More Algae

The Ocean Blog

Often it's the tiniest organisms that do the most harm. One example is microscopic algae, which can grow rapidly to form harmful algal blooms . Such blooms (some are called "red tides") create...
Convict surgeonfish ( Acanthurus triostegus ) are the roaming sheep of the reef but, instead of noshing on grass, they feed on algae. Their grazing helps to balance the growth of algae and coral on...
Regardless of what continent you live on, the waters that surround it are home to marine invaders. The ocean is teeming with plants and animals willing and able to move beyond their native habitats...
In this close-up photo, you can actually see the photosynthetic algae, or zooxanthellae, living inside a tiny coral polyp. Look for the brownish-green specks in the colorless polyp. Corals depend on...
“Sea grapes” may sound like something Poseidon would snack on, and not a killer algae. Yet Caulerpa racemosa var. cylindracea poses a serious threat to marine life. Spread by the bilge water of boats...
Algae, like all organisms, normally grow in balance with their ecosystems, limited by the amount of nutrients in the water. But sometimes, certain species of algae reproduce so rapidly that they...
Seagrasses growing on the seafloor of the Chesapeake Bay rely on light to grow—but, thanks to pollution, that sunlight has become more scarce. Nutrient runoff from fertilizers causes microscopic...
Closest to the seeps, where the pH is lowest and the water is most acidic, corals no longer grow. Instead there are sand, rubble and seagrasses that are able to survive. Read more about how reef...
Giant kelp ( Macrocystis pyrifera ) is large, brown algae that grows in dense forests along coasts around the world. Long stalks anchor each plant to the seafloor, and they grow meters high like...
Dugongs , along with manatees , make up a group of marine mammals called sirenians or seacows . In the modern world, only one species of seacow is found in any one place in the world. However, the...
In the ocean, microscopic forms of algae, known as dinoflagellates , can "bloom" into dense patches near the surface, often referred to as "red tides." Some of these harmful algal blooms (HABs) are...
Many species of pink coralline algae cover a reef surface in the Southern Line Islands. Often unnoticed, these pink algae crusts help to cement coral reefs together, providing extra support and...
The open ocean is surprisingly barren to the naked eye. Every now and again you will encounter a school of fish and their attendant predators, but most of the life that you find is gathered around...
Around 100 million years ago, grass from land adapted to live and reproduce while submerged in seawater—the modern-day seagrasses. This sea invasion by land plants happened four separate times,...
Stare at a tide pool and you will often see a crust of pink coating the bottom. No, this is not bubblegum from some careless teenager’s shoe: it’s a stony kind of seaweed that, like other seaweeds,...
Unlike the green, leafy algae we're used to seeing on the seafloor, coralline algae has a hard crust—which you can see here at the molecular level in a photo from a scanning electron microscope. Each...
A strain of this green seaweed, native to the Indian and Pacific Oceans, escaped public and private aquariums in California, Japan, Australia, and Monaco. It has spread widely in the Mediterranean,...
A diet of algae and seagrasses gives this turtle ( Chelonia mydas ) greenish colored fat—and its name. Weighing as much as 500 pounds, the threatened green sea turtle lives its life at sea, with only...
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