Amazon Expedition in Search of Climate Clues

The crew from USF College of Marine Science Paleolab have started their last week on their expedition off the coast of Brazil to investigate climate change. Thus far, they’ve collected scores of sediment core and water samples that will help them explain how climate in this sensitive part of the world has changed over the last 60,000 years.

Follow them as they finish their journey and head home to USF. 

 

Go to their blog: Expedition USF

 

 

By Vickie Chachere

ST. PETERSBURG, Fla.  – For ages, the Amazon River has kept a silent record of  the region’s climate, flowing into an ocean basin where it deposited layer upon layer of minerals and organic material which has recorded the ebbs and flows of the world’s most diverse environment.

For USF researcher David Hollander and six of his colleagues from the College of Marine Science, the secret to some 60,000 years of the Earth’s climate history is buried in the deep mud below the Amazon River basin off the coast of Brazil. And for the next three weeks, the team will begin the process of revealing that long-buried history - one long, thick cylinder of sediment at a time.

What they are looking for are the chemical fingerprints of climate change in hopes that what occurred in the past will shed light on what’s happening now. For Hollander, a chemical oceanographer who has explored the world in search of climate records beneath the earth’s surface, the secrets of the past lay below the ocean’s murky waters adjacent to the world’s greatest river.

“When you split these cores and open them up, it’s like opening up the pages of a history book,” Hollander said. “By looking at the past, it helps us understand future climate changes.”

The voyage can be followed on the crew’s blog, Expedition USF.

The 26-day, National Science Foundation-funded expedition is a major event for the scientists, who will do their work in collaboration with scientists from Duke University aboard the R/V Knorr, the research ship owned by Woods Hole Oceanographic Institute which carried a crew in 1985 to another famed find: the discovery of the R.M.S. Titanic. Joining Hollander on the expedition are students Julie Richey, Carlie Williams, Kara Radabaugh, Enrique Montes and Laura Lorenzoni.

While not as melodramatic as that single discovery, the work being conducted by Hollander and his colleagues in the College of Marine Science’s Paleolab is nonetheless significant in the ongoing effort to understand how the earth’s climate and hydrologic cycle has changed and developed throughout time.

The USF team is working in conjunction with researchers from Duke University and the Netherlands.

Understanding climate change in the Amazon is crucial to today’s environmental challenges. The regions high levels of rainfall, diverse plant and animal life and massive stores of carbon make it so crucial to the world’s climate that some scientists refer to the region as the world’s “lung.” The World Wildlife Fund describes the Amazon’s hydrological cycle as the key driver of global climate, thus making the climate sensitive to changes in the Amazon.

The research being conducted is sensitive. The Brazilian government has been protective of the coastline and the river’s basin and no study of this nature has ever been conducted in the Amazon River basin, Hollander said. The scientists will have to first conduct seismic tests to determine where to drill, and will do so with minimal disruption to the environment.

The Knorr is able to accommodate the drilling equipment needed to sink down through 1,000 to 2,000 meters of water to drill through another 50 meters of sediment to remove the cores – which come up from the mud as long, cylinders or compressed mud and organic material.

Once at the shipboard lab, the cores are split lengthwise and then thin cross-sections are preserved for analysis. The scientists are looking for the telltale signs of climate change – the decayed remnants of plant and bacteria that would be more predominant in rainy or dry conditions or the mineral sediments that would wash into the river from the South American continent at different rates depending on climate change and the variations in the intensity of the tropical hydrologic cycle.

It is the same technique that has allowed researchers in the Paleolab to reconstruct the climate history of the Gulf of Mexico, recently discovering the area is more sensitive to climate than previously thought, and to explore 2,000 years of climate change in Florida by extracting cores from Lake Tulane near Sebring.

The changes in input of specific land-derived organic molecules – a pollen specialist from Brazil will even be on hand - in the sediment records allow scientists to track how the Rainforest and the river fared over time, even how the Rainforest has regenerated itself over the ages.

“The questions we’re asking are: Are the tropics getting wetter? Are they getting drier? During droughts, how fast are those changes occurring?  And, overall, how have the Rainforest changed over time?” Hollander said. “This project will answer those questions going back thousands of years.”

 

See related story: “USF Marine Scientist Finds “Little Ice Age” Had Dramatic  Effect of Gulf”

Photos by Joseph Gamble

 

The University of South Florida is one of the nation's top 63 public research universities and one of only 25 public research universities nationwide with very high research activity that is designated as community engaged by the Carnegie Foundation for the Advancement of Teaching.  USF was awarded $380.4 million in research contracts and grants in FY 2008/2009. The university offers 232 degree programs at the undergraduate, graduate, specialist and doctoral levels, including the doctor of medicine. The USF System has a $1.8 billion annual budget, an annual economic impact of $3.2 billion, and serves more than 47,000 students on institutions/campuses in Tampa, St. Petersburg, Sarasota-Manatee and Lakeland. USF is a member of the Big East Athletic Conference.

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