Vibrant green algae exposed at low tide at Tregardock Beach, North Cornwall, England, United Kingdom, Europe

Nudibranch on coral, Papua New Guinea, Pacific

Rock details near Marwick Head, Mainland, Orkney Islands, Scotland, United Kingdom, Europe

Vibrant sea cucumbers, tunicates, hydroids, and other invertebrates cling to a reef in Raja Ampat, Indonesia.

Vibrant pink water lily blooming in a tranquil pond with green algae and lily pads, reflecting serene beauty in nature at Kew Gardens, London, England, United Kingdom, Europe

Mouth detail of a colourful and healthy Mushroom coral, Fungia fungites, that is growing on a tropical coral reef in the Philippines. Mushroom coral is unique in the coral world, in that it does not attach itself to the bottom, Philippines

Mouth detail of a colorful and healthy mushroom coral (Fungia fungites) that is growing on a tropical coral reef. Mushroom coral is unique in the coral world, in that it does not attach itself to the bottom, Philippines

This red encrusting sponge (Clathria sp.) is the most common of this family found in Hawaii. Here it has covered the calcium carbonate-producing seaweed, Halimeda kanaloana, Hawaii, United States of America