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Adam: Studying past climates through (micro) fossils (Part II)

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When we left off in my previous post, Dr. Kate Davis and I had collected foraminifera offshore Bodega Marine Laboratory and brought them into the lab for observation.

Now we came to the part of the experiment that involved feeding. Each "foram" was moved from their falcon flask to a water dish for observation. Specially prepared diatoms were transferred into the dish in direct proximity to the foram. The diatoms would be caught by the forams’ rhizopodia and drawn into the foram itself. Each foram was left in the dish for 20-30 minutes to feed before being rinsed in filtered seawater and transported back to its original container. This process was conducted every other day until the foram completed its life cycle.

Throughout the experiment we observed growth and death of the forams.  We were able to see that the size of the shells had increased. The forams eventually underwent gametogenosis, the conversion of their cytoplasm for reproduction, thus representing the end of their life cycle.

An example of foraminiferal observation during this study (photo credit: C. Davis.)

An example of foraminiferal observation during this study (photo credit: C. Davis.)

When these observations were complete the forams had to be cleaned of organic matter. This process consisted of running each individual shell through a cleaning solution meant to rid the foraminifera of the leftover organic matter and then through a water bath that ran sonic waves through the water.

The final stage of the experiment involved analyzing the composition of the shells using laser ablation mass spectrometry. Laser ablation mass spectrometry is a process by which a laser essentially blows up layers of the subject and extracts what has been released and measures the chemical composition. Each chamber of each foram was put through this process, and Dr. Davis is now analyzing and interpreting the results!  This research will aid in understanding how foraminifera record the environment around them.

~ A. Rueckert is a recent graduate of UC Davis, with a B.S. in Marine & Coastal Science.

 

For more information on student research in the Hill lab, check out these posts: