engleski

Algal motility as an indicator of environmental stress

The increasing instability of climate dynamics, caused by pervasive anthropogenic pressures, demands profound ecosystem management through environmental protection and sustainable development. The most widely used environmental indicator for monitoring climate change is temperature, while heavy metals such as cadmium reflect anthropogenic activities. Nowadays, there is a high need to use a parameter for direct and high-throughput analysis of the behavior of intact cells in aquatic samples. This study aims to investigate the potential of cell motility as a direct indicator of environmental stress using two flagellated green algae that differ in cell barrier and flagellar system morphology. The open- source image processing software was used to quantitatively characterize changes in motility behavior in terms of swimming speed and search radius based on video data acquisition. The results showed that the change in growth temperature from favorable conditions caused a decrease in swimming speed and search radius of the two green algae studied. Moreover, the presence of heavy metal cadmium in the growth medium caused a decrease in the swimming speed and search radius of species possessing a soft cell envelope in contrast to specie with a rigid cell envelope. Thus, the response of algae to stressors in batch culture appears to be species-specific, with cell morphology contributing to stress tolerance. Algal cells with soft glycocalyx membranes appear to be more sensitive to temperature and heavy metals than cells encased in a stiffer calcite theca. Concurrent studies revealed concomitant changes in algal cell surface properties and physiological activity when exposed to the corresponding stressors, which contributes to the understanding of motility behavior at the single-cell level. Based on the presented results, the changes in algal motility may be used to indicate disturbances in the aquatic system and serve for monitoring needs.

motility ; Dunaliella ; Tetraselmis

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