Algae Basics




Eager to engage with seaweed, but don’t know where to begin? There is a steep learning curve for understanding the ecological nuance, economic structures, and regulatory framework for wild harvested and farmed marine algae.


What is seaweed? 

Seaweed is a common term for marine macroalgae. If it's growing in the sea, looks plant-like, and is not a coral, it is probably marine algae. Seaweed is classified into three biological categories: Rhodophyta (red), Phaeophyta (brown), and Chlorophyta (green), each of which with its own unique lifecycles, reproductive strategies, and biological patterns. Seaweeds are biologically classified as algae, not plants. As such, they use their entire bodies to photosynthesize.


Where does it live?

Translucent, hearty, and nimble, seaweeds survive in some of the most difficult habitat niches on the planet. They live in the intertidal zone, between nearshore and foreshore. There are four tidal zones--low, mid, high, and spray--with various seaweed species growing differentially according to the zones. If you look at low tide, you can use specific seaweed species growth as a guide to tell where one tidal zone ends and the next begins. 


What is its ecological role? 

Micro and macro algae form the basis of the marine food web. At the low trophic level, seaweeds support the critters, oxygenate the waters, and constitute the foundational flourishing of intertidal places. The seaweeds photosynthesize, fix carbon, oxygenate the water column, and protect the coastline by absorbing storm surges. Algae growth, fresh or salty, acts as a material indicator of waters’ happenings. Agricultural runoff springs toxic freshwater algae blooms while the warming and acidifying and otterless bays cause kelp forests to dwindle. As such, seaweed can be understood as a material indicator of the ocean's health. That which is difficult for humans to discern, the state of water, is made visible through the seaweed. 



The physical characteristics and morphology of seaweeds are hugely diverse and differential across species and color classification. Here are some basic terms and descriptions to look out for at the shore. 

Blade: akin to a plant leaf

Stipe: akin to a plant stem

Float: sac containing air or seawater, enables the seaweed to float up towards the sunlight

Holdfast: akin to a plant root, attached directly to rock or substrate




The appetite for algae for food, industrial materials, and fertilizer continues to grow. Currently, seaweed is undergoing a global pulse of extraction. Large international corporations like Acadian Seaplants LLC, Dupont, Cascadia, and more. A few years ago they began their wild harvest in Ireland, much to the dismay of traditional harvesters, coastwatchers, and those concerned about ecologically sensitive areas of the coast where these seaweed forests are important. Other local companies threatened Bantry Bay with mechanized extraction of subtidal kelp forests, spurring the formation of a diverse group of citizens devoted to the protection of these swaying kelp forests and the marine community that depends on them. 



Globally, there are hugely differential seaweed regulatory and policy frameworks. California has strict regulations for wild seaweed harvest, so strict that long-time harvesters are struggling to retain access to the sites where they harvest, whereas Main's regulations are minimal and not enforced. European regulators are far ahead of US states in terms of creating constraints for the development of aquaculture.



In the West, a recent uptick and interest in seaweed led to the formation of this site. In the dominant discourse, seaweed is touted as a miracle product. The hype for kelp burgers and kelp biofuels and kelp plastics may reside mostly in the business section of the newspapers, with big investments, big promises, and bio biotech companies creating shiny futurist ‘save the world’ narratives. Seaweed farming is being represented as a solution to climate change, a solution to fisheries collapse, a solution to energy shortage. Seaweed Commons is skeptical of the intentions behind these claims. WILD seaweed is already saving the world! 


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