DOI: 10.5194/hess-20-3077-2016
Scopus记录号: 2-s2.0-84980335960
论文题名: Assessing land-ocean connectivity via submarine groundwater discharge (SGD) in the Ria Formosa Lagoon (Portugal): Combining radon measurements and stable isotope hydrology
作者: Rocha C ; , Veiga-Pires C ; , Scholten J ; , Knoeller K ; , Gröcke D ; R ; , Carvalho L ; , Anibal J ; , Wilson J
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2016
卷: 20, 期: 8 起始页码: 3077
结束页码: 3098
语种: 英语
Scopus关键词: Budget control
; Catchments
; Estuaries
; Groundwater
; Isotopes
; Lakes
; Seawater
; Sediments
; Submarines
; Uncertainty analysis
; Allochthonous sources
; Discharge mechanisms
; Non-point source
; Radon measurements
; Ria formosa lagoons
; Spatial and temporal scale
; Stable isotope hydrologies
; Submarine groundwater discharge
; Discharge (fluid mechanics)
; assessment method
; autochthon
; beach
; catchment
; discharge
; dispersion
; hydrology
; hypersaline environment
; land-sea interaction
; meteoric water
; radon
; seawater
; stable isotope
; underwater environment
; Faro [Portugal]
; Portugal
; Ria Formosa
英文摘要: Natural radioactive tracer-based assessments of basin-scale submarine groundwater discharge (SGD) are well developed. However, SGD takes place in different modes and the flow and discharge mechanisms involved occur over a wide range of spatial and temporal scales. Quantifying SGD while discriminating its source functions therefore remains a major challenge. However, correctly identifying both the fluid source and composition is critical. When multiple sources of the tracer of interest are present, failure to adequately discriminate between them leads to inaccurate attribution and the resulting uncertainties will affect the reliability of SGD solute loading estimates. This lack of reliability then extends to the closure of local biogeochemical budgets, confusing measures aiming to mitigate pollution. Here, we report a multi-tracer study to identify the sources of SGD, distinguish its component parts and elucidate the mechanisms of their dispersion throughout the Ria Formosa - a seasonally hypersaline lagoon in Portugal. We combine radon budgets that determine the total SGD (meteoric + recirculated seawater) in the system with stable isotopes in water (δ2H, δ18O), to specifically identify SGD source functions and characterize active hydrological pathways in the catchment. Using this approach, SGD in the Ria Formosa could be separated into two modes, a net meteoric water input and another involving no net water transfer, i.e., originating in lagoon water re-circulated through permeable sediments. The former SGD mode is present occasionally on a multi-annual timescale, while the latter is a dominant feature of the system. In the absence of meteoric SGD inputs, seawater recirculation through beach sediments occurs at a rate of ∼1/4 × 106 m3 day-1. This implies that the entire tidal-averaged volume of the lagoon is filtered through local sandy sediments within 100 days (∼3.5 times a year), driving an estimated nitrogen (N) load of ∼350 Ton N yr-1 into the system as NO3 -. Land-borne SGD could add a further ∼61 Ton N yr-1 to the lagoon. The former source is autochthonous, continuous and responsible for a large fraction (59 %) of the estimated total N inputs into the system via non-point sources, while the latter is an occasional allochthonous source capable of driving new production in the system. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78773
Appears in Collections: 气候变化事实与影响
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作者单位: Biogeochemistry Research Group, Geography Department, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland; CIMA-Marine and Environmental Research Center, Universidade do Algarve, Portugal; Institute of Geosciences, University of Kiel, Germany; UFZ, Helmholtz Centre for Environmental Research Leipzig, Halle, Germany; Department of Earth Sciences, Durham University, South Road, Durham, County Durham, United Kingdom
Recommended Citation:
Rocha C,, Veiga-Pires C,, Scholten J,et al. Assessing land-ocean connectivity via submarine groundwater discharge (SGD) in the Ria Formosa Lagoon (Portugal): Combining radon measurements and stable isotope hydrology[J]. Hydrology and Earth System Sciences,2016-01-01,20(8)