Tracing submarine groundwater discharge flux in Tolo Harbor, Hong Kong (China)

Liu, Yi; Jiao, Jiu Jimmy; Cheng, Ho Kwan

doi:10.1007/s10040-018-1736-z

Cited by 17 publications

(24 citation statements)

References 81 publications

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“…The nutrient inventory and nutrient flux are calculated based on the mass balance model described previously. The fresh groundwater flux from inland ( F in ) and SGD flux ( F out ) data listed in Table is from Y. Liu, Jiao, and Cheng (). The seawater recharge flux ( F sw ) is calculated based on the water balance as described in equation .…”

Section: Discussionmentioning

confidence: 99%

“…Since both input (remineralization of organic matters, advection from inland area, and seawater recharge induced by tidal pumping) and output (nitrification and discharge to the sea) of NH 4 + in the aquifer are affected by the seasonal variation of the environment, the variation of NH 4 + does not have a clear seasonal trend. The maximum NH 4 + inventory is observed in winter, which potentially results from the coupled effect of a decreased nitrification induced by the temperature drop (Figure S5), a decreased SGD induced by precipitation decline (Y. Liu, Jiao, Cheng, and ), and a medium remineralization rate of organic matter because of medium temperature and high level of DO in groundwater (Figures S3 and S4). The NO x − inventory shows a clear seasonality with maximum value in summer (135.84 mmol/(m coastline)) and minimum value (11.92 mmol/(m coastline)) in spring (Figure ).…”

Section: Discussionmentioning

confidence: 99%

“…In spring, SGD‐derived NH 4 + flux is 114.83 mmol·day −1 ·(m coastline) −1 in which 18% is supported by the advection of groundwater from inland (20.36 mmol·day −1 ·(m coastline) −1 ), 42% is supported by the recharge of seawater (48.47 mmol·day −1 ·(m coastline) −1 ), and the rest 40% is from the production of NH 4 + in the aquifer via remineralization of organic carbon (46 mmol·day −1 ·(m coastline) −1 ). In summer, SGD‐derived NH 4 + flux increases to 271.71 mmol·day −1 ·(m coastline) −1 due to the increase of water flux caused by the rise of precipitation (Y. Liu, Jiao, & Cheng, ). Even though SGD‐derived NH 4 + flux increases from spring to summer, the DIN in harbor seawater drops from 0.128 to 0.045 mg/L (Table ).…”

Section: Discussionmentioning

confidence: 99%

“…These biogeochemical processes are easily altered by the shift of redox conditions, aquifer heterogeneity, diversity of microbial communities, input of terrestrial or oceanic nutrients, and anthropogenic activities. Seasonal hydrologic variations not only introduce variations in hydrodynamics and redox conditions of groundwater (Heiss & Michael, ; Y. Liu et al, ) but also alter the SGD fluxes to oceans (Y. Liu, Jiao, & Cheng, ; Michael et al, ). In addition, Gonneea and Charette () indicated that the differences in nutrient attenuation in the coastal aquifer (Waquoit Bay, MA, United States) between summer and winter are causative factors of more than a doubling of SGD‐associated nitrogen fluxes during the summer compared to winter.…”

Section: Introductionmentioning

confidence: 99%

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Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

2018

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Biogeochemical reactions in coastal aquifers highly affect the nutrient flux associated with submarine groundwater discharge (SGD) to the ocean, which subsequently influences the oceanic environment and ecology. This study investigates a seasonal variation of SGD-derived nutrient flux to the ocean and nutrient biogeochemistry in an intertidal aquifer of Tolo Harbor, Hong Kong. The results show that the inventory of NO x À and PO 4 3À in the intertidal aquifer has a clear seasonality with a large inventory in summer, a small inventory in spring, and a median inventory in autumn and winter, respectively. Differently, the inventory of NH 4 + is large in winter and summer and small in spring and autumn, which results from the coupled effects of seasonal change of both production and removal of NH 4 + in the aquifer. The SGD-derived nutrient (NH 4 + , NO x À , and PO 4 3À ) flux is the highest in summer (271.71, 24.86, and 116.66 mmol·day À1 ·(m coastline) À1 ) and is the lowest in spring (114.83, 1.70, and 20.26 mmol·day À1 ·(m coastline) À1 ). The majority of SGD-derived nutrient flux is supported by the local remineralization of organic matter along with seawater infiltration. In autumn, the recharge of seawater induced by tidal pumping significantly shifts the biogeochemical balance of nutrients and is the major source of groundwater nutrients in the intertidal aquifer. Among the various nutrient fluxes (SGD, river discharge, atmospheric deposition, and benthic sediment diffusion) to Tolo Harbor, SGD-derived PO 4 3À flux is the second major source of seawater PO 4 3À in addition to benthic sediment diffusion. The PO 4 3À loading via SGD is of significance to the primary production in the phosphorus-limited environment in Tolo Harbor. After considering the natural attenuation of nutrients in a sandy/silty beach aquifer, this study suggests the overestimation of SGD-derived nutrient loading estimated previously that simply use average nutrient concentration of fresh SGD endmember and saline SGD endmember as the nutrient concentration of total SGD endmember.Plain Language Summary The biogeochemical reactions in the intertidal aquifer are the crucial influencing factors affecting the groundwater nutrients that are essential for oceanic environment and ecology. Seasonal hydrologic variations are of significance to the biogeochemical reactions in the aquifer and nutrient speciation and concentrations in coastal groundwater. The results of this study indicate that both nutrient inventories in the aquifer and nutrient fluxes to the sea are higher in summer and autumn than winter and spring. By comparing the nutrient flux carried by the submarine groundwater discharge with other pathways, nutrient flux carried by coastal groundwater is a major source of phosphorus in the sea and supports the primary production in the harbor, which can be demonstrated by the positive trend between the nutrient flux and chlorophyll-a concentration in seawater. However, the red tide occurrence in the harbor does not have a similar seasonal tr...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

