(Table 1) Composition of bottom sediments from the East Pacific

Adsorption of ion, nickel, cobalt, and manganese from ocean water by calcareous sediments, diatomaceous ooze, hydrogenous sediments, and red clay was studied under close to natural conditions using a tracer method. It was found that hydrogenous sediments selectively remove manganese from seawater. This may be associated with formation of chemical compounds between manganese and sediment material. It was also found that nickel, manganese, and iron exist in the ocean in several ionic and neutral forms. Cobalt typically present in only one ionic form Co(2+).

Concentrations of chemical elements in bottom sediments from the Southeast Pacific

Data from the Appendix to the PhD Thesis of the author.

(Table 2) Chemical element contents in the surface sediment layer on the submeridional section through the Eastern Pacific

Paper devoted to geochemistry of antimony in metalliferous and transitional sediments from the Southeast Pacific.

(Table 1) Planktonic foraminifera counts and stable oxygen isotope ratios of Pacific Ocean surface sediments

Core-top samples from the eastern tropical Pacific (10°N to 20°S) were used to test whether the ratio between Globorotalia menardii cultrata and Neogloboquadrina dutertrei abundance (Rc/d) and the oxygen isotope composition (?18O) of planktonic foraminifera can be used as proxies for the latitudinal position of the Equatorial Front. Specifically, this study compares the ?18O values of eight species of planktonic foraminifera (Globigerinoides ruber sensu stricto (ss) and sensu lato (sl), Globigerinoides sacculifer, Globigerinoides triloba, Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globorotalia menardii menardii, Globorotalia menardii cultrata and Globorotalia tumida) with the seasonal hydrography of the region, and evaluates the application of each species or combination of species for paleoceanographic reconstructions. The results are consistent with sea surface temperature and water column stratification patterns. We found that in samples north of 1°N, the Rc/d values tend to be higher and d18O values of G. ruber, G. sacculifer, G. triloba, P. obliquiloculata, N. dutertrei, and G. menardii cultrata tend to be lower than those from samples located south of 1°N. We suggest that the combined use of Rc/d and the d18O difference between G. ruber and G. tumida or between P. obliquiloculata and G. tumida are the most suitable tools for reconstructing changes in the latitudinal position of the Equatorial Front and changes in the thermal stratification of the upper water column in the eastern tropical Pacific.

(Appendix B) Dinoflagellate cysts in Southeast Pacific Ocean surface sediments

orty-eight surface sediment samples from the southeast (SE) Pacific (25-53°S) are investigated for the determination of the spatial distribution of organic-walled dinoflagellate cysts along the western South American continental margin. Fifty-five different taxa are recorded and reflect oceanic or coastal assemblages. The oceanic assemblages are characterised by low cyst concentrations and the dominance of autotrophs, while the coastal assemblages generally contain a higher number of cysts, which are mainly produced by heterotrophic species. Highest cyst concentrations are observed in the active upwelling system offshore Concepción (35-37°S). Brigantedinium spp., Echinidinium aculeatum, Echinidinium granulatum/delicatum and cysts of Protoperidinium americanum dominate assemblages related to upwelling. Echinidinium aculeatum appears to be the best indicator for the presence of all year round active upwelling cells. Other protoperidinioid cysts may also occur in high relative abundances in coastal regions outside active upwelling systems, if the availability of nutrients, co-responsible for the presence/absence of their main food sources such as diatoms and other protists, is sufficient. The importance of nutrient availability as a determining environmental variable influencing cyst signals on a regional scale (SE Pacific) is demonstrated through statistical analyses of the data. Because of the importance of nutrients, uncertainties about the outcomes of quantitative sea-surface temperature (SST) reconstructions (Modern Analogue Technique) based on dinoflagellate cysts may arise, since no interaction between different hydrographical variables is considered in this approach. The combination of the SE Pacific surface sample dataset with other published cyst data from the Southern Hemisphere resulted in a database which includes 350 samples: the 'SH350 database'. This database is used to test the accuracy of the quantitative reconstructions by calculating and comparing the estimated versus observed values for each site. An attempt to perform quantitative SST reconstructions on the last 25 cal ka of site ODP1233 (41°S; 74°27'W) is made and again stresses the importance of other environmental variables such as nutrient availability in determining the dinoflagellate cyst assemblages.

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.

Chemical composition of Fe-Mn nodules, micronodules, and host bottom sediments of the Northeast Pacific

A set of methods has been used for studying composition, structure and distribution of Fe-Mn-micronodules in bottom sediments of the Northeast Pacific. It has been shown that there are two types of Fe-Mn micronodules differing in size, external shape, internal structure and composition of constituent manganese minerals.

Planktonic foraminiferal faunas from surface-sediment samples from the South China Sea and the western Pacific

We present 30 new planktonic foraminiferal census data of surface sediment samples from the South China Sea, recovered between 630 and 2883 m water depth. These new data, together with the 131 earlier published data sets from the western Pacific, are used for calibrating the SIMMAX-28 transfer function to estimate past sea-surface temperatures. This regional SIMMAX method offers a slightly better understanding of the marginal sea conditions of the South China Sea than the linear transfer function FP-12E, which is based only on open-ocean data. However, both methods are biased toward the tropical temperature regime because of the very limited data from temperate to subpolar regions. The SIMMAX formula was applied to sediment core 17940 from the northeastern South China Sea, with sedimentation rates of 20-80 cm/ka. Results revealed nearly unchanged summer temperatures around 28°C for the last 30 ky, while winter temperatures varied between 19.5°C in the last glacial maximum and 26°C during the Holocene. During Termination 1A, the winter estimates show a Younger Dryas cooling by 3°C subsequent to a temperature optimum of 24°C during the Bölling=Alleröd. Estimates of winter temperature differences between 0 and 100 m water depth document the seasonal variations in the thickness of the mixed layer and provide a new proxy for estimating past changes in the strength of the winter monsoon.

Calcium carbonate preservation in the equatorial Pacific

The Pliocene-Pleistocene history of CaCO3 preservation in the central equatorial Pacific is reconstructed from a suite of deep-sea cores and is compared to fluctuations in global ice volume inferred from delta18O records. The results are highlighted by: (1) a strong covariation between CaCO3 preservation and ice volume over 104 to 106 year time scales; (2) a long-term increase in ice volume and CaCO3 preservation since 3.9 Ma demonstrated by a deepening of the lysocline and the carbonate critical depth; (3) a dramatic shift to greater CaCO3 preservation at 2.9 Ma; (4) distinctive ice-volume growth and CaCO3 preservation events at 2.4 Ma, which are associated with the significant intensification of northern hemisphere glaciation; (5) a mid-Pleistocene transition to 100-kyr cyclicity in both CaCO3 preservation and ice volume; and (6) a 600-kyr Brunhes dissolution cycle superimposed on the late Pleistocene glacial/interglacial 100-kyr cycles. CaCO3 preservation primarily reflects the carbonate chemistry of abyssal waters and is controlled by long-term (106 year) and short-term (104 to 105 year) biogeochemical cycling and by distinct paleoclimatic events. We attribute the long-term increase in CaCO3 preservation primarily to a fractionation of CaCO3 deposition from continental shelf to ocean basin, and secondarily to a gradual rise in the riverine and glaciofluvial flux of Ca++. On shorter time scales, the fluctuations in CaCO3 preservation slightly lag ice volume fluctuations and are attributed to climatically induced changes in the circulation and chemistry of Pacific deep water.

Trace element contents in bottom sediments from the North Indian Ocean

Contents and distributions of Cu, Ni, Co, V, Cr, Zn, Pb, Mo, W, and Zr in near-coast and pelagic sediments of the Northern Indian Ocean are under consideration in the paper. Chemical analyses showed enrichment of pelagic clayey radiolarian oozes by Mn, Cu, Ni, Co, Pb, W, and Mo. According to enrichment factors these elements have the following order: Mo> Mn> Cu> Ni> Co> Pb> W. Enrichment of pelagic sediments from the Indian Ocean is mainly determined by the mechanism of the sedimentation process. Enrichment factors of Cu, Ni, Co, W, Mo, and Mn in pelagic sediments of the North Indian Ocean are intermediate between ones in pelagic sediments of the Pacific and Atlantic Oceans.

