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
Affiliations: Aquaculture Research Laboratory, Ocean University of
Qingdao, Qingdao 266003, China. E-mail: Liujw@lib.ouqd.edu.cn
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.