Planktic foraminifera and shelled pteropods are some of the major producers calcium carbonate (CaCO 3 ) in ocean. Their calcitic (foraminifera) aragonitic (pteropods) shells particularly sensitive to changes chemistry play an important role for inorganic organic carbon pump Here, we have studied abundance distribution planktic (individuals m –3 their contribution standing stocks (μg export prod...

While sliding at seismic slip-rates of ?1 m/s, natural faults undergo an abrupt decrease shear stress called dynamic weakening. Asperity-scale (<<mm) processes related to flash heating and weakening and, meso-scale (mm-cm) involving across the bulk slip-zone, frictional melting or viscous flow minerals, have been invoked explain pronounced velocity-dependent Here we present a compilation ?100 e...

We present results of laboratory investigation slag-like artifacts, found on an archaeological site near Boršice, known by occurrence artifacts from the Early Neolithic (5 700–5 000 BC), Bronze and Medieval Ages. The grey-coloured foamy reach up to 5 cm in size often display original lava-like surface. These slags are formed especially strongly potassic (15–23 wt. % K2O) silicic (54–72 SiO2) gl...

Natural weathering is known as one of the key mechanisms causing degradation in building materials. Great efforts have been made to develop new materials and processes for protecting those that already exist. stones are an example a natural material has extensively used construction since ancient times. In addition, they fit durability, aesthetic, mechanical requirements. Thus, still great impo...

Abstract Phytoplankton dynamics in coastal ecosystems is increasingly altered by land‐based human activities. Yet, this global vision conceals major disparities, among sites and through time. As conventional monitoring time series are quite sparse relatively short, biological records of environmental variability appear as relevant tools to gain insights into phytoplankton over larger temporal s...

Microbially-induced CaCO3 precipitation (MICP) is a naturally occurring process wherein durable carbonates are formed as a result of microbial metabolic activities. In recent years, MICP technology has been widely harnessed for applications in civil engineering wherein synthesis of calcium carbonate crystals occurs at ambient temperature paving way for low energy biocement. MICP using pure urea...

Carbonate concretions can form as a result of organic matter degradation within sediments. However, the ability to determine specific processes and formation temperatures of particular concretions has remained elusive. Here, we employ concentrations of carbonate-associated sulfate (CAS), SCAS and clumped isotopes (along with more traditional approaches) to characterize the nature of concretion ...

Echinoderms possess a skeleton with a unique and distinctive meshlike microstructure called stereom that is underpinned by a specific family of genes. Stereom is thus considered the major echinoderm synapomorphy and is recognized already in some Cambrian echinoderm clades. However, data on the skeletal microstructures of early echinoderms are still sparse and come only from isolated ossicles of...

This study focuses on two main questions: (1) what types of shell damage occur in the death assemblage of upper Chesapeake Bay benthic mollusks; and (2) how does shell damage differ according to intrinsic factors such as life habit, shell mineralogy, and shell organic content. Extrinsic and intrinsic factors, ranging from the environment to shell composition, interact to influence the quality o...

UNLABELLED BACKGROUND Mollusc shells are commonly investigated using high-resolution imaging techniques based on cryo-fixation. Less detailed information is available regarding the light-optical properties. Sea shells of Haliotis pulcherina were embedded for polishing in defined orientations in order to investigate the interface between prismatic calcite and nacreous aragonite by standard m...