Seaweed
Seaweed or macroalgae refers to several species of macroscopic, multicellular, marine algae. The term includes some types of red, brown, and green macroalgae. Marine algae species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; ocean algae species from seaweeds to planktons play a vital role in carbon capture, producing up to 90 percent of the planet's oxygen. Understanding these roles provides guiding principles for conservation and sustainable use of seaweeds to take precedence over industrial exploitation. Mechanical dredging of kelp, for instance, destroys the resource and dependent fisheries. Certain species of seaweed are valuable for nutrition, biomedicine, bioremediation, and other uses.
Seaweed
Seaweeds are also used as animal feeds. They have long been grazed by sheep, horses and cattle in Northern Europe. They are currently particularly valuable for fish production. Adding seaweed to livestock feed can substantially reduce methane emissions from cattle.
Rotting seaweed is a potent source of hydrogen sulfide, a highly toxic gas, and has been implicated in some incidents of apparent hydrogen-sulphide poisoning. It can cause vomiting and diarrhea.