Palaeoproductivity and associated changes in the north-eastern Indian Ocean since the last glacial: Evidence from benthic foraminifera and stable isotopes

Devendra, Dhanushka; Xiang, Rong; Zhong, Fangchuan; Tang, Leiwen

doi:10.1016/j.jseaes.2019.103913

Cited by 7 publications

(1 citation statement)

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“…The salinity has experienced some changes during the Holocene, and hence the variations of other solutes in the seawater endmember during the Holocene can be decided based on their ratios to salinity. The synchronous changes of salinity and nutrient level can be supported by carbon isotopic records of corals (Su et al, 2014), and dynamics of primary productivity in the South China Sea (Devendra et al, 2019;Zhang et al, 2016). The boundary concentrations at the freshwater endmember were determined as the lowest ones in our observed groundwater samples and were treated as constants during the Holocene.…”

Section: Groundwater Flow and Solute Transport Modelingmentioning

confidence: 79%

Evolutionary history of the groundwater system in the Pearl River Delta (China) during the Holocene

Jiao

Luo

et al. 2023

Geology

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Coastal groundwater reservoirs are sensitive to the complicated evolution of marine transgressions and regressions in river delta regions. We integrated hydrogeological investigation and hydrogeochemical data with numerical modeling to assess the evolution of the groundwater system in the Pearl River Delta’s aquifer system (in southeastern China). We studied the effects of flow dynamics and redox conditions on the biogeochemical processes of nutrients in the regional groundwater flow systems in response to the transient states related to variable paleoprecipitation and seawater salinity decline from the late Pleistocene to the Holocene. The results from paleo-hydrogeological reconstruction of the aquifer-aquitard system showed that the saline groundwater formed by paleo-seawater intrusion was still present in the old marine aquitard and affected groundwater salinity and chemicals in the adjacent aquifers, while most of the groundwater in the shallow young marine aquitard has been freshened by infiltrated old/fresh rainwater. Consequently, total ammonium and carbon stored in the Pearl River Delta were estimated to be (1.91 ± 1.13) × 107 mol m–1 and (5.74 ± 4.05) × 107 mol m–1, respectively, and the ammonium and bicarbonate fluxes derived from groundwater discharge to the sea were calculated as (90.6 ± 55.9) mol m–1 yr–1 and (301.02 ± 196.23) mol m–1 yr–1, respectively. If the buried ammonium in the delta is released to the sea, it would be equivalent to nearly 205 ± 123 yr of Pearl River fluvial loading. These findings suggest that the chemicals trapped in the deltaic aquifer system during the Holocene could contribute to future ocean eutrophication and acidification.

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Section: Groundwater Flow and Solute Transport Modelingmentioning

confidence: 79%