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 Thalassia testudinum in the Mexican Caribbean based, primarily, on aging of plant material. We found T. testudinum to be able to reach high biomass (> 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 the rhizomes) in the Mexican Caribbean. The plants appeared to grow slowly, as reflected in longer time intervals in between production of leaves and shoots, and slower rhizome elongation rates and leaf production rates than found in the past, possibly as a result of their low nutrient, 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 mortality 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.