Seaweed, including various species of Ulva (e.g., Ulva intestinalis, U. fasciata, U. lactuca, and U. rigida), is essential for maintaining the balance of aquatic ecosystems. These algae are found worldwide and have a high growth rate in diverse habitats. This article analyzes the composition of these Ulva spp (including carbohydrates, proteins, lipids, and ash). It also investigates the environmental factors that affect their growth and composition, such as pH, temperature, water depth, salinity, and nutrient availability. Understanding the variations in composition and environmental influences among Ulva spp highlights the importance of studying their ecological impact and genetic diversity.