This is the second paper on principles of demineralization. The initial paper is dedicated to the common definitions and the history of demineralization. In present work we review the principles and mechanisms of decalcification, i.e., removing the mineral Ca-containing compounds (phosphates and carbonates) from the organic matrix in its two main aspects: natural and artificial. Natural chemica...

Abstract Chalk has been used since Antiquity for various purposes, and Gothic preparatory layers of painted cultural heritage objects. Several materials are called chalk in Cultural Heritage, but this work especially focuses on composed calcareous nannofossils (up to 98%). These fossil remains photoautotrophic algae generally smaller than 30 μm. They mainly visible as platelets shapes under a c...

Large benthic foraminifera are major carbonate components in tropical platforms, important producers, stratigraphic tools and powerful bioindicators (proxies) of environmental change. The application large coral reef environments has gained considerable momentum recent years. These modern ecological assessments often carried out by micropalaeontologists or ecologists with expertise the identifi...

The Paleocene-Eocene Thermal Maximum (PETM) is associated with major extinctions in the deep ocean, and significant paleogeographic ecological changes surface ocean terrestrial environments. However, impact of environmental change on shelf biota less well understood. Here, we present a new PETM record low paleolatitude shallow-marine carbonate platform from Meghalaya, NE India (eastern Tethys)....

Maerl beds are composed of unattached red calcareous coralline algae. When located in shallow ecosystems, these macroalgae provide substrates for the development fleshy epiphytic macroalgae, which contribute to productivity maerl beds. To assess importance their contribution, we estimated primary production main taxa (Solieria chordalis or Rhodomelaceae), growing 2 distinct Lithothamnion corall...

The objective of this study is to understand the calcareous nannoplankton response to past environmental changes in the Strait of Hormuz during the Holocene. Calcareous nannoplankton is well abundant in the living phytoplankton community and a key component of the marine sediments. Due to its distinct reaction to environment changes and its good preservation potential, it is well suited for p...

It is difficult to obtain high quality samples of natural material covering a range of densities and degree of cementation, so study on the sample preparation techniques with similar mechanical properties of natural samples are very important. Experiments were carried out to study the effects of cementation of different materials on the mechanical properties of calcareous sand, e.g., the effect...

Nitrogen fixation blue-green algae make a major contribution to the fertility of soil. It has been suggested that blue-green algae (BGA) assist higher plant growth by supplying growth substances. There are numerous works about roles of blue-green algae in paddy soils and rice growth but little on other plants. In this research, 19 morphospecies belonging to three families of heterocystous and n...