Publications by authors named "Sigal Abramovich"

Foraminifera are unicellular protists capable of precipitating calcite tests, which fossilize and preserve geochemical signatures of past environmental conditions dating back to the Cambrian period. The biomineralization mechanisms responsible for the mineral structures, which are key to interpreting palaeoceanographic signals, are poorly understood. Here, we present an extensive analysis of the test-bound proteins.

View Article and Find Full Text PDF

Due to ongoing ocean warming, subtropical environments are becoming accessible to tropical species. Among these environments are the vermetid reefs of the Southeastern Mediterranean (SEM). In the last decades, these valuable coastal habitats witnessed the proliferation of numerous alien species of tropical origin.

View Article and Find Full Text PDF

Foraminifera are unicellular organisms that established the most diverse algal symbioses in the marine realm. Endosymbiosis repeatedly evolved in several lineages, while some engaged in the sequestration of chloroplasts, known as kleptoplasty. So far, kleptoplasty has been documented exclusively in the rotaliid clade.

View Article and Find Full Text PDF

Among the most successful Lessepsian invaders is the symbiont-bearing benthic foraminifera Amphistegina lobifera. In its newly conquered habitat, this prolific calcifier and ecosystem engineer is exposed to environmental conditions that exceed the range of its native habitat. To disentangle which processes facilitated the invasion success of A.

View Article and Find Full Text PDF

Environmental disturbances resulting from anthropogenic energy pollution are intensely growing and represent a concern for the marine environment. Benthic organisms are the significant fauna exposed to this kind of pollution; among them, foraminifera are largely used as pollution bioindicators in marine environments, but studies on the effects induced by electrical stimulation are not documented. In the present research, we evaluated the effects of short-term different electric current densities on the viability of benthic foraminiferal species by checking the pseudopodial activity and defined the threshold electrical density range.

View Article and Find Full Text PDF

The evaluation of the effects of pollution (e.g., Hg pollution) is a difficult task and relies mostly on biomonitoring based on bioindicators.

View Article and Find Full Text PDF

Rising sea surface temperatures and extreme heat waves are affecting symbiont-bearing tropical calcifiers such as corals and Large Benthic Foraminifera (LBF). In many ecosystems, parallel to warming, global change unleashes a host of additional changes to the marine environment, and the combined effect of such multiple stressors may be far greater than those of temperature alone. One such additional stressor, positively correlated to temperature in evaporation-dominated shallow-water settings is rising salinity.

View Article and Find Full Text PDF

Proteins are essential to life, and the evaluation of their content, identification, and modification represents a fundamental assay in biochemistry research. Different analytical techniques and protocols have been specifically designed but have rarely been compared. Here, we test and compare a variety of methodologies and treatments for the quantification of proteins in , a larger symbiont-bearing benthic foraminiferal species.

View Article and Find Full Text PDF

Considering the thermal limits of coastal macroalgae habitats in the South-Eastern Mediterranean, it is important to study the response of the associated meiofauna to better understand the expected feedback of ecosystems to future warming. In this study, we compared benthic foraminiferal assemblages from two common macroalgal habitats, Turf and Coralline algae, based on ecological monitoring of a thermally polluted station representing near future warming, and an undisturbed environment. None of the common local species is confined to a specific algal habitat.

View Article and Find Full Text PDF

This study was promoted by the recent efforts using larger benthic foraminiferal (LBF) shells geochemistry for the monitoring of heavy metals (HMs) pollution in the marine environment. The shell itself acts as a recorder of the ambient water chemistry in low to extreme HMs-polluted environments, allowing the monitoring of recent-past pollution events. This concept, known as sclerochronology, requires the addition of new parts (i.

View Article and Find Full Text PDF

Desalination plants along the Mediterranean Israeli coastline currently provide ~587 million m3 drinking water/year, and their production is planned to increase gradually. Production of drinking water is accompanied by a nearly equivalent volume of brine discharge with a salinity of ~80 that is twice the normal, which can potentially impact marine ecosystems. The goal of this study was to examine whether benthic foraminifera, a known sensitive marine bio-indicator, are affected by this brine-discharge.

