Seawater carbonate chemistry and community calcification near Lizar Island, 2011

It is predicted that surface ocean pH will reach 7.9, possibly 7.8 by the end of this century due to increased carbon dioxide (CO2) in the atmosphere and in the surface ocean. While aragonite-rich sediments don't begin to dissolve until a threshold pH of ~ 7.8 is reached, dissolution from high-Mg calcites is evident with any drop in pH. Indeed, it is high-Mg calcite that dominates the reaction of carbonate sediments with increased CO2, which undergoes a rapid neomorphism process to a more stable, low-Mg calcite. This has major implications for the future of the high-Mg calcite producing organisms within coral reef ecosystems. In order to understand any potential buffering system offered by the dissolution of carbonate sediments under a lower oceanic pH, this process of high-Mg calcite dissolution in the reef environment must be further elucidated.

据预测，受大气及表层海水二氧化碳（CO₂）含量升高影响，到本世纪末表层海水pH值将降至7.9，甚至可能达到7.8。富文石沉积物仅当pH阈值达到约7.8时才会开始溶解，而高镁方解石（high-Mg calcite）的溶解作用会随pH的任何下降而显现。事实上，在碳酸盐沉积物与升高的CO₂的反应中，高镁方解石占据主导地位，其会经历快速的新生变形作用，转变为更稳定的低镁方解石（low-Mg calcite）。这对珊瑚礁生态系统中产生高镁方解石的生物的生存前景具有重大影响。为了明确海洋pH降低条件下碳酸盐沉积物溶解所提供的潜在缓冲体系，必须进一步阐明礁体环境中的高镁方解石溶解过程。