Are Dead Zones Spreading?

What We Can't Sea

Are dead zones spreading? is an episode that discusses the growing problem of ocean dead zones? Dead zones are areas of the ocean where there is insufficient oxygen to support marine life.

"Do you ever wonder what happens to the water in your pipes when it leaves your house? Or what about that extra fertilizer you spread on your lawn? In developed countries, water from our homes gets carried to a wastewater treatment plant that cleans the water before it is released back into the environment, often into a river or bay. As for the fertilizer, rainwater from storms can carry the fertilizer into sewer drains or directly into a nearby water body. Even though we have improved our wastewater and stormwater cleaning practices over the years, some of those pollutants still make it to the coast. So, what happens when that water gets into a bay? Water from runoff and wastewater are full of nutrients, such as nitrate and phosphate, that can cause algae growth when released into the water. After the algae die, they sink and get eaten by bacteria that suck the oxygen out of the water. When this happens, fish and other small animals can die because they do not have enough oxygen to breathe. This is how we get ocean “dead zones."