There are perks to being the instructor of Penn State’s Science Diving Program. Not so long ago, Tim White was scuba diving in the tropical waters of Curacao, leading Penn State students in the southern Caribbean Sea to study coral reefs.
But that wasn’t the thought on White’s mind when he plunged into the frigid Susquehanna River on a snowy Sunday earlier this month.
“Even with a drysuit on, it’s cold,” said White, a senior researcher in Penn State’s Earth and Environmental Systems Institute, part of the College of Earth and Mineral Sciences.
Swimming in the ice-covered Susquehanna River in March probably sounds less appealing than diving in the clear, blue water of the tropics. It might even sound crazy.
One thing the cold is good for, it turns out, is training.
That’s why White found himself trekking on the frozen river just outside Williamsport with a group of scuba diving enthusiasts in the middle of a snow storm.
White helped the men cut a hole in the ice and dig markers in the snow, visible from underneath, that pointed the way back to the opening. Then he disappeared into the 34 degree water, connected to the surface only by a rope held by a tender.
“The fun part of it, it’s being at the ice-water interface,” he said. “Ice dives aren’t typically involving depth. You want to crawl around beneath the ice, because that’s where it’s fun.”
Navigating under the ice and maintaining focus in the numbing cold are good ways to keep your skills sharp. And that’s just what White needs to effectively teach diving to students and to watch them when they are in the water together.
The icy water also is the closest he’s going to get to simulating a dive in Alaska, where White travels most years to conduct research off the coast. His work in Alaska focuses on a particularly warm period in Earth’s history, the Paleocene-Eocene Thermal Maximum, and what it can tell us about our future.
Approximately 55 million years ago, during the PETM, the Earth was nearly free of icy glaciers and alligators could be found crawling in northern Greenland, White said.
“By a fairly large group of scientists, it’s thought to be the closest analogy to where the Earth is headed in the next 500 years or so,” he said. “It was a very warm time, when all the information that we’re capable of gathering suggests there was very little if any polar ice — little, if any, in Greenland; little, if any, in Antarctica.”
But bits of sediment found in the fossil record lead White think there may have been ice on the ocean after all, at least seasonally.
Today, when the ocean freezes in the winter, ice forms right up to the coastline. There, where it’s shallow, the water freezes down to the bottom and into the sediment on the ocean floor.
“When things start to melt from the surface, what’s frozen into the bottom of the ice eventually floats up and is carried out to sea with a whole bunch of sediment frozen into it,” he said.
That’s the process White studies when he dives off the coast of Alaska. He snaps photos, takes measurements and occasionally collects samples. His goal is to determine whether the process happens on a large-enough scale to fit what’s seen in the ancient rock record.
If so, it could mean at least some ice formed on the ocean during a time when many believe there was little, if any, on the planet. It might not radically differ from what the current reconstructions of that time suggest, but even if it means a temperature difference of a few degrees, it could lead to more accurate predictions for the future, White said.
“We really want to nail this stuff and be able to inform decision-makers in an accurate way,” he said. “We need to be really confident in our reconstructions.”
Maybe that’s what White was thinking when he felt his way underneath the ice that Sunday in the Susquehanna River. Or maybe he was just wishing he was warm.
“Oh, I’ll take the warmth anytime,” White said. “This (training) is fun and good. It’s what I do. But I’ll go with the tropics anytime.”