The Great Barrier Reef (GBR) is a globally significant coral reef system supporting productive and diverse ecosystems. The GBR is under increasing threat from climate change and local anthropogenic stressors, with its general condition degrading over recent decades. In response to this, a number of techniques have been proposed to offset or ameliorate environmental changes. In this study, we use a coupled hydrodynamic-biogeochemical model of the GBR and surrounding ocean to simulate artificial ocean alkalinisation (AOA) as a means to reverse the impact of global ocean acidification on GBR reefs. Our results demonstrate that a continuous release of 90 000 t of alkalinity every 3 d over one year along the entire length of the GBR, following the Gladstone-Weipa bulk carrier route, increases the mean aragonite saturation state () across the GBR’s 3860 reefs by 0.05. This change offsets just over 4 years (∼4.2) of ocean acidification under the present rate of anthropogenic carbon emissions. The injection raises in the 250 reefs closest to the route by , reversing further projected Ocean Acidification. Following cessation of alkalinity injection returns to the value of the waters in the absence of AOA over a 6 month period, primarily due to transport of additional alkalinity into the Coral Sea. Significantly, our study provides for the first time a model of AOA applied along existing shipping infrastructure that has been used to investigate shelf scale impacts. Thus, amelioration of decades of OA on the GBR is feasible using existing infrastructure, but is likely to be extremely expensive, include as yet unquantified risks, and would need to be undertaken continuously until such time, probably centuries in the future, when atmospheric CO₂ concentrations have returned to today’s values.

大堡礁 (GBR) 是一个全球重要的珊瑚礁系统，支持多产和多样化的生态系统。GBR 受到气候变化和当地人为压力因素的威胁越来越大，近几十年来其总体状况正在恶化。针对这一点，已经提出了许多技术来抵消或改善环境变化。在这项研究中，我们使用 GBR 和周围海洋的耦合水动力-生物地球化学模型来模拟人工海洋碱化 (AOA)，以此作为逆转全球海洋酸化对 GBR 珊瑚礁影响的一种手段。我们的结果表明，沿着格莱斯顿-韦帕散货船路线，在一年内每 3 天持续释放 90 000 吨碱度，沿着 GBR 的整个长度，增加了平均文石饱和状态（) 跨越 GBR 的 3860 个珊瑚礁 0.05。在目前的人为碳排放速度下，这种变化抵消了仅仅超过 4 年（~4.2）的海洋酸化。注入在距离路线最近的 250 个珊瑚礁中升高，逆转了进一步预测的海洋酸化。碱注入停止后在没有 AOA 的 6 个月内恢复到水域的价值，这主要是由于将额外的碱度输送到珊瑚海。重要的是，我们的研究首次提供了沿现有航运基础设施应用的 AOA 模型，该模型已用于调查货架规模影响。因此，使用现有基础设施改善 GBR 上数十年的 OA 是可行的，但可能非常昂贵，包括尚未量化的风险，并且需要持续进行直到这样的时间，可能是未来几个世纪，当大气 CO ₂浓度已恢复到今天的值。