Comparative studies on utilizing nitrogen capacity between two macroalgae Gracilaria tenuistipitata var. liui (rhodophyta) and Ulva pertusa ( chlorophyta ) I. Nitrogen storage under nitrogen enrichment and starvation

Article type: Research Article

Authors: Liu, Jing-Wen | Dong, Shuang-Lin

Affiliations: Aquaculture Research Laboratory, Ocean University of Qingdao, Qingdao 266003, China. E-mail: [email protected]

Abstract: This paper deals with the N storage of Gracilaria tenuistipitata var. liui and Ulva pertusa under ammonium enrichment and starvation. After 10 days of ammonium enrichment, ammonium NH_4^+, free amino acid (FAA), protein (pro), chlorophyll (Chl),phycoerythrin (PE) and total dissolved nitrogen (TDN) of the two macroalgae increased significantly. Total nitrogen (TN) increased significantly from 3.65% to 5.78% dry weight of G. tenuistipitata var. liui and 2.82% to 5.07% dw of U. pertusa, respectively. Protein and FAA were the most important N storage pools in the macroalgae. During N-starvation period, individual N pools of the two species were depleted at exponential rates. Each N pool in U. pertusa decreased more rapidly than in G. tenuistipitata, var. liui and the latter was able to sustain fast growth for more time (> 20 days) than U. pertusa. N demands for supporting growth were different between the two species,U. pertusa grew more rapidly and had higher N demands than G. tenuistipitata var. liui did.

Keywords: nitrogen pools, storage, macroalgae

Journal: Journal of Environmental Sciences, vol. 13, no. 3, pp. 318-322, 2001