Abstrak
Chlorella vulgaris merupakan salah satu jenis fitoplankton yang banyak dimanfaatkan dalam berbagai bidang, potensi tersebut dapat dikembangkan dengan budidaya Chlorella vulgaris. Pertumbuhan Chlorella ini sangat dipengaruhi oleh ketersediaan nutrien, salah satunya ion magnesium (Mg2+) yang berperan penting dalam pembentukan klorofil guna porses fotosintesis. Penelitian ini bertujuan untuk menganalisis pertumbuhan Chlorella vulgaris dengan penambahan ion magnesium (Mg2+) pada media kultur. Penelitian ini dilakukan selama 7 hari dengan lima perlakuan konsentrasi ion Mg2+, yaitu 0 ppm; 0,4 ppm; 0,8 ppm; 1,2 ppm; dan 1,6 ppm, masing-masing dua ulangan. Parameter kualitas air yang diukur suhu, salinitas dan, pH. Hasil penelitian menunjukkan bahwa perlakuan penambahan ion Mg2+ 0,4 ppm memberikan pertumbuhan tertinggi sebanyak 24.720 × 10⁴ sel/mL pada hari ke-6 pengamatan, sedangkan laju pertumbuhan spesifik tertinggi pada perlakuan penambahan ion Mg2+ 1,6 ppm sebesar 2.59 sel/mL hingga 7 hari pengamatan. Berdasarkan hasil tersebut dapat disimpulkan penambahan ion Mg2+ mampu memberikan pertumbuhan Chlorella vulgaris. Chlorella vulgaris is a phytoplankton species widely utilized in various sectors, including aquaculture, biotechnology, and environmental management. Its production potential can be optimized through the cultivation of C. vulgaris. The growth of C. vulgaris is strongly influenced by nutrient availability, particularly magnesium ions (Mg²⁺), which play a crucial role in chlorophyll formation for the photosynthesis process. This study aimed to analyze the growth of Chlorella vulgaris with the addition of magnesium ions (Mg²⁺) in the culture media. The experiment was conducted over seven days using five treatments of Mg²⁺ concentrations: 0 ppm, 0.4 ppm, 0.8 ppm, 1.2 ppm, and 1.6 ppm, each with two replications. Water quality parameters measured included temperature, salinity, and pH. The results showed that the treatment with the addition of 0.4 ppm Mg²⁺ yielded the highest growth, reaching 24,720 × 10⁴ cells/mL on the sixth day of observation. Meanwhile, the highest specific growth rate was recorded in the 1.6 ppm Mg²⁺ treatment, reaching 2.59 cells/mL over the seven-day observation period. Based on these results, it can be concluded that the addition of Mg²⁺ ions enhances the growth of Chlorella vulgaris.