Optimizing Ulva ohnoi cultivation in biofloc systems: Influence of salinity

Ana Paula Mariane de Morais; Ivanilson de Lima Santos; Carmen Simioni; Leila Hayashi; Marco Antônio de Lorenzo; Walter Quadros Seiffert; Felipe Boéchat Vieira

doi:10.20950/1678-2305/bip.2026.52.e997

Optimizing Ulva ohnoi cultivation in biofloc systems: Influence of salinity

Authors

Ana Paula Mariane de Morais Universidade Federal de Santa Catarina – Departamento de Aquicultura, Laboratório de Camarões Marinhos – Florianópolis (SC), Brazil. https://orcid.org/0000-0002-6639-823X
Ivanilson de Lima Santos Universidade Federal do Rio Grande – Instituto de Oceanografia, Laboratório para Avaliação de Impactos da Aquicultura – Rio Grande (RS), Brazil. https://orcid.org/0000-0003-1866-0499
Carmen Simioni Universidade Federal de Santa Catarina – Departamento de Aquicultura, Laboratório de Camarões Marinhos – Florianópolis (SC), Brazil. https://orcid.org/0000-0001-5629-9361
Leila Hayashi Departamento de Aquicultura, Laboratório de Camarões Marinhos – Florianópolis (SC), Brazil. https://orcid.org/0000-0002-1602-9815
Marco Antônio de Lorenzo Universidade Federal de Santa Catarina – Reitoria – Florianópolis (SC), Brazil. https://orcid.org/0000-0003-3203-8807
Walter Quadros Seiffert Universidade Federal de Santa Catarina – Departamento de Aquicultura, Laboratório de Camarões Marinhos – Florianópolis (SC), Brazil. https://orcid.org/0000-0001-6362-349X
Felipe Boéchat Vieira Universidade Federal de Santa Catarina – Departamento de Aquicultura, Laboratório de Camarões Marinhos – Florianópolis (SC), Brazil. https://orcid.org/0000-0001-9794-8671

DOI:

https://doi.org/10.20950/1678-2305/bip.2026.52.e997

Keywords:

Salinity tolerance, Seaweed, Biomass production, Antioxidant compounds, Integrated aquaculture

Abstract

This study evaluated the salinity tolerance of the macroalga Ulva ohnoi cultivated in a biofloc system over a 14-day period. Five salinity treatments (10, 15, 20, 25, and 30‰) were tested, using 40-L tanks. Algae were acclimated to the target salinities before the cultivation phase and stocked at the density of 2 g∙L^-1. Water quality parameters (ammonia, nitrite, nitrate, orthophosphate, alkalinity, and pH), biomass gain, daily growth rate, phenolic compounds, chlorophyll, and carotenoids were evaluated. Water quality remained within acceptable ranges across treatments, although alkalinity showed significant differences. Complete mortality of U. ohnoi was observed at 10‰, and reduced growth was recorded at 15‰. In contrast, salinities of 20, 25, and 30‰ supported higher biomass gains and daily growth rates, with no significant differences in antioxidant compound concentrations among these treatments. Growth was significantly higher at salinities of 20–30‰, with biomass gains of 318–400 g and daily growth rates of 5.4–6.4% day^-1, whereas at 15‰ biomass gain reached only ~111 g and growth rate ~1.2% day^-1. These findings highlight the potential of U. ohnoi for integration into low-salinity biofloc systems and multitrophic aquaculture strategies, contributing to sustainable aquaculture practices by recycling nutrients and producing valuable biomass.

References

Alamrousi, A., Casais, E., García-Cardesín, É., Masaló, I., Pintado, J., & Cremades, J. (2022). Influence of pH, N, P, N:P ratio, and dissolved inorganic carbon on Ulva ohnoi growth and biomass quality: Potential implications in IMTA-RAS. Aquaculture Journal, 2(4), 285-301. https://doi.org/10.3390/aquacj2040017

Ale, M. T., Mikkelsen, J. D., & Meyer, A. S. (2011). Differential growth response of Ulva lactuca to ammonium and nitrate assimilation. Journal of Applied Phycology, 23, 345-351. https://doi.org/10.1007/s10811-010-9546-2

Angell, A. R., Mata, L., Nys, R., & Paul, N. A. (2015). Indirect and direct effects of salinity on the quantity and quality of total amino acids in Ulva ohnoi (Chlorophyta). Journal of Phycology, 51(3), 536-545. https://doi.org/10.1111/jpy.12300

APHA, AWWA & WEF (2012). Standard Methods for the Examination of Water and Wastewater (22nd ed.). American Public Health Association.

