We use a modern Earth system model to approximate the relative importance of ice versus temperature on Arctic marine ecosystem dynamics. We show that while the model adequately simulates ice volume, water temperature, air‐sea CO₂ flux, and annual primary production in the Arctic, itunderestimates upper water column nitrate across the region. This nitrate bias is likely responsible for the apparent underestimation of ice algae production. Despite this shortcoming, the model appears to be a useful tool for exploring the impacts of environmental change on phytoplankton production and carbon dynamics over the Arctic Ocean. Our experiments indicate that under a warmer climate scenario, the percentage of ocean warming that could be apportioned to a reduction in ice area ranged from 11% to 100%, while decreasing ice area could account for 22–100% of the increase in annual ocean primary production. The change to CO₂ air‐sea flux in response to ice and temperature changes averaged an Arctic‐wide 5.5 Tg C yr⁻¹ (3.5%) increase, into the ocean. This increased carbon sink may be short‐lived, as ice cover continues to decrease and the ocean warms. The change in carbon fixation from phytoplankton in response to increased temperatures and reduced ice was generally more than a magnitude larger than the changes to CO₂ flux, highlighting the importance of fully considering changes to the marine ecosystem when assessing Arctic carbon cycle dynamics. Our work demonstrates the importance of ice dynamics in controlling ocean warming and production and thus the need for well‐behaved ice and BGC models within Earth system models if we hope to accurately predict Arctic changes.

中文翻译：

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海冰和温度变化对北极海洋生产的相对影响

我们使用现代地球系统模型来估算冰与温度对北极海洋生态系统动力学的相对重要性。我们表明，尽管该模型可以充分模拟冰量，水温，海气CO ₂北极的通量和每年的初级生产量低估了整个区域的上水柱硝酸盐含量。这种硝酸盐偏差可能是造成冰藻产量明显低估的原因。尽管存在这些缺点，该模型仍是探索环境变化对北冰洋浮游植物生产和碳动态影响的有用工具。我们的实验表明，在气候变暖的情况下，可归因于冰面积减少的海洋变暖百分比范围为11％至100％，而冰面积减少可占年度海洋增加量的22–100％初级生产。响应于冰和温度变化，CO ₂气海通量的变化平均为整个北极范围的5.5 Tg C yr ^-1（3.5％）增加，进入海洋。随着冰层的继续减少和海洋变暖，这种增加的碳汇可能是短暂的。浮游植物对固碳的响应相对于温度升高和冰量减少的变化通常比对CO ₂通量的变化大一个数量级，这突出了在评估北极碳循环动态时充分考虑海洋生态系统变化的重要性。我们的工作证明了冰动力学在控制海洋变暖和生产中的重要性，因此，如果我们希望准确地预测北极的变化，则需要在地球系统模型中使用行为良好的冰和BGC模型。