Primary productivity of two adjacent atolls of Lakshadweep islands differing in the presence of Cymode
cea serrulata (R.Br.) Aschers beds as measured from the diurnal oxygen curve was compared. Arnini atoll
which sustains extensive beds of seagrass vegetation showed 6S0/0 more productivity than the nearest atoll
Kadamat which is totally lacking seagrass vegetation. The net primary production of C. serrulata was measured
to be 6.4 g C.m-3.d-' and this was 6 times more than that of the phytoplankton alone. High rate of production
of oxygen by Cymodocea beds during intensive photosynthesis is discussed in the light d oxygen
budget of the atol
