Post-Doctoral Research Summary Statement

1. Overview

I propose a multiproxy study to better understand the: 1) migration of the intertropical convergence zone (ITCZ) in relation to the Panamanian Isthmus; and 2) climate variability, sea surface temperatures (SSTs), and the vegetation evolution in Costa Rica and Panama, Pacific Ocean / southern Central America during the last 5 Ma. During past glacial periods, the extent of ice sheets and low temperatures in the Northern Hemisphere triggered the deflection of the polar jet stream to the Southern Hemisphere in relation to the southward migration of the ITCZ (Broccoli et al., 2006). Consequently, this triggered the late Pliocene – late Pleistocene glaciations, during which drier or arid conditions dominated the Central American landscape and affected terrestrial and aquatic biota diversity. The regional implications include the expansion of the savanna to the tropics and lower SSTs in the Pacific Ocean. In addition, this directly facilitated the Great America Biota Interchange (GABI), and biogenic productivity which enhanced the bloom of the zooplankton (e.g. dinoflagellate cysts, marine algae) during glacial times.

The interactions between the ITZC, GABI, SSTs and climate change are marked by regional environmental perturbations. For this reason, I propose to test how the position of the ITCZ in relation to the Panamanian Isthmus (Volcanic Orography) and climate change influenced the biota diversity in the Pacific basin using the following concepts and proxies: 1) Vegetation pattern to evaluate changes in terrestrial ecological niches and past climate during the last 5 Ma; pollen, spores, and particulate organic matter (palynofacies) will provide valuable information; and 2) SST reconstructions, biogenic productivity (sediment/nutrient supply), and fresh water plume/fluvial paleodischarge in the Pacific Ocean; these will be evaluated using dinoflagellate cysts, nonmarine algae, palynofacies, lithofacies, stable isotope data from foraminifera (Mg/Ca ratio, oxygen, carbon), AMS dating, C/N, and Fe/Ca. The multiproxy data will be statistically analyzed, and I anticipate that this approach has the potential to provide an insight into the future timing and impacts of the ITCZ on climate change for the sustainable preservation of terrestrial ecology and zooplankton (e.g., dinoflagellates, algae, fish, etc.) inhabiting the shelf and coastal realms. For the first time, vegetation patterns (savanna, mangrove, montane, rainforest) inferred for the region based on the position of the ITZC will also contribute to the existing understanding of the “GABI and Habitat Hypothesis” (Jaramillo et al., 2016).

2. Intellectual Merit:

The mechanisms that control or drive (e.g., ITCZ) the internal components of climate systems (vegetation, sea, land, air) have not been studied in the region due to limited understanding of precessional forcing. This knowledge is essential if we are to forecast the regional and global future development/management of tropical vegetation, SSTs on aquatic ecosystems (foraminifera, fish, and zooplankton) and eutrophication in the region. In particular, additional research is required to tie successive variations using multiple proxies with key parameters associated with climate. It is anticipated that the core and outcrop data will provide the first effects and paradigm shifts of the ITCZ forcing for the regional coherence of the vegetation pattern and Pacific Ocean circulations. Possible additional outcome of detailed palynological and foraminiferal analysis would be the identification of new taxa.

3 . Broader Impact:

The proposed study will contribute to capacity building through educational and research opportunities for graduate students and early career scientists. I anticipate that we will generate experimental data that will be useful for sustainability efforts and array of data-set applicable to different fields, such as climatology, evolutionary biology, and oceanography. In addition, I plan to develop an exhibit at the National Museum as part of our outreach efforts, present our results at national and international conferences, and publish in peer-reviewed journals.

Currently funded by Missouri University of Science & Technology, US. To be funded by National Science Fundation of US in the future (---2018).