What do trees and fish have in common?

Its an important question the University of Arizona is answering.

The schools Laboratory of Tree-Ring Research (LTRR) is the worlds largest and most diverse collection of tree-ring specimens.

We use trees to give us very long histories, much longer than instrumental or written records could provide, associate professor Bryan Black told KGUN. Some tree-ring chronologies can go back 10,000 years or more.

Black says those rings can show anything from climate variability to insect outbreaks, fires, and even archaeological history.

In the same facility, Black is studying the rings inside tiny fish bonesand ear stones called otolithswhich look just like tree rings.

I can apply the same exact techniques we use for trees to the growth increments in fish and clams and corals, he explained.

Like trees, varying widths of rings inside fish or clams can tell us how long fish have lived, how theyve responded to changes in the climate, and even how well theyve been able to reproduce.

When combined with climate data and tree-ring data, researchers can discover the long term effect of climate change on Earths oceans.

We have thousands of publicly-available tree ring chronologies, but our knowledge of the ocean is much more limited, said Black. And these marine organisms are direct indicators of the marine environment So the trees give us one perspective from the forest and the mountains, and the clams and the fish give us their perspective, and when we put them together, we yield even more information.

Its a method that saves time and money.

By sampling these fish and generating long chronologies, were kind of bypassing repeated cruises that would take generations of scientists to go out and measure fish size and productivity and cost millions of dollars, said Black.

Its also critical for predicting the future, as scientists figure out how to respond to climate change and warming trends our oceans have not seen before.

And by understanding how it is climate affects fish growth, how is it that we might expect ocean productivity to continue to change as this warming trend increases, said Black.

Ironically, some of the most important work being done in the ocean is happening in the Sonoran Desert.