Appling Plankton-index of Biology Integrity to Assess Aquatic Ecosystem Health of River Network in Hangzhou Bay New District, Ningbo

Using the field sampling data obtained in November 2012, the aquatic ecosystem health of river network in Hangzhou Bay New District in Ningbo was assessed with Plankton Index of Biology Integrity (P-IBI). In these samples, 125 species of phytoplankton and 19 species of zooplankton were identified and the dominant phytoplankton species of each sampling sites were almost pollution indicator species. Through the judgment of 17 candidate metrics reflecting plankton community structure characteristic, algae diversity index, the proportion of edible algae and the abundance ratio of cyanobacteria to total algae this three candidate metrics were selected to assess the aquatic ecosystem health of the river network in Hangzhou Bay New Zone in Ningbo. P-IBI was calculated by using ratio scoring method, the assessment result showed among the 14 sampling sites, the aquatic ecosystem health of 4 sampling sites were excellent, 7 good, 2 inferior and 1 poor.