Науково-практичний семінар “Архівна україніка: пошук, реєстрація та комплектування архівів”

28 жовтня 2010 р. у Державному комітеті архівів України відбувся науково-практичний семінар “Архівна україніка: пошук, реєстрація та комплектування архівів”, організований Державним комітетом спільно з Центральним державним архівом зарубіжної україніки (ЦДАЗ У) і Українським науково-дослідним інститутом архівної справи та документознавства (УНДІА СД) на виконання Указу Президента України від 13.10.2006 № 875/2006 “Про національну концепцію співпраці із закордонними українцями, державної програми співпраці із закордонним українством та галузевої програми “Зарубіжна україніка”

Calibration and application of foraminiferal based trace metal proxies in the Mediterranean Sea

Fossil remnants of benthic foraminifera consist of carbonate tests and their organic linings. The macromolecular and stable isotopic composition of these benthic foraminiferal organic linings was characterized to evaluate their potential use as paleoclimate proxies. Using Curie point pyrolysis–GC–MS (Py–GC–MS) we show that benthic foraminiferal organic linings consist of protein and polysaccharides, bound together in a complex macromolecular structure. Both chitin derivatives and traces of guaiacols and syringols, usually assigned to lignin, are found. Although the five species of benthic foraminifera all contain chitin derivatives and proteins, the relative contribution of these compounds tends to vary considerably. Oxygen stable isotopic analyses of the organic linings of the benthic foraminiferal species Ammonia tepida indicates that δ18OOL values are in line with fractionation between seawater and organic matter. In contrast a δ13C deliberate tracer experiment showed that metabolic carbon is the main source for the carbon fixed in the organic lining. The different pathways of carbon and oxygen stable isotopes into the foraminiferal linings have important implications for future proxy development as they reflect different components of the environment compared to the carbonate bound stable isotopes. Still, the future application of benthic foraminiferal organic linings and their isotopic values critically relies on improvements in calibration and sample size required for isotopic analyses

Calibration and application of foraminiferal based trace metal proxies in the Mediterranean Sea

Fossil remnants of benthic foraminifera consist of carbonate tests and their organic linings. The macromolecular and stable isotopic composition of these benthic foraminiferal organic linings was characterized to evaluate their potential use as paleoclimate proxies. Using Curie point pyrolysis–GC–MS (Py–GC–MS) we show that benthic foraminiferal organic linings consist of protein and polysaccharides, bound together in a complex macromolecular structure. Both chitin derivatives and traces of guaiacols and syringols, usually assigned to lignin, are found. Although the five species of benthic foraminifera all contain chitin derivatives and proteins, the relative contribution of these compounds tends to vary considerably. Oxygen stable isotopic analyses of the organic linings of the benthic foraminiferal species Ammonia tepida indicates that δ18OOL values are in line with fractionation between seawater and organic matter. In contrast a δ13C deliberate tracer experiment showed that metabolic carbon is the main source for the carbon fixed in the organic lining. The different pathways of carbon and oxygen stable isotopes into the foraminiferal linings have important implications for future proxy development as they reflect different components of the environment compared to the carbonate bound stable isotopes. Still, the future application of benthic foraminiferal organic linings and their isotopic values critically relies on improvements in calibration and sample size required for isotopic analyses

Manganese incorporation in living (stained) benthic foraminiferal shells : a bathymetric and in-sediment study in the Gulf of Lions (NW Mediterranean)

Manganese geochemistry in deep-sea sediments is known to vary greatly over the first few centimeters, which overlaps the in-sediment depth habitats of several benthic foraminiferal species. Here we investigated manganese incorporation in benthic foraminiferal shell carbonate across a six-station depth transect in the Gulf of Lions, NW Mediterranean, to unravel the impacts of foraminiferal ecology and Mn pore water geochemistry. Over this transect water depth increases from 350 to 1987m, while temperature (∼ 13°C) and salinity (∼ 38.5) remained relatively constant. Manganese concentrations in the tests of living (rose bengal stained) benthic foraminiferal specimens of Hoeglundina elegans, Melonis barleeanus, Uvigerina mediterranea, and Uvigerina peregrina were measured using laser ablation inductively coupled mass spectrometry (laser ablation ICP-MS). Pore water manganese concentrations show a decrease from shallow to deeper waters, which corresponds to a generally decreasing organic-matter flux with water depth. Differences in organic-matter loading at the sediment-water interface affects oxygen penetration depth into the sediment and hence Mn pore water profiles. Mn/Ca values for the investigated foraminiferal species reflect pore water geochemistry and species-specific microhabitat in the sediment. The observed degree of variability within a single species is in line with known ranges in depth habitat and gradients in redox conditions. Both the Mn/Ca ratio and interspecific variability hence reflect past Mn cycling and related early diagenetic processes within the sediment, making this a potential tool for bottom-water oxygenation and organic-matter fluxes. Dynamics of both in-sediment foraminiferal depth habitats and Mn cycling, however, limit the application of such a proxy to settings with relatively stable environmental conditions

