Fig. 2

a Circular visualization of dominant diatoms at genus level in six sample types. Inner circular diagram shows relative abundance of different diatom genus in six sample types. Only the dominant genus with a mean relative abundance of ≥ 1% in all samples is depicted. The width of ribbons for each diatoms is directly proportional to their relative abundance in each sample type. Similarly, different colored ribbons of different width for each sample type describe the distribution of different genera. b Representative diatoms genera in different landform types from the river source to mouth along the Yangtze River