Abiotic parameters
The average irradiance value recorded during the day considering all the experiments was 145.52 ± 20.65 µmol photons m− 2 s− 1 and the total light energy received by the cultures varied between 938.89 and 1,552.19 kJ m− 2 The water temperature in the algae tanks varied between 10.72°C and 23.85°C, with a global average value of 16.43 ± 2.92°C. Irradiance and temperature evolution during the experiments can be seen in Supplementary Material (Fig. S1). The final pH was significantly influenced by the interaction of nitrogen source and initial nitrogen concentration (ANOVA: F(2) = 113.5, p < 0.001, table S1). The values varied from 8.15 to 8.58 for treatments with N-NH4+ and from 8.40 to 9.82 for treatments with N-NO3− (Fig. S2).
Nutrient removal
Considering the total experimental time of 1440 min (24 h), the reduction of nitrogen nutrients was complete for both N-NH4+ and N-NO3− treatments (Fig. 1). However, some differences were visible and statistically significant (Tables 1, S1, S2). The reductions were more abrupt in the treatments with N-NH4+ (Fig. 1a, b), especially in the first 60 min and at the lowest initial concentration (150 µmol L− 1). Regarding the biomass density, the reductions were greater in the treatments with 10 g L− 1 (RM ANOVA, SNK; p < 0.001). In treatments with N-NO3− (Fig. 1c, d) the smoothest pattern of reduction was similar between treatments with different initial biomass densities, following almost linear trends. These results were influenced by the interaction between the factors initial concentrations, exposure time and biomass densities (RM ANOVA: N-NH4+ = F(10) = 52.9, p < 0.001; N-NO3− = F(10) = 4.3, p < 0.001).
By analyzing the nutrient removal efficiency (NUE) data, the nutrient removal patterns become clearer (Fig. 2). For treatments with 6 g L− 1 of N-NH4+, the removal reaches 90% already at 180 min in the case of the initial concentration of 150 µmol L− 1, and at 300 min for concentrations of 300 and 500 µmol L− 1 (Fig. 2a). In treatments with 10 g L− 1 of N-NH4+ the removal reaches 90% in 180 min for the initial concentrations of 150 and 300 µmol L− 1 (RM ANOVA, SNK; p > 0.100), taking a little longer (300 min) for the concentration of 500 µmol L− 1 (Fig. 2b). In contrast, for N-NO3− treatments, both biomasses presented similar removal efficiencies and no significant difference was observed in 60 min (RM ANOVA, SNK; p > 0.600) (Fig. 2c, d). For 6 g L− 1, removal efficiencies above 90% were only observed at 1440 min with 150 and 500 µmol L− 1 and at 420 min with 300 µmol L− 1 (RM ANOVA, SNK; p > 0.900) (Fig. 2c). In a similar manner, when biomass density was 10 g L− 1 this removal efficiency was only reached after 1440 min (RM ANOVA, SNK; p > 0.700) (Fig. 2d).
The nutrient uptake rates (NUR) also exhibited different patterns for the different N-sources (Fig. 3). For N-NH4+ values decreased continuously over time for both biomass densities used (Fig. 3a, b). In treatments with 6 g L− 1 of biomass similar results were showed throughout the experiment for initial concentrations of 150 and 300 µmol L− 1, and a decay was observed from a maximum of 149.8 ± 10.0 µmol g− 1 DW h− 1 to a minimum of 7.7 ± 0.2 µmol g− 1 DW h− 1 between 60 and 1440 min of experiment (Fig. 3a). For initial concentrations of 500 µmol L− 1 a maximum uptake rate of 180.4 ± 7.3 µmol g− 1 DW min− 1 was observed after 60 min and a minimum value of 26.0 ± 0.0 µmol g− 1 DW h− 1 was observed at the end of the experiment (Fig. 3a). A similar pattern was observed for treatments with 10 g L− 1 of biomass (Fig. 3b). The maximum uptake rates occurred after the first 60 min of the experiment for concentrations of 500 µmol L− 1 (193.0 ± 4.2 µmol g− 1 DW h− 1), followed by concentrations of 300 µmol L− 1 and 150 µmol L− 1 (106.4 ± 2.5 µmol g− 1 DW min− 1) (Fig. 3b). At the end of the experiment, the uptake rate decreased to minimum levels of 4.7, 9.4 and 15.6 µmol g− 1 DW h− 1, respectively for the three initial concentrations used.