Laser ablation Mn/Ca ratios of single foraminiferal shells from the Gulf of Lions

Foraminiferal trace element concentrations were determined using two laser ablation ICP-MS systems. Prior to laser ablation, all samples were gently cleaned in methanol (x1) and UHQ water (x4). Between each rinse, the samples were placed in a sonic bath for several seconds to thoroughly clean the tests. Benthic foraminifera from 745m (station D), 980m (station C), 1488m (station B), and 1987m (station A) were measured at Utrecht University using a deep UV (193 nm) ArF excimer laser (Lambda Physik) with GeoLas 200Q optics. Ablation was performed at a pulse repetition rate of 10 Hz and an energy density of 1.4 J/cm², with a crater size of 80 μm. Ablated particles were measured by a quadrupole ICP-MS (Micromass Platform) equipped with a collision and reaction cell. Such a collision and reaction cell improves carbonate analyses by eliminating interferences on mass 44. Scanned masses included 24Mg, 26Mg, 27Al, 42Ca, 43Ca, 55Mn, 88Sr, 137Ba, 138Ba, and 208Pb. Benthic foraminifera from stations F (350 m) and E (552 m) were analyzed at ETH Zurich (due to laboratory renovations at Utrecht University). The laser type and ablation parameters were identical to those detailed above. The ablated particles were measured using a quadrupole ICP-MS (ELAN 6100 DRC, PerkinElmer). In both cases, calibration was performed using an international standard (NIST610) with Ca as an internal standard (Jochum et al., 2011). The same masses as measured in Utrecht were monitored, in addition to 7Li, 23Na, 47Ti, 60Ni, 61Ni, and 89Y. Interlaboratory compatibility was monitored using a matrix-matched calcite standard. For Mn, reported here, this standard showed a precision better than 3%over all analyses, at ETH and UU, and with an offset of less than 5%from an offline-determined (solution ICP-AES) concentration analyzing discrete subsamples. The matrix-matched standard is routinely included in the analyses and has been monitored since 2010 at Utrecht University. Analytical error (equivalent to 1 sigma), based on repeated measurement of an external standard, was < 5% for reported elements. Each laser ablation measurement was screened for contamination by monitoring Al and Pb. On encountering surface contamination, the data integration interval was adjusted to exclude any Al or Pb enrichment. Cross-plots between Al and Pb versus Mn showed that they are unrelated, confirming the accuracy of the integrations

Reconstructing the seafloor environment during sapropel formation using benthic foraminiferal trace metals, stable isotopes, and sediment composition

The evolution of productivity, redox conditions, temperature, and ventilation during the deposition of an Aegean sapropel (S1) is independently constrained using bulk sediment composition and high-resolution single specimen benthic foraminiferal trace metal and stable isotope data. The occurrence of benthic foraminifer, Hoeglundina elegans (H. elegans), through a shallow water (260 m) sapropel, permits for the first time a comparison between dissolved and particulate concentrations of Ba and Mn and the construction of a Mg/Ca–based temperature record through sapropel S1. The simultaneous increase in sedimentary Ba and incorporated Ba in foraminiferal test carbonate, (Ba/Ca)H. elegans, points to a close coupling between Ba cycling and export productivity. During sapropel deposition, sedimentary Mn content ((Mn/Al)sed) is reduced, corresponding to enhanced Mn2+ mobilization from sedimentary Mn oxides under suboxic conditions. The consequently elevated dissolved Mn2+ concentrations are reflected in enhanced (Mn/Ca)H. elegans levels. The magnitude and duration of the sapropel interruption and other short-term cooling events are constrained using Mg/Ca thermometry. Based on integrating productivity and ventilation records with the temperature record, we propose a two-mode hysteresis model for sapropel formation