More Algae

The Ocean Blog

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...
Macroscopic algae ( Ventricaria ventricosa ), also known as "bubble algae" or "sea pearl," is widespread algal species that can withstand low light. Each of the bubbles is a single cell, making it...
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...
Munch, munch. The queen parrotfish ( Scarus vetula ) scrapes algae from Caribbean coral reefs with its parrot-like beak. While feeding, hard stone and coral inevitably get mixed into its lunch, which...
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 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...
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...
What are corals? Corals themselves are animals. But tropical reef-building corals have tiny plant-like organisms living in their tissue. The corals couldn’t survive without these microscopic algae–...
The sargassum fish ( Histrio histrio ) is a member of the frogfish family (Antennariidae) and typically lives in open waters near floating sargassum seaweed, which offers camouflage. Although capable...
“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...
Macroscopic Algae ( Acetabularia crenulata ). More about mangrove ecosystems can be found in the Mangroves section .
Algae has overtaken this coral reef off heavily populated Kiritimati, or Christmas Island. Few fish swim in the murky waters. The causes include pollution, overfishing, and increased water...
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...
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...
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...
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...
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...
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...
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