Algae and Cyanobacteria

Guide to the Oceans, by Dr. John Peretta, is just that, a referencework, rather than a detailed treatise on any particular oceonographical subject. But I'm using it as a starting point for such discussions, starting with the inhabitants of the oceans, with segues into coastal geography, underwater research, etc. which I hope will tie together chronologically and interestingly.

The modern study of marine and freshwater algae is called either phycology or algology.

According to Guide to the Oceans:

Cyanobacteria (blue-green algae) photosynthesize. Not all are blue-green, some are yellow, red, purple or black, depending on the type of photosynthetic pigments they contain.

Cyanobacteria used to be considered algae (when it was called blue-green algae), but is now classified as bacteria. They are prokaryotes.

What is algae, and when was the term coined. Looking the word up at Dictionary.com will tell us:

any of numerous groups of chlorophyll-containing, mainly aquatic eukaryotic organisms ranging from microscopic single-celled forms to multicellular forms 100 ft. (30 m) or more long, distinguished from plants by the absence of true roots, stems, and leaves and by a lack of nonreproductive cells in the reproductive structures: classified into the six phyla Euglenophyta, Crysophyta, Pyrrophyta, Chlorophyta, Phaeophyta, and Rhodophyta.

and the origin of the word:

algae : (plural), 1794, from alga (sing.), 1551, from L. alga "seaweed," of uncertain origin, perhaps from a PIE base meaning "to putrefy, rot."

and fron the Science dictionary:

Any of various green, red, or brown organisms that grow mostly in water, ranging in size from single cells to large spreading seaweeds. Like plants, algae manufacture their own food through photosynthesis and release large amounts of oxygen into the atmosphere. They also fix large amounts of carbon, which would otherwise exist in the atmosphere as carbon dioxide. Algae form a major component of marine plankton and are often visible as pond scum and blooms in tidal pools. [Land species mostly live in moist soil and on tree trunks or rocks. Some species live in extreme environments, such as deserts, hot springs, and glaciers.]

Although they were once classified as plants, the algae are now considered to be protists, with the exception of the cyanobacteria, formerly called blue-green algae. The algae do not form a distinct phylogenetic group, but the word alga serves as a convenient catch-all term for various photosynthetic protist phyla, including the green algae, brown algae, and red algae.

And of course that definition gives rise to another question...what does "protist" mean?

any of various one-celled organisms, classified in the kingdom Protista, that are either free-living or aggregated into simple colonies and that have diverse reproductive and nutritional modes, including the protozoans, eukaryotic algae, and slime molds: some classification schemes also include the fungi and the more primitive bacteria and blue-green algae or may distribute the organisms between the kingdoms Plantae and Animalia according to dominant characteristics.

Note that the purpose of this blog is to chronicle the history of marine exploration, so I'm not so much interested in what algae and cyanobacteria are (and to find out you need to buy text books that cost hundreds of dollars!) but rather when and where they were discovered, formally given their names, and so on.

It is not just modern-day scientists of the 1800s onward who knew algae, the Greeks and others studied it as well...