Illustration of manganese nodules and crust collected from the Suiko Seamount, Northwestern Pacific Ocean

An initial investigation has been undertaken on the chemical composition of the manganese nodules. The results of chemical analyses on each layer of single nodules reveal the periodic patterns of distribution for Mn, Fe, Cu, Pb, Zn, Ni and Co contents. The variations strongly suggest that those of the elements in nodules from this region are, at least, climatically controlled.

Illustration of manganese nodules and crust collected from the Suiko Seamount, Northwestern Pacific Ocean

Manganese nodules from the Suiko Seamount exhibit the significant characteristics in mineral compositions. Well crystallized todorokite and birnessite, which are principal manganese mineral phase in nodules, only occur in the oxide layer directly incasing pebbles and coarse sand. The preferential formation of todorokite or birnessite phases seem to be principally controlled by the reaction rate of iron-manganese oxides with trace elements such as Cu, Ni, Co, Zn, Pb concentrated in nodules, rather than redox characteristics of sedimentary environment or mineralogical diagenetic process.

Concentrations of floating plastic debris in northwestern Mediterranean Sea measured in summer 2013 during Expeditions MED cruise

Floating plastic debris sampled in surface waters of northwestern Mediterranean Sea during summer 2013. Geographical coordinates and dates of sampling are available in the dataset.

Morphometry and biomass of the cultured mangrove oyster Crassostrea rhizophorae at the Urindeua river, eastern Amazonia, northern Brazil

The malacocultura, particularly oyster farming, appears on the world stage as one of the most viable alternatives to fishing decline and supply of fresh product. In Brazil, the development of mollusc cultivationis through the genus oyster cultivation Crassostrea, among them Crassostrea rhizophorae (Guilding, 1828), known for oyster-the-swamp, one of the main species of farmed bivalves in the state of Pará. This so it aimed to characterize the biomorphometrics relations, estimate the Shape Stabilization Index (IEF) of the shell and the yield of edible meat C. rhizophorae grown in an Amazonian coast, state of Pará, northern Brazil. When all is sampled 1,028 individuals, in April 2016, measuring the external morphometric measures (length, width and height) and total and visceral biomass. The results obtained are C. rhizophorae with (1) excellent biomorphometrics relationships among both external measures, the measures of the shell and biomass generating equations that satisfy morphometric pet species, (2) yield of edible meat 15% of the total biomass and variation in the shell along its development to adulthood, with a tendency to stabilize the reach 60mm in length.

Physical oceanography from the northwestern Weddell Sea

We analyzed hydrographic data from the northwestern Weddell Sea continental shelf of the three austral winters 1989, 1997, and 2006 and two summers following the last winter cruise. During summer a thermal front exists at ~64° S separating cold southern waters from warm northern waters that have similar characteristics as the deep waters of the central basin of the Bransfield Strait. In winter, the whole continental shelf exhibits southern characteristics with high Neon (Ne) concentrations, indicating a significant input of glacial melt water. The comparison of the winter data from the shallow shelf off the tip of the Antarctic Peninsula, spanning a period of 17 yr, shows a salinity decrease of 0.09 for the whole water column, which has a residence time of <1 yr. We interpret this freshening as being caused by a combination of reduced salt input due to a southward sea ice retreat and higher precipitation during the late 20th century on the western Weddell Sea continental shelf. However, less salinification might also result from a delicate interplay between enhanced salt input due to sea ice formation in coastal areas formerly occupied by Larsen A and B ice shelves and increased Larsen C ice loss.

Sedimentology of the northwestern Weddel Sea continental shelf and slope

Geologie cores on two profiles oriented normaly to the continental shelf and slope, have been investigated to reconstruct the Quaternary sedimentary history of the southeast continental border of South Orkney (NW Weddell Sea). The sediments were described macroscopically and their fabric investigated by use of X-radiographs. Laboratory work comprised detailed grain-size analysis, determination of the watercontent, carbonate, organic carbon and sand fraction.composition. Stable oxygen and carbon isotopes have been measured On planktonic foraminifera. Palaeomagnetism, analysis of 230Th-content and detailed comparison of the lithlogic Parameters with the oxygen isotope stages (Martinson curve) were used for stratigraphic classification of the sediments. The sediment cores from the continental slope comprise a maximum age of 300,000 years B. P.. Bottom currents, ice rafting and biogenic input are the main sources of sediment. Based on lithologic parameters a distinction between glacial and interglacial facies is possible. Silty clays without microfossils and few bioturbation characterise the sediments of the glacial facies. Only small amounts of icerafted debris can be recognized. This type of sediment was accumulated during times of lower sea-level and drastically reduced rate of bottom water production. Based on grain-size distribution, bottom current velocities of 0.01 cmls were calculated. Thick sea-ice coverage reduced biogenic production in the surface water, and as consequence benthic communities were depleted. Because of the reduced benthic life, sediments are only slithly bioturbated. At the beginning of the interglacial Stage, the sea-level rised rapidly, and calving rate of icebergs, combined with input of ice-rafted material, increased considerably. Sediments of this transition facies are silty cliiys with a high proportion of coarse ice-rafted debris, but without microfossils. With the onset of bottom water production in connection with shelf ice water, sediments of interglacial facies were formed. They consist of silty clays to clayey silts with considerable content of sand and gravel. Sediments are strongly bioturbated. Based On the sediment caracteristics, current velocities of the bottom water were calculated to be of 0.96 cmls for interglacials. At the southern slope of a NW/SE-striking ridge, bottom water current is channelized, resulting in a drastic increase of current velocities. Current velocities up to 7.5 cm/s lead to formation of residual sediments. While the continental slope has predominantly fine sediments, the South Orkney shelf are mainly sandy silts and silty sands with a high proportion of gravel. These sediments were formed dominantly by ice-rafting during Brunhes- and Matuyama-Epoch. Currents removed the fine fraction of the sediments. Based on microfossil contents it was not possible to differentiate sediments from glacial to interglacial. In the upper Parts of the cores graded sequences truncated by erosion were observed. These sequences were formed during Brunhes-Epoch by strong currents with velocities decreasing periodically from about 7.5 cm/s to about 1 cm/s. Sediments with a high proportion of siliceous microfossils but barren of foraminifera compose the lower part of the shelf cores. These sediments have formed during the warmer Matuyama-Epoch.

Sediment and pore water chemistry of cores 214 and 755 recovered during Meteor M72/1 and POSEIDON cruise POS317/2, northwestern Black Sea

High-resolution sedimentary records of major and minor elements (Al, Ba, Ca, Sr, Ti), total organic carbon (TOC), and profiles of pore water constituents (SO42-, CH4, Ca2+, Ba2+, Mg2+, alkalinity) were obtained for two gravity cores (core 755, 501 m water depth and core 214, 1686 m water depth) from the northwestern Black Sea. The records were examined in order to gain insight into the cycling of Ba in anoxic marine sediments characterized by a shallow sulfate-methane transition (SMT) as well as the applicability of barite as a primary productivity proxy in such a setting. The Ba records are strongly overprinted by diagenetic barite (BaSO4) precipitation and remobilization; authigenic Ba enrichments were found at both sites at and slightly above the current SMT. Transport reaction modeling was applied to simulate the migration of the SMT during the changing geochemical conditions after the Holocene seawater intrusion into the Black Sea. Based on this, sediment intervals affected by diagenetic Ba redistribution were identified. Results reveal that the intense overprint of Ba and Baxs (Ba excess above detrital average) strongly limits its correlation to primary productivity. These findings have implications for other modern and ancient anoxic basins, such as sections covering the Oceanic Anoxic Events for which Ba is frequently used as a primary productivity indicator. Our study also demonstrates the limitations concerning the use of Baxs as a tracer for downward migrations of the SMT: due to high sedimentation rates at the investigated sites, diagenetic barite fronts are buried below the SMT within a relatively short period. Thus, 'relict' barite fronts would only be preserved for a few thousands of years, if at all.

Carbon and oxygen isotope ratios, and geochemistry of the Precambrian-Cambrian Sukharikha River section, northwestern Siberian platform

A high-resolution carbon isotope profile through the uppermost Neoproterozoic-Lower Cambrian part of the Sukharikha section at the northwestern margin of the Siberian platform shows prominent secular oscillations of d13C with peak-to-peak range of 6-10 ?. There are six minima, 1n-6n, and seven maxima 1p-7p, in the Sukharikha Formation and a rising trend of d13C from the minimum 1n of -8.6 ? to maximum 6p of +6.4 ?. The trough 1n probably coincides with the isotopic minimum at the Precambrian-Cambrian boundary worldwide. Highly positive d13C values of peaks 5p and 6p are typical of the upper portion of the Precambrian-Cambrian transitional beds just beneath the Tommotian Stage in Siberia. A second rising trend of d13C is observed through the Krasnoporog and lower Shumny formations. It consists of four excursions with four major maxima that can be cor related with Tommotian-Botomian peaks II, IV, V, and VII of the reference profile from the southeastern Siberian platform. According to the chemostratigraphic cor relation, the first appearances of the index forms of archaeocyaths are earlier in the Sukharikha section than in the Lena-Aldan region.

Description of manganese nodules and crust collected from the Hakurei Maru Cruise GH76-2, March-May, 1976, in Northwestern Pacific Ocean

The cores and dredges described in this report were taken on the GH76-2 Expedition in March-May, 1976 by the Geological Survey of Japan from the R/V Hakurei Maru. A total of 47 cores and dredges sites have been visited. The survey covered the whole of the Pacific side of the Tohoku Arc, the southern part of the Kurile Arc and the northern margin of the Izu-Ogasawara (Bonin) Arc. The surveyed area covered the continental shelves, slopes, trenches and Pacific basin along the trenches.

Description of manganese nodules and crust collected from the Hakuho Maru Cruise KH-68-3, July-August, 1968, in Northwestern Pacific Ocean

The cores and dredges described in this report were taken on the KH-68-3 Expedition in July-August, 1968 by the Ocean Research Institute, University of Tokyo from the Hakuho Maru. A total of 16 cores and dredges sites have been were.