MARINE ECOSYSTEM HISTORY: MICROPALEONTOLOGICAL PERSPECTIVE ON ECOLOGICAL RESPONSES TO CLIMATE CHANGES AND HUMAN-INDUCED ENVIRONMENTAL DISTURBANCES

The history of marine ecosystems is reconstructing using microfossil records in sediment cores with sufficient time-resolution (decadal to multi-millennial) to provide robust baseline information to better understand ongoing and future human-induced ecosystem degradation. In this presentation, I review how marine benthic ecosystems have responded to climate and human-induced environmental changes using ostracods and foraminifera. In deep sea ecosystems, species diversity and faunal composition show large-amplitude changes during the Pliocene and Quaternary, especially in tropical latitudes, that correlate with 41 and 100 ka Milankovitch cycles. These dynamic faunal changes indicate pervasive patterns of changing latitudinal species diversity gradients over orbital time scales such that the latitudinal diversity gradient was weakened or absent during glacial periods. Over suborbital time-scales, benthic faunal collapses in the deep sea were triggered by oceanographic changes during abrupt cooling events such as the Younger Dryas and other deglacial and Holocene stadials. During the last few centuries, the footprints of human activity have increased especially in coastal shallow-marine areas where industrialization and land-use changes have triggered rapid ecosystem degradation that continue today. I will discuss case studies illustrating processes of the human-induced ecosystem degradation from micropaleontological perspective, which provide insights into the timing, regional differences/commonality, and faunal structure during these disruptions.