Can changes in river flux affect the diversity of fish species in estuarine environments? And how have massive rivers such as the Amazon rerouted over time—despite being far away from fault lines or tectonic activity?
These are some of the research questions that motivate Brazilian geologist Pedro Val. He became fascinated with tectonic geomorphology at the end of his undergraduate years at the Universidade Federal do Amazonas. “Geology disciplines were interesting, but when my adviser, Clauzionor Silva, first showed me the change in river flows due to tectonic activity, I didn’t want to know about anything else,” he said with a laugh.
Now, Val is an assistant professor of Earth and environmental sciences at Queens College, City University of New York. Two of his research collaborators are his parents, both biologists at the Instituto Nacional de Pesquisas da Amazônia, Brazil’s Amazonian research institute. “They definitely had an influence on my choice for a career in science,” he said.
In his doctoral research, Val combined tools from environmental science, hydrology, and climate studies to advance the use of cosmogenic isotopes to study Earth’s surface.
“As rocks get stashed between sandpiles, these isotopes, hidden in quartz, decay. And we look for them to see how old sediments are.”
This helps researchers understand how basins such as the Amazon have changed through time. For instance, about 10 million years ago, the Amazon River ran toward the Pacific Ocean. With the rise of the Andes, it began flowing out to the Atlantic. This change, Val said, is also recorded in fish DNA—and could possibly explain the diversity of species in the tropical river.
“Fish populations that were together before might have been separated with this change in river flux and started taking different genetic paths,” Val said. This is an area he will continue to research in the eastern Paraná Basin, using funds from a National Science Foundation CAREER Award he received in late 2023.
—Meghie Rodrigues (@meghier), Science Writer
This profile is part of a special series in our August 2024 issue on science careers.
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