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

在东地中海盆地的晚第四纪记录中，表明周期性缺氧的冲积层很早就得到了承认。最近的研究表明，这些形成是对地中海自然施肥的响应，并且每2.3万年发生一次，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在海洋表层生态系统中的传播机制仍然知之甚少。这限制了我们使用缺氧事件来预测由于当今气候变化和富营养化而可能出现的类似情况的能力。将采用一种新的多代理方法来重建海洋生产力的响应程度和支持气候变化的养分通量。此外，我们的目标是通过分析关键的地中海钙化海洋浮游植物球石藻来监测碳系统的变化。为了量化过去营养条件的变化，我们将使用培养样本、沉积物陷阱材料、岩心顶部沉积物和亚近期沉积物的独特组合来完善我们的代理。然后将这些改进的代用物应用于过去200年中生育率提高的三个确定阶段的时间间隔。

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...