Macrobenthos can serve as an indicator of hypoxia in the estuarine ecosystem. This comparative study surveyed macrobenthos from hypoxic and non-hypoxic areas of the Zhujiang (Pearl) River Estuary (PRE), and explores the effects of environmental factor on the macrobenthos community structure. In July 2020, 49 macrobenthos species were collected from the hypoxic area, contrasting with 91 species found in the non-hypoxic area. July 2021 recorded 51 species in the hypoxic area and 76 in the non-hypoxic area. Analysis of similarities (ANOSIM) and non-metric multidimentional scaling (NMDS) showed no significant difference in the macrobenthos community structure between the two areas. However, Polychaeta displays higher species richness, abundance, and biomass in the hypoxic zone, negatively correlating to dissolved oxygen (DO). Canonical correspondence analysis (CCA) also showed that the abundance of Polychaeta was negatively correlated with that of Crustacea. Interestingly, despite the differences in Polychaeta, macrobenthos community structure remains stable between hypoxic and non-hypoxic samples. This study suggests Polychaeta’s potential adaptation to hypoxic conditions in the PRE’s hypoxic area. Finally, Spearman correlation analysis showed that DO have a significant negative correlation with total phosphorus (TP), total nitrogen (TN) and total organic carbon (TOC) in the PRE, indicating that water eutrophication would exacerbate the occurrence of hypoxia.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |