6 weeks 6 days
What are you doing in the middle of the Pacific?
Submitted by Steve Hovan on Thu, 06/04/2009 - 16:21
So, a fair question to ask is "what are you doing out there in the middle of the Pacific Ocean poking holes in the seafloor?" I suppose the easy answer is "because we want to." We want to not as much for the hole it makes, but for the sediments that we drill and recover when we make the hole. These sediments have been piling up out here for millions of years. And when we recover them, we can look at layer after layer to learn about whatever conditions affected these sediments when they were deposited. It's very much like having a geological history book... all we have to do is turn to the page of history we're interested in learning more about, and "read" the sediment.
That said, let me say a little more about why we're here in this particular part of the ocean, the equatorial Pacific. Today, like it has been in the past, the equatorial Pacific Ocean plays a key role in our Earth's climate system. It's the place where a great deal of heat is exchanged between the atmosphere and the oceans, and perhaps more importantly, a place where greenhouse gases like carbon dioxide move in/out of the oceans. Unlike many parts of the deep ocean, there is a great deal of biological activity out here. It shows up in fun ways, like the school of Mahi Mahi that's been circling the boat for the past couple of weeks or the sea turtle that came lumbering alongside us the other day. And it's biologically active because this region has a great deal of tiny plants and animals that live in the nutrient-rich waters. These tiny plants and animals "feed" the rest of the food chain, and when they die, they leave behind their tiny shells and skeletons that drop to the seafloor and make a big mound of sediments. And that's another reason why we're here... to learn more about this pile of sediments and what it can tell us about the ancient climates.
There are many different kinds of scientists out here. Some look specifically at the fossil remains of these plants and animals to learn about how they've evolved and to understand "when" they evolved (time markers). We call these folks paleontologists. Others are studying ancient climates and ocean conditions by looking in more detail at the chemical composition of the fossil shells of these tiny plants and animals. You see, since these organisms live in seawater, they must make their skeletons and shells out of the seawater itself. They always say, you are what you eat! And when it comes to ocean sediments, it cant be more true. The chemical composition of the skeletons tells us something about the chemistry and temperature of the seawater when these things were alive. In a way, they are like tiny little thermometers and chemical recorders that are waiting to tell you about what the seawater was like in the ancient past!
Me? I study dust! It's hard to find in these sediments, but it's there. The tiny microscopic particles of dirt that blow off land and over the oceans eventually make their way down to the seafloor with all the other skeletons and shells. What I do is extract out the dust, then analyze its composition and size to learn more about the winds that carried it to the sea. While other scientists are studying little fossilized thermometers and chemical recorders, I study ancient weather vanes! If we can learn more about the winds, we can learn more about the water that moves because of the winds and all the heat and carbon dioxide that is moved with it.
So in a nutshell, we're all out here to study what the ancient climate systems were like and we do this with the goal of learning enough about how the Earth's climate works so that we can better predict future climate changes. And as you know, this is something that we ALL need to start thinking about. As I'm fond of tellilng my students... even if I dont know what the "right answer" is, I am certain that the more we know about the problem, the more likely we are to find the "right answer!" We are out here to learn more about the problem so we have a better shot at making the right decisions!
Ok... next time I'll talk more about a typical day at sea. I'm often asked about what it's like to be at sea for two months... what do you do for fun? I'll tell you... next time. -Steve