Climate Detectives: Challenge

Introduction

Have you ever wondered how we know that our climate has changed in the past? How we know that at times in our past no ice existed on Earth and it was so warm that palm trees grew in Alaska, and hippos lived in rivers north of the Arctic Circle? How we know that during ice ages that a mile thick sheet of ice covered much of North America? Science proceeds because we are naturally curious and strive to determine what has happened in the past, and in many cases—to predict what will happen in the future. But science is hard work! Scientists work, sometimes for many years on end, to collect evidence to support explanations of what climate was like in the past. In a real sense, science is a quest, a desire to build new knowledge. To that end, scientists develop instruments and tools to help them in their quest.

One important method they use to find out about past climate involves studying layers of ocean sediments. In the summer of 2013, diverse team of scientists on board the JOIDES Resolution sailed to the Gulf of Alaska to collect sediments to investigate Earth's past climate and study the connection between climate and tectonic activity. Led by co-chief scientists Sean Gulick (UTIG) and John Jaeger (U. of Florida), IODP Expedition 341 used sediment cores to answer questions about Earth's history.

The Challenge

Scenario: You are a young scientist with a passion for understanding how the Earth's climate has changed over the past 7 million years. To help with your research you will board the JOIDES Resolution to spend a summer at sea in the Gulf of Alaska collecting sediments from beneath the ocean floor with an international team of scientists and crew. This modern day expedition will help you answer a series of questions about what the climatic conditions on Earth were like millions of years ago.

Using a section of sediment core from Expedition 341, you will work collaboratively with members of the science party (in reality, party = team) and use different types of science data from the expedition to answer the following questions related to past climate in south Alaska:

• What is the present geologic setting in this region?
• How have environmental conditions in in the Gulf of Alaska changed during the time when the sediments in this core were deposited?
• What does the presence of types of diatoms (plants) and their abundance in the core reveal about the timing of the cycles of the advance and retreat of glaciers and ice sheets?
• What is the timeline represented by this section of sediment core?

And, as a team you'll need to develop background knowledge in several key areas. Over the next two weeks, you will conduct a number of investigations and work along side Joides Resolution scientists to learn:

• How scientists from many different countries and with different expertise collaborate as a team to examine a science problem.
• How sedimentary cores are retrieved from beneath the seafloor.
• What kinds of information can be extracted from the features of sediment cores to give clues to climate change.
• About the different types of data, including proxy data, used to detect changes in Earth's climate.
• Methods used to determine when changes in climate occurred in sediment cores.

Well, grab your gear and get ready to board the Joides Resolution for a voyage of discovery. What will you and your collaborators uncover about dynamic changes in our past climate and what caused those changes?