Skeletal integrity of a marine keystone predator (Asterias rubens) threatened by ocean acidification

Di Giglio, Sarah, Lein, Etienne, Hu, Marian Y., Stumpp, Meike, Melzner, Frank, Malet, Loïc, Pernet, Philippe and Dubois, Philippe (2020) Skeletal integrity of a marine keystone predator (Asterias rubens) threatened by ocean acidification Journal of Experimental Marine Biology and Ecology, 526 . Art.Nr. 151335. DOI 10.1016/j.jembe.2020.151335.

[img] Text
DiGiglio etal 2020 JEMBE.pdf - Published Version
Restricted to Registered users only

Download (1433Kb) | Contact

Supplementary data:

Abstract

The current increase in atmospheric CO2 concentration induces changes in the seawater carbonate system resulting in decreased pH and calcium carbonate saturation state, a phenomenon called ocean acidification (OA). OA has long been considered as a major threat to echinoderms because their extensive endoskeleton is made of high‑magnesium calcite, one of the most soluble forms of calcium carbonate. Numerous studies addressed this question in sea urchins, but very few questioned the impact of OA on the sea star skeleton, although members of this taxon do not compensate their extracellular pH, contrary to most sea urchins. In the present study, adults of the common sea star, Asterias rubens from Kiel Fjord, a site experiencing natural acidification events exceeding pCO2 levels of 2500 μatm, were chronically exposed to different levels of simulated ocean acidification (pHT-SW 8.0, 7.4, 7.2), encompassing present and future conditions, for the duration of 109 days. Corrosion and mechanical properties of skeletal elements were studied using scanning electron microscopy, three-point bending tests as well as nanoindentation. The spines were significantly corroded at pHT-SW 7.4 and below while the ambulacral plates were only affected at pHT-SW 7.2. Nanoindentation of newly formed spines and ambulacral plates did not reveal significant CO2-induced differences in skeleton hardness or elasticity across treatments. Results of three-point bending tests revealed significantly reduced characteristic strength and fracture force of ambulacral plates from the median arm segment at pHT-SW 7.4 and below. These plates are those supporting the tube feet involved in the opening of bivalves during feeding and in the animal attachment to the substrate. Under reduced seawater pH, this might result in fracture of sea star plates during predation on mussel. The present results predict a possible impact of ocean acidification on the skeletal integrity of a marine keystone predator.

Document Type: Article
Keywords: Ocean acidification; Echinoderms; Asterias rubens; Skeleton; Mechanics; Acclimation
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
Kiel University
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Refereed: Yes
DOI etc.: 10.1016/j.jembe.2020.151335
ISSN: 0022-0981
Projects: Future Ocean
Date Deposited: 26 Feb 2020 09:34
Last Modified: 26 Feb 2020 10:46
URI: http://eprints.uni-kiel.de/id/eprint/49051

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...