Seagrass ecosystems contain globally significant organic carbon (C) stocks. However, climate change and increasing frequency of extreme events threaten their preservation. Shark Bay, Western Australia, has the largest C stock reported for a seagrass ecosystem, containing up to 1.3% of the total C stored within the top metre of seagrass sediments worldwide. On the basis of field studies and satellite imagery, we estimate that 36% of Shark Bay’s seagrass meadows were damaged following a marine heatwave in 2010/2011. Assuming that 10 to 50% of the seagrass sediment C stock was exposed to oxic conditions after disturbance, between 2 and 9 Tg CO₂ could have been released to the atmosphere during the following three years, increasing emissions from land-use change in Australia by 4–21% per annum. With heatwaves predicted to increase with further climate warming, conservation of seagrass ecosystems is essential to avoid adverse feedbacks on the climate system.

海草生态系统包含全球范围内重要的有机碳（C）储量。但是，气候变化和极端事件发生频率的增加威胁着其保存。西澳大利亚州的鲨鱼湾拥有海藻生态系统中最大的碳储量，占全球海藻沉积物最高表层存储的总碳的1.3％。根据实地研究和卫星图像，我们估计，在2010/2011年的海洋热浪中，鲨鱼湾36％的海草草甸遭到了破坏。假设在扰动后，海草沉积物C储量的10％至5​​0％暴露于有氧条件，即2至9 Tg CO ₂可能会在接下来的三年内释放到大气中，从而使澳大利亚土地用途变化带来的排放量每年增加4-21％。随着热浪预计会随着气候进一步变暖而增加，海草生态系统的保护对于避免对气候系统的不利反馈至关重要。