2018

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“…According to the geological map (Figure a), bedrock in the Tolo harbor area is mainly volcanic rocks and some Devonian‐Permian sedimentary rocks at the north of Tolo Channel (Figure b). Six rivers (SM River, TPK River, TP River, LT River, TT Stream, and SL Stream in Figure b) in the catchment discharge to the harbor with a rate of ∼0.247 cm d −1 (Lee et al, ; Liu et al, ). In addition to river discharge, SGD, with a rate of 0.8–11.8 cm d −1 (Luo & Jiao, ), is another pathway by which meteorological water flows back to the sea.…”

Section: Methodsmentioning

confidence: 99%

Using Tidal Fluctuation‐Induced Dynamics of Radium Isotopes (²²⁴Ra, ²²³Ra, and ²²⁸Ra) to Trace the Hydrodynamics and Geochemical Reactions in a Coastal Groundwater Mixing Zone

Liu

Jiao

Liang

et al. 2018

Water Resources Research

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The reactive transport of radium isotopes (224Ra, 223Ra, and 228Ra) in coastal groundwater mixing zones (CGMZs) is sensitive to shifts of redox conditions and geochemical reactions induced by tidal fluctuation. This study presents a spatial distribution and temporal variation of radium isotopes in the CGMZ for the first time. Results show that the activity of radium isotopes in the upper saline plume (USP) is comparatively low due to a short residence time and mixing loss induced by the infiltration of low radium seawater whereas the activity of radium isotopes in the salt wedge (SW) is comparatively high due to a long residence time in the aquifer. The spatial distribution of radium isotopes is determined by the partitioning of radium isotopes, groundwater residence time, and relative ingrowth rates of radium isotopes. In addition, the variation of radium isotopes in the USP lags slightly (∼0 h) whereas the fluctuation of radium isotopes in the SW lags significantly (∼12 h) behind sea level oscillation. Tidal fluctuation affects the partitioning of radium isotopes through controlling seawater infiltration and subsequently influences the dynamics of radium isotopes in the USP. Concurrently, seawater infiltration significantly affects geochemical processes such as the production of nutrients and total alkalinity. Therefore, radium dynamics in the USP have implications for these geochemical processes. The variation of radium isotopes in the USP also has potential implications for transformation of trace metals such as iron and manganese because of the close affinity of radium isotopes to manganese and iron oxides.

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Spatial distribution and export of nutrients and metal elements in the subterranean estuary of Daya Bay

Liu,

Ge,

Wang

et al. 2023

Acta Oceanol. Sin.

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Tracing submarine groundwater discharge flux in Tolo Harbor, Hong Kong (China)

Cited by 17 publications

References 81 publications

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Using Tidal Fluctuation‐Induced Dynamics of Radium Isotopes (²²⁴Ra, ²²³Ra, and ²²⁸Ra) to Trace the Hydrodynamics and Geochemical Reactions in a Coastal Groundwater Mixing Zone

Spatial distribution and export of nutrients and metal elements in the subterranean estuary of Daya Bay

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Tracing submarine groundwater discharge flux in Tolo Harbor, Hong Kong (China)

Cited by 17 publications

References 81 publications

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Using Tidal Fluctuation‐Induced Dynamics of Radium Isotopes (224Ra, 223Ra, and 228Ra) to Trace the Hydrodynamics and Geochemical Reactions in a Coastal Groundwater Mixing Zone

Spatial distribution and export of nutrients and metal elements in the subterranean estuary of Daya Bay

Contact Info

Product

Resources

About

Using Tidal Fluctuation‐Induced Dynamics of Radium Isotopes (²²⁴Ra, ²²³Ra, and ²²⁸Ra) to Trace the Hydrodynamics and Geochemical Reactions in a Coastal Groundwater Mixing Zone