Abstract:
The ecological environment of the Pearl River Estuary has become increasingly prominent. Phytoplankton is an important reference index for evaluating water quality, ecological functions, etc., which can provide a scientific basis for the protection and management of the ecological environment of this sea area. In order to better understand the distribution characteristics and environmental conditions of phytoplankton in the Pearl River Estuary during wet season, we analyzed the phytoplankton community structure characteristics and its environmental impact factors in the Pearl River Estuary during wet season, based on the phytoplankton survey data collected in this sea area in September 2020 and May 2021. A total of 102 species of phytoplankton belonging to 56 genera and 7 phyla were identified, among which diatom species (69 species) accounted for 67.65%, and dinoflagellate species (17 species) accounted for 16.67%. The abundance level in May 2021 (
1191.86×10
4 cells·m
−3) was higher than that in September 2020 (103.64×10
4 cells·m
−3), and the abundance composition was mainly diatoms, followed by cyanobacteria or dinoflagellate. The diversity index and evenness index in May 2021 (2.08, 0.49) were higher than those in September 2020 (1.65, 0.41), both of which were relatively low. NMDS analysis shows that the phytoplankton community in this sea area can be divided into two groups, north and south, with S8 as the boundary. The dominant species were
Melosira granulata (Brackish water species) and
Thalassiosira pseudonana (Euryhaline coastal seawater species) in September 2020, while
Eucampis zodiacus (salt-tolerant coastal species) in May 2021. Redundancy analysis (RDA) shows that nitrogen, phosphorus, nitrogen to phosphorus ratio, silicate, pH and salinity were the main environmental factors affecting phytoplankton community in the Pearl River Estuary. The intensity of dilute water in wet season has a great impact on the species composition, abundance distribution and diversity of phytoplankton in the Pearl River Estuary.