Temperature controls carbon cycling and biological evolution in the ocean twilight zone

Theory suggests that the ocean's biological carbon pump, the process by which organic matter is produced at the surface and transferred to the deep ocean, is sensitive to temperature because temperature controls photosynthesis and respiration rates. We applied a combined data-modeling approach to investigate carbon and nutrient recycling rates across the world ocean over the past 15 million years of global cooling. We found that the efficiency of the biological carbon pump increased with ocean cooling as the result of a temperature-dependent reduction in the rate of remineralization (degradation) of sinking organic matter. Increased food delivery at depth prompted the development of new deep-water niches, triggering deep plankton evolution and the expansion of the mesopelagic "twilight zone" ecosystem.

理论表明，海洋的生物碳泵（即有机物在海洋表面产生并转移至深海的过程）对温度敏感，因为温度控制着光合作用和呼吸速率。我们采用了一种数据与模型相结合的方法，研究了在过去1500万年全球变冷期间世界海洋中碳和营养物质的循环速率。我们发现，随着海洋变冷，生物碳泵的效率提高了，这是下沉有机物再矿化（降解）速率因温度降低而减少的结果。深海食物供应的增加促使新的深水生态位的形成，引发了深海浮游生物的进化以及中层“暮光区”生态系统的扩张。