Temporal variation in chemical composition of Ulva lactuca and Corallina mediterranea

Abstract

The chemical profiles of green seaweed Ulva lactuca and red seaweed Corallina mediterranea of Egypt were studied. In this investigation, we studied the relation between the nutrient contents of selected species and the environmental changes during four seasons from summer 2016 to spring 2017. Seawater parameters such as pH, temperature and salinity were assessed. The protein contents were ranged between 10.7 ± 0.14 and 23.2 ± 0.1% DW, and the maximum amount was recorded in U. lactuca. Also, highly significant of seasonal changes (p < 0.05) for both studied species was showed in protein contents. Carbohydrate contents of two selected algae varied from 17.2 ± 0.19 to 29.0 ± 0.03% DW, where the C. mediterranea were recorded the maximum amount during spring season. The carbohydrate levels were significantly correlated with the changes in water temperature, pH and salinity at (p < 0.05). Lipid amounts were the minimum listed chemical content and change slightly between two tested seaweeds. The content of ash was greatest in C. mediterranea (39 ± 0.2) than in U. lactuca (25.8 ± 0.2). Both two seaweeds have a large amount of fiber during all seasons. The changes in pigment fractions were positively correlated with the changes in the environmental parameters (temperature, pH and salinity) during the four seasons. Through all studied seasons, U. lactuca was recorded the maximum content of total fatty acids, whereas the unsaturated fatty acids were dominant in C. mediterranea. For both studied algae, palmitic acid was the most fundamental saturated fatty acid and recorded the maximum values. The major component of amino acids was proline in two selected seaweeds, and the maximum values were recorded in C. mediterranea. Generally, the diversity in chemical constitution of two algal species was related to fluctuations of environmental conditions. Principal component analysis of fatty acid composition and amino acid contents of both species indicated that there is a relationship between the ecological variations during the different seasons and fatty acids or amino acids of algal species.