Microscopy techniques have been widely applied to observe cellular ultrastructure. Most of these techniques, such as transmission electron microscopy, produce high‐resolution images, but they may require extensive preparation, hampering their application for in vivo examination. Other approaches, such as fluorescent and fluorogenic probes, can be applied not only to fixed specimens but also to living cells when the probes are nontoxic. Fluorescence‐based methods, which are generally relatively easy to use, allow visual and (semi)quantitative studies of the ultrastructural organization and processes of the cell under natural as well as manipulated conditions. To date, there are relatively few published studies on the nearly ubiquitous marine protistan group Foraminifera that have used fluorescent and fluorogenic probes, despite their huge potential. The aim of the present contribution is to document the feasible application of a wide array of these probes to foraminiferal biology. More specifically, we applied fluorescence‐based probes to study esterase activity, cell viability, calcium signaling, pH variation, reactive oxygen species, neutral and polar lipids, lipid droplets, cytoskeleton structures, Golgi complex, acidic vesicles, nuclei, and mitochondria in selected foraminiferal species.
Phosphorus (P) adsorption-desorption behaviors on the airborne dust have been investigated by using simulation with numerical modeling. Dust samples were collected during summer 2011 along coastline of Kuwait Bay. Dust storms results showed that substantial nutrients increase in Kuwait Bay which is led to, subsequently, frequent algal blooms and ecological stress. Numerous physical processes give rise to nutrient levels including sediment adsorption/ desorption processes. This correlation was incorporated into a three-dimensional hydrodynamic model (Delft3D-FLOW) and a 3D water quality model (Delft3D-WAQ), originated by Deltares, the Netherlands and was linked to a sediment transport model. Simulations showed an enhanced prediction of dissolved phosphorus in Kuwait Bay during the last dust storm in 2011.
Heavy metals are one of the most hazardous pollutants in marine environments because of their bioaccumulation and biomagnification capabilities. Among them, cadmium (Cd) has been considered as one of the most dangerous for marine organisms. Here we incubated Ammonia cf. parkinsoniana specimens, a benthic foraminiferal taxon used in previous experiments, for up to 48 h in natural seawater with different concentrations of Cd to unravel the physiological change. We document a reduced pseudopodial activity of the Cd-treated specimens at concentrations >10–100 ppb in comparison with the control specimens. Moreover, confocal images of Cd-treated specimens using Nile Red as a fluorescent probe reveal an enhanced intracellular neutral lipid accumulation in the form of lipid droplets at 6 h and 12 h. This bioassay experiment allows for the direct evaluation of Cd-dose to A. cf. parkinsoniana-response relationships under laboratory controlled conditions and provides complementary information to field observations as well as to water quality guidelines and thresholds.
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