Though it resembles a tall grass, giant kelp is not a plant. Instead, it is a brown alga and is part of the large kingdom of life known as the Protista. Most protists are single-celled organisms, but the giant kelp is a complex species and is the largest protist in the world. Since the giant kelp is not a plant, it does not have roots. Instead, it obtains all of the necessary nutrients directly from the water and is attached to the rocky bottom by a structure known as a holdfast.
This species is one of the fastest growing species in the world, and under perfect conditions, it has been known to grow up to two feet 60 cm in a single day. Once and individual giant kelp reaches the sea surface, it continues to grow horizontally, floating in large mats that shade the water column and sea floor below. In order to remain upright, each giant kelp blade leaf includes a gas-filled pod that floats. Several individuals growing together can create dense forests that are an important ecosystem in temperate, coastal areas where they live.
Monterey Bay Aquarium. Marine Ecosystems Kelp Forests. Home Marine Life Marine Ecosystems. Distribution Worldwide in temperate to polar latitudes Physical Ocean Characteristics Cold, shallow, nutrient-rich, medium-energy waters Keystone Species Kelps, sea urchins, rockfishes, sea otters, seals Ecosystem Services Fisheries, ecotourism, kelp bio-products Share. Some kelp species can measure up to 45 metres long. If living in ideal physical conditions, kelp can grow 45 centimetres a day. Kelp forests compromise one of the ocean's most diverse ecosystems.
Many fish species use kelp forests as nurseries for their young, while seabirds and marine mammals like sea lions and sea otters use them as shelter from predators and storms. Sea urchins can destroy entire kelp forests at a rate of 9 metres per month by moving in herds. Sea otters play a key role in stabilizing sea urchin populations, by eating them, so that kelp forests can thrive.
Not so much its tendency to snag our boards while sliding down a wave, but for other reasons. Anchored to the rocky bottom with strong holdfasts, kelp provided a convenient anchor to hold onto and stay put in strong currents, and tended to prevent local winds from making the surface of the water choppy and chaotic.
We also used it to condition our hair, popping open the gas-filled floats that keep kelp plants standing upright in the water, and rubbing the insides of the floats, which are coated with a slimy substance, into our locks. There are lots of hair products available that contain algae, so we figured going straight to the source would be great. One day, my friends and I were enthusiastically smoothing algae slime onto our heads while we bobbed on our surfboards, when a fellow surfer paddled over. Suddenly, I second-guessed our beauty routine.
Was he right? Was I preventing the adult kelp from making baby kelp? Kelp grows in temperate water, often in thick beds called forests. Kelp and other types of algae are used for a range of products, including cosmetics like shampoo and toothpaste, and food like salad dressing and ice cream. Agar, carrageenan, and alginate are some of the compounds extracted from different types of algae, and mostly used as thickeners. Kelp is like a plant — it is photosynthetic and has structures that look like roots the kelp holdfast , stems the stipe and leaves blades — but kelp and other algae belong to a separate kingdom of life from plants, called protists.
So: do kelp gas bladders double as reproductive organs? Well, no. The way kelp actually reproduces is much more interesting. Instead, they produce an intermediate stage, microscopic spores produced by special blades without floats near the holdfast at the base of the adult kelp.
Spores are different from seeds because they are single cells and only contain half of the chromosomes of the adult; they will mature and produce either sperm or eggs. Seeds are multi-cellular and are already fertilized, containing a full set of chromosomes; they are ready to produce an adult plant as they mature. Once fertilized, the egg develops into a sporophyte that takes over the female gametophyte. The sporophyte eventually grows to form the large fronds many meters tall that we recognize as kelp.
Can you think of any species that live on land and reproduce similarly, with a microscopic spore stage instead of via sexual reproduction? In what kinds of environments do they tend to live? Neushul, M. Studies on the giant kelp, Macrocystis.
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