The Great Black Swamp: Toxic Algae, Toxic Relationships, and the Most Interesting Place in America that Nobody's Ever Heard Of

by Patrick Wensink

In the summer of 2014, a strange thing happened to one of the largest freshwater bodies on the Lake Erie's western shore turned bright green with toxic algae that could have killed 400,000 Ohioans. Stranger still, it was kind of Patrick Wensink's fault. Okay, partially his fault, but also to blame was industrial corn farming, greenhouse gasses, the Worst Road In America, his attraction to toxic relationships, Richard Nixon, Charles Dickens, cyanobacteria, high school bullies, and, most importantly, the untold history of the Great Black a large swatch of what is now Ohio and Indiana that was once a dangerous, malaria-ridden wetland. Toxic green algae has become a global problem. While the scientific community scrambles to find a solution, Wensink discovers that the answer might be hiding in his former home, a million acres of table-flat farmland so desolate that even other Ohioans look down upon it. Great Black Toxic Algae, Toxic Relationships, and the Most Interesting Place Nobody's Ever Heard Of mixes ecological reporting, Midwestern history, and memoir. As Wensink travels through Northwest Ohio, he tells us about his childhood there, his failing marriage, American history, Lake Erie, and the hopeful ecological interventions scientists are performing in the former Great Black Swamp.

Genres: Nonfiction, Nature

272 pages, Paperback

Published November 11, 2025

About the author

Patrick Wensink was born in Deshler, OH in 1979. Since that time he has done a lot of things he is not proud of. But he's also done some pretty interesting stuff. Over the years he has bottled and sold his own line of Wentastic BBQ Sauce, got married in a doughnut shop and even found the time to author a few greeting cards.

The Louisville Courier-Journal called Sex Dungeon for Sale!, "A deliciously dark and funny book," which probably made his mom very happy.

Reviews

[Bon · Rating 5 out of 5]

"Disasters do not happen overnight. And rarely do they have a single source to blame for all their destruction. Rather, disasters are often the product of long stretches of negligence and bad decisions and optimistic best intentions that coalesce in a single catastrophic moment. In most cases, we don’t see those elements combining, or if we do, the alarms they set off tend to get overlooked in favor of normalcy."

[Ben S · Rating 4 out of 5]

For 3 years and 4 months I lived in the heart of the former Great Black Swamp—fifteen miles or so from Wensink’s hometown of Deshler. Suffice it to say, I share a lot of his interest for the region, but little of his affection. When I learned this book existed—I quickly sought it out.

I wasn’t sure initially if it would all hold together. The history, the ecology, the 2014 Toledo algae bloom—sure. But Wensink’s childhood and failing marriage? I was skeptical. I have to say—he manages it well, and this book feels like an exercise in finding oneself in both the micro and the macro. It’s also a brisk and accessible read, even when talking about Cyanobacteria and road construction and divorce.

Wensink ends the book on a note of hope based in scientific work and the people of northwest Ohio. I’m glad for the science but admit that I think the solution to all of Northwest Ohio’s problems is rewilding it…until then, I’ll take small progress.

[Julie · Rating 4 out of 5]

The 2nd half of the book was more interesting to me. 3.5 stars. I grew up in a town situated along the Maumee river (the "muddy Maumee") which is featured in this book. I honestly don't remember a time when we thought it was safe to swim in Lake Erie. I always thought it was strange that my grandfather fished in Lake Erie (could this be why I don't like fish?) but he had been doing it since the at least the 40s. I am happy that the Black Swamp Conservancy was mentioned- my dad served on the board for several years. Their work is worth supporting, and it is shameful that so much restorative work that was on the precipice and was providing some hope was destroyed almost overnight with the actions of the current administration.

[Scott Erickson · Rating 5 out of 5]

A fascinating and moving book that perfectly combines investigative journalism and personal memoir. Like probably 99.99 percent of Americans, I’d never heard of the Great Black Swamp. What a fascinating story it turns out to be. I also learned a lot from the author about navigating huge personal life changes. My family is from the Midwest (Minnesota, to be specific) so I readily identify with the pragmatic, humble, anti-emotionalism of Northwest Ohio. The descriptions of this curious quality were some of the must humorous parts of the book. Because the book is extremely informative, but parts of it are very funny.

[Chase Fleece · Rating 4 out of 5]

A honest, and heartfelt, exploration into Ohio’s most unique and overlooked historical ecosystem. With immense clarity, Wensink lays bare its trials and tribulations while also, importantly, reminding us that hope is far from absent. A must-read for locals, newcomers, and most especially, the occasional passerby.

[David Jex · Rating 3 out of 5]

This book may be of more interest to NW Ohio readers than others.

[Ryan-Ashley Anderson · Rating 5 out of 5]

An account of disappearing landscapes, surviving transitions, and an exploration into personal and ecological rewilding, THE GREAT BLACK SWAMP will break your heart.