Algae are simple photosynthetic plants living in water. Most species of algae
are very small and can only be observed with a microscope. Some species of
algae live an independent existence, floating or swimming as what we call
plankton. Other species of algae grow together into large “plant ”structures and vegetation.
We call these types of algae seaweed. For example, kelp is the largest of the seaweeds,
growing up to several hundred meters in length. Kelp can form dense underwater forests,
and are ideal spaces for many fish to hide or escape would be predators.
Algae has many uses. Algae has been collected in Japan and China for thousands of years as a food source.
Algae are used as added ingredients in many foods and industrial products as well. Farmers have fine-tuned
their methods for harvesting and collecting large amounts of algae. The red-algae, Porphyra, is grown by
placing spores on oyster shells and placing these shells in a water-filled tank. The new spores that form
are then transferred to strings, which are then placed into shallow bodies of water. Within a few months,
the algae grow and are then stripped from the string for preparation as a food source. You’ve most likely
eaten this algae, if you’ve eaten sushi, since the portions are usually wrapped in this algae.
Algae is also added to foods to help them maintain their consistency. Agar, is a polysaccharide
from algae, and helps to solidify anything that it is added to. This makes it an ideal ingredient
for cakes, pies, cookies, etc., functioning as a thickening agent. Alginic acid from algae is
also used as an emulsifier in foods. Brown algae contain carageenan, a a cell-wall product,
which is also used as an emulsifier. Algae also help keep our teeth clean. When planktonic
algae die, their outer skeleton remains. As they die in colonies, remaining skeletons form
large deposits, which accumulate. We call this accumulation diatomaceous earth. This
accumulated substance can be ground up, and is abrasive, sort of like the limestone that you
sprinkle in your garden. This tough remaining component of algae is used in toothpastes and
polishes, to clean the surfaces that they are rubbed onto.
Some algae can pose threats to aquatic creatures living in nearby waters. These algae
(the dinoflagellates) have the ability to synthesize toxins. The toxins can cause illness
and death for the local aquatic creatures who are exposed to this. Sometimes, when the
algae multiply in large areas, one can observe a reddish, or brown hue in the water.
This is referred to as a “red tide,” and is one of nature’s warnings of dangerous circumstances.
Humans harvesting or collecting and consuming shellfish, fish, etc., that have accumulated
toxins, can also be equally affected. The toxin has the ability to affect the nervous system,
causing respiratory depression, other effects of neurotoxicity and even death, if artificial
respiration and medical attention is not immediately given.
Algal blooms and its associated problems are not very common. And we must not forget that
many types of microbiological forms of life produce dangerous substances. The trick is
living in harmony with nature and learning its pitfalls and what and when to avoid.
Nevertheless, algae are an important source of nutrition, and they taste great.