Impact of gateway closure on carbonate ecosytems diversifications

该专题侧重于巴拿马太平洋沿岸当今碳酸盐生态系统的发展，这与巴拿马门户的中新世/上新世关闭有关。大约2.73 Ma的最后关口导致加勒比海西大西洋暖池的形成，同时在巴拿马太平洋沿岸区域由西向信风驱动的上升条件发展。在巴拿马湾，今天生产碳酸盐的底栖生物生态系统已经适应了这种通过上升流增加营养供应的新情况。相比之下，奇里奎湾的珊瑚礁代表着一种残存的珊瑚礁生态系统，据推测，在地峡关闭之前，加勒比地区普遍存在这种生态系统。今天的巴拿马西南海岸受到西大西洋气候系统和热带太平洋气候(厄尔尼诺)的影响，因此占据着连接这两个系统的关键位置。在上升流和非上升流条件下发生的碳酸盐工厂的沉积学比较将扩大我们对巴拿马闭合导致的海洋环境、相模式和生物群演化之间相互作用的认识。在珊瑚、苔藓虫和软体动物中发现的稳定的同位素/微量元素信号被用来重建海洋学和气候变化(季节性、厄尔尼诺、由NAO引发的信风强度)及其对热带碳酸盐生产的影响。

The theme focuses on the development of the present-day carbonate ecosystems at the Pacific coast of Panama, which is related to the Miocene/Pliocene closure of the Panama gateway. The final gateway closure around 2.73 Ma led to formation of the West Atlantic warm pool in the Caribbean while upwelling conditions driven by the west-bound trade winds regionally developed along the Pacific coast of Panama. In the Gulf of Panama, the present-day carbonate producing benthic ecosystem has adapted itself to this new situation governed by increased nutrient supply through upwelling. In contrast, roal reefs in the Gulf of Chiriquí represent a relict reef ecosystem that is presumably was occurred widespread in the Caribbean before the closure of the isthmus. The present-day southwestern coast of Panama is influenced by the West Atlantic climate system and the tropical Pacific climate (El Nino) and thus hold a key position connecting both systems. The sedimentological comparison between carbonate factories that occur under upwelling and non-upwelling conditions will expand our knowledge on the interaction between the ocean environment, facies patterns, and evolution of biota resulting from the Panama closure. Stable isotope/trace element signals found in corals, bryozoans, and molluscs are used to reconstruct oceanographik and climatic variations (seasonal, El Nino, trade wind intensity triggered by NAO) and their impact on tropical carbonate production.