Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 3.480
IF3.480
IF 5-year value: 4.194
IF 5-year
4.194
CiteScore value: 6.7
CiteScore
6.7
SNIP value: 1.143
SNIP1.143
IPP value: 3.65
IPP3.65
SJR value: 1.761
SJR1.761
Scimago H <br class='widget-line-break'>index value: 118
Scimago H
index
118
h5-index value: 60
h5-index60
Preprints
https://doi.org/10.5194/bg-2018-438
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2018-438
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

  15 Oct 2018

15 Oct 2018

Review status
This preprint has been withdrawn by the authors.

Assessment of paleo-ocean pH records from boron isotope ratio in the Pacific and Atlantic ocean corals: Role of anthropogenic CO2 forcing and oceanographic factors to pH variability

Mohd Tarique and Waliur Rahaman Mohd Tarique and Waliur Rahaman
  • National Centre for Polar & Ocean Research, Goa

Abstract. Boron isotopes (δ11B) records from tropical ocean corals have been used to reconstruct paleo-pH of ocean for the past several decades to few centuries which are comparable to the resolution of instrumental records. In most of the studies, attempts have been made to decipher the role of anthropogenic CO2 forcing to recent trend of ocean acidification based on δ11B derived paleo-pH records. However, such attempts in past were often hindered by limited knowledge of oceanographic factors that contributed to past pH variability and changes. In this study, we have evaluated pH records reconstructed using δ11B records from the Pacific and the Atlantic Oceans corals and investigated major forcing factors that contributed to sub annual-decadal scale pH variability and changes since the industrial era ~ 1850 AD.

To the best of our knowledge, total eight δ11B records from the Pacific and two from the Atlantic Oceans are available in published literatures. The compilations of these records show large variability; range between 26.27–20.82 ‰ which corresponds to pH range 8.40–7.63 respectively. Our investigation of pH records from the Pacific ocean based on principal component analysis (PCA) reveals that atmospheric CO2 can explains maximum up to ~ 26 % of the total pH variability during 1950–2004 AD, followed by the ocean-climate oscillations (i.e. ENSO and PDO) driven oceanographic factors up to ~ 17 %. The remaining large variability (~ 57 %) could not be explained by above forcing factors and hence we invoke possible influence of metabolic processes of corals and/or changes in micro-environments within the reefs which are often neglected in interpreting paleo-pH records. Therefore, we highlight the need for detailed investigation in future studies to understand about the exact mechanism, processes/factors that controlled boron isotope fractionations in coral reef environments. Further, our investigation reveals that amplitude of the ENSO driven pH variability shows fivefold increase during 1980–2000 AD compared to the previous three decades (1950–1980 AD). This observation is consistent with the historical records of global coral bleaching events and therefore underscores role of ENSO driven environmental stress responsible for coral bleaching events. Considering model based projections of increasing frequency and amplitude of extreme ENSO events in the backdrop of recent global warming, bleaching events are likely to increase in the next decades/centuries.

This preprint has been withdrawn.

Mohd Tarique and Waliur Rahaman

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Mohd Tarique and Waliur Rahaman

Mohd Tarique and Waliur Rahaman

Viewed

Total article views: 646 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
431 200 15 646 41 13 19
  • HTML: 431
  • PDF: 200
  • XML: 15
  • Total: 646
  • Supplement: 41
  • BibTeX: 13
  • EndNote: 19
Views and downloads (calculated since 15 Oct 2018)
Cumulative views and downloads (calculated since 15 Oct 2018)

Viewed (geographical distribution)

Total article views: 619 (including HTML, PDF, and XML) Thereof 619 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 27 Nov 2020
Publications Copernicus
Download
Withdrawal notice

This preprint has been withdrawn.

Citation
Altmetrics