Saved by seaweeds: phyconomic contributions in times of crises

Abstract

Seaweeds (macroalgae) are, together with microalgae, main contributors to the Earth's production of organic matter and atmospheric oxygen as well as fixation of carbon dioxide. In addition, they contain a bounty of fibres and minerals, as well as macro- and micronutrients that can serve both technical and medicinal purposes, as well as be a healthy and nutritious food for humans and animals. It is therefore natural that seaweeds and humans have had a myriad of interwoven relationships both on evolutionary timescales as well as in recent millennia and centuries all the way into the Anthropocene. It is no wonder that seaweeds have also entered and served as a saviour for humankind around the globe in many periods of severe needs and crises. Indeed, they have sometimes been the last resort, be it during times of famine, warfare, outbreak of diseases, nuclear accidents, or as components of securing the fabric of social stability. The present topical review presents testimony from the history of human interaction with seaweeds to the way humankind has, over and over again, been 'saved by seaweeds'. It remains a historical fact that in extreme conditions, such as shortage and wars, humans have turned to seaweeds in times of 'needs must' and created new opportunities for their uses in order to mitigate disasters. Lessons to be learned from this history can be used as reminders and inspiration, and as a guide as how to turn to seaweeds in current and inevitable, future times of crises, not least for the present needs of how to deal with changing climates and the pressing challenges of sustainable and healthy eating.

Keywords: Crisis; Famine; Human diseases; Nuclear accidents; Seaweeds; Unemployment; War.

Fig. 1

Poor families collecting seaweeds at the West Coast of Ireland during the Great Famine, 1845–1849

Fig. 2

A Byzantine ship uses Greek Fire against a ship of the rebel. Twelfth century illustration from the Madrid Skylitzes. (Public Domain) (https://bit.ly/30TwEKM)

Fig. 3

The Hercules Powder Company in Southern California (South Bay Historical Society) which harvested kelp to produce potash to manufacture gun powder during WW1. (CC BY 2.0) (https://bit.ly/2AGryXM)

Fig. 4

Burning of kelp at the coast of Northern Brittany. The ashes contained various salts like potash and iodine from the brown seaweeds

Fig. 5

Women cultivate Spinosum (Eucheuma denticulatum) in Zanzibar for carrageenan production. Courtesy of Marie Frost

Fig. 6

French advertisement praising marine algae as a marine cure for sick children and elderly. (CC BY 4.0) (https://bit.ly/3dahByZ)

Fig. 7

British advertisement appraising Irish moss (Chondrus crispus) for curing infectious diseases like colds and coughs. (Public Domain) (https://bit.ly/2N7ZoqW)

Fig. 8

On-land aquaculture of seaweeds (Chondrus crispus) at Acadian Seaplants, Nova Scotia, Canada

Fig. 9

The green seaweed Chaetomorpha linum sn used as a natural filter in some estuaries from Cádiz Bay, Spain. Courtesy of Juan José Vergara

Fig. 10

An edible and biodegradable pouch made of seaweeds as a handy container for fresh water. https://shorturl.at/bjEJQ

Fig. 11

Seaweeds for production of biofuels. (CC BY-SA 3.0) (https://bit.ly/2ANu6mS)

Fig. 12

Seaweed salad composed of mixed species. Courtesy of Jonas Drotner Mouritsen