A comparison of methods for the non-destructive fresh weight determination of filamentous algae for growth rate analysis and dry weight estimation

Abstract

The determination of rates of macroalgal growth and productivity via temporal fresh weight (FW) measurements is attractive, as it does not necessitate the sacrifice of biomass. However, there is no standardised method for FW analysis; this may lead to potential discrepancies when determining growth rates or productivity and make literature comparison problematic. This study systematically assessed a variety of lab-scale methods for macroalgal FW measurement for growth rate determination. Method efficacy was assessed over a 14-day period as impact upon algal physiology, growth rate on basis of FW and dry weight (DW), nitrate removal, and maintenance of structural integrity. The choice of method is critical to both accuracy and inter-study comparability of the data generated. In this study, it was observed that the choice of protocol had an impact upon the DW yield (P values = 0.036–0.51). For instance, those involving regular mechanical pressing resulted in a >25% reduction in the final DW in two of the three species studied when compared to algae not subjected to any treatment. This study proposes a standardised FW determination method employing a reticulated spinner that is rapid, reliable, and non-destructive and provides an accurate growth estimation.Electronic supplementary materialThe online version of this article (doi:10.1007/s10811-017-1157-8) contains supplementary material, which is available to authorized users.

Nitrogen uptake by the macro-algae Cladophora coelothrix and Cladophora parriaudii: Influence on growth, nitrogen preference and biochemical composition

“…For instance, Luo et al [37] reported that Ulva prolifera had higher rates of growth and nutrient uptake than Ulva linza across a range of temperatures, irradiances, and N concentrations, most likely as a result of them having a different thallus morphology. A similar explanation may be valid in this case: Ross et al [13] noted that C. parriaudii grows rapidly outwards in a loose skein, whereas C. coelothrix grows slowly in tightly knit clusters. The denser growth strategy exhibited by C. coelothrix, as opposed to C. parriaudii, will likely enhance the effects of growth-limiting factors, such as self-shading and low nutrient availability within the tightly knit colony, as observed in other members of Cladophoraceae [38,39].…”

“…for FW determination and water chemistry analysis. On each sampling day, FW was determined by placing the biomass into a reticulated spinner (Chef'N Salad Spinner), spinning for 90 s to remove residual water and weighed gravimetrically in an analytical balance (PS-60, Fisher Brand, UK) [13]. Biomass was then returned to its original, corresponding flask and cultivated under the conditions described above.…”

“…However, C. coelothrix has been reported to be a robust species [13] and merits further study in conditions more representative of WWT, where it may exhibit a higher degree of tolerance and growth in comparison to C. parriaudii [40]. In addition, as N removal by C.…”

“…these include the supply of low N concentrations (<35 µM) and/or the use of short incubation times (<24 h), with no data provided on algal growth rates [11,12]. The determination of algal growth is one of the most fundamental parameters in phycological research, used for the comparison between treatments, assessment of biomass production and optimisation of culture conditions [13]. In addition, studies often employ the use of an algal inoculum that has been pre-acclimated in conditions designed to lower their internal nutrient reserves [14].…”

A Practical Electronic Health Record-Based Dry Weight Supervision Model for Hemodialysis Patients

“…We used the naive linear regression method to model the EMD baseline (EMD base ). The formula is defined by equation (9).…”