Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design

Abstract

2012Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design JOURNAL OF APPLIED PHYCOLOGY, DORDRECHT, v. 24, n. 6, pp. 1419-1426, DEC, 2012 Abstract In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18-26°C; L, 74-162 μmol photons m −2 s . In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5-7.0% d −1. The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X L , (α00.05). On the other hand, the only significant quadratic term (X Q ) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R adjusted 2 00.9540).

Temperature- and light-dependent growth and metabolism of the invasive red algaeGracilaria vermiculophylla– a comparison with two native macroalgae

“…Growth of macroalgae is fundamentally regulated by temperature and light (Lobban & Harrison, 1994;Raikar et al, 2001;Mendes et al, 2012) and knowing a species' physiological response to these parameters is of vital importance to predict future distributions of non-indigenous macroalgae. Without quantitative data, predictive modelling is impossible (Kearney & Porter, 2009).…”

Prediction of mono‐, bi‐, and trivalent metal cation relative toxicity to the seaweed Gracilaria domingensis (Gracilariales, Rhodophyta) in synthetic seawater

“…The DGR values were determined by using the expression Δ m(m final – m initial )/ Δ t(t final – t initial ) , where m is the mass and Δ t is 48 h. The average DGR values of triplicates were used to calculate the IC50 values (fitting growth sigmoidal curves with a dose–response function). The G. domingensis cultures were cultivated and maintained at optimal conditions as determined previously by a multivariate factorial analysis . The concentration of metal cations was determined with inductively coupled plasma atomic emission spectroscopy according to the standard methods of the US Environmental Protection Agency (USEPA, method 6010C).…”

“…The result of the last combination, or covalent index (X m 2 r), reflects the cation-binding tendency of soft ligands as sulfur-containing biomolecules [19,21]. Despite the considerable ecological and economic importance of marine seaweeds from the Gracilaria genus to the pharmaceutical industry and as raw materials for agar production [22][23][24][25], metal toxicity studies using the QICAR approach are scarce. For the present study, we modeled the effects of some metal cation physicochemical parameters on their toxicity to a representative species of the red seaweed Gracilaria domingensis (Kütz.)…”

New drugs with antiprotozoal activity from marine algae: a review

“…Therefore, algae are considered to be the most important aquatic bioremediator due to their ability to absorb metals and organic pollutants. Metals are then sequestered by glutathione and stored in vacuoles, and the organic compounds are metabolized to yield small molecules (Leitão et al, 2003;Mendes et al, 2012). These organisms represent a great diversity of species, and are of great importance in the food, pharmaceutical, cosmetic and biotechnology industries as the source of several compounds with economic impact (Cardozo et al, 2006;Guaratini et al, 2007).…”