Show simple item record  

dc.contributor.authorLiao, Jinen_NZ
dc.contributor.authorHu, Chaoyongen_NZ
dc.contributor.authorWang, Miaoen_NZ
dc.contributor.authorLi, Xiulien_NZ
dc.contributor.authorRuan, Jiaoyangen_NZ
dc.contributor.authorZhu, Yingen_NZ
dc.contributor.authorFairchild, Ian J.en_NZ
dc.contributor.authorHartland, Adamen_NZ
dc.date.accessioned2018-12-03T22:04:17Z
dc.date.available2018-01-01en_NZ
dc.date.available2018-12-03T22:04:17Z
dc.date.issued2018en_NZ
dc.identifier.citationLiao, J., Hu, C., Wang, M., Li, X., Ruan, J., Zhu, Y., … Hartland, A. (2018). Assessing acid rain and climate effects on the temporal variation of dissolved organic matter in the unsaturated zone of a karstic system from southern China. Journal of Hydrology, 556, 475–487. https://doi.org/10.1016/j.jhydrol.2017.11.043en
dc.identifier.issn0022-1694en_NZ
dc.identifier.urihttps://hdl.handle.net/10289/12226
dc.description.abstractAcid rain has the potential to significantly impact the quantity and quality of dissolved organic matter (DOM) leached from soil to groundwater. Yet, to date, the effects of acid rain have not been investigated in karstic systems, which are expected to strongly buffer the pH of atmospheric rainfall. This study presents a nine-year DOM fluorescence dataset from a karst unsaturated zone collected from two drip sites (HS4, HS6) in Heshang Cave, southern China between 2005 and 2014. Cross-correlograms show that fluorescence intensity of both dripwaters lagged behind rainfall by ∼1 year (∼11 months lag for HS4, and ∼13 months for HS6), whereas drip rates responded quite quickly to rainfall (0 months lag for HS4, and ∼3 months for HS6), based on optimal correlation coefficients. The rapid response of drip rates to rainfall is related to the change of reservoir head pressure in summer, associated with higher rainfall. In winter, low rainfall has a limited effect on head pressure, and drip rates gradually slow to a constant value associated with base flow from the overlying reservoir- this effect being most evident on inter-annual timescales (R2 = 0.80 for HS4 and R2 = 0.86 for HS6, n = 9, p < 0.01). We ascribed the ∼1 year lag of fluorescence intensity to the effect of the soil moisture deficit and the karst process on delaying water and solute transport. After eliminating the one year lag, the congruent seasonal pacing and amplitude between fluorescence intensity and rainfall observed suggests that the seasonality of fluorescence intensity was mainly controlled by the monsoonal rains which can govern the output of DOM from the soil, as well as the residence time of water in the unsaturated zone. On inter-annual timescales, a robust linear relationship between fluorescence intensity and annual (effective) precipitation amount (R2 = 0.86 for HS4 and R2 = 0.77 for HS6, n = 9, p < 0.01) was identified, implying that annual (effective) precipitation is the main determinant of DOM concentration in the aquifer. Conversely, the insensitivity of fluorescence intensity and fluorescence wavelength maxima to variations in the pH of local rainfall suggests that acid rain over the study period (∼pH 5.6 to ∼ 4.5) had no discernable effect on the quantity and quality of DOM in karst soil and soil solution, likely being strongly buffered by soil carbonates. Therefore, despite large increases in anthropogenic acid rain in recent Chinese history, hydrologic forcing is the predominant factor driving variations in DOM in karst aquifers.
dc.format.mimetypeapplication/pdf
dc.language.isoenen_NZ
dc.publisherElsevieren_NZ
dc.rightsThis is an author’s accepted version of an article published in the journal: Journal of Hydrology. © 2018 Elsevier.
dc.subjectScience & Technologyen_NZ
dc.subjectTechnologyen_NZ
dc.subjectPhysical Sciencesen_NZ
dc.subjectEngineering, Civilen_NZ
dc.subjectGeosciences, Multidisciplinaryen_NZ
dc.subjectWater Resourcesen_NZ
dc.subjectEngineeringen_NZ
dc.subjectGeologyen_NZ
dc.subjectKarst groundwateren_NZ
dc.subjectUnsaturated zoneen_NZ
dc.subjectDissolved organic Matteren_NZ
dc.subjectFluorescenceen_NZ
dc.subjectClimate changeen_NZ
dc.subjectAcid rainen_NZ
dc.subjectTRACE-ELEMENT GEOCHEMISTRYen_NZ
dc.subjectNOM-METAL COMPLEXESen_NZ
dc.subjectFOREST SOILSen_NZ
dc.subjectFLUORESCENCE SPECTROSCOPYen_NZ
dc.subjectCURRENT KNOWLEDGEen_NZ
dc.subjectHUMIC SUBSTANCESen_NZ
dc.subjectMARENGO CAVEen_NZ
dc.subjectHESHANG CAVEen_NZ
dc.subjectDRIP WATERSen_NZ
dc.subjectCARBONen_NZ
dc.titleAssessing acid rain and climate effects on the temporal variation of dissolved organic matter in the unsaturated zone of a karstic system from southern Chinaen_NZ
dc.typeJournal Article
dc.identifier.doi10.1016/j.jhydrol.2017.11.043en_NZ
dc.relation.isPartOfJournal of Hydrologyen_NZ
pubs.begin-page475
pubs.elements-id213275
pubs.end-page487
pubs.publication-statusPublisheden_NZ
pubs.volume556en_NZ
dc.identifier.eissn1879-2707en_NZ


Files in this item

This item appears in the following Collection(s)

Show simple item record