In contrast, the uptake rate of cultures treated with N-NO3− showed a different trend. The values in the initial 60 min were low when compared to the treatments with N-NH4+ (14.3 ± 3.7 µmol g− 1 DW h− 1 in cultures with 150 µmol L− 1 and 45.6 ± 0.19 µmol g− 1 DW h− 1 in cultures with 300 and 500 µmol L− 1), increasing a little between 180 and 300 min, decreasing again thereafter (Fig. 3c, d). The values did not show statistical differences among the factors: nutrient’s initial concentrations, biomass densities, and time (RM ANOVA: N-NO3− = F(4) = 6.68, p < 0.001). For cultures with biomass density of 6 g L− 1, N-NO3− uptake rate rose initially from 60 min to 180 min, with small variation in values up to 300 min, decreasing progressively until the end (1440 min) (Fig. 3c). Maximum value of 63.3 ± 1.8 µmol g− 1 DW h− 1 was reached at 180 min by the treatment with 300 µmol L− 1 (Fig. 3c). For cultures with 10 g L− 1 of biomass, the N-NO3− uptake rate occurred at an almost constant rate (between 12.3 ± 5.1 and 10.3 ± 1.7 µmol g− 1 DW h− 1) in incubations with 150 µmol L− 1, decreasing at the end to 4.4 ± 0.2 µmol g− 1 DW h− 1 (Fig. 3d). In incubations with 300 and 500 µmol L− 1 of N-NO3− the maximum uptake rates occurred after 180 min reaching values of 35.0 ± 4.8 and 38.4 ± 6.6 µmol g− 1 DW h− 1. At the end of the experiment, the same treatments decreased to 9.4 and 15.6 µmol g− 1 DW h− 1, respectively.
Table 1
Repeated measures ANOVA effects on nutrient’s concentrations (umol L⁻¹), uptake efficiency (%), and uptake rate (g-1 DW h-1) of U. pseudorotundata. Data are shown under diferent nutrient’s initial concentrations (N-NH4+ or N-NO3- : 150, 300, and 500 umol L⁻¹), Ulva’s biomass densities (FW 6 g L⁻¹ and FW 10 g L⁻¹), and time (0, 60, 180, 300, 420, and 1440 minutes) conditions. df: degree of freedom; F: F-statistic. The significance differences (p < 0.05) are shown in bold.
| | Nutrient's concentrations | | | | |
Nutrient source | N-NH₄⁺ | | N-NO₃⁻ |
Source | | df | F | p | | F | p |
Nutrient's initial concentration (1) | 2 | 5286.85 | 0.00 | | 1199.24 | 0.00 |
Biomass density (2) | 1 | 722.03 | 0.00 | | 0.78 | 0.40 |
(1) x (2) | | 2 | 141.36 | 0.00 | | 4.57 | 0.03 |
Time (3) | | 5 | 13946.14 | 0.00 | | 2824.30 | 0.00 |
(1) x (3) | | 10 | 1751.11 | 0.00 | | 315.48 | 0.00 |
(2) x (3) | | 5 | 284.74 | 0.00 | | 3.29 | 0.01 |
(1) x (2) x (3) | 10 | 52.90 | 0.00 | | 4.29 | 0.00 |
| | Nutrient's uptake efficiency | | | |
Nutrient's initial concentration (1) | 2 | 402.26 | 0.00 | | 39.29 | 0.00 |
Biomass density (2) | 1 | 643.13 | 0.00 | | 3.37 | 0.09 |
(1) x (2) | | 2 | 51.66 | 0.00 | | 3.31 | 0.07 |
Time (3) | | 4 | 1955.09 | 0.00 | | 1084.90 | 0.00 |
(1) x (3) | | 8 | 231.04 | 0.00 | | 23.81 | 0.00 |
(2) x (3) | | 4 | 196.69 | 0.00 | | 4.15 | 0.01 |
(1) x (2) x (3) | 8 | 20.05 | 0.00 | | 2.20 | 0.04 |
| | Nutrient's uptake rate | | | | |
Nutrient's initial concentration (1) | 2 | 1895.27 | 0.00 | | 89.05 | 0.00 |
Biomass density (2) | 1 | 553.66 | 0.00 | | 80.52 | 0.00 |
(1) x (2) | | 2 | 8.10 | 0.01 | | 4.71 | 0.03 |
Time (3) | | 4 | 4673.01 | 0.00 | | 78.36 | 0.00 |
