Physiological Adaptation Of Freshwater Algae To Abiotic Stresses
Keywords:
freshwater algae, abiotic stress, salinity tolerance, antioxidant enzymes, chlorophyll degradation, oxidative stress, biomass accumulationAbstract
Freshwater algae occupy a physiologically exposed position in aquatic systems, absorbing fluctuations in salinity,
temperature, light, and pH long before these shifts register at higher trophic levels. This study examines how three
freshwater genera Chlamydomonas reinhardtii, Scenedesmus obliquus, and Chlorella vulgaris respond
physiologically to a set of abiotic stressors imposed under controlled laboratory conditions [1]. Chlorophyll a
degradation, specific growth rate, antioxidant enzyme induction (SOD, CAT, POD), biomass accumulation, and
malondialdehyde-based lipid peroxidation were measured across gradients of salinity (0–25 g/L), temperature
(10–40°C), stress duration (0–10 days), light intensity (50–350 μmol m⁻² s⁻¹), and pH (4–10) [2]. Results show a
consistent pattern: moderate stress intensities trigger compensatory enzymatic defense, while stress beyond
genus-specific thresholds produces irreversible pigment loss and oxidative damage. These findings connect
measurable biochemical markers to whole-organism outcomes and offer a physiological basis for using
freshwater algae as early bioindicators of abiotic environmental stress, with direct relevance to water quality
monitoring and algal biomass cultivation planning.
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