Established and Emerging Techniques for Characterising the Formation, Structure and Performance of Calcified Structures under Ocean Acidification

Fitzer, Susan C.; Chan, Vera B. S.; Yuan, Meng; Rajan, Kanmani Chandra; Suzuki, Masayuki; Not, Christelle; Toyofuku, Takashi; Falkenberg, Laura J.; Byrne, Maria; Harvey, Ben P.; Wit, Pierre De; Cusack, Maggie; Gao, K. S.; Taylor, Paul; Dupont, Sam; Hall‐Spencer, Jason M.; Thiyagarajan, V.

doi:10.1201/9780429026379-2

Cited by 11 publications

(15 citation statements)

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“…As highlighted here with a limited number of species, there will almost certainly be a tractable animal model in our oceans to cover any question related to this subject. Over the years, the sophistication of experiments manipulating marine organisms has not only expanded to include parental conditioning and transgenerational plasticity but also become more multidisciplinary, for example by enabling more accurate tracking of calcium at the cellular level (Fitzer et al, 2019). However, there is still scope for expanding the temporal and spatial scales of individual laboratory experiments.…”

Section: Discussionmentioning

confidence: 99%

Molecular mechanisms of biomineralization in marine invertebrates

Clark

2020

Journal of Experimental Biology

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Much 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.

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Section: Discussionmentioning

confidence: 99%

Molecular mechanisms of biomineralization in marine invertebrates

Clark

2020

Journal of Experimental Biology

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“…Shell properties that are useful for estimating fitness under environmental stressors, especially to OA, include shell growth rate, shell crystal orientation analysis and shell hardness, to name a few (Fitzer, Chan, et al, 2019). Crystal orientation of marine calcareous structures is well known to be influenced by environmental condition and this influence is referred to as crystallographic vital effect (CVE; Coronado et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Oyster biomineralization under ocean acidification: From genes to shell

Rajan

Yuan

et al. 2021

Global Change Biology

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Biomineralization is one of the key processes that is notably affected in marine calcifiers such as oysters under ocean acidification (OA). Understanding molecular changes in the biomineralization process under OA and its heritability, therefore, is key to developing conservation strategies for protecting ecologically and economically important oyster species. To do this, in this study, we have explicitly chosen the tissue involved in biomineralization (mantle) of an estuarine commercial oyster species, Crassostrea hongkongensis. The primary aim of this study is to understand the influence of DNA methylation over gene expression of mantle tissue under decreased ~pH 7.4, a proxy of OA, and to extrapolate if these molecular changes can be observed in the product of biomineralization—the shell. We grew early juvenile C. hongkongensis, under decreased ~pH 7.4 and control ~pH 8.0 over 4.5 months and studied OA‐induced DNA methylation and gene expression patterns along with shell properties such as microstructure, crystal orientation and hardness. The population of oysters used in this study was found to be moderately resilient to OA at the end of the experiment. The expression of key biomineralization‐related genes such as carbonic anhydrase and alkaline phosphatase remained unaffected; thus, the mechanical properties of the shell (shell growth rate, hardness and crystal orientation) were also maintained without any significant difference between control and OA conditions with signs of severe dissolution. In addition, this study makes three major conclusions: (1) higher expression of Ca2+ binding/signalling‐related genes in the mantle plays a key role in maintaining biomineralization under OA; (2) DNA methylation changes occur in response to OA; however, these methylation changes do not directly control gene expression; and (3) OA would be more of a ‘dissolution problem’ rather than a ‘biomineralization problem’ for resilient species that maintain calcification rate with normal shell growth and mechanical properties.

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“…This is addressed here in a review of recent research, where advanced microscopy is used to visualize the internal microstructure and crystallography of biomineral in calcifiers that have been exposed to experimental (laboratory) or natural (vents, coastal run off) acidification (Table 1). Changes in microstructure have been revealed by the application of scanning electron microscopy (SEM) to view surface changes and microcomputed tomography (μCT) to generate three-dimensional reconstructions of entire shells and skeletons (Fitzer et al ., 2019a).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, nanoindentation can be used to determine the elastic modulus (Young’s modulus— E ) of the surface of the shell (Fitzer et al ., 2015a; Milano et al ., 2016; Meng et al ., 2018). Details of the advanced microscopy and materials science techniques that have been used to investigate marine skeletons in an OA context are reviewed in Fitzer et al . (2019a).…”

Section: Introductionmentioning

confidence: 99%

The impact of environmental acidification on the microstructure and mechanical integrity of marine invertebrate skeletons

Byrne

Fitzer

2019

Conservation Physiology

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Ocean acidification (OA), from seawater uptake of anthropogenic CO2, has a suite of negative effects on the ability of marine invertebrates to produce and maintain their skeletons. Increased organism pCO2 causes hypercapnia, an energetically costly physiological stress. OA alters seawater carbonate chemistry, limiting the carbonate available to form the calcium carbonate (CaCO3) minerals used to build skeletons. The reduced saturation state of CaCO3 also causes corrosion of CaCO3 structures. Global change is also accelerating coastal acidification driven by land-run off (e.g. acid soil leachates, tannic acid). Building and maintaining marine biomaterials in the face of changing climate will depend on the balance between calcification and dissolution. Overall, in response to environmental acidification, many calcifiers produce less biomineral and so have smaller body size. Studies of skeleton development in echinoderms and molluscs across life stages show the stunting effect of OA. For corals, linear extension may be maintained, but at the expense of less dense biomineral. Conventional metrics used to quantify growth and calcification need to be augmented by characterisation of the changes to biomineral structure and mechanical integrity caused by environmental acidification. Scanning electron microscopy and microcomputed tomography of corals, tube worms and sea urchins exposed to experimental (laboratory) and natural (vents, coastal run off) acidification show a less dense biomineral with greater porosity and a larger void space. For bivalves, CaCO3 crystal deposition is more chaotic in response to both ocean and coastal acidification. Biomechanics tests reveal that these changes result in weaker, more fragile skeletons, compromising their vital protective roles. Vulnerabilities differ among taxa and depend on acidification level. Climate warming has the potential to ameliorate some of the negative effects of acidification but may also make matters worse. The integrative morphology-ecomechanics approach is key to understanding how marine biominerals will perform in the face of changing climate.

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Established and Emerging Techniques for Characterising the Formation, Structure and Performance of Calcified Structures under Ocean Acidification

Cited by 11 publications

References 0 publications

Molecular mechanisms of biomineralization in marine invertebrates

Molecular mechanisms of biomineralization in marine invertebrates

Oyster biomineralization under ocean acidification: From genes to shell

The impact of environmental acidification on the microstructure and mechanical integrity of marine invertebrate skeletons

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