(1) x (3) | | 8 | 74.42 | 0.00 | | 6.58 | 0.00 |
(2) x (3) | | 4 | 46.14 | 0.00 | | 6.68 | 0.00 |
(1) x (2) x (3) | 8 | 33.07 | 0.00 | | 1.41 | 0.21 |
Photosynthetic performance
In-situ estimation of Electron Transport Rate
Photosynthetic Electron Transport Rates (ETR) through PSII measured in situ (Fig. 4) were significantly affected by the interaction of N-source, nutrient concentrations, and time (ANOVA: F(2.0) = 13.74, p < 0.001, Table 2). Then, considering this interaction, a significant decay on ETRsitu was verified in the concentrations of 150 and 300 µmol L− 1 from 15 min to 1440 min using N-NH4+ as a source of nutrient (ANOVA, SNK; p < 0.001). For N-NO3−, in the same time interval, a decay on ETRsitu was observed for the concentration of of 300 µmol L− 1 (ANOVA, SNK; p < 0.001) and no statisticaly diference was observed for treatments of 150 µmol L− 1 (ANOVA, SNK; p = 0.09) and 500 µmol L− 1 (ANOVA, SNK; p = 0.13).
Table 2
Multifactorial ANOVA effects on ETRsitu of U. pseudorotundata, using a Pocket-PAM fluorometer. Data are shown under diferent Ulva’s biomass densities (FW 6 g L⁻¹ and FW 10 g L⁻¹), nutrient’s source (N-NH4+ and N-NO3-), nutrient’s initial concentrations (N-NH4+ or N-NO3-; 150, 300, and 500 umol L⁻¹), and time (15 and 1440 minutes) conditions. df: degree of freedom; F: F-statistic. The significance differences (p < 0.05) are shown in bold.
Variable | | ETRsitu | |
Source | | df | F | p |
Biomass density (1) | 1 | 590.85 | 0.00 |
Nutrient source (2) | 1 | 19.06 | 0.00 |
Nutrient's initial concentration (3) | 2 | 157.41 | 0.00 |
Time (4) | | 1 | 83.46 | 0.00 |
(1) x (2) | | 1 | 1.48 | 0.22 |
(1) x (3) | | 2 | 212.26 | 0.00 |
(2) x (3) | | 2 | 59.97 | 0.00 |
(1) x (4) | | 1 | 54.85 | 0.00 |
(2) x (4) | | 1 | 13.31 | 0.00 |
(3) x (4) | | 2 | 11.25 | 0.00 |
(1) x (2) x (3) | 2 | 58.65 | 0.00 |
(1) x (2) x (4) | 1 | 3.92 | 0.05 |
(1) x (3) x (4) | 2 | 1.43 | 0.24 |
(2) x (3) x (4) | 2 | 13.74 | 0.00 |
(1) x (2) x (3) x (4) | 2 | 0.86 | 0.42 |
Ex-situ rapid light-responses curves
The maximal quantum yield (Fv/Fm), which is used as a sensitive indicator of seaweed photosynthetic performance, was significantly affected (ANOVA: Fv/Fm = F(6) = 3.58, p < 0.05) by the interaction among U. pseudorotundata biomass density, nutrient concentrations and time, but no significant difference (ANOVA, p = 0.52) was found between the different N-source treatments (Fig. 5, Table 3). The Fv/Fm significantly decreased after 420 min of experiment just for cultures with 6 g L− 1 of biomass, cultivated on 150 µmol L− 1 of nutrients. At this point, the minimal value of Fv/Fm observed was 0.35 ± 0.11.
Maximal electron transport rate (ETRmax), described as an indicator of photosynthetic capacity, was influenced by a significant interaction (ANOVA: F(6.0) = 6.46, p < 0.05) among N-source, nutrient concentrations and time, but not by biomass density (ANOVA: F(6.0) = 0.65, p = 0.69; Fig. 6, Table 3). In an overview, the ETRmax showed the lowest values in the N-NH4+ treatments at 15 min of the experiment, although some data at later times, especially among N-NH4+ treatments, did not show significant differences.
