The effect of acidified seawater on shell characteristics of blood cockle, Tegillarca granosa

Abstract

Our ocean currently has been recorded to absorb about 25% of anthropogenic CO 2 on an annual basis. This has estimated the global average sea surface pH to decrease from 8.2 to 8.1 units since the pre-industrial revolution and to further drop between 0.1 to 0.3 units by the end of the 21 st century. This possesses a potential impact on wide range of marine organisms' especially marine calcifiers where the CO 3 2is a fundamental mineral for shell and skeleton formation. In a 7-day experiment, this study investigated the effect of different pH treatments, which were pH 7.10, pH 7.50 and control pH (pH 7.81) on shell properties of the blood cockle, Tegillarca granosa. The shell weight and shell density of T. granosa was significantly reduced at pH 7.10. The smaller mean ratio for weight and density at pH 7.10 indicated there was a large difference between the initial and final value for weight and density. Furthermore, the scanning electron micrograph revealed the rough outer shell surface (periostracum) of T. granosa under decreased pH treatment (pH 7.10). However, the ocean acidification level of pH 7.50 which predicted to occur by the year 2300 showed no significant decrease in shell weight and shell density of T. granosa compared to the control pH treatment (pH 7.81).

An Assessment of the Potential Value for Climate Remediation of Ocean Calcifiers in Sequestration of Atmospheric Carbon

“…"…However, the ocean acidification level of pH 7.50 which is predicted to occur by the year 2300 showed no significant decrease in shell weight and shell density of T. granosa compared to the control pH treatment (pH 7.81)" (Nithiyaa et al 2021 [35]). [36] have demonstrated significant changes in the hydrated and dehydrated forms of amorphous CaCO3 in the crystalline layers of shells of the blue (or 'common') mussel (Mytilus edulis) cultured under experimental acidification conditions.…”

“…Other examples are experiments studying the effect of different pH treatments on shell properties of the blood cockle (or blood clam), Tegillarca granosa, that used experimental pH values of 7.1 and 7.5 and a pH of 7.81 as a control [35]. This clam occurs in the intertidal zone throughout the Indo-Pacific region, from South Africa through to Southeast Asia, Australia, and Japan.…”

“…This clam occurs in the intertidal zone throughout the Indo-Pacific region, from South Africa through to Southeast Asia, Australia, and Japan. It is widely harvested in coastal and estuarine mudflats so the finding that "…The shell weight and shell density of T. granosa was significantly reduced at pH 7.10…" [35] could have severe economic consequences for the industry. However, this reduction in weight and density is in comparison with a control pH value (of 7.81) which is not expected to be reached in our oceans until 2100 AD.…”

An Assessment of the Potential Value for Climate Remediation of Ocean Calcifiers in Sequestration of Atmospheric Carbon

“…Other examples are experiments studying the effect of different pH treatments on shell properties of the blood cockle (or blood clam), Tegillarca granosa, that used experimental pH values of 7.1 and 7.5 and a pH of 7.81 as a control [36]. This clam occurs in the intertidal zone throughout the Indo-Pacific region, from South Africa through to Southeast Asia, Australia, and Japan.…”

Effect of Seawater Acidification on Physiological and Energy Metabolism Responses of the Common Cockle (Anadara Antiquata) of Gazi Bay, Kenya

“…Studies on the impact of ocean acidification on cockles (Cerastoderma edule) from Oosterschelde estuary, Netherlands (Ong et al, 2017), and from Ria de Aveiro coastal lagoon, Portugal (Magalhães et al, 2018), as well as cockle (Tegillarca granosa) of Kuala Juru, Penang, Malaysia (Nithiyaa et al, 2021), have been conducted. However, there is limited information on how OA will impact the cockles (Anadara antiquata) of Gazi Bay, Kenya.…”