Improvement of evaluation of water age and submarine groundwater discharge: a case study in Daya Bay, China

2020 ◽  
Author(s):  
Yan Zhang ◽  
Xuejing Wang ◽  
Hailong Li
Keyword(s):  
Primary Production ◽  
Submarine Groundwater Discharge ◽  
Sea Water ◽  
Groundwater Discharge ◽  
Daya Bay ◽  
Water Age ◽  
Radium Isotopes ◽  
Open Sea ◽  
Submarine Groundwater

<p>The water age in coastal waters can be estimated by a simplified formula defined by activity ratio of radium isotopes when neglecting the effects of four factors including recirculated seawater (RSGD), open sea water end-member, sediments and rivers. Although this formula has been widely used, sometimes it is applied without checking the assumptions of neglecting the effects of the above-mentioned four factors. Here an attempt is made to give a generalized formula for estimating water age explicitly incorporating all the above-mentioned effects. The formula is then applied in Daya Bay, China by comprehensively using all the radium quartet (<sup>223,224,226,228</sup>Ra) data to assess the water age and submarine groundwater discharge (SGD). Data analyses indicate that the factors such as RSGD, open sea water end-member, sediments and rivers should be included in the general radium model when there are various radium sources and their contributions are unknown. It is found that in Daya Bay, neglecting the effects of RSGD underestimates the water age by 25.5-45.7% and neglecting the effects of open sea water end-member overestimates the water age by 120-130%. The SGD-derived fluxes of nutrients and trace elements are significantly higher than those from local rivers. SGD can support approximately 63-70% of the total primary production. Overall, this study emphasizes again the importance of the general radium model and enhances accuracy in estimating water age and SGD. Our results also reveal that SGD significantly influences coastal primary production in Daya Bay and other similar aquatic ecosystems.</p>

Improvement of evaluation of water age and submarine groundwater discharge: A case study in Daya Bay, China

2020 ◽  
Vol 586 ◽  
pp. 124775 ◽  
Author(s):  
Yan Zhang ◽  
Hailong Li ◽  
Huaming Guo ◽  
Chunmiao Zheng ◽  
Xuejing Wang ◽  
...  
Keyword(s):  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Daya Bay ◽  
Water Age ◽  
Submarine Groundwater

scholarly journals Evaluation of flushing time, groundwater discharge and associated nutrient fluxes in Daya Bay, China

2018 ◽  
Author(s):  
Yan Zhang ◽  
Meng Zhang ◽  
Hailong Li ◽  
Xuejing Wang ◽  
Wenjing Qu ◽  
...  
Keyword(s):  
Primary Production ◽  
Sea Water ◽  
Nutrient Balance ◽  
Groundwater Discharge ◽  
Daya Bay ◽  
Nutrient Fluxes ◽  
Red Tides ◽  
Radium Isotopes ◽  
Flushing Time ◽  
Improved Model

Abstract. Radium quartet have been widely used to quantify the flushing time of water body and submarine groundwater discharge (SGD) in coastal zones. However, previous apparent age model based on mass balance of radium isotopes usually neglected the effects of rivers, open sea water end-member, sedimentary input, atmospheric deposits and recirculated seawater (RSGD). To enhance accuracy in estimating flushing time and SGD, here we present an improved model and then apply in Daya Bay, China. The flushing time estimated by the improved model is 11.8–27.7 d in Daya Bay. It is found that the previous model overestimated the flushing time by 10.7 %–103 %. Considering the radium losses caused by RSGD, the SGD flux is estimated to be (3.87–5.09) × 107 m3 d−1 based on the derived flushing time. The SGD associated nutrient fluxes are estimated to be (1.36–1.76) × 106 mol d−1 and (2.53–3.26) × 104 mol d−1 for DIN and DIP, respectively, about 20 times greater than those from local rivers. The primary production supported by all the external DIN inputs is determined to be 323–390 mg C m−2 d−1, in which SGD provide approximately 73.1 % of total primary production. Our results reveals that SGD plays an important role in nutrient balance and may be responsible for the frequent outburst of red tides in Daya Bay. The present study provides baseline data for evaluating environmental effects in Daya Bay and similar coastal bay systems elsewhere.

scholarly journals Submarine groundwater discharge revealed by radium isotopes (Ra-223 and Ra-224) near a paleochannel on the Southern Brazilian continental shelf

2013 ◽  
Vol 61 (3) ◽  
pp. 195-200 ◽  
Author(s):  
Karina Kammer Attisano ◽  
Isaac Rodrigues Santos ◽  
Carlos Francisco Ferreira de Andrade ◽  
Mariele Lopes de Paiva ◽  
Idel Cristina Bigliardi Milani ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Submarine Groundwater Discharge ◽  
Water Mass ◽  
Groundwater Discharge ◽  
Dissolved Nutrients ◽  
Radium Isotopes ◽  
Submarine Groundwater ◽  
Lines Of Evidence

Submarine Groundwater Discharge (SGD) has been recognized as an important component of the ocean-continent interface. The few previous studies in Brazil have focused on nearshore areas. This paper explores SGD on the Southern Brazilian Continental Shelf using multiple lines of evidence that include radium isotopes, dissolved nutrients, and water mass observations. The results indicated that SGD may be occurring on the Continental Shelf in the Albardão region, near a paleochannel located 50 km offshore. This paleochannel may thus be a preferential pathway for the delivery of nutrient- and metal-enriched groundwater and porewater into continental shelf waters.

scholarly journals Studies on Groundwater Problems in an Area Subjected to Sea Water Ingression and Seepage Into Groundwater in Karaikal District Using GIS

2018 ◽  
Vol 7 (3.10) ◽  
pp. 150
Author(s):  
T Subramani ◽  
P Krishnan
Keyword(s):  
Water Quality ◽  
Coastal Waters ◽  
Submarine Groundwater Discharge ◽  
Sea Water ◽  
Groundwater Discharge ◽  
Treated Wastewater ◽  
Coastal Zones ◽  
Fresh Groundwater ◽  
Submarine Groundwater ◽  
Pumping Rates

Fresh groundwater quality and accessibility in coastal zones is influenced via seawater interruption into coastal aquifers, and coastal water quality and biological community status might be altogether influenced by groundwater pollutants that are transported into coastal waters by submarine groundwater discharge (SGD). SGD and its pertinent evaluation as one associating part  among the different principle local pathways of freshwater and tracer/poison contributions from land to sea and the coordinated framework working of both and as primary segments of the same coastal groundwater framework. An elective technique might be to control seawater interruption through fake groundwater revive, for example by adequately treated wastewater, which may impressively decrease long haul patterns of saltiness increment in pumped groundwater, notwithstanding for little simulated energize rates contrasted with pumping rates. Both the outside sources and the interior wellsprings of water seepage might be distinguished via doing infrared thermo-realistic assessments subsequent to directing water snugness tests, flooding tests or pressure driven tests as suitable. A contextual investigation was led to discover the examinations on groundwater issues in a region subjected to sea water ingression and seepage into groundwater in Karaikal   

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