Molecular mechanisms of biomineralization in marine invertebrates.

Melody S Clark

doi:10.1242/jeb.206961

Abstract

ABSTRACTMuch recent marine research has been directed towards understanding the effects of anthropogenic-induced environmental change on marine biodiversity, particularly for those animals with heavily calcified exoskeletons, such as corals, molluscs and urchins. This is because life in our oceans is becoming more challenging for these animals with changes in temperature, pH and salinity. In the future, it will be more energetically expensive to make marine skeletons and the increasingly corrosive conditions in seawater are expected to result in the dissolution of these external skeletons. However, initial predictions of wide-scale sensitivity are changing as we understand more about the mechanisms underpinning skeletal production (biomineralization). These studies demonstrate the complexity of calcification pathways and the cellular responses of animals to these altered conditions. Factors including parental conditioning, phenotypic plasticity and epigenetics can significantly impact the production of skeletons and thus future population success. This understanding is paralleled by an increase in our knowledge of the genes and proteins involved in biomineralization, particularly in some phyla, such as urchins, molluscs and corals. This Review will provide a broad overview of our current understanding of the factors affecting skeletal production in marine invertebrates. It will focus on the molecular mechanisms underpinning biomineralization and how knowledge of these processes affects experimental design and our ability to predict responses to climate change. Understanding marine biomineralization has many tangible benefits in our changing world, including improvements in conservation and aquaculture and exploitation of natural calcified structure design using biomimicry approaches that are aimed at producing novel biocomposites.

Highlights

Biomineralization is a fundamental process in the world’s oceans; it is the biological mechanism whereby the calcium dissolved in seawater is used to produce solid crystal mineralized structures, namely skeletons and exoskeletons
The process whereby our oceans absorb CO2 is an important buffer for future increases in atmospheric CO2 and an important weapon in global resilience to anthropogenic climate change
Many of the molecular responses of species such as urchins, corals, pteropods and molluscs to reductions in seawater pH or PCO2 and/or temperature have revealed significant reductions in gene expression levels associated with a range of functions, namely biomineralization, the cell stress response, cellular energetics and acid–base metabolism (Todgham and Hofmann, 2009; Barshis et al, 2013; Evans et al, 2015; Li et al, 2016; Johnson and Hofmann, 2017; Liu et al, 2017; Maas et al, 2018)

Summary

Introduction

Biomineralization is a fundamental process in the world’s oceans; it is the biological mechanism whereby the calcium dissolved in seawater is used to produce solid crystal mineralized structures, namely skeletons and exoskeletons. Changing conditions can affect the energetic costs of calcification for marine animals, because skeletal production in calcifying animals requires more energy when the saturation state of calcium carbonate minerals in the ocean is reduced.

Results

Conclusion