Algal response to nutrient enrichment; insights into growth and chemical concentrations in two algae, Halimeda macroloba Decaisne and Turbinaria conoides (J. Agardh) Kützing

The effect of nutrient enrichment on the growth and chemical concentrations of two different algal life strategies, Halimeda macroloba and Turbinaria conoides were assessed to test the predictions of the Carbon-Nutrient Balance Hypothesis (CNBH). We concluded that nutrient enrichment had no strong effects on the growth but had a direct effect on the polyphenol concentration of both H. macroloba and T. conoides. These results support the CNBH that nutrient plays an important role in the polyphenol concentrations of these two species. Polyphenol concentrations of H. macroloba and T. conoides were higher at the ambient site than the enriched site. However, the growth of both species did not change significantly and did not vary throughout the time. When comparing the responses of H. macroloba and T. conoides to the nutrient enrichment, we found that Halimeda allocated resources to growth and defense while Turbinaria allocated more resources into defense than growth.