THALASSIA-TESTUDINUM LEAF DYNAMICS IN A MEXICAN CARIBBEAN CORAL-REEF LAGOON

Shoot density, leaf growth, initiation, biomass and primary production in Thalassia testudinum (Banks ex Konig) were monitored at monthly intervals from August 1990 until January 1992 at three stations in the tropical coral reef of Puerto Morelos lagoon, Mexico. Leaf growth decreased with increasing leaf length, declining rapidly once the tips of leaves had started to decay; however, the leaves continued to grow until complete senescence. Maximum potential leaf age was >90 d. Leaf growth, biomass and primary production were highest at the station in the vicinity of mangrove discharges, intermediate at the nearshore fringe of the seagrass meadow, and lowest at the back-reef station. Leaf growth, leaf initiation, biomass and primary production were minimum in the winter months and maximum in the summer. Leaf growth and primary production were significantly correlated with water temperature or/and the hours of daylight. This is the first report of temperature- or/and hours of daylight-related seasonal variability in T. testudinum production from the tropical Caribbean.