Outer organic layer and internal repair mechanism protects pteropod Limacina helicina from ocean acidification

Peck, Victoria L and Tarling, Geraint A and Manno, Clara and Harper, Elizabeth M. and Tynan, Eithne (2016) Outer organic layer and internal repair mechanism protects pteropod Limacina helicina from ocean acidification. Deep Sea Research Part II: Topical Studies in Oceanography, 127. pp. 41-52. ISSN 0967-0645 DOI 10.1016/j.dsr2.2015.12.005

[img]
Preview
Text
Peck et al 2016_accepted.pdf - Accepted Version
Available under License Creative Commons Attribution Non-commercial.

Download (2MB) | Preview
Official URL: http://doi.org/10.1016/j.dsr2.2015.12.005

Abstract

Scarred shells of polar pteropod Limacina helicina collected from the Greenland Sea in June 2012 reveal a history of damage, most likely failed predation, in earlier life stages. Evidence of shell fracture and subsequent re-growth is commonly observed in specimens recovered from the sub-Arctic and further afield. However, at one site within sea–ice on the Greenland shelf, shells that had been subject to mechanical damage were also found to exhibit considerable dissolution. It was evident that shell dissolution was localised to areas where the organic, periostracal sheet that covers the outer shell had been damaged at some earlier stage during the animal’s life. Where the periostracum remained intact, the shell appeared pristine with no sign of dissolution. Specimens which appeared to be pristine following collection were incubated for four days. Scarring of shells that received periostracal damage during collection only became evident in specimens that were incubated in waters undersaturated with respect to aragonite, ΩAr≤1. While the waters from which the damaged specimens were collected at the Greenland Sea sea–ice margin were not ΩAr≤1, the water column did exhibit the lowest ΩAr values observed in the Greenland and Barents Seas, and was likely to have approached ΩAr≤1 during the winter months. We demonstrate that L. helicina shells are only susceptible to dissolution where both the periostracum has been breached and the aragonite beneath the breach is exposed to waters of ΩAr≤1. Exposure of multiple layers of aragonite in areas of deep dissolution indicate that, as with many molluscs, L. helicina is able to patch up dissolution damage to the shell by secreting additional aragonite internally and maintain their shell. We conclude that, unless breached, the periostracum provides an effective shield for pteropod shells against dissolution in waters ΩAr≤1, and when dissolution does occur the animal has an effective means of self-repair. We suggest that future studies of pteropod shell condition are undertaken on specimens from which the periostracum has not been removed in preparation.

Item Type: Article
Uncontrolled Keywords: 2015AREP; IA70;
Subjects: 04 - Palaeobiology
Divisions: 04 - Palaeobiology
08 - Green Open Access
Journal or Publication Title: Deep Sea Research Part II: Topical Studies in Oceanography
Volume: 127
Page Range: pp. 41-52
Identification Number: 10.1016/j.dsr2.2015.12.005
Depositing User: Sarah Humbert
Date Deposited: 01 May 2016 01:20
Last Modified: 15 Jun 2016 00:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/3654

Actions (login required)

View Item View Item

About cookies