PDF
Full
Outline
To understand nitrogen pollution and sources of Laizhou Bay, nitrogen sources and transformation processes in the coastal rivers entering the sea of Laizhou Bay were studied. Water quality parameters, nitrogen content, and stable isotopes were used to clarify the sources and key processes in river estuary. The results indicate strong temporal and spatial consistency between δD and δ18O of water, EC, and salinity, suggesting significant seawater mixing effects in the estuary, which was significantly weakened upstream of the river. NO3--N was found to be the dominant form to inorganic nitrogen in most reaches of the river during high flow and low flow seasons, ranging from 37.2% to 81.7% and 29.5% to 95.9%, respectively, except for a few sites. Furthermore, extreme values of ρ(TN) and ρ(NH4+-N) values were observed at some sample sites during low flow season, which were significantly higher than those during the high flow season. Some water samples had ρ(NH4+-N) values exceeding 2mg/L, resulting in an inferior Category V water quality. The long-term variation of ρ(NO3--N) from 2005 to 2023 showed an initial increase followed by a decrease in rivers entering Laizhou Bay. The δ15N-NO3- varied from +5.7‰ to +18.6‰ and from +4.5‰ to +20.0‰ during the high flow and low flow seasons, respectively, while the δ18O-NO3- varied from +4.2‰ to +13.8‰ and from -0.5‰ to +20.1‰, with no obvious seasonal variations. The nitrate isotope results showed that nitrification was major process affecting riverine nitrogen entering Lanzhou Bay, and that some river samples were also influenced by denitrification. During low flow season, NO3--N at the low salinity sampling sites was mainly sourced from manure and sewage, while most estuary sites during the high flow season were affected by the salty tide backflow, and agricultural fertilization impacted most river sections. This study provides insights into the emission characteristics of nitrogen pollution sources and spatial and temporal variability in Laizhou Bay’s coastal zone estuaries, offering valuable research demonstrations and data references for future prevention, control, and management efforts for nitrogen pollution in rivers entering the sea around the Bohai Sea.
PDF
36
17
| 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 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
