The ocean, the kingdom of water, has a very interesting ecosystem. There exists a level relationship, the marine food chain, or "nutrition chain", in marine biotic community. Material and energy switches and flows in every part of the food chain, thus keeps circulation of materials and energy flows in the marine ecosystem.

The structure of this food chain made by marine animals and plants which form an energy flow is very similar to that of the pyramid. Just as the saying goes: “Those smaller animals are eaten by bigger ones”.

 

Marine plants

Marine plants are ancestors of all plants in the nature. They are gradually evolved from unicellular algae and can be mainly divided into two kinds -- phytoplankton and benthic plants. Whether kelp, Undaria pinnatifida and seaweed people love to eat or diatom used as industrial raw materials, they all show the huge economic value of marine plants.

 

Main Species of Marine Plants

Phytoplankton

Phytoplankton can directly absorb inorganic substances in seawater, so there’s no need for them to take root in earth like land plants. They are different in shape. Some are like wheels; others are like small boxes or gourds.

Mangrove Plants

Mangrove plants such as mangrove, candel and upriver orange mangrove are woody plants living in tropical intertidal zones. When the tide ebbs mangrove plants seem like "sea forest" by the sea. Some people also call these trees “oasis in the sea."

Seaweed

Algae, large group of plants, are primitive lower plants which widespread in rivers, lakes, seas and oceans. They are of wide varieties and with different shapes. Some of the more common seaweed is diatoms, blue-green algae, green algae, etc.

Seagrass

Seagrasses are herbaceous monocotyledons which grow in shallow coastal waters in temperate sea. They usually form vast seagrass meadow on offshore slope along the shallow. The meadow is a good place for shrimp and juvenile fish and a best habitat for sea birds.

Benthic Plants

Benthic plants are marine plants that take root in seabed. In addition to green algae, brown algae and red algae, there are a few flowering benthic plants in the sea like Zostera, etc. Benthic plants include algae.

 

The Earliest Marine Animals

Invertebrates are the first animals that appeared in the ocean. The golden time of invertebrates was 130 -500 million years ago during which shallow seas was everywhere on the earth where invertebrates lived.

Invertebrates first lived in the ocean, and then moved to rivers, lakes and marshes and finally to the land, leading a development to terrestrial vertebrates.

Invertebrates refer to animals with no spine on the back. They account for about 95% of the total species of animals. The representing invertebrates are worms and sponges (sponges in sea look like plants but they are actually animals.)