Seasonal variation in productivity, chemical composition and nutrient uptake of Ulva spp. (Chlorophyta) strains

Abstract

Applications of seaweeds require the supply of uniform biomass, yet performance of Ulva is generally characterised by a wide variation across study sites and seasons, as well as among species or strains. This study aimed to determine the variation in growth, biochemical composition and nutrient uptake of five Ulva strains collected in the Eastern Scheldt estuary (the Netherlands) and cultivated under standardised outdoor conditions from July to November. Surprisingly, only two strains performed well (maximum 291 ± 95 and 570 ± 122 kg FW ha−1 day−1 for VEE and YER strain), one strain showed slow growth (maximum 155 ± 91 kg FW ha−1 day−1 for SCH strain), and the last two strains (JAC and KOM) did not grow at all. Chemical composition was only determined for the well-performing strains. For most of the parameters, strong seasonality was observed; growth, crude fat (0.4–1.3%), ash (16–25%) and starch (3–11%) decreased, whereas fibres (37–45%) and proteins (7–22% crude; 6–18% true) increased. To evaluate the bio-remediation potential, nutrient uptake of YER, VEE and SCH strains was determined from in- and outflowing water (453–2027 µmol DIN; 4–101 µmol PO4 kg FW h−1). Highest rates were observed for the SCH strain which was not in accordance with growth nor composition, suggesting that nutrients were not (all) directed towards vegetative growth. This study demonstrates a large variation in performance between different Ulva strains collected in relatively close proximity and thereby highlights the importance to test a variety of local seaweed strains prior to commercial farming.

A Fully Integrated Biorefinery Process for the Valorization of Ulva fasciata into Different Green and Sustainable Value-Added Products

“…All the listed data in Tables 1-5 are comparable to those recorded for different Ulva species [34][35][36][37][38][39][40][41][42][43][44][45]. The protein content (Table 1) is comparable to that reported by Labib and Hosny [46] for Ulva fasciata which recorded 11.68-13.43%, but better than that reported for Ulva lactuca, which recorded 7.16% [12].…”

Programmable flow injection: a versatile technique for benchtop and autonomous analysis of phosphate and silicate in seawater

“…The relatively constant concentrations of phosphate observed in the control tank confirm active phosphate uptake by Ulva lobata as opposed to uncontrolled factors. While a detailed analysis of these data falls beyond the scope of this manuscript, specific phosphate uptake rates that ranged from 6-10 µmol L -1 PO 4 kg FW -1 hr -1 at a concentration of ~1.0 µmol L -1 PO 4 , fall within the range of values reported in a similar study involving Ulva spp (Jansen et al, 2022). This was achieved at a much higher temporal resolution than can be achieved with discrete sampling and opens the door for more complex seaweed nutrient uptake rate evaluations using pFI.…”

Early hatchery protocols for tetrasporogenesis of the antimethanogenic seaweed Asparagopsis armata

“…Variation in the effects of environmental factors on tetrasporogenesis are expected across geographically isolated strains of seaweed due to the reproductive synchrony of seaweeds with their surrounding environment (Ims 1990;Rule et al 2013). Moreover, such variation may also occur across geographically separated populations of the same strain, or between co-existing strains as a result of underlying genetic differences (Mata et al 2017;Jansen et al 2022). The samples used in the present study were most likely of the L1B lineage, which is part of one of the two lineages (L1B and L2B within two cryptic clades L1 and L2) of A. armata found within New Zealand (Preuss et al 2022).…”