The αETR, considered as a descriptor of photosynthetic efficiency, was significantly affected by the interaction among biomass density, nutrient concentration and time (ANOVA: αETR = F(6) = 3.60, p < 0.05, Table 3) (Fig. 7), but no significantly difference (ANOVA, p = 0.59) was found between the different N-source treatments. Data obtained from αETR showed a slight decrease at evening (420 min) for the treatment 150 µmol L− 1 and 6 g L− 1 of biomass.
Table 3
Multifactorial ANOVA effects on photosynthetic parameters of U. pseudorotundata. Data are shown under different Ulva’s biomass densities (6 g L⁻¹ and 10 g FW L⁻¹), nutrient’s source (N-NH4+ and N-NO3-), nutrient’s initial concentrations (150, 300, and 500 umol L⁻¹), and time (15, 180, 420, and 1440 minutes) conditions. df: degree of freedom; F: F-statistic. The significance differences (p < 0.05) are shown in bold.
Variables | | Fv/Fm | | | ETRmax | | αETR | |
Source | df | F | p | | F | p | | F | p |
Biomass density (1) | 1 | 6.18 | 0.01 | | 10.89 | 0.00 | | 3.66 | 0.06 |
Nutrient source (2) | 1 | 0.00 | 0.99 | | 176.89 | 0.00 | | 1.10 | 0.30 |
Nutrient's initial concentration (3) | 2 | 2.20 | 0.12 | | 5.37 | 0.01 | | 2.19 | 0.12 |
Time (4) | 3 | 11.38 | 0.00 | | 7.17 | 0.00 | | 12.13 | 0.00 |
(1) x (2) | 1 | 4.29 | 0.04 | | 0.76 | 0.39 | | 7.42 | 0.01 |
(1) x (3) | 2 | 1.15 | 0.32 | | 6.42 | 0.00 | | 2.41 | 0.10 |
(2) x (3) | 2 | 9.60 | 0.00 | | 5.83 | 0.00 | | 16.36 | 0.00 |
(1) x (4) | 3 | 0.11 | 0.96 | | 0.49 | 0.69 | | 0.36 | 0.78 |
(2) x (4) | 3 | 7.45 | 0.00 | | 6.29 | 0.00 | | 5.82 | 0.00 |
(3) x (4) | 6 | 0.51 | 0.80 | | 0.94 | 0.47 | | 1.70 | 0.13 |
(1) x (2) x (3) | 2 | 0.44 | 0.64 | | 0.04 | 0.96 | | 0.24 | 0.79 |
(1) x (2) x (4) | 3 | 0.91 | 0.44 | | 1.17 | 0.32 | | 0.67 | 0.57 |
(1) x (3) x (4) | 6 | 3.58 | 0.00 | | 1.09 | 0.37 | | 3.60 | 0.00 |
(2) x (3) x (4) | 6 | 1.03 | 0.41 | | 6.46 | 0.00 | | 1.60 | 0.16 |
(1) x (2) x (3) x (4) | 6 | 0.87 | 0.52 | | 0.65 | 0.69 | | 0.78 | 0.59 |
Elemental and biochemical composition
The elemental composition of U. pseudorotundata biomass at the initial time of the experiments presented significant variability related to the combined conditions used (significant interaction among the factors nitrogen source, initial nutrient concentration and initial algae biomass) (Table 4, Fig. 8a). Regarding the initial carbon content, the values ranged from 30.7 to 36.5% under N-NH4+ and from 32.1 to 35.5 under N-NO3−. However, there was no significant difference in the final carbon values between the treatments, which presented a general average value of 32.3 ± 2.7% (ANOVA: F(2) = 0.07, p = 0.94, Table 4, Fig. 8b). Initial nitrogen content also showed differences among treatments (ANOVA: F(2) = 3.92 p < 0.05, Table 4, Fig. 8b), but final values showed significant differences only for nitrogen source (ANOVA: F(1) = 37.02 p < 0.05, Table 4, Fig. 8b). The