Characteristics of Chlorophyll a Distribution in Jiaozhou Bay in Summer and Winter

An investigation on distribution characteristics of chlorophyll a in Jiaozhou Bay was carried in August 2006(summer) and February 2007(winter).Results showed sigmificant? seasonal variations in Summer and Winter: the average chlorophyll a concentration of the study area was 3.80 mg/m3,which was much higher than 1.32 mg/m3 in winter.We also found an obvious characteristic in the horizontal distribution,ie..the average chlorophyll a concentration in the mouth of the bay was much higher than that within the bay in summer,with the reverse in winter.As to the vertical distribution,the chlorophyll a concentration decreased from surface to bottom with the exception of the 5 m layer,which had the highest concentration compared to other layers in summer.The vertical variation presented a similar tendency in winter,but the change was not as obvious as that in the summer.Moreover,a diurnal rhythm was found in the changes of chlorophyll a concentration,and the concentration in daytime was higher than that at night.