Mayfly populations falling fast in North America

A team of researchers from the University of Oklahoma, Virginia Tech and the University of Notre Dame has found that populations of mayflies in parts of North America have fallen dramatically in recent years. In their paper ...

Blue-green algae found to produce greenhouse gas methane

An international team of researchers has found that cyanobacteria (blue-green algae) produce the greenhouse gas methane. In their paper published in the journal Science Advances, the group describes tests they carried out ...

Large 'herbivores of the sea' help keep coral reefs healthy

Selective fishing can disrupt the delicate balance maintained between corals and algae in embattled Caribbean coral reefs. Removing large parrotfish, which graze on algae like large land mammals graze on grasses, can allow ...

How do corals make the most of their symbiotic algae?

Corals depend on their symbiotic relationships with the algae that they host. But how do they keep algal population growth in check? The answer to this fundamental question could help reefs survive in a changing climate.

Structures in seaweed shed light on sustainability

Brown algae are not just seaweed that float in the ocean and tangle swimmers' feet—they also contains a secret. In its cell wall, brown algae hold the polysaccharide alginate, one of the most abundant carbohydrates in the ...

Image: Baltic blooms

The Copernicus Sentinel-2 mission takes us over the green algae blooms swirling around the Baltic Sea.

Scientists reveal the structure of viral rhodopsins

The structure of an Organic Lake Phycodnavirus rhodopsin II (OLPVRII), which is a unique protein found in the genome of giant viruses, has been determined thanks to the work of MIPT graduates and Ph.D. students. The paper ...

Scientists clarify light harvesting in green algae

Algae are indispensable because they generate about 50% of primary organic matter and account for about 50% of all oxygen on Earth. They produce oxygen through oxygenic photosynthesis—a biological process that "harvests" ...

Health threat from blue-green blooms extends beyond single toxin

As blue-green algae proliferates around the world, a University of Saskatchewan (USask) researcher cautions that current municipal drinking water monitoring that focuses on a single toxin associated with the cyanobacteria ...

page 1 from 23

Algae

Algae (pronounced /ˈældʒiː/; singular alga /ˈælɡə/, Latin for "seaweed") are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are currently excluded from being considered plants.

Though the prokaryotic Cyanobacteria (commonly referred to as Blue-green Algae) were traditionally included as "Algae" in older textbooks, many modern sources regard this as outdated and restrict the term Algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group, as they do not include all the descendants of the last universal ancestor nor do they all descend from a common algal ancestor, although their chloroplasts seem to have a single origin.

Algae lack the various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have limited or no photosynthetic apparatus.

Nearly all algae have photosynthetic machinery ultimately derived from the Cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria. Fossilized filamentous algae from the Vindhya basin have been dating back to 1.6 to 1.7 billion years ago.

The first alga to have its genome sequenced was Cyanidioschyzon merolae.

This text uses material from Wikipedia, licensed under CC BY-SA