Algae: Difference between revisions

Algae has several applications in sustainability:

• Carbon capture of carbon-rich waste streams
• Carbon sequestration - Algal blooms trapping carbon and storing it on the ocean floor.
• Algae fuel (biofuel)
• One of the organisms of importance in wastewater treatment
• Production of paper

Pond scum to the rescue

More on this soon as J. Craig Ventner is on 'it'. He is working "in the Lab" on this and states that at least ten years are needed for some form of completion.

For perspective, Protists solely occupy Chapter 26 out of the total 33 Chapters in this example [ of a book - The Microbial World - Fifth Edition - Stanier, Ingraham, Wheelis and Painter - Prentice-Hall - 1957 to 1986 - excerpted below. ]

One step up from Bacteria we find The Protists. These are microorganisms with a eukaryotic Cell structure; they perform oxygenic photosynthesis and possess chloroplasts.

Their morphology may be unicellular, filamentous, colonial, or coenocytic, while some may have a plant-like structure. There are numerous transitions between algae, protozoa and fungi.

Classification

The primary classification of algae is based upon Cell properties: the chemical nature of the Cell wall {if present}, the organic reserve materials produced by the Cell, the nature of the photosynthetic pigments, and the nature and arrangement of the flagella borne by motile cells.

These properties are compartmentalized in these categories:

1) The photosynthetic flagellates: Marked leaf shaped polarity; includes Euglenophyta: Euglena;

2) The non-flagellate unicellular algae: Either immotile or motion by other means: includes specialized and elaborate Desmids (Chlorophyta) and Diatoms (Chrysophyta);

The Natural Distribution of Algae:

Most algae are aquatic organisms that inhabit either fresh water or the Oceans. These aquatic forms are principally free-living, yet certain unicellular marine algae have established durable symbiotic relationships with specific marine invertebrate animals (e.g., sponges, corals, various groups of marine worms) and grow within the Cells of the host Animal. Some terrestrial algae grow in soil or on the bark of trees. Others have established symbiotic relationships with fungi, to produce the curious, two-membered natural associations termed lichens, which form slowly growing colonies in many arid and inhospitable environments, notably on the surface of rocks.

The marine algae play a very important role in the cycles of matter on Earth, since their total mass (and consequently their gross photosynthetic activity) is equal to that of all land plants and is probably much greater. This role is by no means evident, because the most conspicuous of marine algae, the seaweeds, occupy a very limited area of the Oceans, being attached to rocks in the intertidal zone and the shallow coastal waters of the continental shelves. The great bulk of marine algae are uniCellular floating (planktonic) organisms, predominantly diatoms and dinoflagellates, distributed through the surface waters of the Oceans. Although they sometimes become abundant enough to impart a definite brown or red color to local areas of the sea, their density is usually so low that there is no gross sign of their presence. It is the enormous total volume of the Earth's Oceans which makes them the most abundant of all photosynthetic organisms.

The Nutritional Versatility of Algae

The ability to perform photosynthesis confers on many algae very simple nutrient requirements, in the light they can grow in a completely inorganic medium. However, many algae have specific vitamin requirements, a requirement for Vitamin B12 being particularly common. In Nature the source of these vitamins is probably bacteria that inhabit the same environment. The ability to perform Photosynthesis does not necessarily preclude the utilization of organic compounds as the principal source of carbon and energy, and many algae have a mixotrophic metabolism.

Even when growing in light, certain algae (e.g., the green alga Chlamydobotrys) cannot use CO2 as their principal source of carbon and are therefore dependent on the presence of acetate or some other suitable organic compound to fulfill their carbon requirements. This is caused by a defective photosynthetic machinery: although these algae can obtain energy from their photosynthetic activity, they cannot obtain the reducing power to convert CO2 to organic Cell materials.

Many algae that perform normal photosynthesis in the light, using CO2 as the carbon source, can grow well in the dark at the expense of a variety of organic compounds; such forms can thus shift from photosynthetic to respiratory metabolism, the shift being determined primarily by the presence or absence of light.

The Leucophytic Algae

Loss of the chloroplast from a eukaryotic Cell is an irreversible event, which results in a permanent loss of photosynthetic ability. Such a change appears to have taken place many times among unicellular algal groups with a mixotrophic nutrition, to yield nonpigmented counterparts, which can be clearly recognized on the basis of other Cellular characters as nonphotosynthetic derivatives of algae. Such organisms, known collectively as leucophytes, exist in many flagellate groups, in diatoms, and in nonmotile groups among the green algae. The recognition of leucophytes is often easy, since they may have preserved a virtually complete structural identity with a particular photosynthetic counterpart.