View Article and Find Full Text PDF

The Eastern Mediterranean is experiencing a large-scale invasion of alien tropical species from the Red Sea. This "Lessepsian invasion" began with the opening of the Suez Canal and is promoted by the ongoing oceanic warming. The environmental differences between the Red Sea and the Mediterranean act as a buffer allowing the invasion of certain species.

View Article and Find Full Text PDF

A microorganism template approach has been explored for the fabrication of various well-defined three-dimensional (3D) structures. However, most of these templates suffer from small size (few μm), difficulty to remove the template, or low surface area, which affect their potential use in different applications or makes industrial scale-up difficult. Conversely, foraminifer's microorganisms are large (up to 200 mm), consist of CaCO (easy to dissolve in mild acid), and have a relatively high surface area (≈5 m g).

View Article and Find Full Text PDF

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

View Article and Find Full Text PDF

Large benthic foraminifera (LBF) are marine calcifying protists that commonly harbor algae as symbionts. These organisms are major calcium carbonate producers and important contributors to primary production in the photic zones. Light is one of the main known factors limiting their distribution, and species of this group developed specific mechanisms that allow them to occupy different habitats across the light gradient.

View Article and Find Full Text PDF

In order to establish environmentally sustainable industries there is a need for high-resolution temporal and spatial monitoring of heavy metal pollutants even at low concentrations before they become hazardous for local ecosystems. Here we present single chamber records of Cu, Zn and Pb in shells of two benthic foraminifera species with different shell types from two shallow coastal stations in Israel: An area adjacent to an electrical power plant and desalination factory (Hadera) and an industrially free nature reserve (Nachsholim). Records of both foraminifera species show elevated metal concentrations in Hadera clearly identifying the footprint of the local industrial facilities.

View Article and Find Full Text PDF

Shallow marine calcifiers play an important role as marine ecosystem engineers and in the global carbon cycle. Understanding their response to warming is essential to evaluate the fate of marine ecosystems under global change scenarios. A rare opportunity to test the effect of warming acting on natural ecosystems is by investigation of heat-polluted areas.

View Article and Find Full Text PDF

Persistent thermohaline pollution at a site along the northern coast of Israel, due to power and desalination plants, is used as a natural laboratory to evaluate the effects of rising temperature and salinity levels on benthic foraminifera living in shallow hard-bottom habitats. Biomonitoring of the disturbed area and a control station shows that elevated temperature is a more significant stressor compared to salinity, thus causing a decrease in abundance and richness. Critical temperature thresholds were observed at 30 and 35°C, the latter representing the most thermally tolerant species in the studied area Pararotalia calcariformata, which is the only symbiont-bearing species observed within the core of the heated area.

View Article and Find Full Text PDF

Textularia agglutinans d'Orbigny is a non-symbiont bearing and comparatively large benthic foraminiferal species with a widespread distribution across all oceans. In recent years, its populations have considerably expanded along the Israeli Mediterranean coast of the eastern Levantine basin. Despite its exceptionally widespread occurrence, no molecular data have yet been obtained.

View Article and Find Full Text PDF

The eastern Mediterranean is a hotspot of biological invasions. Numerous species of Indo-pacific origin have colonized the Mediterranean in recent times, including tropical symbiont-bearing foraminifera. Among these is the species Pararotalia calcariformata.

View Article and Find Full Text PDF

Background: On Late Cretaceous Tethyan upwelling sediments from the Mishash/Ghareb Formation (Negev, Israel), bulk geochemical and biomarker analyses were performed to explain the high proportion of phosphates in the lower part and of organic matter (OM) preserved in upper parts of the studied section. The profile is composed of three facies types; the underlying Phosphate Member (PM), the Oil Shale Member (OSM) and the overlying Marl Member (MM).

Results: Total organic carbon (TOC) contents are highly variable over the whole profile reaching from 0.

View Article and Find Full Text PDF

The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF) that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean.

View Article and Find Full Text PDF

The thermal pollution patch of Hadera power plant was used as a natural laboratory to evaluate the potential long-term effects of rise in Eastern Mediterranean SST on living benthic foraminifera. Their sensitivity to environmental changes makes foraminifera ideal for this study. Ten monthly sampling campaigns were performed in four stations located along a temperature gradient up to 10 °C from the discharge site of heated seawater to a control station.

View Article and Find Full Text PDF