Fish and Water Contaminants

Water quality matters not just to fish in our lakes and rivers, but also to the people who eat them. Research from the
U of M and the Grand Portage Band of Lake Superior Chippewa shows that 18 of 19 test sites in northern Minnesota contain what are known as “contaminants of emerging concern,” (CECs), including pharmaceuticals, hormones, and personal care products.

Researchers compared how three different approaches could evaluate the health of fish exposed to CECs. They identified 24 different CECs in fish in the region, including from lakes in wilderness areas. Indicators revealed potentially concerning health effects at the organism level. What’s more, the health of fish in undeveloped sites was sometimes as poor as, or even poorer than, fish in developed areas and wastewater.

“Understanding the impacts of chronic, low concentrations of chemical mixtures, such as those we are detecting in our Minnesota ecosystems, is greatly needed,” says Tiffany Wolf, a professor in the College of Veterinary Medicine. “This research lays the groundwork for future, long-term monitoring studies that can help us better understand how these and other emerging environmental contaminants are impacting fish and other populations on which we depend.”

“Indigenous people have rights to harvest nontoxic foods and waters for subsistence,“ adds Seth Moore, director of Natural Resources, Grand Portage Band of Lake Superior Chippewa. “As the natural environment becomes more degraded through pollution and other human impacts, projects like this can provide factual information to community members and policy-makers.”

Originally published in the August 1, 2023 issue of Integrated Environmental Assessment and Management.

Ape Fossils Contain Surprises

For decades, the story of human evolution has gone something like this: Forested regions in Africa became drier and turned into grasslands, which forced apes to abandon living in trees and become bipedal. Now, U of M researchers have helped show that this concept is incorrect.

Researchers, including 30 experts from Africa, North America, and Europe, conducted fieldwork at nine fossil sites in eastern Africa, collecting thousands of fossil plant and animal remains. They also sampled fossil deposits to reconstruct the ancient habitats.

Their findings helped outline paleoecological reconstructions of early ape fossil sites dated to the early Miocene Epoch—between 23 and 16 million years ago. They showed early apes lived in a wide variety of habitats, including open scrublands and wooded grasslands that existed 10 million years earlier than previously known.

“None of us could have reached these conclusions working in isolation at individual fossil sites,” says Kieran McNulty, a professor of anthropology in the College of Liberal Arts, lead author and organizer of the decade-long Research on East African Catarrhine and Hominoid Evolution (REACHE) project. “It’s like a 4D puzzle,where each team member can only see some of the pieces.”

This research first appeared in the April 13, 2023 issue of Science.

Fire and Praries

When it comes to large prairies, fire helps maintain plant diversity, reduces shade, and improves seed production. But what about smaller patches of prairie common across the Midwest?

Scientists from the U of M and the Negaunee Institute for Plant Conservation Science and Action at the Chicago Botanic Garden studied how fires stimulate flowering and pollination.

Over six years, researchers focused on the narrow-leaved purple coneflower (Echinacea angustifolia), which is native to tall grass prairies and used as a model organism to study perennial plants in grasslands. The researchers did 22 artificial burns in prairie patches across western Minnesota to learn more about fire and plant reproduction. They determined that the beneficial effects of fire on plant reproduction in North American prairies depends on the size of the plant population and that pollination and seed yield increased the most in prairies with small populations (30-100 individuals).

“Land managers decide which prairies to burn and how frequently to burn them,” says Amy Waananen, a postdoctoral research scientist at the U of M and coauthor of the study.“Our findings help guide those decisions. In particular, we learned that prescribed burns really help smaller populations. It is important to act soon to preserve species. If a population becomes too small, fire probably will not be able to bring it back.”

This study originally appeared in the September 18, 2023 issue of Proceedings of the National Academy of Sciences.

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