Winter nutrient pollution often sets the stage for harmful algal blooms in spring. When nitrogen and phosphorus enter waterways during snowmelt or mid-winter thaws, they tend to remain there because cold temperatures slow biological activity. Once sunlight increases and water warms, the abundance of stored nutrients fuels rapid algae growth.
This early nutrient boost can help algae gain a foothold before natural controls, such as competing plants or active microbial communities, become strong enough to keep them in check. This connection is one reason managing winter nutrient runoff is so criticical for protecting water quality later in the year.
