Biomechanical Characterization of Scallop Shells Exposed to Ocean Acidification and Warming.

Aldo Abarca-Ortega,Estefano Muñoz-Moya,Nelson A Lagos,Diego J Celentano,Matías Pacheco Alarcón,Claudio M García-Herrera,Marco A Lardies

doi:10.3389/fbioe.2021.813537

Abstract

Increased carbon dioxide levels (CO2) in the atmosphere triggered a cascade of physical and chemical changes in the ocean surface. Marine organisms producing carbonate shells are regarded as vulnerable to these physical (warming), and chemical (acidification) changes occurring in the oceans. In the last decade, the aquaculture production of the bivalve scallop Argopecten purpuratus (AP) showed declined trends along the Chilean coast. These negative trends have been ascribed to ecophysiological and biomineralization constraints in shell carbonate production. This work experimentally characterizes the biomechanical response of AP scallop shells subjected to climate change scenarios (acidification and warming) via quasi-static tensile and bending tests. The experimental results indicate the adaptation of mechanical properties to hostile growth scenarios in terms of temperature and water acidification. In addition, the mechanical response of the AP subjected to control climate conditions was analyzed with finite element simulations including an anisotropic elastic constitutive model for a two-fold purpose: Firstly, to calibrate the material model parameters using the tensile test curves in two mutually perpendicular directions (representative of the mechanical behavior of the material). Secondly, to validate this characterization procedure in predicting the material’s behavior in two mechanical tests.

Highlights

It is known that about one third of the CO2 emissions produced by human activities are deposited on the ocean surface (Sabine et al, 2004)
The methods developed and explained in the present work can be further applied to different species to characterize their biomechanical properties
Other factors related to climate change need to be evaluated in further studies

Summary

Introduction

It is known that about one third of the CO2 emissions produced by human activities are deposited on the ocean surface (Sabine et al, 2004). These conditions are exposed to progressive acidification described for other coasts such as Oregon and California upwelling ecosystems (Feely et al, 2008; Gruber et al, 2012; Kim et al, 2013). In these regions, the significant impacts of ocean acidification were evidenced in a substantial reduction in the production of the cultured oyster Crassostrea gigas (Barton et al, 2012). A recent study suggests that Argopecten purpuratus (AP) in its juvenile stage prioritizes calcification at the expense of growth under acidic conditions, being a factor not so sensitive compared to the temperature of its habitat, which is associated with early or late mortalities, observing significantly higher mortality at 18°C than at 14°C (Ramajo et al, 2019; Ramajo et al, 2020)

Objectives

Methods

Results

Conclusion