Whether they knew him or knew of him, Minnesotans across the state's vast conservation landscape are mourning and paying tribute to a man whose advocacy for state waters ran as deep as his interests.

Darby Nelson, schooled in aquatic ecology and by a life outdoors, was a passionate mentor and teacher at Anoka-Ramsey Community College for 35 years. That career overlapped with his service as a DFL legislator from 1983-1988, where he carried on his environmentalism, writing bills that created the state's Board of Water and Soils Resources, protected public lands, and even created a funding mechanism for cross-country ski trails.

Later, he was a charter member of the Lessard-Sams Outdoor Heritage Council, created in 2008 by the Clean Water, Land and Legacy Amendment approved by voters. The act secured additional sales tax revenue, some of it directed to protect and preserve natural resources.

As much as water trails, ski trails were never far from his mind. Nelson was the only person to have skied every Vasaloppet in Mora, Minn., since the race began in 1973, and had hoped to continue his streak this year: It would have been his 50th start.

Nelson, 80, died Jan. 13 of Alzheimer's at his longtime home in Champlin. But memories of his active mind, work ethic and gentle way have filled his void. Some people have paid tribute online.

Nelson moved people with his writing, too, producing "For the Love of Lakes" in 2012 and later "For the Love of a River: The Minnesota," an appreciation of a beloved waterway that coursed past his childhood home (Morton, Minn.) and inspired him.

He was comfortable in board rooms and served for multiple nonprofits, such as Conservation Minnesota.

Its executive director, Paul Austin, said Nelson was an invaluable mentor since they met 18 years ago, helping him learn how to present conservation issues in meaningful ways that transcended partisanship.

Austin said Nelson's legacy partly is his love to educate others — and always with patience and generosity.

"When you combined his passions of nature and teaching and people, there was a spark that was lit in him, and you could see it in his eyes," Austin said.

Friend John Hickman of Bloomington, a writer and filmmaker, can attest. He recalled Nelson introducing himself during a break at the inaugural meeting of the Lessard-Sams council. Little did they know at the time that their shared love of the Minnesota River would entwine in the next several years. Hickman, too, had served on Gov. Arne Carlson's Minnesota River Advisory Committee in the early 1990s.

Nelson's first book matched a scientist's keen sense of discovery with a poet's lyricism. Wrote the Star Tribune, in review: "FOR THE LOVE OF LAKES is an ode to the beauty of lakes and the high stakes of what we have to lose; it's also an eyes-wide-open cautionary tale of how things are changing for the worse, and what has already been lost."

He followed that with a nod to something closer to his heart, "For the Love of a River: The Minnesota," several years in the making and published in 2019. Nelson was diagnosed with mild cognitive impairment in 2011 and, as his mental health declined toward Alzheimer's, so did his ability to finish the second book.

In 2016 and struggling to edit the manuscript, Nelson and his wife of 53 years, Geri, contacted Hickman, who'd produced a film about the Minnesota, "River Revival: Working Together to Save the Minnesota River," in 2011.

Given the river's sullied reputation and negative press, Hickman said he was excited that someone of Nelson's stature would come to its defense.

"I recognized right away that if Darby Nelson was writing a book about how he loved the Minnesota River, it could be influential," he said.

Hickman said while there were heaps of awards and achievements, Nelson would have been most gratified to see his work for the Board of Water & Social Resources, Conservation Minnesota, the Freshwater Society and others continue through their missions.

"All those things," Hickman said, "his work was foundational."

As bedrock as the paddle trip taken by Nelson and Geri on the Minnesota from its headwaters to the Twin Cities in advance of the second book. It was another chapter in their outdoor lives, sealed when the two met in 1966 at the University of Minnesota's Itasca Biological Station. Geri had degrees in biology and secondary education.

"It was a partnership that made us each do more than we ever could have alone," she said.

For sure, there was more reading and writing to be done, Geri said this week, noting the three folders at home full of clippings and Darby's jottings on books he wanted to read.

She said his presence is everywhere, in ways that are heartfelt. That, with the outpouring for her husband, gives her peace.

"I feel like our spirits are still joined," Geri said.

Visitation is from 6-8 p.m. March 4, and 10 a.m. March 5, preceding an 11 a.m. service at Champlin United Methodist Church.