The element phosphorus is essential for the formation of our genes and bones — and absolutely crucial for thriving agriculture and ecosystems in general.

But excess phosphorus runoff from farms, feedlots and cities often pollutes rivers, lakes and oceans. And serious concerns have been raised about how much longer we can continue to mine cheap phosphorus for use in fertilizers.

University of Montana Professor James Elser will address these issues in an Orcas Currents lecture in the Orcas Island Community Church on Saturday, Oct. 28, at 4 p.m. He will examine both sides of this challenging conundrum, focusing on phosphorus and its roles in agriculture and water quality while highlighting pathways toward a sustainable food system.

Elser is the Bierman Professor of Ecology at the University of Montana and has served since March 2016 as the Director of its Flathead Lake Biological Station at Yellow Bay. He is also a research professor at Arizona State University.

Trained as a limnologist, Elser is widely recognized for his research on the balance of energy and chemical elements in ecological systems. A Fellow of the American Association for the Advancement of Science, he received the 2012 G. E. Hutchinson Award of the Association for the Sciences of Limnology and Oceanography, for which he recently served as President.

This Orcas Currents event, cosponsored by Janet Alderton, should be of great interest to island farmers, gardeners and those concerned about the condition of our water supplies. Admission is free, but donations are welcome at the door.