A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

authored by

G. Dishon, J. Fisch, I. Horn, K. Kaczmarek, J. Bijma, D. F. Gruber, O. Nir, Y. Popovich, D. Tchernov

Abstract

Coral reefs occupy only ∼ 0.1 percent of the ocean's habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced a significant global decline due to a variety of causes, one of the major causes being widespread coral bleaching events. During bleaching, the coral expels its symbiotic algae, thereby losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) to demonstrate a distinct biologically induced decline of boron (B) isotopic composition (δ11B) as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleo-coral bleaching events. Based on a literature review of published δ11B data and our recorded vital effect of coral bleaching on the δ11B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure. Understanding the frequency of bleaching events is also critical for determining the relationship between natural and anthropogenic causes of these events.

Organisation(s)

Institute of Mineralogy

External Organisation(s)

University of Haifa
University of Miami (UM)
Alfred Wegener Institute (AWI) Helmholtz Centre for Polar and Marine Research
City University of New York

Type

Article

Journal

BIOGEOSCIENCES

Volume

12

Pages

5677-5687

No. of pages

11

ISSN

1726-4170

Publication date

08.10.2015

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.5194/bg-12-5677-2015 (Access: Open)
https://doi.org/10.15488/1076 (Access: Open)