Abstract: Based on three scenes of TM imagery in 1988, 1998 and 2003, the patch size area of the farmland, forestland, resident area, and constructing area in Nanjing urban district was classified into sixteen levels, and the quantitative variation of different level patches in the process of landscape fragmentation was studied. The results showed that farmland displayed diminished area and increased fragmentation degree, with the number of small-to-medium sized patches increased steadily. Forestland had a little fluctuation in its total area, with a stable amount of medium-to-large sized patches but a greatly variednumber of small-to-medium sized patches. Resident area expanded muchbased on the existed patches from 1988 to 1998, but new patches mushroomed from 1998 to 2003. Constructing area developed rapidly, and its land use scale enlarged. All of these indicated that both the type and size of patch had definite effects on the patch stability and its change trend.

Key words: Phytoplankton, Red tide, Abundance, Water dynamics, Changjiang River estuary