Ben-Ari, T., Neori, A., Ben-Ezra, D., Shauli, L., Odintsov, V., & Shpigel, M. (2014). Management of Ulva lactuca as a biofilter of mariculture effluents in IMTA system. Aquaculture, 434, 493-498. https://doi.org/10.1016/j.aquaculture.2014.08.034

Bews, E., Booher, L., Polizzi, T., Long, C., Kim, J. H., & Edwards, M. S. (2021). Effects of salinity and nutrients on metabolism and growth of Ulva lactuca: Implications for bioremediation of coastal watersheds. Marine Pollution Bulletin, 166, 112199. https://doi.org/10.1016/j.marpolbul.2021.112199

Carvalho, A., Braga, Í., Chaar, F., Cardozo, A. P., Monserrat, J. M., Ramírez, J. R. B., Wasielesky Jr., W., & Poersch, L. H. (2024). Production of the macroalgae Ulva lactuca integrated with the shrimp Penaeus vannamei in a biofloc system: effect of total suspended solids and nutrient concentrations. Phycology, 4(1), 37-52. https://doi.org/10.3390/phycology4010002

Carvalho, A., Costa, L. C. O., Holanda, M., Gonçalves, M., Santos, J., Costa, C. S. B., Turan, G., & Poersch, L. H. (2023). Growth of the macroalgae Ulva lactuca cultivated at different depths in a biofloc integrated system with shrimp and fish. Phycology, 3(2), 280-293. https://doi.org/10.3390/phycology3020018

Chopin, T., Buschmann, A. H., Halling, C., Troell, M., Kautsky, N., Neori, A., Kraemer, G. P., Zertuche-González, J. A., Yarish, C., & Neefus, C. (2001). Integrating seaweeds into marine aquaculture systems: A key toward sustainability. Journal of Phycology, 37(6), 975-986. https://doi.org/10.1046/j.1529-8817.2001.01137.x

Cikos, A. M., Jerković, I., Molnar, M., Šubarić, D., & Jokić, S. (2021). New trends for macroalgal natural products applications. Natural Product Research, 35(7), 1180-1191. https://doi.org/10.1080/14786419.2019.1644629

Cotas, J., Leandro, A., Monteiro, P., Pacheco, D., Figueirinha, A., Gonçalves, A. M., Silva, G. J., & Pereira, L. (2020). Seaweed phenolics: from extraction to applications. Marine Drugs, 18(8), 384. https://doi.org/10.3390/md18080384

Eismann, A. I., Reis, R. P., Silva, A. F., & Cavalcanti, D. N. (2020). Ulva spp. carotenoids: Responses to environmental conditions. Algal Research, 48, 101916. https://doi.org/10.1016/j.algal.2020.101916

Fort, A., Monteiro, J. P., Simon, C., Domingues, M. R., & Sulpice, R. (2024). Short term decreases in salinity, combined with the right choice of species, can allow for a more nutritious sea lettuce lipid profile. Food Chemistry, 437(Pt 1), 137865. https://doi.org/10.1016/j.foodchem.2023.137865

Imchen, T. (2012). Recruitment potential of a green alga Ulva flexuosa Wulfen dark preserved zoospore and its development. PLoS One, 7(2), e32651. https://doi.org/10.1371/journal.pone.0032651

Kakinuma, M., Coury, D. A., Sato, Y., Yokoyama, A., Obika, H., & Miyachi, S. (2006). Physiological and biochemical responses to thermal and salinity stresses in a sterile mutant of Ulva pertusa (Ulvales, Chlorophyta). Marine Biology, 149, 97-106. https://doi.org/10.1007/s00227-005-0215-y

Kakinuma, M., Kuno, Y., & Amano, H. (2004). Salinity stress responses of a sterile mutant of Ulva pertusa (Ulvales, Chlorophyta). Fisheries Science, 70(6), 1177-1179. https://doi.org/10.1111/j.1444-2906.2004.00921.x

