Physiological responses and biofilter potential of Hypnea aspera (Rhodophyta, Gigartinales) cultivated in different availabilities of nitrate, ammonium, and phosphate

Author(s)

Ribeiro, Ana Livia N. L. ; Chiozzini, Vitor G. ; Braga, Elisabete S. ; Yokoya, Nair S.

• Document type: Journal article
• Source: JOURNAL OF APPLIED PHYCOLOGY; v. 29, n. 2, p. 683-694, APR 2017.
• Web of Science Citations: 1

Abstract

Along with the search for new species of seaweeds with biofilter capacity, it is also necessary to understand the physiological and biochemical responses of these seaweeds cultivated in different availabilities of nitrate, ammonium, and phosphate. To accomplish this, a laboratory study was performed to evaluate the ability of Hypnea aspera Kutzing (Gigartinales, Rhodophyta), to growth under different nitrate, ammonium, and phosphate availabilities and to uptake, assimilate, and remove these nutrients from seawater. Treatments were composed of sterilized seawater enriched with quarter-strength von Stosch's nutrient solution modified (without any nitrogen and phosphorus compounds). Nitrate or ammonium, together with phosphate, was added in combined N/P ratios of 100:1 and 10:1. Nitrate concentrations varied from 0 to 150 mu M, and ammonium concentrations varied from 0 to 70 mu M. Growth rates of H. aspera increased with nitrate addition, and the highest value was 4.68 +/- 0.76 % day(-1) in 150 mu M, but the addition of high ammonium concentration (70 mu M) in N/P ratio of 10:1 inhibited the growth rates (-3.89 +/- 1.03 % day(-1)). Nitrogen was accumulated as proteins and phycobiliproteins, mainly phycoerythrin, at higher phosphate availability (N/P ratio of 10:1) for nitrate addition (150 mu M for proteins and 50, 100, and 150 mu M for phycoerythrin), and lower phosphate availability (N/P ratio of 100:1) for ammonium addition (50 and 70 mu M for proteins and 50 mu M for phycoerythrin). Nitrogen and phosphate were assimilated into thallus in all treatments with nutrient addition. Hypnea aspera showed high removal efficiency (higher than 90 %) of nitrate, nitrite, ammonium, and phosphate present in the seawater. These results suggest that H. aspera could be cultivated in integrated multitrophic aquaculture systems to reduce nutrient loading in eutrophic seawater. (AU)

• FAPESP's process: 12/19148-5 - Effects of the increase CO2, nitrogen and temperature in seawater in the metabolism of red benthic seaweeds
• Grantee: Ana Lívia Negrão Leite Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate