We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Impacts of microplastic and seawater acidification on unicellular red algae: Growth response, photosynthesis, antioxidant enzymes, and extracellular polymer substances
Summary
Researchers examined the individual and combined effects of polystyrene microplastics and seawater acidification on unicellular red algae, which play an important role in marine primary production. They measured impacts on growth, photosynthesis, antioxidant enzyme activity, and extracellular polymer production. The study found that the combined stressors had more pronounced effects than either one alone, suggesting that ocean acidification may worsen the ecological impact of microplastic pollution on marine algae.
Microplastics (MPs) pollution and seawater acidification have increasingly become huge threats to the ocean ecosystem. Their impacts on microalgae are of great importance, since microalgae are the main primary producers and play a critical role in marine ecosystems. However, the impact of microplastics and acidification on unicellular red algae, which have a unique phycobiliprotein antenna system, remains unclear. Therefore, the impacts of polystyrene-MPs alone and the combined effects of MPs and seawater acidification on the typical unicellular marine red algae Porphyridium purpureum were investigated in the current study. The result showed that, under normal seawater condition, microalgae densities were increased by 17.75-41.67 % compared to the control when microalgae were exposed to small-sized MPs (0.1 μm) at concentrations of 5-100 mg L. In addition, the photosystem II and antioxidant enzyme system were not subjected to negative effects. The large-sized MPs (1 μm) boosted microalgae growth at a low concentration of MPs (5 mg L). However, it was observed that microalgae growth was significantly inhibited when MPs concentration increased up to 50 and 100 mg L, accompanied by the remarkably reduced F/F value and the elevated levels of SOD, CAT enzymes, phycoerythrin (PE), and extracellular polysaccharide (EPS). Compared to the normal seawater condition, microalgae densities were enhanced by 52.11-332.56 % under seawater acidification, depending on MPs sizes and concentrations, due to the formed CO-enrichment condition and appropriate pH range. PE content in microalgal cells was significantly enhanced, but SOD and CAT activities as well as EPS content markedly decreased under acidification conditions. Overall, the impacts of seawater acidification were more pronounced than MPs impacts on microalgae growth and physiological responses. These findings will contribute to a substantial understanding of the effects of MPs on marine unicellular red microalgae, especially in future seawater acidification scenarios.
Sign in to start a discussion.
More Papers Like This
Dual impacts of elevated pCO2 on the ecological effects induced by microplastics and nanoplastics: A study with Chlamydomonas reinhardtii
Researchers examined how freshwater acidification from elevated carbon dioxide interacts with polystyrene micro- and nanoplastics to affect a common green algae species. They found that smaller nanoplastics caused greater harm than larger microplastics, primarily through oxidative stress, while acidification alone actually promoted algal growth. The study reveals that climate change and plastic pollution can interact in unexpected ways, with acidification sometimes masking or modifying the toxic effects of plastic particles.
Warming coupled with elevated pCO2 modulates microplastic inhibition in a commercial red alga Pyropia haitanensis
Researchers cultured the commercially important red seaweed Pyropia haitanensis under elevated CO₂, warming, and a range of microplastic concentrations, finding that microplastics caused strong concentration-dependent stress on growth and photosynthesis, but that elevated pCO₂ modulated these inhibitory effects.
Adverse effects of microplastics on the growth, photosynthesis, and astaxanthin synthesis of Haematococcus pluvialis
Researchers exposed the microalga Haematococcus pluvialis to polystyrene microplastics and found that while short-term contact briefly stimulated growth, longer exposure inhibited photosynthesis, caused oxidative stress, and impaired the organism's ability to produce astaxanthin, a valuable natural antioxidant. The findings highlight how microplastic pollution could disrupt both aquatic ecosystems and the commercial production of beneficial compounds from algae.
The effect of microplastics pollution in microalgal biomass production: A biochemical study
Scientists exposed the marine microalga Phaeodactylum tricornutum to polystyrene microplastics and found that both short- and long-term exposure at environmentally relevant concentrations disrupted biochemical composition including proteins, carbohydrates, and lipids.
Evaluating physiological responses of microalgae towards environmentally coexisting microplastics: A meta-analysis
A meta-analysis of 52 studies found that microplastics inhibit microalgal growth and photosynthesis and induce oxidative damage, though microalgae can recover over time. Cyanobacteria are more vulnerable than green algae, and the relative size of microplastics to algal cells governs the mechanism of impact, while aged versus pristine microplastics have opposite effects on extracellular polymeric substance and microcystin production.