Abstract: In September 2007 and in April and July 2008, sediment samples were collected from the southern intertidal area of Yellow River Delta to study the distribution pattern of benthic chlorophyll-a (Chl-a) content and its relations to sediment grain size. In study area, the Chl-a content increased from the north to the south. In the spring, the Chl-a content ranged from 0.623-8.734 μg·g^-1 with an average of 2.542 μg·g^-1 and increased from high tide zone to low tide zone; while in summer and autumn, the Chl-a content ranged from 0.307-5.195 μg·g^-1 (averaging 1.832 μg·g^-1) and 0.426-4.749 μg·g^-1 (averaging 1.591 μg·g^-1), respectively, and decreased from high tide zone to low tide zone. The sediments were unanimously composed of silt, with the median size ranging from 0.025-0.081 mm (averaging 0.045 mm) and increased from high tide zone to low tide zone. The distribution pattern of benthic Chl-a was primarily affected by the grain size of sediment, and had significant correlation with the content of fine particles. There was anegative relationship between benthic Chl-a content and elevation height, suggesting that soft, flat, and stable sediment could benefit the growth and reproduction of benthic micro-algae.

Key words: Cone picking, Korean pine, Seed resource, Animal, Natural regeneration