initial values ranged from 2.5 to 3.8% in the experiments treated with N-NH4+, and from 3.8 to 4.6% in the experiments treated with N-NO3−, and the final values were lower in treatments with N-NH4+ (3.1% ± 0.5 SD) than for those with N-NO3− (4.0% ± 0.4 SD). The initial hydrogen content, in turn, varied significantly between 4.4 and 5.4% for treatments with N-NH4+ and between 5.7 and 6.3% for treatments with N-NO3− (ANOVA: F(2) = 10.47 p < 0.05, Table 4, Fig. 8b). The final values were influenced only by the nitrogen source (ANOVA: F(1) = 6.62 p < 0.05, Table 4, Fig. 8b), with lower values for N-NH4+ treatments (5.23% ± 0.2 SD) when compared to N-NO3− treatments (5.43% ± 0.2 SD). Finally, the C:N ratio also showed significantly different initial values ranging from 9.5 to 14.5 in the treatments with N-NH4+ and from 7.8 to 9.2 in the treatments with N-NO3− (ANOVA: F(2) = 7.83 p < 0.05, Table 4, Fig. 8b). Final values were also influenced by nitrogen source with higher values for N-NH4+ treatments (10.9 ± 1.4 SD) when compared to N-NO3− treatments (7.9 ± 0.6 SD) (ANOVA: F(1) = 80.92 p < 0.05, Table 4, Fig. 8b). Regarding the biochemical composition (Fig. 9), the protein content followed the same pattern described above for nitrogen content, since the protein value derives from this variable, with initial values ranging from 13.7 to 20.9% for the treatments with N-NH4+ and 20.5 to 25.1% for treatments with N-NO3− (ANOVA: F(2) = 3.92 p < 0.05, Table 5, Fig. 9a). Final values, were lower for N-NH4+ treatments (16.8% ± 2.5 SD) than for N-NO3− treatments (22.0% ± 2.2 SD) (ANOVA: F(1) = 37.02 p < 0.05, Table 5, Fig. 9b). The initial carbohydrate concentration was not influenced by the interaction between nitrogen source, initial nutrient concentration and initial algae biomass, with average values of 36.9 (± 4.4 SD) for treatments with N-NH4+ and 31.8 (± 6.0 SD) for treatments with N-NO3− (ANOVA: F(2) = 0.14 p = 0.87, Table 5, Fig. 9a). At the end, the values were influenced by the interaction between nitrogen source and algal biomass density (ANOVA: F(1) = 4.94 p < 0.05, Table 5), being higher in treatments with N-NH4+ (36.83% ± 6.14 SD) than in those treated with N-NO3− (29.53% ± 5.34 SD), especially for initial algal biomass of 6 g L− 1 which reached 38.9% (Fig. 9b).
Table 4
Multifactorial ANOVA effects for elemental composition of dried U. pseudorotundata biomass in the beginning and end of experiment cultivation in different combinations of nitrogen sources (N-NH4+ and N-NO3-), biomass densities (6 g L-1 and 10 g L-1), and nutrient initial concentrations: 150, 300, and 500 umol L-1. Content of the parameters: carbon (C), nitrogen (N), and hydrogen (H) are presented as their percentage of alga biomass. C:N ratio was obtained from the measurements of %C and %N. df: degree of freedom; F: F-statistic. The significance differences (p < 0.05) are shown in bold.
