Hysteresis Between Coral Reef Calcification and the Seawater Aragonite Saturation State

Authors

Ashly McMahon, Southern Cross University - Lismore, Australia
Isaac R. Santos, Southern Cross University - Lismore, Australia
Tyler Cyronak, Southern Cross University - Lismore, AustraliaFollow
Bradley D. Eyre, Southern Cross University - Lismore, Australia

ORCID

0000-0003-3556-7616

Document Type

Article

Publication Title

Geophysical Research Letters

ISSN

0094-8276

Publication Date

8-1-2013

Keywords

Ocean acidification, Permeable sediments, Carbon dioxide, Coastal waters, Calcite, Aragonite

Abstract

Some predictions of how ocean acidification (OA) will affect coral reefs assume a linear functional relationship between the ambient seawater aragonite saturation state (Ω_a) and net ecosystem calcification (NEC). We quantified NEC in a healthy coral reef lagoon in the Great Barrier Reef during different times of the day. Our observations revealed a diel hysteresis pattern in the NEC versus Ω_a relationship, with peak NEC rates occurring before the Ω_a peak and relatively steady nighttime NEC in spite of variable Ω_a. Net ecosystem production had stronger correlations with NEC than light, temperature, nutrients, pH, and Ω_a. The observed hysteresis may represent an overlooked challenge for predicting the effects of OA on coral reefs. If widespread, the hysteresis could prevent the use of a linear extrapolation to determine critical Ω_a threshold levels required to shift coral reefs from a net calcifying to a net dissolving state.

DOI

10.1002/grl.50802

Volume

40

Issue

17

First Page

4675

Last Page

4679

Comments

©2013. American Geophysical Union. All Rights Reserved.

Additional Comments

ARC grant #: DP110103638

NSUWorks Citation

Ashly McMahon, Isaac R. Santos, Tyler Cyronak, and Bradley D. Eyre. 2013. Hysteresis Between Coral Reef Calcification and the Seawater Aragonite Saturation State .Geophysical Research Letters , (17) : 4675 -4679. https://nsuworks.nova.edu/occ_facarticles/1038.