## 1 Introduction  
The carbon dioxide (CO\({}_{2}\)) concentration in the atmosphere has greatly increased since the beginning of the Industrial Revolution, and the emission of carbon dioxide is the main reason for global warming [1]. It has been shown that almost 30% of the CO\({}_{2}\) emitted by man is eventually absorbed by the ocean, causing ocean acidification (OA) [2], which significantly impacts the marine ecosystem [3, 4]. Carbon dioxide sequestration is one of the most important means of reducing carbon dioxide emissions [5]. Marine carbon sequestration is a new kind of carbon dioxide sequestration which has much greater potential and security than terrestrial carbon sequestration [6]. However, it is a new technology that is underdeveloped, and there may be a risk of leakage due to the immature technology. The increase of dissolved carbon dioxide in the seawater leads to a decrease in pH and a perturbation of the carbonate chemistry [7]. The average pH of surface ocean has decreased by about 0.12 units since the preindustrial era and is predicted to drop by a further 0.3-0.4 units until 2100, with a pH value of 7.8 [8]. The decrease of seawater pH will cause the dissolution of carbonate minerals, and the stability of carbonate sediments may be implicated [9]. [PERSON] et al. [10] found that the calcium carbonate-rich shallow sediments in the Behamas dissolved when the pH value was below 8.0. [PERSON] et al. [11] conducted a broad-scale geochemical survey of across the Florida Reef Tract in 2009-2010 and found that the reefs experienced dissolution due to the acidification of water. [PERSON] et al. [12] studied cold vent areas off Ischia in Italy where seawater was almost acidified by CO\({}_{2}\). The researchers found that the skeletons of calcified organisms dissolved in a short time, although the pH value of seawater was about 7.3. The carbonate dissolution occurred on the surfaces, and in the nooks and crannies of the limestone foundation. Therefore, the limestone foundation became more porous and weaker [13; 14]. In addition, the physical and mechanical properties of reef sediments changed with a CO\({}_{2}\) acid system, and the dissolution rates increased when OA continued [15]. Coral reef limestone is a special biogenic carbonate which is mainly composed of calcium carbonate. It is a common marine sedimentary rock and the main load-bearing medium of coral reefs [16]. Research has shown that calcite easily dissolves when brought into contact with a CO\({}_{2}\) weak acid solution [17]. Therefore, it is important to have a holistic understanding of fluid-rock interacting between CO\({}_{2}\), seawater and reef limestones. Several studies have been devoted to the experimental investigation of the CO\({}_{2}\)-water-rock interaction. Some studies have indicated that minerals of the rocks dissolve or precipitate during the process, and the physical and mechanical properties of the rock change during the reaction [18; 19; 20; 21; 22; 23; 24; 25]. However, not all studies have yielded the same results. [PERSON] et al. [26] found that there was no obvious mineralization reaction when the condition was of low temperature and pressure in their tests. Similarly, CO\({}_{2}\) had no obvious effect on the tensile strength of sandstone, shale and chalk [27]. [PERSON] et al. [28] suggested that the effects of CO\({}_{2}\)-acid brines on carbonate with different types are quite different. The reef limestones are special carbonates with diverse structure types and are quite different compared to other continental and marine sedimentary rocks [29]. The effect of CO\({}_{2}\) on the physical and mechanical properties of reef limestones remains unclear. In the current work, experiments were conducted to simulate the reaction process of CO\({}_{2}\), seawater and reef limestone to investigate the destruction of both the physical and mechanical properties of reef limestone due to the acidification of seawater. The solution was analyzed for dissolved Ca\({}^{2+}\) concentration during the reaction.