Dinoflagellate

Dinoflagellates are microorganisms located in either fresh or salt water. They are the unicellular structures that are often referred to as algae. Their exact locations depend mainly on the temperature and depth of the water. A single characteristic which is the main reason for their classification is the flagellum that comes off of the inner part of their body. They are the main producers of the water, as they are small organisms that perform photosynthesis. Some of these can even be parasitic.

Anatomy
These microscopic organisms have a star-like shape with arms reaching out from the circular shaped body. The two arms are referred to as flagellum. The flagellum that forms off the posterior end is called the longitudinal flagellum and the flagellum that forms off the opposite end is called the transverse flagellum. 

They have a unique membrane made up mainly of condensed "vesicles" referred to as alveoli and an unusual nucleus usually known as the dinokaryotic nucleus. This means that it has neither a prokaryotic nor a eukaryotic nucleus. In the dinokaryotic nucleus, the chromosomes are packed together permanently within the membrane. A division of two plates of cellulose is made upon the cell wall. It is known as the theca. The odd nucleus of these cells remains the same throughout their lifetime and also has a large reason for their classifications. 

Dinoflagellates are photosynthetic creatures surrounded by three separate membranes. These membranes usually contain chlorophyll a and c and many other types of coloring pigments. Sometimes the chloroplasts have unusual types of color and build while others are seemingly colorless. All of these organisms, however, have the same structures as other known microorganisms (an endoplasmic reticulum, vacuoles for digesting food and lipids, mitochondria, and golgi.) Some even have an eye-like structure that is sensitive to the light. 

Life Cycle
When conditions in the dinoflagellates life become unstable (i.e. no food or light source), they have to change themselves dramatically. At this point, two of these organisms will form together, creating a "planozygote." Then it goes through another stage, which is much like that of hibernation, called hypnozygote. During this stage, the microorganism will take in fat and oils to change its shape and allow its case to become harder. When the circumstances in the weather change, the dinoflagellate will break out of the shell and take on its familiar form with the dinokaryote nucleus.

Reproduction
Dinoflagellates reproduce primarily by a process called fission, though some sexual and asexual reproduction may also take place at this time.  Any type of these reproduction processes happen mainly in the warmest parts of summer months. Millions of cells may be produced at a single time. Because of the great amount of reproduction at one time, the water in which they are produced in can appear to be a reddish or golden color. This is often referred to as the "red tide." 

Ecology


Dinoflagellates move by means of their flagellum. The transverse flagellum allows the micromachine to move forward or backward by spinning in circles in order to propel it in either direction. The longitudinal flagellum acts mainly as its means of steering. It also provides extra pressure to help force it in the direction it wants to head. 

There are two types of dinoflagellates known - heterotrophic and autotrophic. The heterotrophic organism eats and depends upon other types of organisms whereas autotrophs produce their own food by a process called photosynthesis, though some may be a combination of the two. 

These microorganisms can sometimes produce neurotoxins during red tide. These toxins will ultimately kill fish or infect those which humans eat, thereby passing the disease to the human. The red tide can increase with human input of salts and phosphate acid. When humans consume fish with these neurotoxins, it can be fatal. Medical and economic studies are being made on this particular subject in order to decrease the happenings of these red tides. 

However, not all types of these miraculous reproductive tides are harmful. At night, blue flashes may be seen in the ocean. This is because of the dinoflagellates ability to produce their own light. Much like the firefly, they contain the a substance bioluminescence which allows them seemingly to glow. These lights occur mainly when the dinoflagellate is disrupted.