Khhoi, L. V., & Fotedar, R. (2011). Integration of western king prawn (Penaeus latisulcatus Kishinouye, 1896) and green seaweed (Ulva lactuca Linnaeus, 1753) in a closed recirculating aquaculture system. Aquaculture, 322-323, 201-209. https://doi.org/10.1016/j.aquaculture.2011.09.030

Kirst, G. O. (1990). Salinity tolerance of eukaryotic marine algae. Annual Review of Plant Physiology and Plant Molecular Biology, 41, 21-53. https://doi.org/10.1146/annurev.pp.41.060190.000321

Kraft, L. G., Kraft, G. T., & Waller, R. F. (2010). Investigations into southern Australian Ulva (Ulvophyceae, Chlorophyta) taxonomy and molecular phylogeny indicate both cosmopolitanism and endemic cryptic species. Journal of Phycology, 46(6), 1257-1277. https://doi.org/10.1111/j.1529-8817.2010.00909.x

Kuhn, D. D., Smith, S. A., Boardman, G. D., Angier, M. W., Marsh, L., & Flick, G. J. (2010). Chronic toxicity of nitrate to Pacific white shrimp, Litopenaeus vannamei: Impacts on survival, growth, antennae length, and pathology. Aquaculture, 309(1-4), 109-114. https://doi.org/10.1016/j.aquaculture.2010.09.014

Legarda, E. C., Crab, L. A., Soares, R., Vinatea, L., Schveitzer, R., & Emerenciano, M. (2021a). Sea lettuce integrated with Pacific white shrimp and mullet cultivation in biofloc impact system performance and the sea lettuce nutritional composition. Aquaculture, 534, 736265. https://doi.org/10.1016/j.aquaculture.2020.736265

Legarda, E. C., Viana, M. T., Zaragoza, O. B. D. R., Skrzynska, A. K., Braga, A., Lorenzo, M. A., & Vieira, F. N. (2021b). Effects on fatty acids profile of Seriola dorsalis muscle tissue fed diets supplemented with different levels of Ulva fasciata from an Integrated Multi-Trophic Aquaculture system. Aquaculture, 535, 736414. https://doi.org/10.1016/j.aquaculture.2021.736414

Lignell, A., & Pedersén, M. (1989). Agar composition as a function of morphology and growth rate. Studies on some morphological strains of Gracilaria secundata and Gracilaria verrucosa (Rhodophyta). Botanica Marina, 32(3), 219-228. https://doi.org/10.1515/botm.1989.32.3.219

Lobban, C. S., & Harrison, P. J. (1994). Seaweed ecology and physiology. Cambridge University Press. https://doi.org/10.1017/CBO9780511626210

Luo, M. B., Liu, F., & Xu, Z. L. (2012). Growth and nutrient uptake capacity of two co-occurring species, Ulva prolifera and Ulva linza. Aquatic Botany, 100, 18-24. https://doi.org/10.1016/j.aquabot.2012.03.006

Martins, M. A., Silva, V. F., Tarapuez, P. R., Hayashi, L., & Vieira, F. N. (2020). Cultivation of the seaweed Ulva Spp. with effluent from a shrimp biofloc rearing system: diferente species and stocking density. Boletim do Instituto de Pesca, 46(3), e602. https://doi.org/ 10.20950/1678-2305.2020.46.3.602

Moustafa, Y. T. A., & Eladel, H. M. (2016). Amino acid profile of Ulva sp. macroalgae collected off the coast of Alexandria, Egypt: a potential food resource. Point Journal of Botany and Microbiology Research, 1(2), 15-22.

Morais, A. P., Santos, I., Carneiro, R. F. S., Routledge, E. A., Hayashi, L., Lorenzo, M. A., & Vieira, F. B. (2023). Integrated multitrophic aquaculture system applied to shrimp, tilapia, and seaweed (Ulva ohnoi) using biofloc technology. Aquaculture, 572, 739492. https://doi.org/10.1016/j.aquaculture.2023.739492

Naldi, M., & Wheeler, P. A. (2002). 15N measurements of ammonium and nitrate uptake by Ulva fenestrata (Chlorophyta) and Gracilaria pacifica (Rhodophyta): Comparison of net nutrient disappearance, release of ammonium and nitrate, and 15N accumulation in algal tissue. Journal of Phycology, 38(1), 135-144. https://doi.org/10.1046/j.1529-8817.2002.01070.x

Notoya, M. (1999). Utilization of Ulva spp. and environmental restoration. Seizandou.

