Halbrand (Sauron) and Galadriel almost did not make when surrounded by the sea.* That’s how harsh the sea environment is! Glad she eventually did! Sauron - not so much! He can go $#$%…(ummm, let’s keep it civil here).
Anyway, how does seaweed survive in salty seawater? Based on the principle of osmosis, shouldn’t the high salt concentration technically force water out of the seaweed. Isn’t it amazing that the seaweed counteracts that?
Sodium ions are like evil villains lurking around. Here’s how the seaweed tackles it.
Lock it up!
Seaweeds locks up the sodium in vacuoles within its cells. This keeps the salt safely separated from the vital processes the seaweed needs to function.
Keep the enemies of sodium closer!
Instead of just sodium alone, it actively absorbs a ton of other ions like nitrogen (N), phosphorus (P), and potassium (K+) from the ocean to counter the ionic imbalance. Basically, it acts like a sponge. This property is why seaweed is rich in minerals (if planted in good environments) and can be used to absorb and filter out heavy metals from wastewater (when planted in toxic environments).
Hold on to moisture much like dwarves held on to mithril*
Whenever a plant or algae (in the case of seaweed) is like, “I am sorry sir/madam, I am not going to give up my hard earned water back to the environment”, they usually use sticky gums and slimy polysaccharides to hold on to the water tightly. Look at my post on guar gums extracted from plants that survive in dessert conditions.
Many seaweeds produce complex polysaccharides such as algin, carrageenan, and agar. These substances are viscous keeping it hydrated and resistant to the surrounding salinity. This gelling and thickening property is incredibly useful in the food processing industry. Extracts from seaweed are commonly used to make confectionery jellies, cakes, whipped desserts, marshmallows, and more.
Is seaweed good or bad for the environment?
Any organism that captures carbon dioxide and converts it into biomass through photosynthesis should be a good thing, right? So, when battling climate change, we should all be “team seaweed”, right? While this seems like a straightforward solution, why isn’t the world fully embracing it?
The challenge lies in the unintended consequences. Runoff from fertilizers into rivers and oceans has led to the overgrowth of certain types of seaweed, like Sargassum. Initially anchored by a holdfast, Sargassum soon grows into free-floating mats with air bladders that allow it to drift on the surface. When these massive mats reach the shore, they can’t survive on land anymore. They decompose, releasing hydrogen sulfide and clogging up the coastline, necessitating costly cleanup efforts by coastal cities.
Fun fact, the fear of Sargassum mats isn’t new. In 1492, Christopher Columbus’s ship (more like real-life Sauron? cough! cough!), the Santa Maria, was trapped for 21 days by thick Sargassum mats in the North Atlantic Ocean. The ship was eventually freed when the tides rose, but the experience left a lasting impression on the sailors of that time.
Mother of the sea
Reproduction in plants and animals - pshaaw! we humans understand it. It is easy. No problemo!! But algae sex, much like mushroom sex, is kinda hard to figure out.
Back in the 1940’s Japanese seaweed farmers were having great difficulty trying to cultivate Nori seaweed in a predictable manner. Relying on wild foraging alone was not enough to feed the growing demands. Completely unaware of this problem, a British researcher Dr. Kathleen Mary Drew-Baker was solving a puzzle of her own. She was trying to find out how to propogate a species of laver (Porphyra umbilicalis) found along English coast.
9 years of work later, she figured out that the spores from the seaweed would germinate if allowed to settle on calcium-rich shells. Eventually a Japanese phycologist (which means- an algae studying person) saw her research and was able to use that info. She is now honored in Japan as the "Mother of the Sea" for saving a critical part of their food industry. Alas, as most stories of scientific women in the last-century go, she had no idea that her research would become so useful. Unfortunately, she died in 1957 before she could be recognized and honored.
So, the next you eat sushi, you might want to want to slip a quick thanks skywards to her!
References
Mechanisms employed by seaweed to cope with salinity stress
The weirdest ingredient you should be using
*Rings of Power reference (For Lord of the Rings fans)