When walking among the tide pools around Oak Bay, the abundance and diversity of seaweeds often goes unnoticed. Or, the seaweed is thought of as a hazard and people carefully tread over the slimy rocks to take a peek in the glistening pools of water.
In my opinion, seaweed is quite fascinating and is actually used by humans more often than one would think.
Seaweeds are split up into three main groups – greens, reds and browns.
Seaweed is not a vascular plant due to its lack of a vascular system, roots, leaves, steams and flowers. Rather, seaweed is a multicellular algae that contain chlorophyll and use the sun’s energy to produce food, just like plants on land. Thus, most seaweed is found in the sunlit upper waters of the ocean, so that photosynthesis can take place.
Seaweeds range in size, shape, colour, texture and even smell. The gorgeous bull kelp (nereocystis luetkeana), found off BC’s coast forms dense forests and can grow to a maximum of 36 metres, often growing several feet a day in the summer.
Sargassum, is an invasive species to BC, that does not attach to a substrate, but floats around on the sea surface.
Some red seaweeds, like the coralline algae, are rather delicate and look almost coral-like due to calcareous deposits in their cell walls.
Dead man fingers, an appropriately named seaweed due to the finger-like sacs it forms, squirt out water in all directions when squished, almost like a natural water gun.
The species listed above are just a snapshot of the thousands of seaweeds that exist. Seaweeds have evolved some cool adaptations for surviving in a variety of conditions. Seaweeds that live in the high intertidal must be able to resist drying out when the tide is low; thus intertidal seaweeds often have a gelatinous layer to prevent internal water from evaporating. Other species have gas filled bulbs (like the bull kelp) that help keep their long blades floating at the surface in order to photosynthesize. Some seaweed species even produce noxious chemicals to defend themselves against predation.
Seaweed is a major player in the marine ecosystem. Some animals such as sea urchins rely on seaweeds as their main food source and have been known to mow down entire kelp beds.
Seaweeds are also home-sweet-home to many marine species that hide among the swaying blades and feast on tasty prey.
Last, but not least, seaweeds act as nurseries, a safe haven where animals lay their eggs and raise young.
Not only do seaweeds have important functions in the ocean, humans have also found dozens of uses for seaweeds and algae in day-to-day life.
Anyone who enjoys a tasty dynamite roll dipped in soya-sauce and wasabi knows too well how nutritious and delicious seaweeds can be. However, did you know that a property of red seaweeds, carrageenan, is used as thickening, gelling or stabilizing agent in many different foods, including ice cream?
Carrageenan is also found in other daily products like toothpaste, shampoo and cosmetic creams. Seaweeds have all sorts of other practical uses and are commonly found in bio fuels, fertilizers, pet food and medicines.
Much research is currently being done on algae and its uses, particularly in the medical field. Different forms of algae are thought to assist in many health disorders from diabetes to ADHD, although there is some uncertainty.
I find it amazing that something so “simple” as seaweed can provide so many important uses. The next time you’re at the beach take a moment to admire the beauty and diversity of seaweeds.
As previously discussed, humans are inextricably linked to the ocean.
Whether one lives five minutes or five days away from the ocean, the marine ecosystem surrounds us everyday; at least if you brush your teeth.
Combining her passions for education and the marine ecosystem Natasha Ewing inspires K-12 teachers and students to incorporate hands-on experiential ocean science into the classroom for Ocean Networks Canada.