Spatial, seasonal, and within-plant variation in total fatty acid content and composition in the brown seaweeds Dictyota bartayresii and Dictyopteris australis (Dictyotales, Phaeophyceae)

Abstract

We investigated the spatial, seasonal, and withinplant variation in total fatty acids (TFA) and fatty acid (FA) composition in the brown seaweeds Dictyota bartayresii sampled from Nelly Bay, Orpheus Island, and Kissing Point (Northern Queensland, Australia) and Dictyopteris australis sampled from Nelly Bay. Both species were present year round, but with no consistent seasonal pattern in plant size, and had an annualized mean content of TFA of 5 % dry weight (dw) that is among the highest recorded for seaweeds. For Dictyota, larger plants had a higher content of TFA and a higher proportion of polyunsaturated omega-3 FA (PUFA(n-3)) than smaller plants, while for Dictyopteris, the TFA content and the proportion of PUFA(n-3) were unrelated to plant size. TFA in Dictyota varied considerably between locations (~40 %) (3.5-5.5 % dw) and to a lesser degree between seasons (~10 %) with a lower content of TFA and higher proportion of PUFA(n-3) in winter. Dictyopteris had añ 10 % higher content of TFA in winter but with no seasonal pattern in the composition of FA. There was also within-plant variation in FA, as TFA decreased from the tips toward the base in both species, and in Dictyopteris, the tips had a higher proportion of saturated FA (SFA) and PUFA(n-3) than the base. The presence of site-and species-specific variation in the content and composition of fatty acids reinforces the need for detailed analyses of the biochemical profile of seaweed biomass, including their extracts or purified compounds, if the focus is nutritional applications based on lipids.

Water and Lipid-Soluble Component Profile of <i>Sargassum cristaefolium</i> from Different Coastal Areas in Indonesia with Potential for Developing Functional Ingredient

“…Samples of AB and PI had higher total sugar and crude fiber than UGB and SHB . Factors that may affect these outcomes are the presence of nutrients as well as water conditions that determine nutrient transport during the growth process of the brown algae 22,23 . As reported by several studies, the current velocity of the southern water of Java is in the range of 15-45 cm/s 21,24 , while the northern water of Java has a lower current velocity ranging from 1.62 to 10 cm/s 25,26 .…”

“…In addition, the blade is a vital organ for the photosynthetic process, thus the increase of its proportion in plant structure will increase the amount of pigment, PUFA, and ratio n-3:n-6 58 . Other factors affecting seaweed lipid and fatty acid composition are genetic, hydrodynamic condition, light intensity, temperature, annual cycle, salinity, and mineral content of medium 23,50 . In S. piluliferum, increasing salinity was associated with increasing levels of C18:4n3, C20:4n6, C20:5n3, total n-3, and total n-6 PUFAs 59 .…”

Environmental effects on growth and fatty acids in three isolates of Derbesia tenuissima (Bryopsidales, Chlorophyta)

“…However, the increased unsaturation with decreased temperature occurs in many [22,64], but not all species of microalgae [61] investigated to date. This temperature effect on the composition of fatty acids has been investigated experimentally for only a few species of seaweed [13,14], but similar to microalgae there seems to be no general trend as many field based studies also show increased PUFA(n-3) contents during the warmer summer months [10,12] and species-specific interactions between light and growth rates therefore seem likely. Nevertheless, we provide here the first evidence for the temperature dependence of PUFA(n-3) content in D. tenuissima, and the observed variation of this temperature effect below the species level has implications for strain selection for different climates.…”

“…While there is extensive literature on environmental effects on the content and composition of fatty acids in microalgae [7,8], research on seaweeds is largely restricted to field studies based on broad environmental correlations with fatty acids [9][10][11][12] and only a few studies in a limited number of species have experimentally quantified the effects of temperature [13,14] and light [15,16] on fatty acids. Additionally, while the effect of nitrogen starvation can lead to substantial increases in content and composition of PUFA(n-3) in microalgae [17], the quantification of the effects of nitrogen availability on the content and composition of fatty acids in seaweeds is restricted to a few species of Ulva [18][19][20] and Gracilaria [21].…”

“…Importantly however, genotypic variation in the content and composition of fatty acids, in particular the nutritionally important PUFA(n-3), within seaweeds has not been demonstrated [24]. Although field based studies have quantified variability in the content and composition of fatty acids between individual conspecific individuals from within and between spatially isolated populations of seaweeds [1,10], the distinctions between the effects of local environmental conditions and a genetic component remain speculative.…”