Nature – The Giant Algae

Growing in cold, clear, nutrient-rich marine environments are underwater forests of giant plants known as kelp. Kelp are large seaweeds (algae) belonging to a class known as the brown algae. There are about 300 different genera of kelp with the most widely recognized species being the giant kelps. The giant kelps are known for their fast growth rates, some species growing up to half a meter a day under ideal conditions and ultimately reaching heights of 30 to 80 meters. Like all algae, the physical structure or body of kelp is known as a thallus rather than a plant. The thallus consists of three basic structures: the holdfast, the stipe, and the fronds. The holdfast is a root-like mass that anchors the thallus to the sea floor. Unlike true roots, the holdfast does not absorb nutrients for the thallus. The main framework of the thallus is the stipe, which is analogous to a plant stalk. Growing out of the stipe, often along most of its length, are the fronds which are leaf-like structures where nutrient uptake and photosynthesis occur. Many kelp species have pneumatocysts, or gas filled bladders, that provide the necessary buoyancy for kelp to maintain an upright position in the water column.

Kelp forests occur worldwide throughout temperate and polar coastal oceans and even occasionally in tropical waters. A dependence upon light for photosynthesis restricts them to clear, shallow water, where they rarely grow any deeper than 15 to 40 meters. The larger forests are restricted to temperatures less than 68 degrees F. Kelp forests are among the most beautiful and biologically productive ecosystems on earth. These forests provide a unique three-dimensional habitat for marine organisms which in many ways resemble microenvironments associated with terrestrial forests. These microenvironments consist of a sunny canopy region, a partially shaded mid-story, and a darkened seafloor. Each of these microenvironments has its own unique associated organisms consisting of fishes, crustaceans, bivalves, gastropods, echinoderms, etc. The kelp is grazed by herbivores such as sea urchins and various fish which in turn provide food for carnivores such as starfish and larger predatory fishes. In some kelp forest, sea urchins will destroy the whole kelp forest ecosystem in a short period if numbers are not kept in balance by predators such as sea otters. Kelp forests even sometimes provide cover for Gray Whales when they are being pursued by Killer Whale packs.

Just as the kelp’s fast growth and great height are attained from rich nutrients and ideal environment, so similarly the Christian’s spiritual growth and heights attained are related to their environment and what they feed on spiritually. “If the follower of Christ would grow up ‘unto a perfect man, unto the measure of the stature of the fulness of Christ’ (Ephesians 4:13), he must eat of the bread of life, and drink of the water of salvation.” The Review and Herald, August 31, 1911. “The soul needs food, and in order to get this food, the Word of God must be studied. …. The breathing of pure air is essential for the cure of disease. And it is no less essential that the atmosphere we breathe in the spiritual life shall be pure. This is essential for a healthy growth in grace. Breathe the pure atmosphere which produces pure thoughts and noble words. Choose Christian society. The Christian will not have spiritual health unless he is guarded in regard to his associations. … Every Christian who is indeed a Christian must grow. He must constantly increase in wisdom and knowledge. Day by day he must approach more nearly to the full stature of a man in Christ Jesus. In order to be a follower of the Master, he must grow.” Upward Look, 174.

David Arbour writes from his home in De Queen, Arkansas. He may be contacted by e-mail at: