Studying Ocean and Lake Sediments
Layers of ocean and lake sediments provide hints to temperatures and weather patterns of the past.
Ocean floors and lake basins accumulate tons of sediment annually. Scientists collect sediment cores to study tiny fossils, debris, and chemicals that appear in the layers. These items can reveal information about past climates earlier than, during and after the last Ice Age.
Scientists select a study area based on their phenomenon of interest and the best probability of retrieving an accurate sediment core. They use large ships equipped with heavy-duty winches to collect core sample. To extract the sediment core, they drive a steel barrel into the mud on the ocean bottom, then pull it up and on-board with a winch. They try to get the longest sample possible. They also record seismic profiles of the area. Every research cruise collects tens of meters of sediment cores that are then transported back to shore and stored at a research laboratory. Scientists will then use x-radiographs to examine the color, characteristics, and contents of the cores to understand the history of climate change in that area including how much ice existed.