Investigation of submarine groundwater discharge and associated nutrient inputs into Laizhou Bay (China) using radium quartet

• Published in: Marine pollution bulletin Vol. 157; p. 111359
• Main Authors: Wang, Xuejing, Li, Hailong, Zhang, Yan, Zheng, Chunmiao, Gao, Maosheng
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2020; Elsevier BV
• Subjects: Coastal environments; Coastal zone; Dry season; Flushing; Flushing (water); Flushing time; Fluxes; Groundwater; Groundwater discharge; Groundwater levels; Groundwater table; Hydraulic gradient; Laizhou Bay; Mean sea level; Mineral nutrients; Nutrients; Radium; Radium quartet; Rainy season; River discharge; River flow; Rivers; Sea level; Seasonal variations; Seasons; Submarine groundwater discharge (SGD); Water discharge; Water table; Wet season; China; Laizhou Bay; Seasonal variations; Nutrients; Submarine groundwater discharge (SGD); Radium quartet; Laizhou Bay
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2020.111359

Radium is widely used to estimate flushing time, submarine groundwater discharge (SGD), and submarine fresh groundwater discharge (SFGD), however there are important sources of uncertainty in current methods. Here an improved method is proposed, incorporating all radium quartet information to estimate flushing time, SFGD, SGD, and associated nutrient fluxes during wet and dry seasons in Laizhou Bay, China. Both SGD and SFGD in dry season are comparable to that in wet season, likely due to higher groundwater hydraulic gradients resulting from higher groundwater table and lower mean sea level in dry season. Estimated dry and wet season SFGD are of the same order of magnitude as the annually-averaged Yellow River discharge, highlighting SFGD's importance to the bay environment. Nutrient inputs into Laizhou Bay were estimated for the wet season, suggesting that SGD-derived nutrients are indeed important and significant for coastal environments compared to local river discharge estimates. •Using radium quartet for simultaneous estimation of flushing time, SGD and SFGD•Both SGD and SFGD in dry season are comparable to that in wet season in Laizhou Bay.•Effects of RSGD were taken into account for calculating SGD driven nutrient fluxes.•SGD-derived nutrients are significantly higher than those from the Yellow River.