(Plate 3) Manganese nodules and deep-sea sediment core from Pacific Ocean

A synoptic review of the studies of well-known occurrences of palagonite tuffs is presented. Included are palagonite tuffs from Iceland, and pillow-lava palagonite complexes from Columbia River basalts and from the central Oregon coast. Additional petrologic and x-ray defraction data for selected samples are presented. Petrologic evidence shows that basaltic glass of aqueous tuffs and breccias consists of sideromelane, which is susceptible to palagonitization. It is shown that palagonitization is a selective alteration process, involving hydration, oxidation and zeolitization. Some of the manganese nodules dredged from the Pacific Ocean floor contain nucleus of palagonite-tuff breccias or of zeolite. A brief megascopic and microscopic description of nodules from the south Pacific, the Mendocino ridge and the 'Horizon' Nodule from the north Pacific is presented. Petrographic studies of palagonite-tuff breccias of manganese nodules and other palagonites suggest that migration and segregation of metallic elements occur during and subsequent to palagonitization. During the palagonitization of sideromelane, nearly 30 percent of sea water is absorbed. The hydration of sideromelane is also accompanied by oxidation of iron and other elements. These oxides may be released either in colloidal form or in true solution and tend to precipitate first from the unstable palagonite.

Mineralogy of sea-floor surface sediments, Sonne cruise SO202/1 to the North Pacific and Bering Sea

During expedition 202 of research vessel SONNE in 2009, 39 sea-floor surface sediments were sampled over a wide area across the North Pacific and the Bering Sea, which are well suited as reference archives of modern environmental processes. In this study, we used the samples to infer the documentation of land-ocean linkages of terrigenous sediment supply. We followed an integrated approach of grain-size analysis, bulk mineralogy, and clay mineralogy in combination with statistical data evaluation (end-member modelling of grain-size data, fuzzy-cluster analysis of mineralogical data), in order to identify the significant sources and modes of sediment transport in an overregional context. We also compiled literature data on clay mineralogy and updated those with the new data. Today, two processes of terrigenous sediment supply prevail in the study area: far-distant aeolian sediment supply to the pelagic North Pacific as well as hemipelagic sediment dispersal from nearby land sources by ocean currents along the continental margins and island arcs of the study area. The aeolian particles show the finest grain sizes (clay and fine silt), while the hemipelagic sediments have high abundances of sortable silt, particles >10 microns.

Age, 232Th, 230Th, 238U, CaCO3, organic carbon, lithogenic fraction and opal concentrations of 4 sediment cores from the southwest Pacific, with calculated 230Th-normalized mass flux

No clear scenario has yet been able to explain the full carbon drawdown that occurred during the Last Glacial Maximum (LGM); however, increased export production (EP) in the Subantarctic Zone (SAZ) of the Southern Ocean due to iron (Fe) fertilisation has been proposed to have provided a key mechanism affecting the air-sea partitioning of carbon. We chronicle changes in marine EP based on four sediment cores in Subtropical Waters (STW) and SAZ around New Zealand since the LGM. For the first time in this region, we present 230-Thorium normalised fluxes of biogenic opal, carbonate (CaCO3), excess Barium (xsBa), and organic Carbon (Corg). In STW and SAZ, these flux variations show that EP did not change markedly since the LGM. The only exception was a site in the SAZ close to the STF, where we suggest the STF shifted over the core site, driving increased EP. To understand why EP was mostly low and constant we investigated dust deposition changes by measuring lithogenic fluxes at the four sites. These data are coherent with an increased dust deposition in the southwest Pacific during the LGM. Additionally, we infer an increased lithogenic material discharge from erosion and glacier melts during the deglaciation, limited to the Campbell Plateau. Therefore, we propose that even though increased glacial dust deposition may have relieved Fe limitation within the SAZ, the availability of silicic acid (Si(OH)4) limited any resultant increase in carbon export during the LGM. Consequently, we infer low Si(OH)4 concentrations in the SAZ that have not significantly changed since the LGM. This result suggests that both Si(OH)4 and Fe co-limit EP in the SAZ around New Zealand, which would be consistent with modern process studies.

Global distributions of diazotrophs Gamma-A nifH genes abundance - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs Gamma-A nifH genes abundance, computed from a collection of source data sets.