Variables | | | | %CB | | | %CE | | | %NB | | | %NE | | | %HB | | | %HE | | | C:NB | | | C:NE | |
Source | | df | | F | p | | F | p | | F | p | | F | p | | F | p | | F | p | | F | p | | F | p |
Nutrient source (1) | | 1 | | 0.02 | 0.90 | | 2.93 | 0.10 | | 42.43 | 0.00 | | 37.02 | 0.00 | | 121.16 | 0.00 | | 6.62 | 0.02 | | 88.06 | 0.00 | | 80.92 | 0.00 |
Nutrient's initial concentration (2) | 2 | | 0.22 | 0.80 | | 2.33 | 0.12 | | 0.00 | 1.00 | | 0.08 | 0.92 | | 0.00 | 1.00 | | 0.85 | 0.44 | | 2.98 | 0.07 | | 2.59 | 0.10 |
Biomass density (3) | | 1 | | 4.90 | 0.04 | | 3.50 | 0.07 | | 6.39 | 0.02 | | 0.00 | 0.95 | | 0.06 | 0.81 | | 2.09 | 0.16 | | 6.24 | 0.02 | | 0.23 | 0.63 |
(1) x (2) | | 2 | | 4.67 | 0.02 | | 0.04 | 0.96 | | 0.73 | 0.49 | | 0.09 | 0.91 | | 5.95 | 0.01 | | 0.46 | 0.63 | | 1.91 | 0.17 | | 0.45 | 0.64 |
(1) x (3) | | 1 | | 0.09 | 0.76 | | 2.23 | 0.15 | | 3.76 | 0.06 | | 3.78 | 0.06 | | 6.19 | 0.02 | | 0.19 | 0.67 | | 0.56 | 0.46 | | 1.59 | 0.22 |
(2) x (3) | | 2 | | 3.66 | 0.04 | | 1.54 | 0.23 | | 6.08 | 0.01 | | 0.19 | 0.83 | | 2.09 | 0.15 | | 0.14 | 0.87 | | 12.11 | 0.00 | | 2.48 | 0.10 |
(1) x (2) x (3) | | 2 | | 7.00 | 0.00 | | 0.07 | 0.94 | | 3.92 | 0.03 | | 0.39 | 0.68 | | 10.47 | 0.00 | | 0.01 | 0.99 | | 7.83 | 0.00 | | 0.93 | 0.41 |
Table 5
Multifactorial ANOVA effects for biochemical composition of dried U. pseudorotundata biomass in the beginning and end of experiment cultivation in different combinations of nitrogen sources (N-NH4+ and N-NO3-), biomass densities (6 g L-1 and 10 g L-1), and nutrient initial concentrations: 150, 300, and 500 umol L-1. Content of the parameters: carbohydrate and protein are presented as their percentage of alga biomass. Values are mean (± SD), n = 3. df: degree of freedom; F: F-statistic. The significance differences (p < 0.05) are shown in bold.
Variables | | | | %Carb.B | | | %Carb.E | | %Prot.B | | %Prot.E | |
Source | | df | | F | p | | F | p | | F | p | | F | p |
Nutrient source (1) | | 1 | | 33.96 | 0.00 | | 60.94 | 0.00 | | 42.43 | 0.00 | | 37.02 | 0.00 |
Nutrient's initial concentration (2) | 2 | | 46.83 | 0.00 | | 52.56 | 0.00 | | 0.00 | 1.00 | | 0.08 | 0.92 |
Biomass density (3) | | 1 | | 5.48 | 0.03 | | 5.53 | 0.03 | | 6.39 | 0.02 | | 0.00 | 0.95 |
(1) x (2) | | 2 | | 3.13 | 0.06 | | 0.06 | 0.94 | | 0.73 | 0.49 | | 0.09 | 0.91 |
(1) x (3) | | 1 | | 0.00 | 0.99 | | 4.94 | 0.04 | | 3.76 | 0.06 | | 3.78 | 0.06 |
(2) x (3) | | 2 | | 1.35 | 0.28 | | 1.28 | 0.30 | | 6.08 | 0.01 | | 0.19 | 0.83 |
(1) x (2) x (3) | | 2 | | 0.14 | 0.87 | | 0.34 | 0.71 | | 3.92 | 0.03 | | 0.39 | 0.68 |
Principal Component Analysis
The PCA showed in an integrated way the main relationships among the variables determined in the experimental tanks. In the presented analysis (Fig. 10) the first principal component explained 58.5% of the variance and the second component 23.3% of the variance. The first component axis clearly showed differences between the treatments with N-NH4+ and N-NO3−, where the NUR at 60 min and NUE at 180 and at 300 min were the variables with greater load in the treatments with N-NH4+ (positive side of component 1). The initial and final C:N ratios also showed greater loads in the first component than in the second, although with low values. In opposition, photosynthetic parameters like ETRsitu at 15 and 1440 min, ETRmax at 15 min and also initial and final protein contents were higher for N-NO3−, treatments (negative side of component 1). In the second principal component, NUR at 144, 180, 300 and 420 min showed high loadings in the positive side of the axis, in opposition with Fv/Fm data and initial and final carbohydrate contents in the negative side of the axis.
