It's Cottonwood time and more than likely it's the cottonwood seed floating on the pond and combining with the usual scum. Once the cotton gets wet it doesn't look fuzzy anymore. This stuff sticks to everything. A warm welcome to the GLF site.
Here is a link for a small MI company in my neck of the woods. 36 inch track is about $50 new. http://shop.markiesmounts.com/product.sc?productId=17&categoryId=1