I am an Assistant Professor in the Physical Sciences Unit of the Natural Sciences Department at Hostos Community College, where I teach courses in Chemistry and Earth and Environmental Sciences.
I am also an Adjunct Associate Research Scientisit in the Geochemistry Division at Columbia University's Lamont-Doherty Earth Observatory (LDEO). My research interests involve the application of isotope geochemistry to Paleoceanography. An overarching theme of my research is how the “Global Conveyor Belt” or thermohaline circulation (THC) was different in the past. Many studies have focused on the deep arm of the THC, trying to assess changes in the strength of North Atlantic Deep Water (NADW) formation and its characteristic properties over glacial-interglacial and millennial timescales. My research focuses on the surface return flow of the THC.
I am particularly excited about involving undergraduate students in scientific research. Contact me if you are a Hostos Community College student interested in working on a research project with me.
Please follow the links above to learn more about my teaching and research.
Introduction to Earth and Atmospheric Science
Environmental Science I
Environmental Science I Laboratory
Introduction to General Chemistry
General Chemistry I
For current syllabi, assignments and other materials, access the class page through Blackboard.
My research interests are in paleoceanography and modern marine geochemistry. I use trace elements and their isotopes (TEIs) as proxies to understand the relationships between water column structure, ocean circulation and global climate. Increasing our knowledge of such relationships in the past and present will ultimately improve our understanding of the climate system and our ability to predict future climate change. The key paleoceanographic issue I aim to address is how the surface and intermediate flow through ocean gateways relate to changes in the strength of North Atlantic Deep Water (NADW) formation and the intensity of global thermohaline circulation (THC) during the Pleistocene glacial cycles. It has already been shown that NADW was weaker during the cold periods of the glacial cycles, and stronger during warm interglacials. My current research focuses more on the warm, surface return flow of the THC, specifically the Agulhas Leakage.
The Agulhas Current system is an important part of the warm return route of the THC. The Agulhas Current transports surface and intermediate waters from the tropical Indian Ocean southward along the east coast of Africa. As it passes the southern tip of Africa, the Current turns eastward, back towards the Indian Ocean. The extreme turbulence associated with this Retroflection causes large rings and eddies to be shed into the South Atlantic. This so-called Agulhas Leakage is the primary mechanism of interocean exchange south of Africa and is recognized as an important source of heat and salt to the Atlantic Ocean. Read on for information about my current and past projects on the Agulhas Current System.
I measure radiogenic isotopes in terrigenous sediments deposited south of Africa to reconstruct their transport pathways, and thereby understand past changes in ocean circulation patterns. For example, a map of the strontium isotope ratio of modern sediments shows that the regions underlying the Agulhas Current and the Agulhas Return Current have more radiogenic strontium than surrounding sediments. The region of radiogenic strontium can therefore be used to trace the path of the Agulhas Current, Retroflection and Return Current through time. The key results of this work describe a scenario with a weaker Agulhas Current, reduced Agulhas Leakage and no significant change in the Retroflection position during the Last Glacial Maximum (LGM, ~20,000 years ago) (Franzese et al., 2006, Franzese et al., 2009). This is in contrast to the prevailing hypothesis concerning the Agulhas Leakage; that reduced Leakage should be caused by a stronger Agulhas Current or a more upstream Retroflection.
Most of the modern oceanographic data and numerical models suggest that reduced Leakage should be caused by a stronger Agulhas Current or a by more upstream Retroflection. For the LGM however, my results, as well as those of many other published studies, suggest reduced Agulhas Leakage along with a weaker Agulhas Current and no significant change in the Retroflection position. The discrepancy between the model results and the glacial data reveals our poor understanding of the Agulhas Current system and underscores the need for further work in this region.
Click on the link below to learn more about my current research projects.
Current Research ProjectsIntroduction to Earth and Atmospheric Science
Environmental Science I
Environmental Science I Laboratory
Introduction to General Chemistry
General Chemistry I
For current syllabi, assignments and other materials, access the class page through Blackboard.