Why are plants at the bottom of the ocean red?

Why are plants at the bottom of the ocean red?

Light that reaches the bottom of the ocean is not the same as white light that reaches plants on land. Photosynthetic algae have developed different pigments to use solar energy at the bottom of the ocean. These are red, purple and brown pigments, unlike green algae, which can be seen on land and closer to the surface.

It's a generally accepted truth that all plants are green... right?

After all, they need chlorophyll to help them take photosynthesis to produce this delicious and necessary sugar.

Actually, it's not!

Some of the earliest plants on Earth appeared in the ocean, known as cyanobacteria, or, most often, blue-green algae. It is in the ocean that algae has become so diverse and developed in many different directions: brown, red, purple, and even fluorescent.

The question is, how do they photosynthesize if they're red, what makes them red or brown?

What gives the objects color?

When light hits an object, it makes one of two things: either reflection or absorption. When light is reflected, it emits a certain color. The color that you see is the color that is reflected when light hits an object.

The color of the object also depends on the colors it absorbs. The best explanation for this is to look at the leaves on the tree. They're green, and everyone knows it's from chlorophyll. The white light is on the leaf.

So in order for an object to look red like our deep seaweed, it has to absorb green and blue light and reflect red, but what makes them swallow blue and green light? Water has its own behavior when it passes through it.

Why do red algae need blue light?

The water in the oceans absorbs red light at a faster rate than other colors, especially blue light, all blue light is reflected back, so the oceans seem blue.

This means that the light energy that can be used by plants at this depth,

Photosynthesis in deep waters

Green plants use two types of chlorophyll.

Surprisingly, these red algae contain chlorophyll, which means that one pigment absorbs blue and orange-yellow light, but the energy they get from it is not enough to produce food.

Instead of chlorophyll, they have an interesting family of pigments called phycoeritrins.


In contrast to most plants that rely mainly on chlorophyll to use solar energy, red algae uses phycoeritrin as the main photosynthetic pigments. In fact, according to this study, the amount of phycoeritrin in these plants can be five times larger than chlorophyll.

It also has an interesting effect on the product of their photosynthesis.

Different pigments, different products

The existence of different pigments affects even the kind of food that red algae can produce. In plants on the surface, food is stored in the form of starchmal. We have all heard about starchmal, which is known for its large amounts in potatoes. A lot of glucose molecules connect to each other in a very large chain, and as a result we get the granules of starchmal.

The red algae stores its food in the form of a Florida starchmal. This starch has its name because it was found in a family of algae found only in Florida, USA. Florida starchal is also a long chain of glucose molecules. The difference is the location of the links between glucose molecules.

Life on our planet has adapted to many interesting and unique ways.

Trying to conquer impossible conditions, they develop incredible devices.