All 21 of Mississippi's state beaches have been shut down, due to a toxic blue-green harmful algal bloom.
The blooms can be triggered by many things, including changes in water temperature and fertilizer run-off, and once the colonies of algae — which are actually cyanobacteria — start growing rapidly, they produce toxins that can cause stomach cramps, diarrhea, vomiting, and rashes. People and their pets are being told to stay out the water and avoid any seafood caught in the affected areas, but they can still be on the sand.
The Jackson Clarion Ledger reports that this bloom was partly caused by the opening of Louisiana's Bonnet Carre spillway, which brought a massive amount of freshwater to the coastline. The National Oceanic and Atmospheric Administration says more and more blooms are happening because of climate change and increasing nutrient pollution.