The Algae

These are aquatic photosynthetic eukaryotic organisms without stems, roots or leaves. You might be more familiar with them as SEAWEED and PHYTOPLANKTON. These organisms are major PRODUCERS OF OXYGEN for the atmosphere and they are a vital FOOD SOURCE for many marine creatures. Some algae are single celled organisms and others are multicellular. The single cell varieties are classified in the kingdom PROTISTA and the multicellular species are classified in the kingdom PLANTAE.

PHYCOLOGISTS divide algae up into the following divisions:

Chrysophyta - the GOLDEN ALGAE and the DIATOMS. Many of these algae are able to concentrate silica from sea water and build intricate shells with it. Diatoms are used as polishing agents and are incorporated into reflective paints.

Euglenophyta - These little single cell FLAGELLATES are capable of both plant-like photosynthesis and animal-like ingestion and movement.

Pyrrhophyta - The DINOFLAGELLATES or the sea whirlers. These single cell marine and fresh water organisms have a silica shell and two flagella which they use to whirl about with. RED TIDES are associated with BLOOMS of certain dinoflagellate species (Gymnodinium and Gonyaulax) which contain red pigments and a powerful neurotoxin. The toxin, which does not harm the shellfish which feed on the dinoflagellates, paralyzes the striated muscles of people who consume the shellfish. This "paralytic shellfish poisoning" is characterized by numbness of the mouth, lips, face and extremities.

Another dinoflagellate, Gambierdiscus toxicus, is responsible for CIGUATERA POISONING. This lipid-like toxin accumulates in the flesh of fish that eat the dinoflagellate without any apparent harm to the fish. Human consumers of the fish flesh will suffer gastrointestinal disturbances, diarrhea, central nervous system disturbances including sensory disturbances, myalgia and face pain sometimes for many months after eating the fish. Cooking the fish does not destroy the toxin. The only test for tainted fish was developed by the UH researcher Yoshitsugi Hokama. Unfortunately this valuable test cannot be marketed nor used because it is caught up in patent rights litigation.

Other dinoflagellates are noted for their BIOLUMINESENCE and there are varieties that live as symbionts inside the cells of corals, clams and other marine animals.

Chlorophyta - The GREEN ALGAE are a huge group of fresh water, marine and even some soil species. Many of these are single celled but some are multicellular - including the various green seaweed varieties.

Phaeophyta - The BROWN ALGAE are multicellular marine seaweeds and kelps.

Rhodophyta - The RED ALGAE are primarily multicellular and marine. These organisms make a number of commercially valuable products including AGAR and CARRAGEENAN which are used in the food industry (and microbiology labs). Recently they have become sources of the phycobilin fluorescent dyes phycoerythrin and phycocyanin which are used in medical research. These dyes or pigments are actually photosynthetic pigments which the algae use to capture the green, violet and blue light in deep water.

PHOTOSYNTHESIS

Photosynthesis is the process by which light energy is trapped and converted into chemical energy. Usually this is accompanied by the reduction of CO₂ (CO₂ is fixed) and the production of glucose. The process of photosynthesis will make ATP, NADPH₂ and O₂.

Photosynthesis can be divided into two parts:

The LIGHT REACTION:

CHLOROPHYLL captures red and blue light energy and uses the energy oxidize water. The electrons and hydrogens from the water are used to make ATP and NADPH (chemical energy). The Oxygen from the water is a waste product.

The DARK REACTION - (Also called the Calvin-Benson Cycle):

Here the chemical energy of the Light Reaction is used to convert CO2 into glucose.