Observing Pearson's correlation matrix among these variables (Table S10) it is possible to verify that most of the relationships described above based on PCA, whether positive or negative, are statistically validated (p < 0.05), evidencing that the main trends shown in the PCA can be confirmed.
Table 6
Maximal removal efficiency of nutrients by seaweed selected to play a role as biofilter in different sorts of cultivation.
Species | Type of cultivation | Incubation time | Nutrient source | Nutrient concentrations (µmol.L− 1) | Nutrient uptake efficiency (%) | Reference |
Ulva pseudorotundata | outdoor conditions - closed system | 5 hours (300 min) | NH₄Cl | 500 µmol L⁻¹ | > 90% | Present work |
| | 24 hours (1440 min) | KNO₃ | 500 µmol L⁻¹ | 100% | |
Ulva clathrata | outdoor conditions - flow-through system | 15 hours | Integrated with shrimp effluent (Litopenaeus vannamei) | 51 to 60 µmol L⁻¹ | 82–85%TAN (total ammonia-N) | Copertino et al. (2009) |
| | | < 2.0 µmol L⁻¹ | 50% phosphate | |
Ulva lactuca | outdoor conditions - flow-through system | - | Integrated with fish effluent (Oreochromis spilurus) | 4.44 µmol L⁻¹ | 97.54% TAN (total ammonia-N) | Al-Hafedhet al. (2014) |
| | | 12 µmol L⁻¹ | 16.4-24.03% phosphate | |
Ulva lactuca | outdoor conditions - flow-through system | - | Integrated with fish effluent (Haliotis rufescens) | 0.889 ± 0.112 µmol L⁻¹ | 86–100% ammonium | Macchiavello & Bulboa (2014) |
| | | 7.21 ± 0.47 µmol L⁻¹ | 65–83% nitrate | |
| | | | 0.97 ± 0.26 µmol L⁻¹ | 13–65% phosphate | |
Ulva ohnoi | laboratory conditions - Algal Turf Scrubber (ATS) system | 24 hours (1440 min) | NH₄Cl | 182.94 µmol L⁻¹ | 99.3% ammonium | Salvi et al. (2021) |
| | Na₂HPO₄·7H₂O | 92.3 µmol L⁻¹ | 100% phosphate | |
Ulva prolifera | laboratory conditions - closed system | 48 hours | KNO₃ | 194.8 ± 9.8 µmol L⁻¹ | 99.24% nitrate | Fan et al. (2014) |
| | | KH₂PO₄ | 25.8 ± 0.6 µmol L⁻¹ | 91.30% phosphate | |
Codium fragile | laboratory conditions - closed system | 6 hours | NH₄Cl | 150 µmol L⁻¹ | 99.5% ammonium | Kang et al. (2007) |
Gracilaria cervicornis | laboratory conditions - closed system | 5 hours | NH₄Cl | 5 µmol L⁻¹ | 85.3% ammonium | Carneiro et al. (2011) |
| | | KNO₃ | 5 µmol L⁻¹ | 97.5% nitrate | |
| | | KH₂PO₄ | 5 µmol L⁻¹ | 81.6% phosphate | |
Gracilaria vermiculophylla | laboratory conditions - closed system | 4 hours | NH₄Cl | 150 µmol L⁻¹ | 63% ammonium | Abreu et al. (2011a) |
| | | NaNO₃ | 450 µmol L⁻¹ | 33% nitrate | |
Hydropuntia cornea | outdoor conditions - flow-through system | - | Integrated with fish effluent (Sparus aurata) | 10 to 200 µmol L⁻¹ | 99.55% TAN (total ammonia-N) | Figueroa et al. (2012) |
| indoor conditions - flow-through system | | 10 to 200µmol L⁻¹ | 96.23% TAN (total ammonia-N) | |
Kappaphycus alvarezii | indoor tanks - flow-through system | - | Integrated with fish effluent (Trachinotus carolinus) | 4.4 ± 0.8 µmol L⁻¹ | 70.54% ammonium | Hayashi et al. (2008) |
| | | 190.6 ± 23.7 µmol L⁻¹ | 18.2% nitrate | |
| | | 12.6 ± 2.7 µmol L⁻¹ | 50.84% nitrite | |
| | | 15.2 ± 1.7 µmol L⁻¹ | 26.76% phosphate | |