Will Climate Change Impacts Aggravate Malnutrition in Concealed Ways? The Effects of Temperature Elevation on Nutritive Value of the Edible Seaweed Ulva fasciata Delile

The edible green seaweed Ulva fasciata which is abundant in Tanzania, is highly nutritious and can therefore help in curbing severe malnutrition currently reported in the country. Seaweeds on the other hand, are reported to be affected by temperature. This study was therefore aimed at investigating the effect of rising temperature on the nutritive value of Ulva fasciata. Samples were collected at the Oysterbay shoreline in Dar es Salaam and grown under controlled conditions at the University of Dar es Salaam. Growth rate and selected nutrients (proteins, vitamin A, carbohydrates, iron, phosphorus, calcium and potassium) were determined using standard analytical methods. Data analysis was done using Paleontological statistics (PAST) version 1.27, 1999-2012 package. The results show that temperature elevation caused a decline in growth rate of Ulva fasciata. Furthermore, its protein content declined sharply from 19.8% dry weight to only 5.8% dry weight when temperature increased above the range of 28-29 °C. With the exception of Phosphorus which increased progressively with temperatures rise, other nutrients including minerals showed a significant decrease when Ulva fasciata was grown in higher temperature ranges. The results suggest that the ongoing global warming will decrease nutritive value of Ulva fasciata.