe- cies studied were less abundant. Astrotylus astrotylus , the representative of the endemic Antarctic genus, was found exclusively deeper than 4500 m, often together with R. antarctica . Acanthopolymastia acanthoxa , the endemic deep- water Antarctic species, was registered at 3000 m. The discovery of suberitid Aaptos robustus sp. nov. at about 2300 m is the first signalization of Aaptos in the Antarctic and at such a considerable depth. The finding of Suberites topsenti deeper than 4700 m is also remarkable. In general the results achieved confirm the high degree of geographical ende- mism of the Antarctic deep-water sponge fauna and the eurybathic distribution of many Antarctic sponge species.

(Tables 1, 3) Details of Agassiz trawl stations and numbers of specimens per macro- and megazoobenthic taxon collected during POLARSTERN cruise ANT-XXII/3 (ANDEEP III)

The assemblages inhabiting the continental shelf around Antarctica are known to be very patchy, in large part due to deep iceberg impacts. The present study shows that richness and abundance of much deeper benthos, at slope and abyssal depths, also vary greatly in the Southern and South Atlantic oceans. On the ANDEEP III expedition, we deployed 16 Agassiz trawls to sample the zoobenthos at depths from 1055 to 4930 m across the northern Weddell Sea and two South Atlantic basins. A total of 5933 specimens, belonging to 44 higher taxonomic groups, were collected. Overall the most frequent taxa were Ophiuroidea, Bivalvia, Polychaeta and Asteroidea, and the most abundant taxa were Malacostraca, Polychaeta and Bivalvia. Species richness per station varied from 6 to 148. The taxonomic composition of assemblages, based on relative taxon richness, varied considerably between sites but showed no relation to depth. The former three most abundant taxa accounted for 10-30% each of all taxa present. Standardised abundances based on trawl catches varied between 1 and 252 individuals per 1000 m2. Abundance significantly decreased with increasing depth, and assemblages showed high patchiness in their distribution. Cluster analysis based on relative abundance showed changes of community structure that were not linked to depth, area, sediment grain size or temperature. Generally abundances of zoobenthos in the abyssal Weddell Sea are lower than shelf abundances by several orders of magnitude.

Annotated record of the detailed examination of Mn deposits from R/V Caryn Cruise 25 stations

The cores described are taken during the R/V Caryn Cruise 25 in August-September 1951 by the Woods Hole Oceanographic Institution. A total of 11 cores were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

Annotated record of the detailed examination of Mn deposits from USS San Pablo Cruises 10 and 11 stations

The cores described are taken during the USS San Pablo Cruises 10 and 11 in 1952 by the Scripps Institute of Oceanography. A total of 21 cores were recovered and are available at Scripps Institute of Oceanography for sampling and study.

Physical oceanography from 120 CTDs, 79 water bottles stations, and 30 helicopter-borne CTDs during POLARSTERN cruise ANT-XXII/2 (ISPOL)

The Ice Station POLarstern (ISPOL) cruise revisited the western Weddell Sea in late 2004 and obtained a comprehensive set of conductivity-temperature-depth (CTD) data. This study describes the thermohaline structure and diapycnal mixing environment observed in 2004 and compares them with conditions observed more than a decade earlier. Hydrographic conditions on the central western Weddell Sea continental slope, off Larsen C Ice Shelf, in late winter/early spring of 2004/2005 can be described as a well-stratified environment with upper layers evidencing relict structures from intense winter near-surface vertical fluxes, an intermediate depth temperature maximum, and a cold near-bottom layer marked by patchy property distributions. A well-developed surface mixed layer, isolated from the underlying Warm Deep Water (WDW) by a pronounced pycnocline and characterized by lack of warming and by minimal sea-ice basal melting, supports the assumption that upper ocean winter conditions persisted during most of the ISPOL experiment. Much of the western Weddell Sea water column has remained essentially unchanged since 1992; however, significant differences were observed in two of the regional water masses. The first, Modified Weddell Deep Water (MWDW), comprises the permanent pycnocline and was less saline than a decade earlier, whereas Weddell Sea Bottom Water (WSBW) was horizontally patchier and colder. Near-bottom temperatures observed in 2004 were the coldest on record for the western Weddell Sea over the continental slope. Minimum temperatures were ~0.4 and ~0.3 °C colder than during 1992-1993, respectively. The 2004 near-bottom temperature/salinity characteristics revealed the presence of two different WSBW types, whereby a warm, fresh layer overlays a colder, saltier layer (both formed in the western Weddell Sea). The deeper layer may have formed locally as high salinity shelf water (HSSW) that flowed intermittently down the continental slope, which is consistent with the observed horizontal patchiness. The latter can be associated with the near-bottom variability found in Powell Basin with consequences for the deep water outflow from the Weddell Sea.

Annotated record of the detailed examination of Mn deposits from ANTIPODE Expedition stations

Deep-sea sediment cores from Scripps Institution of Oceanography's ANTIPODE Expedition were described to identify visually distinct units based on color, texture, or other feature, sedimentary structures, lithology and abundance of component grains, and paleontology. Sixty-eight cores were examined, of which 34 are large diameter piston cores. Photographs and graphic lithology legs are included as PLATES 1-48. ANTIPODE Expedition recovered cores from: the Monterey-Ascension Fan, the Northeast Pacific, the Aleutians, the Northwest Pacific, the Philippine Sea, Indonesia, the Tonga Ridge, the Seychelles, Chagos Archipelago, the Mid-Indian Ridge, the Bay of Bengal, near Sumatra, and near the Cocos Island in the Indian Ocean. The purpose of this report is to present sufficient basic data on ANTIPODE cores for invesiigators to choose samples for their own research.

Annotated record of the detailed examination of Mn deposits from COCOTOW Expedition stations in the intersection of the Siqueiros Transform Fault and the East Pacific Rise

A near-bottom geological and geophysical survey was conducted at the western intersection of the Siqueiros Transform Fault and the East Pacific Rise. Transform-fault shear appears to distort the east flank of the rise crest in an area north of the fracture zone. In ward-facing scarps trend 335° and do not parallel the regional axis of spreading. Small-scale scarps reveal a hummocky bathymetry. The center of spreading is not a central peak but rather a 20-40 m deep, 1 km wide valley superimposed upon an 8 km wide ridge-crest horst. Small-scale topography indicates widespread volcanic flows within the valley. Two 0.75 km wide blocks flank the central valley. Fault scarps are more dominant on the western flank. Their alignment shifts from directions intermediate to parallel to the regional axis of spreading (355°). A median ridge within the fracture zone has a fault-block topography similar to that of the East Pacific Rise to the north. Dominant eastward-facing scarps trending 335° are on the west flank. A central depression, 1 km wide and 30 m deep, separates the dominantly fault-block regime of the west from the smoother topography of the east flank. This ridge originated by uplift due to faulting as well as by volcanism. Detailed mapping was concentrated in a perched basin (Dante's Hole) at the intersection of the rise crest and the fracture zone. Structural features suggest that Dante's Hole is an area subject to extreme shear and tensional drag resulting from transition between non-rigid and rigid crustal behavior. Normal E-W crustal spreading is probably taking place well within the northern confines of the basin. Possible residual spreading of this isolated rise crest coupled with shear drag within the transform fault could explain the structural isolation of Dante's Hole from the remainder of the Siqueiros Transform Fault.

Annotated record of the detailed examination of Mn deposits from the Southern Borderland (SOB) Expedition stations

The cores and dredges described in this report were taken on the Southern Borderland (SOB) Expedition in February-March 1960 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 34 cores and dredges were recovered and are available at Scripps for sampling and study.