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Light microscopy of transverse sections of K. alvarezii stained with Toluidine Blue (AT-O). The metachromatic reaction to AT-O in the cell wall of the cortical cell (cc) and subcortical cells (sc) indicates the presence of carrageenan. a to c samples cultivated in indoor maintenance; d to f samples cultivated in sea cultivation. a and d SF treatment; b and e AF treatment; c and f CF treatment. Scale: 50 µm
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This work aimed to establish the nutrient fertilization regime for indoor maintenance of Kappaphycus alvarezii seedlings during periods of low sea temperatures using biofloc effluent as a fertilizer. Moreover, we evaluated the development of seaweed seedlings after transplantation into the sea cultivation in Santa Catarina, Brazil. Seedlings were f...
Citations
... The proximate contents, including carbohydrates, proteins, and lipids, did not show significant differences across different media (MP1, SFW, and seawater), indicating that nutrient composition in the medium did not markedly influence these biochemical contents [30]. However, the higher protein content in SFW-grown GCC suggests an accumulation of nitrogen, aligning with De Martino et al. [31] observations regarding the impact on seaweed photosynthesis capacity. ...
Gracilaria corticata var. cylindrica (GCC) was studied as a biofilter in shrimp farm water (SFW) and its growth and biochemical attributes in the medium were evaluated. GCC showed significant nutrient absorption from SFW, with maximum nitrate and phosphate uptake observed after the first 48 h. Nitrate depletion happened faster than phosphate, thus showing a higher affinity for nitrate uptake (78.4% removal) by GCC. Nutrient uptake kinetics followed the Michaelis–Menten curve, with V max values of 43.16 μM g dw ⁻¹ h ⁻¹ for nitrate and 67.50 μM g dw ⁻¹ h ⁻¹ for phosphate. Also, GCC’s low K m values (12.53 µM for nitrate, 1.91 µM for phosphate) indicated efficient nutrient utilization. GCC showed rapid growth in SFW, with a daily growth rate of 2.93 ± 0.19% d ⁻¹ , comparable to the commercial MP1 media (3.54 ± 0.19% d ⁻¹ ) and greater to seawater (2.23 ± 0.13% d ⁻¹ ). Proximate analysis revealed consistent biochemical compositions across all three media, with carbohydrate and protein contents of 2.24 ± 0.41% and 0.76 ± 0.12%, respectively, in SFW. Pigment analysis revealed that pigment concentrations varied, with SFW having the greatest R-PE concentration (182.25 ± 32.77 µg g ⁻¹ ), followed by MP1 media and saltwater. R-PC concentrations followed a similar pattern, with SFW having the greatest concentration (85.73 ± 19.33 µg g ⁻¹ ). These findings highlight GCC’s potential as an efficient biofilter for reducing nitrate and phosphate levels in SFW, therefore offering a sustainable solution for aquaculture effluent management and the potential integration of GCC into shrimp farming practices.
... Several experiments were carried out considering the low cost and economic viability of the activity, focusing on fertilization strategies and possible effects on the growth of seedlings after transportation and planting on sea farms. Fertilization methods consider time, duration, and concentration (Martino et al. 2021;Pires et al. 2021); in addition to the type of fertilizers, such as laboratory culture medium, the effluent of shrimp reared in the biofloc system (Pedra et al. 2017;Martino et al. 2021;Pires et al. 2021) or even supplements, such as inorganic carbon addition (Ventura et al. 2020;Baran 2021), were evaluated. One interesting result was that seaweed maintained in tanks under different fertilization methods and fertilizers presented positive responses regarding its biochemical profile, cell structure, and carrageenan yield and quality (Pedra et al. 2017;Ventura et al. 2020;Martino et al. 2021;Baran 2021;Pires et al. 2021). ...
... Several experiments were carried out considering the low cost and economic viability of the activity, focusing on fertilization strategies and possible effects on the growth of seedlings after transportation and planting on sea farms. Fertilization methods consider time, duration, and concentration (Martino et al. 2021;Pires et al. 2021); in addition to the type of fertilizers, such as laboratory culture medium, the effluent of shrimp reared in the biofloc system (Pedra et al. 2017;Martino et al. 2021;Pires et al. 2021) or even supplements, such as inorganic carbon addition (Ventura et al. 2020;Baran 2021), were evaluated. One interesting result was that seaweed maintained in tanks under different fertilization methods and fertilizers presented positive responses regarding its biochemical profile, cell structure, and carrageenan yield and quality (Pedra et al. 2017;Ventura et al. 2020;Martino et al. 2021;Baran 2021;Pires et al. 2021). ...
