Titre du document / Document title

Instability of seawater pH in the South China Sea during the mid-late Holocene : Evidence from boron isotopic composition of corals

Auteur(s) / Author(s)

YI LIU ; WEIGUO LIU ; ZICHENG PENG ; YINGKAI XIAO ; GANGJIAN WEI ; WEIDONG SUN ; JIANFENG HE ; GUIJIAN LIU ; CHOU Chen-Lin ;

Résumé / Abstract

We used positive thermal ionization mass spectrometry (PTIMS) to generate high precision δ¹¹B records in Porites corals of the mid-late Holocene from the South China Sea (SCS). The δ¹¹B values of the Holocene corals vary significantly, ranging from 22.2‰ to 25.5‰. The paleo-pH records of the SCS, reconstructed from the δ¹¹B data, were not stable as previously thought but show a gradual increase from the Holocene thermal optimal and a sharp decrease to modern values. The latter is likely caused by the large amount of anthropogenic CO₂ emissions since the Industrial Revolution but variations of atmospheric pCO₂ cannot explain the pH change of the SCS before the Industrial Revolution. We suggest that variations of monsoon intensity during the mid-late Holocene may have driven the sea surface pH increase from the mid to late Holocene. Results of this study indicate that the impact of anthropogenic atmospheric CO₂ emissions may have reversed the natural pH trend in the SCS since the mid-Holocene. Such ocean pH records in the current interglacial period can help us better understand the physical and biological controls on ocean pH and possibly predict the long-term impact of climate change on future ocean acidification.

Revue / Journal Title

Geochimica et cosmochimica acta    ISSN  0016-7037   CODEN GCACAK 

Source / Source

2009, vol. 73, n^o5, pp. 1264-1272 [9 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Kidlington, ROYAUME-UNI  (1950) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 5743, 35400018696964.0040