Sargasso weed.

[RupertW]

Mostly though....

Sargassum rots quickly when stranded. Within 48 hours, it begins to degrade, releasing hydrogen sulphide and ammonia. At certain concentrations, these gases become not only toxic to the marine environment but also to human health.

There have been a growing number of reported cases of neurological, digestive and respiratory disorders associated with the noxious gases being emitted. Guadeloupe’s air-quality monitoring institute Gwad’Air has issued red alerts in recent years because of dangerous levels of hydrogen sulfide gas being emitted from rotting sargassum.

I know, it’s vile but only a tiny proportion ends up on land so the overall impact is huge and encouraged by more co2 in the water and air so it’s a natural balancing phenomenon.

 

[capnsensible]

Be interesting to know what percentage ends up on land. From what I've seen in Panama, hoof loads.....

Fertilisers, eh? From food to poison.

 

[RupertW]

Be interesting to know what percentage ends up on land. From what I've seen in Panama, hoof loads.....

Fertilisers, eh? From food to poison.

Please don’t argue with figures I’ve just made up.

 

[KevinV]

Sounds like you could patent it under the name "Scimitar"...

If the weed could be made to sink it would sequester lots of carbon...

Already being investigated, though it seems to have as many drawbacks as benefits - like most symptom-reducers

Could Sinking Tons of Seaweed to the Ocean Floor Help Combat Climate Change?