This page is no longer being updated and remains online for informational and historical purposes only. The information is accurate as of the last page update.
For questions about page contents, contact the Communications Division.
Joanna Morabito ’08 (Yorktown Heights, N.Y.) is pursuing a degree in geology. She spent the summer doing research at Brown University with Kira Lawrence, assistant professor of geology and environmental geosciences. The following is a firsthand account of Morabito’s experiences.
This summer, I had the privilege of assisting Professor Kira Lawrence in generating sea surface temperature and productivity records for the North Atlantic Ocean. Productivity and sea surface temperature data are gathered through the analysis of ocean sediment cores. The records we developed, which span from approximately five million years ago to the present, will help to make the distinct changes of the earth’s climate that occurred during the glaciation of the Northern Hemisphere better understood.
This experience was very special because Professor Lawrence gave me the opportunity to work alongside professors, graduate students, and undergraduate students at Brown University. I have always enjoyed research and, now that I have had the chance to work with graduate students and learn about their various scientific investigations, I know that graduate school will be the next step in my future.
During my first three weeks at Brown, I learned the laboratory techniques required for gathering sea surface temperature data from ocean sediment samples. Resistant organic compounds, alkenones, which are generated by ocean surface dwelling algae, must be extracted from the sediment and then analyzed in order to determine sea surface temperature variations. This process was intimidating at first, but with the help of Professor Lawrence and graduate students Laura, Caitlin, and Emily, I quickly caught on.
I also learned that paleoclimatology not only involves geology, but biology and chemistry to study the Earth’s climate and I became very grateful for the chemistry, biology, and oceanography classes I had taken for my geology major. Once the organic compounds had been extracted, we analyzed the alkenones using gas chromatography, which separates the heavier (more saturated) alkenones from lighter (less saturated) alkenones. As sea surface temperature decreases, the algae that produce alkenones make more of the less saturated alkenones. Therefore, sea surface temperature can be determined by analyzing the ratio of the more saturated alkenones to less saturated alkenones extracted from a specific sediment sample.
Not only can alkenones be used to estimate past sea surface temperature, but the concentration of alkenones found in each sediment sample may also give insight on the biological productivity of the ocean’s surface at the time that particular sample was deposited. Based on research that Professor Lawrence has previously conducted, there is a distinct drop in the concentration of alkenones extracted from sediment at the many sites in the North Atlantic that she has studied. This suggests a major change in biologic productivity occurred in association with the glaciation of the Northern Hemisphere. Yet, whether this drop was synchronous or time-transgressive throughout high latitude regions was unclear from previous work.
During the last few weeks of my research, we used another technique commonly performed to measure biologic productivity at ocean sites throughout the world, testing sediment samples from various sites in the North Atlantic for biogenic opal. I gathered preliminary opal data for three sediment cores in the North Atlantic. I feel that the extraction of the biogenic opal was the most interesting, challenging, and rewarding part of my research experience at Brown.
It was interesting, yet frustrating, to see how two of the sites in the Atlantic had no measurable biogenic opal. Although I did not get the desired results at first, I was relieved and thrilled that the third site I tested had a significant amount of biogenic opal. My data from this site confirmed that changes in biologic productivity were time-transgressive across the North Atlantic, occurring between 3.5 and 2.5 million years ago.
This experience was very valuable because I had a chance to learn about an area of geology that I have not yet been exposed to in any class. Professor Lawrence is a very kind and dedicated professor who is very passionate about her research. The excitement she brought everyday to work made this research opportunity memorable.