Chukchi Sea oil & gas lease sale 126 : draft environmental impact statement.

"OCS EIS/EA MMS 90-0035."

Fragm. lat. I 99 - Liber dialogorum (L.II c.1 - 2 Vita s.Benedicti; PL 66,126 - 132)

Trägerband: 15/474; Vorbesitzer: Dominikanerkloster Frankfurt am Main

[Review of] Eigler, Friederike, and Jens Kugele, eds. Heimat. At the Intersection of Memory and Space. Berlin: de Gruyter, 2012. 268 pp. $126.00 hardcover

Book review: Eigler, Friederike, and Jens Kugele, eds. Heimat. At the Intersection of Memory and Space. Berlin: de Gruyter, 2012. 268 pp. $126.00 hardcover.

Global compilation of benthic data sets I

Approaches to quantify the organic carbon accumulation on a global scale generally do not consider the small-scale variability of sedimentary and oceanographic boundary conditions along continental margins. In this study, we present a new approach to regionalize the total organic carbon (TOC) content in surface sediments (<5 cm sediment depth). It is based on a compilation of more than 5500 single measurements from various sources. Global TOC distribution was determined by the application of a combined qualitative and quantitative-geostatistical method. Overall, 33 benthic TOC-based provinces were defined and used to process the global distribution pattern of the TOC content in surface sediments in a 1°x1° grid resolution. Regional dependencies of data points within each single province are expressed by modeled semi-variograms. Measured and estimated TOC values show good correlation, emphasizing the reasonable applicability of the method. The accumulation of organic carbon in marine surface sediments is a key parameter in the control of mineralization processes and the material exchange between the sediment and the ocean water. Our approach will help to improve global budgets of nutrient and carbon cycles.

Organic carbon accumulation in the South Atlantic Ocean

A compilation of 1118 surface sediment samples from the South Atlantic was used to map modern seafloor distribution of organic carbon content in this ocean basin. Using new data on Holocene sedimentation rates, we estimated the annual organic carbon accumulation in the pelagic realm (>3000 m water depth) to be approximately 1.8*10**12 g C/year. In the sediments underlying the divergence zone in the Eastern Equatorial Atlantic (EEA), only small amounts of organic carbon accumulate in spite of the high surface water productivity observed in that area. This implies that in the Eastern Equatorial Atlantic, organic carbon accumulation is strongly reduced by efficient degradation of organic matter prior to its burial. During the Last Glacial Maximum (LGM), accumulation of organic carbon was higher than during the mid-Holocene along the continental margins of Africa and South America (Brazil) as well as in the equatorial region. In the Eastern Equatorial Atlantic in particular, large relative differences between LGM and mid-Holocene accumulation rates are found. This is probably to a great extent due to better preservation of organic matter related to changes in bottom water circulation and not just a result of strongly enhanced export productivity during the glacial period. On average, a two- to three-fold increase in organic carbon accumulation during the LGM compared to mid-Holocene conditions can be deduced from our cores. However, for the deep-sea sediments this cannot be solely attributed to a glacial productivity increase, as changes in South Atlantic deep-water circulation seem to result in better organic carbon preservation during the LGM.

(Table 1, page 126) Concentration of elements in Fe and Mn rich pisoliths (nodules) from Lake Storsjoen, South Norway

A detailed description of the ores of Lake Storsjoen was given by Vogt J. H. L., 1915 who pointed out that the ores may be divided into two principal types; first, iron ore with 2% or less of manganese (ex: Ertemalm), and, second, ores with manganese contents of up to 30% (ex: Korinter). The iron-rich ore sometimes occurs as a conglomerate embedded in manganese-rich ores, clearly demonstrating that two distinctly different precipitates are involved. In the iron-rich ore, a concentric structure is common of which light brown layers of loose, almost dusty material alternate with hard and brittle black layers, the thickness of each being 0.5 mm or less. The analyses presented in this paper seem to demonstrate that the composition of the sedimentary ores of Lake Storsjden could result from fluctuations in the composition of ground waters feeding the lake.