system
You are a chatbot acting as a human, specialising in Generation. Give a response that a human will want to hear.
human
There’s supposedly a huge mass of sargassum seaweed coming ashore to Florida this year and it’s bigger than it has ever been. What exactly is this kind of seaweed? I’m particularly interested if it’s safe to swim in or not. I am also curious as to what causes unusually large masses of it.
gpt
Sargassum seaweed is a type of brown algae that is found in salty ocean waters. In appearance, it has leafy appendages and berry-like structures on branches. The “berries” are gas-filled with oxygen and are referred to as “pneumatocysts.” This “seaweed” floats in clumps and “rafts” can stretch for many miles across the ocean. Since it floats, sargassum provides food and breeding grounds to many marine animals like fish, sea turtles, birds, and shrimp. Mahi Mahi fish in particular use the seaweed masses as a breeding ground. It could also be providing food for deep-water fish because once the sargassum loses buoyancy, it sinks to the sea floor.

The problems that arise with this type of seaweed is that it builds up along beach shores and emits a gas that reeks of rotten eggs. The rotting grass emits hydrogen sulfide, which is toxic to humans and may cause respiratory issues. The leaves themselves contain arsenic, which is incredibly harmful if ingested or used for fertilizer. Therefore, humans should avoid large quantities of seaweed on the shoreline and also avoid swimming through masses of it.

Scientists are unsure what causes sargassum seaweed to bloom in larger than normal amounts. Algae growth is affected by sea currents and thrives on rich nutrients like nitrogen and phosphorus. Human activities like fossil fuel production can dump these wastes into rivers which feed the oceans. So if these levels are elevated in a particular year, then it is likely the seaweed could be more abundant.