Why are there so many different words used to describe seaweed - I have seen "algae", "macroalgae", "marine plant", "seaplant", "sea vegetable", "kelp", "nori" and others?
Are all seaweeds edible?
Are edible seaweeds a seafood, or a vegetable?
How are seaweeds different than land plants?
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1. Why are there so many different words used to describe seaweed - I have seen "algae," "macroalgae," "marine plant," "seaplant," "sea vegetable," "kelp," "nori," and others?
There is indeed a broad terminology used in the world of seaweeds, coupled with a number of inaccuracies found in the popular press.
The terms "seaweed", "algae", "macroalgae", "marine plant" and "seaplant" are all generic terms used to refer to the thousands of species of large photosynthetic plants growing in coastal ocean waters of the world.
The more than 10,000 species of seaweeds are grouped into three broad categories: "green", "red" or "brown". However, only about 50 species are actually cultivated or wild harvested for food or their functional applications. Terms such as "kelp", "nori" and "sea vegetables" are some of the common terms used to refer to specific species or even their end-use products.
2. Are all seaweeds edible?
Theoretically, yes. Overall, less than 50 species of seaweeds are commonly eaten around the world and even fewer make up the majority of the biomass consumed directly as food or used for further processing.
The majority of the other seaweeds are either not stable after harvest, or are unpalatable without further processing (cooking, etc.).
In addition, one should be extremely careful to never collect and consume seaweeds from polluted areas.
3. Are edible seaweeds a seafood, or a vegetable?
We think everyone would agree that fish, crabs, mussels, etc. harvested from the ocean collectively fall within the "seafoods" category, while edible sea vegetables are considered to be both a vegetable and seafood, whether they are harvested from the ocean, or farmed in our land-based tanks.
4. How are seaweeds different from land plants?
While some seaweeds may appear "plant-like", their overall structure is very distinct from land (terrestrial) plants. For instance, marine plants do not possess a root, stem, leaf or vascular tissue and structure like their terrestrial counterparts. Instead, most seaweeds possess a holdfast which is used to anchor them to rocks, coral, animals or other seaweeds as a point of attachment.
Similar to land plants, seaweeds also generate oxygen and food (sugars). They accomplish this through photosynthesis which utilizes the energy of sunlight, water and carbon dioxide. Seaplants are also able to absorb the important minerals and nutrients they require for growth and development from their seawater environment. This is one of the reasons they contain so many beneficial macro- and micro-nutrients and are considered to be healthy foods.