Final answer:
Modern urban development has led to increased pollution, degradation of water quality, and habitat loss along Mississippi's rivers and the Gulf. About 91 percent of US rivers have been modified, affecting aquatic life and reducing the diversity of fish due to altered habitats and flow regimes.
Step-by-step explanation:
Modern urban development has significantly impacted Mississippi's rivers and the Gulf through increased pollution and the degradation of water quality. Due to land development, damming, channelizing, or water removal, approximately 91 percent of the United States river lengths have been modified, leading to habitat destruction for many species. This alteration affects not only flow patterns but also the ecological balance, increasing the risk of habitat loss and contributing to the decline of sensitive species such as fish and amphibians.
The impact of urban development on the rivers leads to excessive soil erosion, loss of fertile soil, and the presence of toxic substances in the water. The diversity of fish in streams is affected as species that cannot adapt to these modified conditions are selected against, resulting in a reduction of rare and specifically adapted species. Furthermore, the loss of natural habitats has been exacerbated by overharvesting and poor environmental regulations in the past, where industrial waste was often directly dumped into rivers without consideration of the downstream consequences.