How Corals Hold Centuries of Ocean Climate Data

Before we can make a plan to protect our oceans from climate change, we need to know what they were like before human impact. Paleoceanographer Nathalie Goodkin shows us how looking at evidence of the past in coral records can help us to protect these organisms, and our oceans, for the future.

To learn more about climate change, visit the new installation in the David S. and Ruth L. Gottesman Hall of Planet Earth featuring linteractive panels where visitors can engage with the evidence for climate change.

July 2018 3:02 min

[MUSIC]

Nathalie Goodkin (Associate Curator, Division of Physical Sciences):

You can look out at a calm ocean, and it looks like nothing’s happening, but in reality, there are so many forces that are happening within that water.

It’s going to change at night. It’s going to change depending on where you are on the planet. You have ice that’s melting and forming. The pH will change as you change how much CO2 gets absorbed. So, really, there’s nothing in the ocean that’s static. And that makes it even harder to study, because any point in time is only really reflective of that point in time.

We’ve only been recording the environment in detail for the last, maybe, 20 years, with some ship data from the past 120 years. We can go ahead and measure for hundreds of years in the future, but the imperative to understand how our climate system works is really now. And so, we need to understand the system back through history.

I think it would surprise people to know that there are natural instruments that we have in the ocean collecting this data for us. Corals grow in these large formations, and they’re building skeleton as they grow. As they secrete their skeletons, they will take in chemicals from the sea water based on the conditions they’re growing in.

And so, we can go back and look at specific chemicals that tell us information about temperature, pH, salinity, and reconstruct those environmental conditions over the past several hundred years. A living coral would go back 500 years, but we can also look at fossil corals that can go back through the last 10,000 years.

At this point, humans are having a very large impact on the environment, a larger impact than we can understand what will happen as a result. Little changes can make such a large difference in how the ocean moves and circulates, and what that means for the life that’s in it. The only way that we can really improve our ability to make good management decisions is to understand how the system worked before we were impacting it.

Protecting corals is important for so many reasons. It’s really, really important for biodiversity. They provide significant coastal protection in storms. And from my perspective, it would take us enormous numbers of years and financial dollars to instrument the earth as well as the reefs are. Being able to preserve these samples provides us with an enormous resource for understanding our climate system, both in the future and back in time.

[END MUSIC]

View more Research and Collections videos

Why Are Fossil Shark Skeletons So Rare? Revealing Climate Through Corals Preserving the Dry Coral Collection