Kara Dennis

Department of Earth Sciences

308 Heroy GL

Email: kedennis@syr.edu

Kara's CV

Masters Student Earth Sciences
Advisor: Chris Junium

Research Interests

I am most interested in learning and better understanding the relationship between the ocean and climate. Since 2/3rds of Earth's surface is covered in liquid water, the ocean does a lot to moderate climatic changes. My research is focused on tracing changes in climate by looking at ocean sediment cores from ODP and IODP cruises and better constraining changes in seawater chemistry. Seawater chemistry has generally considered rather stationary because of the large size of marine basins. The concentrations of major constituents that comprise seawater usually have very long residence times, which imply slow gradual changes in global seawater chemistry. But, increased anthropogenic inputs of carbon dioxide into the atmosphere may be altering the chemistry of the ocean. Thus, in order to better understand the implications of human impacts on global ocean geochemistry, we need to better understand the perturbations in seawater chemistry over time and how the major constituents of seawater chemistry change over time. Sulfate is the third most prevalent constituent of modern seawater chemistry. The sulfur cycle is intimately linked to the carbon and oxygen cycles, and changes in the sulfur isotope record can reflect changes in weathering, ocean circulation and the redox state of the ocean. Since the marine sulfate reservoir has been dynamic over geologic time and is integral to many biogeochemical reactions that affect the global carbon and oxygen cycles, changes in this reservoir need to be better constrained in order to better understand fluctuations in seawater chemistry. My thesis work is focused on studying changes in seawater chemistry, specifically the marine sulfur cycle, during the Early-to-Middle Eocene (about 55-45 million years ago). This time period is of great interest to scientists because it occurs after the Paleocene-Eocene Thermal Maximum, which is possibly one of the best-preserved global warming analogs in the geologic record. My research focuses on squeeze cake samples advisor, Christopher Junium, brought back from IODP expedition 342 to Newfoundland in summer of 2012. I am producing a high-resolution stable sulfur isotope curve for this time period using carbonate-associated sulfate and sedimentary pyrite in attempts to better constrain large increase in the 34S of seawater sulfate 50 million years ago and modeling to better constrain possible changes in the sulfate reservoir during this time.​

Sample location in Atlantic
Kara and sail boat
Kara in lab
Kara in lab
Kara in lab



Oceanography (Fall 2012, Spring 2013)



Contact Us

Department of Earth Sciences
204 Heroy GL
Ph: 315-443-2672
Fx: 315-443-3363

Research Area