A review of seaweeds: Diversity, culture and global economic impact

Seaweeds, commonly referred to as marine macroalgae, represent a highly diverse group of photosynthetic organisms that play an essential role in marine ecosystems and global industries. This review aims to provide an overview of seaweed diversity, cultivation practices, and their growing global economic significance. Seaweeds are broadly categorized into three groups—brown (Phaeophyta), red (Rhodophyta), and green (Chlorophyta)—each with unique pigments, ecological niches, and commercial importance. The industry is predominantly sustained through aquaculture, accounting for over 97% of total production, with Asian countries, particularly China, Indonesia, and South Korea, contributing more than 90% of global supply. Cultivation techniques such as long-line and raft methods offer sustainable approaches requiring minimal natural resources, making seaweed farming an environmentally friendly practice. Results from global industry data highlight the wide-ranging applications of seaweeds across food, agriculture, industrial, and pharmaceutical sectors. In food and nutrition, seaweeds are valued for their high protein, fiber, vitamins, and minerals, especially iodine. Industrially, hydrocolloids such as agar, carrageenan, and alginates derived from seaweeds are essential as gelling, thickening, and stabilizing agents. In agriculture, seaweed extracts serve as natural biostimulants and fertilizers, while in pharmaceuticals, bioactive compounds are being studied for therapeutic and cosmetic applications. Economically, the seaweed industry is estimated at USD 25.38 billion in 2025, with a projected CAGR exceeding 12% through 2029, reflecting rising global demand for sustainable products. Beyond economic growth, seaweed farming also contributes to climate change mitigation through carbon sequestration and provides vital livelihood opportunities for coastal communities. In conclusion, seaweeds stand as a versatile, sustainable resource with immense potential to support global food security, economic development, and environmental conservation, reinforcing their role in the sustainable blue economy.