BIOMASS AND DYNAMICS OF THALASSIA-TESTUDINUM IN THE MEXICAN CARIBBEAN- ELUCIDATING RHIZOME GROWTH

e report here data on biomass and dynamics of shoots and rhizomes of T halassia testudinum in the Mexican Caribbean based, primarily, on agin g of plant material. We found T. testudinum to be able to reach high b iomass (> 1000 g dry wt m-2) and develop highly productive populations 1500 to 4500 g dry wt m-2 annually, of which 10% were allocated to th e rhizomes) in the Mexican Caribbean. The plants appeared to grow slow ly, as reflected in longer time intervals in between production of lea ves and shoots, and slower rhizome elongation rates and leaf productio n rates than found in the past, possibly as a result of their low nutr ient, particularly phosphorus, content. Calculated maximum shoot life spans ranged between 6 and 9 yr, shoot recruitment rates ranged from 0 .02 to 0.07 In units per plastochrone interval (PI) and shoot mortalit y rate was substantial and averaged about 0.045 In units Pl-1. Shoots turned over at ca 0.6 yr-1, which also represents the rhizome turnover rate.