The nitrogen in the fertilizer is creating dead zones: https://www.scientificamerican.com/article/fertilizer-runoff-overwhelms-streams/ https://www.scientificam

The nitrogen in the fertilizer is creating dead zones: https://www.scientificamerican.com/article/fertilizer-runoff-overwhelms-streams/ https://www.scientificamerican.com/article/fertilizer-runoff... A quick googling will show many scholarly papers and articles describing this.