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Thermal evidence of water exchange through a coastal aquifer: Implications for nutrient fluxes
Author(s) -
Moore Willard S.,
Krest James,
Taylor Glenn,
Roggenstein Edward,
Joye Samantha,
Lee Rosalynn
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl014923
Subject(s) - nutrient , aquifer , seawater , oceanography , environmental science , phosphorus , radium , geology , groundwater , hydrology (agriculture) , chemistry , geotechnical engineering , organic chemistry , radiochemistry
We report the discovery of a semi‐confined, high permeability zone (HPZ) 2 meters below the sea bed where exchanges between coastal aquifers and the ocean occur. A temperature probe placed in the HPZ recorded a 1°C semidiurnal cycle. The cycle was in phase with the tide, indicating tidal pumping was driving water exchange through the HPZ. We use these temperature variations to quantify water exchange between the HPZ and the ocean. Water in the HPZ is enriched in nutrients and radium; both total dissolved nitrogen and phosphorus correlate strongly with dissolved 226 Ra. We use these correlations and previously quantified subterranean fluxes of 226 Ra to demonstrate that this system may be a significant source of nutrients to the coastal ocean.