The microplastic menace: a critical review of its impact on marine photoautotrophs and their environment

Seaweeds contribute to the energy input in marine communities and affect the chemical makeup, species composition, nutrient availability, pH, and seawater oxygen levels. However, the annual introduction of 28.5 million tons of plastic waste into oceans makes up 85% of marine litter, which is expected to grow fourfold in the next 25 years, causing a rise in concern for human health and the environment. Microplastics are small plastic particles of 1-5 mm that are either manufactured or formed due to the degradation of large plastic materials. This study analyzes the prevalence of microplastics in marine environments, their interaction with marine macro- and microalgae, environmental implications, genetic responses to microplastic exposure, and potential strategies for mitigating microplastic pollution. The leading causes identified were high plastic production rate (390 million tons annually), increased usage, inefficient waste management, meager recycling (9% is recycled), slow degradation (up to 1200 years), easy distribution via oceanic currents, and industrialization that has led to the accumulation of microplastics in the marine ecosystems. Therefore, it is recommended that the waste management system be strengthened, focusing on recycling, repurposing, reducing single-use plastics, and redirecting plastic waste away from water bodies. Developing reliable detection technologies, studying the long-term effects of microplastics in marine ecosystems, and collaborating with the public and private sectors may be encouraged. Further investigations on microplastic-seaweed interaction, the bioremediation potential of various species, and the involved molecular mechanisms may lead to new strategies for reducing microplastic loads in marine ecosystems.