Preliminary Study of Effect of Internal Wave to Phytoplankton Distribution in the Lombok Strait and Adjacent Areas

Internal wave with a soliton-like, large amplitudes within several kilometers, is frequently observed in the sea surface caused by tidal rectification due to sill or rough topographic changes. Internal waves can perturb current and density field, initiate bottom sediment re -suspension and mix nutrients to photic zone. Previous studies indicate that the appearance of internal wave in the Lombok Strait have been detected in SAR image data. This paper studies effect of internal wave in the Lombok Strait to chlorophyll distribution in the surrounded areas using SeaWiFS and ERS SAR images data during 1996-2001 periods. The preliminary result concludes that the internal waves presumably affect phytoplankton distribution spreading southeastward in the coast off Bali Island. The distribution of phytoplankton at southern coastline off Bali Island when internal wave occurred is elongated and distributed further to westward (from 8.8$^{\circ}$ to 10.7$^{\circ}$LS) than the area when internal wave did not occur on August 2000 (from 9.25$^{\circ}$ to 10.25$^{\circ}$LS) as shown in figure 3. It shown that the surface phytoplankton concentration near coastal area, i.e. from 8.8$^{\circ}$ to 9.25$^{\circ}$ LS, increased when internal wave is occurred.