TY - JOUR
T1 - Sea-water/groundwater interactions along a small catchment of the European Atlantic coast
AU - Einsiedl, Florian
N1 - Funding Information:
This paper was greatly enhanced by the constructive reviews of Prof. S. Bottrell and an anonymous reviewer. I gratefully acknowledge Barbara Petrunic and John Coyne from NUI Galway for their support in the field. Funding for this project was provided by the NUI Galway Griffith Geoscience award that was based on research grant-aided by the Department of Communications, Energy and Natural Resources under the National Geoscience Programme 2007–2013.
PY - 2012/1
Y1 - 2012/1
N2 - The geochemistry and isotopic composition of a karstic coastal aquifer in western Ireland has shed light on the effect of sea-water/groundwater interactions on the water quality of Ireland's Atlantic coastal zone. The use of stable isotope data from the IAEA precipitation station in Valentia, located in SW Ireland has facilitated the characterization of groundwater recharge conditions in the western part of Ireland and suggests that groundwater is mostly replenished by the isotopically light winter precipitation. The dissolved SO42- in the karstic groundwater that was collected during baseflow conditions with δ 34S values between 4.6‰ and 18‰ may be composed of S stemming from three principal sources: SO42- derived from precipitation which is composed of both sea-spray S (δ 34S: 20‰) and an isotopically light anthropogenic source (δ 34S: 1-5‰), SO42-stemming from animal slurries (δ 34S: ~5‰), and intruding sea-water SO42- (δ 34S: 20.2‰). The isotopic composition of δ 18O in dissolved groundwater SO42- collected during baseflow conditions is interpreted as reflecting sea-water intrusion to the karstic coastal groundwater system. The highest δ 18O values in dissolved groundwater SO42- were in samples collected near the coast (4.8±0.4‰) and the lowest (2±0.5‰) were collected further inland. The δ 15N and δ 18O values of groundwater NO3- were between 3.4‰ and 11.4‰ and approximately 7.7‰, respectively, and reflect geochemical conditions in the aquifer that do not promote attenuation of NO3- through denitrification. As a result N loading to Kinvara Bay that is controlled by submarine groundwater discharge (SGD) was calculated as 5tons/day on average compared to an estimated N-input that derives from precipitation of approximately 2.5tons/a. SGD into the bay may result in near coastal sea-water quality changes. These results represent one of the first studies addressing the effect of groundwater quality in Ireland on the European Atlantic coastal zone.
AB - The geochemistry and isotopic composition of a karstic coastal aquifer in western Ireland has shed light on the effect of sea-water/groundwater interactions on the water quality of Ireland's Atlantic coastal zone. The use of stable isotope data from the IAEA precipitation station in Valentia, located in SW Ireland has facilitated the characterization of groundwater recharge conditions in the western part of Ireland and suggests that groundwater is mostly replenished by the isotopically light winter precipitation. The dissolved SO42- in the karstic groundwater that was collected during baseflow conditions with δ 34S values between 4.6‰ and 18‰ may be composed of S stemming from three principal sources: SO42- derived from precipitation which is composed of both sea-spray S (δ 34S: 20‰) and an isotopically light anthropogenic source (δ 34S: 1-5‰), SO42-stemming from animal slurries (δ 34S: ~5‰), and intruding sea-water SO42- (δ 34S: 20.2‰). The isotopic composition of δ 18O in dissolved groundwater SO42- collected during baseflow conditions is interpreted as reflecting sea-water intrusion to the karstic coastal groundwater system. The highest δ 18O values in dissolved groundwater SO42- were in samples collected near the coast (4.8±0.4‰) and the lowest (2±0.5‰) were collected further inland. The δ 15N and δ 18O values of groundwater NO3- were between 3.4‰ and 11.4‰ and approximately 7.7‰, respectively, and reflect geochemical conditions in the aquifer that do not promote attenuation of NO3- through denitrification. As a result N loading to Kinvara Bay that is controlled by submarine groundwater discharge (SGD) was calculated as 5tons/day on average compared to an estimated N-input that derives from precipitation of approximately 2.5tons/a. SGD into the bay may result in near coastal sea-water quality changes. These results represent one of the first studies addressing the effect of groundwater quality in Ireland on the European Atlantic coastal zone.
UR - http://www.scopus.com/inward/record.url?scp=84855437615&partnerID=8YFLogxK
U2 - 10.1016/j.apgeochem.2011.09.004
DO - 10.1016/j.apgeochem.2011.09.004
M3 - Article
AN - SCOPUS:84855437615
SN - 0883-2927
VL - 27
SP - 73
EP - 80
JO - Applied Geochemistry
JF - Applied Geochemistry
IS - 1
ER -