The Chukchi Sea shelf (CSS) is a highly productive region in the Arctic Ocean and it is highly efficient for absorbing atmospheric carbon dioxide and exporting and retaining carbon in the deep sea. However, with global warming, the carbon retention time in CSS may decrease, leading to less efficient carbon export. Here, we investigate the seasonal variability of carbonate chemistry in CSS using three sets of late- vs. early-summer reoccupations of the same transect. Our findings demonstrate substantially increased and rapid degradation of biologically produced organic matter and therefore acidification over time in the southern CSS due to earlier sea-ice retreat, resulting in significantly shorter carbon retention time. In sharp contrast, no increased degradation has been observed in the northern CSS where photosynthesis has just commenced. In the future, climate change would further diminish the carbon export capacity and exacerbate seasonal acidification not only within CSS but also across other polar coastal oceans.

中文翻译：

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海冰损失加速了碳循环并加剧了北极楚科奇海的季节性极端酸化

楚科奇海陆架（CSS）是北冰洋的高产区域，其吸收大气二氧化碳以及向深海输出和保留碳的效率很高。然而，随着全球变暖，CSS中的碳保留时间可能会减少，导致碳输出效率降低。在这里，我们使用同一样带的三组夏末与夏初重新占领来研究 CSS 中碳酸盐化学的季节变化。我们的研究结果表明，由于海冰较早消退，生物产生的有机物的降解显着增加且迅速，因此CSS南部随着时间的推移而酸化，导致碳保留时间显着缩短。与此形成鲜明对比的是，在光合作用刚刚开始的北部CSS中，没有观察到退化加剧。未来，气候变化将进一步削弱碳输出能力，并加剧季节性酸化，不仅在CSS内部，而且在其他极地沿海海洋也是如此。