Seaweed fertiliser, also spelt seaweed fertilizer, several of the 12,000+ varieties in the ocean have been shown to be valuable additions to the organic garden and can be abundantly available free for those living near the coast. However, caution should be observed when collecting seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

, particularly from areas that are liable to pollution

Pollution

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

, such as downriver (including estuaries

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

) of industrial activities as seaweed is susceptible to contamination.