Nitrogen limitation of Codium fragile ssp. tomentosoides as determined by tissue analysis

The critical nitrogen concentration of Codium fragile ssp. tomentosoides (van Goor) Silva was 1.90% on a dry weight basis. Internal nitrogen levels of thalli collected from three Rhode Island populations ranged from 0.75±0.08 to 3.72±0.08%. Internal nitrogen content was minimal in summer and maximal in winter, indicating nitrogen limitation during the summer and nitrogen storage during the winter. Part of this nitrogen storage appeared to support new growth of C. fragile in the spring. Carbon:nitrogen (C:N) ratios were inversely related to the internal nitrogen concentration. Low internal nitrogen content indicated nitrogen limitation better than C:N ratios because the C:N ratio could be influenced by both carbon and nitrogen metabolism.