Porra, R. J., Thompson, W. A., & Kreidemann, P. E. (1989). Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: Verification of the concentration of chlorophyll standards by atomic absorption spectrometry. Biochimica et Biophysica Acta, 975(3), 384-394. https://doi.org/10.1016/S0005-2728(89)80347-0

Ritchie, R. J. (2006). Consistent sets of spectrophotometric chlorophyll equations for acetone, methanol and ethanol solvents. Photosynthesis Research, 89, 27-41. https://doi.org/10.1007/s11120-006-9065-9

Robertson-Andersson, D. V. (2003). The cultivation of Ulva lactuca (Chlorophyta) in an integrated aquaculture system, for the production of abalone feed and the bioremediation of aquaculture effluent [MSc Dissertation]. University of Cape Town. http://hdl.handle.net/11427/6175

Rocha, J. S., Santos, D., Martins, M. A., Bauer, C. M., Maraschin, M., Hayashi, L., & Vieira, F. N. (2023). Sea lettuce (Ulva ohnoi) cultivation in biofloc technology: growth performance and characterization of bioactive compounds. Boletim do Instituto de Pesca, 49, e848. https://doi.org/10.20950/1678-2305/bip.2023.49.e848

Rybak, A. S. (2015). Revision of herbarium specimens of freshwater Enteromorpha-like Ulva (Ulvaceae, Chlorophyta) collected from Central Europe during the years 1849–1959. Phytotaxa, 218(1), 1-19. https://doi.org/10.11646/phytotaxa.218.1.1

Santelices, B., Aedo, D., & Hoffmann, A. (2002). Banks of microscopic forms and survival to darkness of propagules and microscopic stages of macroalgae. Revista Chilena de Historia Natural, 75(3), 547-555. https://doi.org/10.4067/S0716-078X2002000300006

Schiavon, M., Moro, I., Pilon-Smits, E. A., Matozzo, V., Malagoli, M., & Dalla Vecchia, F. (2012). Accumulation of selenium in Ulva sp. and effects on morphology, ultrastructure and antioxidant enzymes and metabolites. Aquatic Toxicology, 122-123, 222-231. https://doi.org/10.1016/j.aquatox.2012.06.014

Sheppard, E. J., Hurd, C. L., Britton, D. D., Reed, D. C., & Bach, L. T. (2023). Seaweed biogeochemistry: Global assessment of C:N and C:P ratios and implications for ocean afforestation. Journal of Phycology, 59(5), 879-892. https://doi.org/10.1111/jpy.13381

Silva, P. H., McBride, S., Nys, R., & Paul, N. A. (2008). Integrating filamentous ‘green tide’ algae into tropical pond-based aquaculture. Aquaculture, 284(1-4), 74-80. https://doi.org/10.1016/j.aquaculture.2008.07.035

Simon, C., McHale, M., & Sulpice, R. (2022). Applications of Ulva biomass and strategies to improve its yield and composition: A perspective for Ulva aquaculture. Biology, 11(11), 1593. https://doi.org/10.3390/biology11111593

Steinhagen, S., Johansson, I., Specht, J., Enge, S., Larsson, K., Undeland, I., & Toth, G. B. (2025). Unlocking economic potential of the Ulva crop for low salinity environments: Exploring the effect of salinity gradients on the performance and valuable compounds of Baltic Sea strains. Botanica Marina, 68(1), 65-82. https://doi.org/10.1515/bot-2024-0079

Strickland, J. D. H., & Parsons, T. R. (1972). A practical handbook of seawater analysis. Fisheries Research Board of Canada.

Taylor, R., Fletcher, R. L., & Raven, J. A. (2001). Preliminary studies on the growth of selected ‘green tide’ algae in laboratory culture: Effects of irradiance, temperature, salinity and nutrients on growth rate. Botanica Marina, 44(4), 327-336. https://doi.org/10.1515/BOT.2001.042

United Nations Educational, Scientific and Cultural Organization (UNESCO) (1983). Chemical methods for use in marine environmental monitoring (No. 53). UNESCO.

Zar, J. H. (2010). Biostatistical analysis (5th ed.). Prentice Hall.