FP 35: Quaternary marine ecosystem response to fertilization: Mediterranean sapropel events and implications for marine carbon uptake

在晚第四纪记录的东地中海盆地，腐泥层指示周期性缺氧早已被确认。最近的研究表明，这些形成响应于地中海的自然施肥，每23.000年发生一次，这表明强迫机制是季风强度的岁差调制。生态变化和营养物质通过表层海洋生态系统传播的机制仍然没有受到充分的限制。这限制了我们使用缺氧事件来预测当今气候变化和富营养化可能导致的类似情况的能力。将采用一种新的多替代方法，以重建海洋生产力和支持性营养通量对气候变化的反应程度。此外，我们的目标是监测碳系统的变化，通过分析关键的地中海钙化海洋浮游植物，颗石藻。为了量化过去营养条件的变化，我们将使用培养样品，沉积物捕集材料，核心顶部沉积物和次近期沉积物的独特组合来完善我们的代理。然后，这些改进的代理将被应用到对应于过去200 kyr的三个定义的生育率提高阶段的时间间隔。

Within the Late Quaternary record of the Eastern Mediterranean basin, sapropel horizons indicating periodic anoxia have long been recognised. Recent research has shown that these form in response to natural fertilization of the Mediterranean Sea and occur every 23.000 years, suggesting that the forcing mechanism is a precessional modulation of monsoon strenght. The mechanisms of ecologcial change and propagation of nutrients through the surface ocean ecosystem remain poorly constrained. This limits our ability to use anoxic events to predict likely analogue situations as a result of present day climate change and eutrophication. A new multi-proxy approach will be implemented to reconstruct both, the extent of the response in marine productivity and the supporting nutrient fluxes to climate change. Further, we aim to monitor changes in the carbon system by analysing the key Mediterranean calcifying marine phytoplankton, coccolithophorids. To quantify the change in trophic conditions in the past, we will refine our proxies using a unique combination of culture samples, sediment trap material, core top sediments, and sub-recent sediments... These refined proxies will then be applied to time intervals corresponding to three defined phases of enhanced fertility over the last 200 kyr...