Algae

Algae is the common name for aquatic, photosynthetic organisms from the taxonomic kingdoms Protista or Plantae. It is one of the most important organism alive today because not only is algae responsible for much of the Earth's oxygen, they are also food for almost all other aquatic life and an original source of petroleum products. Besides being food for the many creatures that live in the ocean some algae help coral reefs grow and stick together by working as an adhesive .Algae can vary from a very small microscopic size to a 50 meter strand of seaweed.Algae can be very helpful to our planet, but can also produce toxins that can be very harmful. Algae live everywhere and are present in most of the bodies of water. Algae is also used to create dynamite after the organism has fossilized. Besides living in the water algae are able to survive in snow and even boiling water.

Anatomy
Algae are unicellular beings that either live alone or assembly themselves into colonies. They possess chlorophyll and their color is accounted on the type of algae that it is. For example, the color of Green Algae can vary from green to light green and from yellowish to brownish green. Algae also do not possess true roots, stems, and leaves. The types of Tropical Reef Algae can be classified into these 3 groups: crustose coralline algae, algal turfs, and macroalgae. They also lack vascular structures. Not all algae are small, some can even be 50 meters in length. An example of that is some of the seaweed found in the ocean. Another type of algae, a diatom, are single celled beings that have a silica shell.

Reproduction
Algae are able to reproduce sexually and asexually. Sexual reproduction in algae is very rare because of the complexity of gamete transportation and because of this most algae may never get to reproduce sexually. There are two types of asexual reproduction in which algae take part in, they are daughter colony formation and sporulation. In daughter colony formation a group of algae will begin to create small duplicates of itself inside of the parent algae. After a while the parent will burst and let loose the daughter algae. Aside from daughter colony formation, algae also use sporulation as a means to reproduce. Sporulation is used by algae more than daughter colony formation. It consists of the parent algae creating reproductive cells within the cell walls. The zoospores(reproductive cells) escape from the parent cell and attach themselves to surface where they turn into filaments. Algae also reproduce sexually and the combination of gametes identifies isogamy and heterogamy,which are two classes of sexual reproduction. Isogametes are gametes that are alike in size and shape. In isogamy, the gametes that are being combined do not have any physical peculiarity amid male and female gametes. The isogametes side with each other's flagellar extremities touching and after a short time they form one, immobile diploid zygote. Unlike isogamy, heterogamy is the uniting of a male gamete and a female gamete. The algae produces sperm in large amounts and the egg cell that is produced is bigger than the sperm and unlike the sperm cell, it is immobile.

Ecology
Problems that some corraline algae have is a lack of space to grow. These algae will grow anywhere, and because of that some of them may collide with each other. One thing that may happen when these two coralline algae collide is that both of them may stop growing. This is bad because one job that coralline algae have is helping keep coral reefs grow and helps hold them together. Besides that, another thing that may happen to them is that one coralline algae will try to grow over the other. Sometimes when this happens one of the is knocked off or even cracked. Many small marine invertebrates use the coralline algae as a means of obtaining food and if they are destroyed then the animals will not be able to get the food that they need. Another important thing that corraline algae do is manufacture chemicals that help provoke metamorphosis in some marine animals.

Some algae can be harmful to humans and animals, but both rely on algae. Since algae are plants, they participate in photosynthesis. Algae is present everywhere within the oceans and since the oceans take up a about 71% of out entire planet surface, most of the oxygen that is found in our atmosphere is created by algae. Algae is also used in place of very deadly chemicals at waste treatment facilities. Also, it is used at powerplants to help control and decrease CO2 emmisions.

Red Tide
Many sea animals depend upon these microscopic autotrophs as a source of nutrition. However, if circumstances are right then some of these algae can manufacture toxins that are harmful and even deadly to the creatures living in the sea. These are called harmful algal blooms. One characteristic of harmful algal blooms is that they can form in large amounts and if there are many algae manufacturing these harmful toxins, the result can be very tremendous. Not all harmful algal blooms are red. It really depends upon the species of algae that it is. The color of these blooms can be greenish brown or even reddish orange. Red Tide can even affect human health. If someone consumes one of the infected fish it could cause serious sickness. Birds that consume the fish could go infect other birds. One case of this was on 1947 in Venice, Florida. The beaches were covered with thousands of dead fish. The toxins released by these organisms may cause a feeling of burning in the eyes, nose and a very strong, dry cough. Red Tide affects all oceans worldwide and has been the cause of death for whales, dolphins, and manatees in the waters of North America. The tide can travel and be very hard to control unless it is in a secluded place. 

Lichen
Algae join with fungi to form lichen. "Trebouxia is the algal genus present in the majority of lichen species worldwide." One researcher found approximately 30 species of the Trebouxia algae worldwide.