GROWTH-RESPONSE OF THE SEAGRASS CYMODOCEA-NODOSA TO EXPERIMENTAL BURIAL AND EROSION

The response of Cymodocea nodosa (Ucria) Aschers. seedlings to experimental burial and erosion was examined to test the extent of coupling between fluctuations in sediment depth and seagrass growth. Shoot survivorship declined with erosion and with increasing burial depth, relative to the controls. Seagrass growth response, described by changes in internodal and leaf sheath length, the rate of appearance of new leaves, and shoot vertical growth showed a bell-shaped response to fluctuations in sediment depth. Shoot internodal and leaf sheath length, the rate of appearance of new leaves, and vertical growth all increased with sediment depth from minimal values under erosion to maximal values at burial of <7 cm. These results demonstrate that C. nodosa seedlings tolerate burial <7 cm, and that burial stimulates the growth of surviving seedlings. Examination of this growth response for C. nodosa and other seagrass species, which allows quantification of tolerable changes in sediment depth, may provide useful information for conservation of seagrass populations.