Dr. Kristine Delong: Under the Sea

Dr. Kristine Delong is a professor and researcher in the field of paleoclimatology, the study of reconstructing past climate patterns. Dr. Delong teaches several classes at LSU, including Sclerochronology: the use of bone and skeleton to tell time. As we walked through her lab it was easy to see that she is fascinated with life on the ocean floor. From coral skeletons and oyster shells to ancient petrified bald cypress trees found underwater, Dr. Delong says she studies “things that have annual chronology; anything that has rings and can be counted.”

On a typical day as a professor and researcher she tends to emails, teaching classes, more emails, talking with students, reading and reviewing papers and proposals. Although she spends a lot of her time dealing with the required administrative work that she describes as a “necessary evil” of her profession, her true passion lies under the sea.

“Just look at the world around you

Right here on the ocean floor

Such wonderful things surround you

What more is you looking for?”

– “Under the Sea”

Her favorite part as a scientist is the fieldwork and the scuba dives that take place within her research. Her team has had opportunities to research areas in New Caledonia, Tahiti, the Pacific and the Gulf of Mexico. On one specific dive Dr. Delong and her team found something truly amazing.

She described a recent dive that took place this past August off of the coast of Orange Beach, Alabama where they collected buried ancient wooden planks from bald cypress trees ten miles off of the coast.

Along with her graduate student, Dr. Delong set off on a shrimp boat out into the Gulf of Mexico to their research site which surrounds buried bald cypress trees.

“The first day was rough and I got see sick which is ironic for an oceanographer,” she said.

On the first day, the team was inside of the boat looking at computer screens and doing geophysical mapping. The team used Sonar to look through the sediments and map the pathometry of the site. Basically, the boat went back and forth over the site all day long, and everybody was sick because the waves were rough. Most people wouldn’t find this part of the job to be too glamorous.

The second day was beautiful and is where Dr. Delong finds her passion. The waves flattened out for them and they were finally able to collect sediment. Based on the geophysical data they collected the day before, they picked six locations to collect the cores. They used a vibrocore system that works under water so they were able to get almost 5 meters off of the first core.

The sample was a meter and a half of sand and the bottom of it was just plyctoseen mud, what you would see in a swamp today. There were roots and little pieces of wood in it. Then they moved closer to the site where there are trees to collect the rest of their samples. That’s where they found several of the samples they showed to us during our lab visit.

She described the site as an underwater forest of cypress stumps. When Hurricane Ivan hit the coast, these stumps of petrified wood were exposed.

“What’s unique about the site is the wood is preserved and wood doesn’t last that long under water. It decomposes.” Dr. Delong showed us samples from the trip, which they dug out of the mud while scuba diving.

(Dr. Delong describes her samples)

Essentially, these tree stumps could potentially redefine our understanding of the Gulf of Mexico’s past climate timeline. The samples are too ancient to accurately carbon date, which means they’re more than 50,000 years old. In fact, the sea level in the Gulf has not been low enough for bald cypress swamps to thrive in that location since the last glacial period: 20,000 to 100,000 years ago. Therefore, the samples are presumed to be from the glacial age! This is important because the location that the stumps were found differs with the previously established climate record of the area, which suggested that the region was too cold and dry for subtropical plants, and bald cypress trees only grow in wetland regions. This could change so much about what we thought we knew about our coast, making this new discovery truly amazing.

For more information visit the PAST Lab Homepage: http://ga.lsu.edu/blog/pastlab/


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