Estimating submarine groundwater discharge in the Jiaozhou Bay using radium isotopes

Abstract

1811-1819<span style="font-size:9.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">Submarine groundwater discharge (SGD) is part of the global water cycles, which delivers a large amount of solutes to the<span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:zh-cn;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">biogeochemical cycle and affects the coastal ecological environment. Natural radium isotopes (224Ra and 226Ra) were used to estimate the SGD in Jiaozhou Bay and the mass balance models were established.  Radium sources including river transport, sediment diffusion, desorption from re-suspended particles, open sea flood tide, municipal wastewater, and SGD are considered. Radium<span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:zh-cn;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">output owning to the radioactive decay and ebb tide are also considered. Our results show the<span style="font-size: 9.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:zh-cn;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">SGD fluxes during September to October in 2011(autumn) and April to May in 2012 (spring)<span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:zh-cn;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">are 15.17<span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:zh-cn;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:9.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:="" "times="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">and 6.53×106 m3·d-1, respectively. In the same period of time, the input of the dissolved inorganic nitrogen<span style="font-size:9.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:simsun;mso-bidi-font-family:"times="" roman";="" mso-ansi-language:en-gb;mso-fareast-language:zh-cn;mso-bidi-language:hi"="" lang="EN-GB"> (DIN) from SGD is very close to that from river, yet, the soluble silicate and reactive phosphate vary seasonally. SGD is the major source of the nutrient input of Jiaozhou Bay.</span