The effects of phosphate on physiological responses and carbohydrate production in Ulva fasciata (Chlorophyta) from upwelling and non-upwelling sites

• Published in: Botanica marina Vol. 64; no. 1; pp. 1 - 11
• Main Authors: Figueira, Tiphane Andrade, Martins, Nuno Tavares, Ayres-Ostrock, Lígia, Plastino, Estela M., Enrich-Prast, Alex, Oliveira, Vinícius Peruzzi de
• Format: Journal Article
• Language: English
• Published: Berlin De Gruyter 23.02.2021; Walter de Gruyter GmbH
• Subjects: Anabolism; carbohydrate production; Carbohydrates; Growth rate; macroalgal cultivation; Nutrient concentrations; Ocean circulation; Phosphate; Phosphates; Phosphorus; phosphorus uptake; Photosystem; Physiological effects; Physiological responses; Physiology; Seaweeds; Stress concentration; Stress response; Ulva fasciata; Uptake; Upwelling
• ISSN: 0006-8055; 1437-4323
• DOI: 10.1515/bot-2020-0051

Phosphorus is a key macronutrient in macroalgal physiology, including carbohydrate anabolism. To determine the effects of phosphorus on different physiological parameters, we cultivated specimens from distinct localities (upwelling and non-upwelling sites) in the presence of different phosphate concentrations (0, 2, and 4 µM ). After 15 days, growth rates were similar (approx. 12% day ) and carbohydrate contents had increased in individuals from both sites. In individuals from the upwelling site, carbohydrate contents were high in all treatments (71% dry mass), whereas non-upwelling site individuals cultivated under the highest phosphate concentration showed the lowest carbohydrate content (46% DM). Nevertheless, we observed higher rates of phosphorus uptake in individuals from the non-upwelling site cultivated under the highest phosphate concentration, indicating a stress response to elevated nutrient concentrations. Individuals from both sites cultivated with phosphate maintained healthy photosystems over the experimental period (  = 0.788), whereas those cultivated in the absence of phosphate showed evidence of photosystem impairment, as indicated by a progressive decline in maximum quantum yield. Altogether, our results indicate that site origin and phosphate concentration influence the carbohydrate content in and that individuals from sites with broad environmental variation, such as upwelling events, can show higher productivity.