... Fertilization methods consider time, duration, and concentration (Martino et al. 2021;Pires et al. 2021); in addition to the type of fertilizers, such as laboratory culture medium, the effluent of shrimp reared in the biofloc system (Pedra et al. 2017;Martino et al. 2021;Pires et al. 2021) or even supplements, such as inorganic carbon addition (Ventura et al. 2020;Baran 2021), were evaluated. One interesting result was that seaweed maintained in tanks under different fertilization methods and fertilizers presented positive responses regarding its biochemical profile, cell structure, and carrageenan yield and quality (Pedra et al. 2017;Ventura et al. 2020;Martino et al. 2021;Baran 2021;Pires et al. 2021). ...
Since our last review in 2017, the main progress related to Kappaphycus alvarezii farming in Brazil came from southern Brazil. The region is a hot spot in marine aquaculture because of its tradition in mollusk farming. In 2020, after 12 years of studies and negotiation with the Brazilian government, the State of Santa Catarina had permission to cultivate the species commercially. However, only in 2021 local producers got the license and has started the commercial production. On the southeast coast, some marine farms were established in Rio de Janeiro, but according to the last report of the Secretary of Aquaculture and Fisheries (SAP) from the Ministry of Agriculture, Livestock, and Supply, there was no production until 2020. Nevertheless, the possibility of expanding the marine farms for K. alvarezii is higher since the SAP debureaucratized the system to apply for marine area grants. Sao Paulo State is still struggling to establish the areas because most of its coastline is protected. Biostimulants seem to be a new product of K. alvarezii production in Brazil. This market has a vast national demand thanks to the importance of agribusiness in the country. The price paid for seaweed is higher than that paid for the carrageenan industry. Moreover, producers can process their seaweeds and directly deliver liquid biostimulant to the industry without depending on the international market. Since the activity is starting fresh, there are many possibilities, and depending on where the species is cultivated in Brazil, the final product can be different.
... Brazil has great potential for seaweed aquaculture, as the country has a wide coastline (around 10,956 km), an exclusive economic zone (EEZ) of 3.5 million km 2 and favorable environmental conditions for seaweed growth (Prates et al. 2012;IBGE 2021). In this perspective, cultivations of the economically important red seaweed Kappaphycus alvarezii (Doty) L.M. Liao have been developed in the South and Southeast regions of Brazil (Hayashi and Reis 2012;Martino et al. 2021). In the Northeast region of Brazil, the genus Gracilaria Greville has been exploited from wild banks and studied for the establishment of cultivation (Marinho-Soriano 2017). ...
Climate change has affected the distribution of economically important marine organisms worldwide. Seaweeds are among the most cultivated marine organisms in aquaculture and whose production has been increasing annually. Environmental Suitability Modeling (ESM) has currently been applied to predict the future distribution of economically important species concerning impacts from climate change. In this context, this study aimed to project how a global change scenario (RCP8.5) will affect the cultivation of the red seaweed Gracilaria birdiae in the Brazilian coast based on ESM. Species occurrence data were obtained from the literature and bioclimatic data were acquired from Bio-ORACLE. The modeling was performed by integrating the MaxEnt algorithm to R software. Significant differences between future and present environmental suitability for the seaweed cultivation were validated by applying the Friedman test. Our results revealed a significant increase in suitable areas for G. birdiae cultivation in the future, mainly in the coast of the Northeast and Southeast regions of Brazil. Our projection is consistent with the assumption that ocean warming will expand warmer water species to formerly colder regions. Temperature and salinity were not the most limiting factors for G. birdiae cultivation, whereas high nitrate concentrations may limit it. Our data revealed that environmental suitability areas for G. birdiae cultivation in Brazil will not be negatively affected by climate change. The seaweed G. birdiae shows a great potential for being cultivated in the Brazilian coast in the present and future, which could be a relevant source of income for coastal communities.
... The plant obtained by this technique prefers to have a cost-effective strategy for large-scale cultivation. The concentration of chlorophyll a and b pigments increased in the plant treated with SFE since the frequency of nutrients concentration increased by making nitrogen available in the cultivation environment similar results were revealed by De Martino et al. (2021) and this was also observed by Hayashi et al. (2008) and made hypothesis stronger that the enriched thalli accumulated nutrients in chlorophyll form (Dodds et al. 1997), however, it was decreased in case of R-Phycoerythrin and R-Phycocyanin this may be due to the high amount of sodium in SFE similar observation was made by Mihriban et al. (2018) in case of Gracilaria gracilis were PE and PC contents were decreased in higher concentration of salinity. Under laboratory conditions, the chlorophyll concentration was stable with no significant differences. ...
The growth and biochemical profile of the red seaweed Gracilaria corticata var. cylindrica was evaluated after in vitro cultivation with effluent from a shrimp Litopenaeus vannamei farming pond. Seaweeds were cultivated for 21 days in sterilized seawater enriched with shrimp effluent with 5 different concentrations (0.1, 1, 10, 50 and 100 mL L-1). Fragments with 50 and 100 mL L-1 ¬showed a higher significant growth rate of 3.53 ± 0.08% and 3.7 ± 0.55% respectively compared to sterilized seawater as control (2.5 ± 0.15%). Survival and regeneration of fragments were higher in the treatments 10, 50 and 100 mL L-1. 100% survival was observed in 10 and 100 mL L-1 while 100-mL L-1 showed 100% regeneration in fragments. The number of branchlets developed per fragment was observed higher (2.33 ± 0.52) and (2.23 ± 0.05) in 50 and 100mL L-1 respectively. 50 mL L-1 showed the highest (124.45 ± 9.28 µg g-1) chlorophyll-a and 100 mL L-1 showed the highest (54.5 ± 5.42 µg g-1) chlorophyll-b content. Agar yield (2.8 ± 0.32% FW), total sugar (72.6 ± 2.7%) and 3,6-anhydrogalactose (8.77 ± 0.63%) was observed highest in 100 mL L-1 treatment of shrimp effluent while sulphate content (1.5 ± 0.8%) found higher in 50 mL L-1. Results showed that effluent treatments positively affected G. corticata var. cylindrica growth and biochemical composition, especially 50 and 100mL L-1, which could be considered as a good bio-stimulator for the making of the seedling. This work presents the potential use of effluents from shrimp cultivation as fertilizer, improving the growth and seedling production for sustainable cultivation of endemic red seaweed Gracilaria corticata var. cylindrica.
Keywords: Agarophyte; Gracilaria; Biofertilizer; Shrimp farming effluent; Growth.
Intensive BFT (Biofloc Technology) system production leads to large amounts of FSW (Floc Solid Waste), but the disposal of this waste is rarely noticed. As one of the novel solid wastes of aquaculture, the FSW was treated through planting within various supplemental dosages to obtain a more comprehensive assessment on its reclamation potential in this experiment. FSW was added to the soil in the following proportions respectively: 0.5% (adding FSW/Soil weight ratio percentage W/W (dry matter/dry matter)), 1%, and 2%. Pure soil was selected as the control and the pot experiment was conducted based on Crown daisy (Glebionis coronaria (L.) Cass. ex Spach) for 40 days. FSW addition considerably increased soil fertility which exhibited the positive correlation except for the soil pH. Adding ratio with 0.5%, and 1.0% provided the best plant growth with the yield of 50.2 g/m2, and 41.5 g/m2 respectively. 2.0% FSW addition inhibited the growth of plants, while certain amount of FSW addition not greatly promoted the quantities of plants. FSW addition obviously altered the original soil rhizobacteria communities and increased abundance of some beneficial bacteria, especially for Bacillus sp, Fictibacillus sp. Through RDA (Redundancy Analysis), the strongly positive relation between soil fertility and functional microorganisms in FSW added treatments has been verified. In conclusion, positive plant growth performance and the facilitation of soil fertilities demonstrated the potential of FSW as soil fertilization and amendments.
