Bacteria

Little is known about Bacteria on The Great Barrier Reef as very few people are currently doing research in this field. Bacteria are possibly the most important form of life on the planet. They are found globally, in every habitat and under every condition and play an important role within the bodies of other organisms, including corals and other reef organisms. Without them, life as we know it, could not exist. They are small, microscopic, single-celled organisms, many of which, serve a positive purpose, such as aiding digestion. Others however, can cause disease and death. Some species form giant structures, such as mats and some Cyano-Bacteria are even capable of forming entire reefs (Stromatolytes).^1,2

Structure

Bacteria are Prokaryotes, meaning that their DNA is not held within a nucleus. Instead, it floats freely within the cell, twisted into a Nucleoid. There are generally no membrane-bound organelles found within Prokaryotes, although this is not true for all species. Planctomycetes, which is associated with “Marine Snow”, may contain organelles. Ribosomes are also present, which build proteins from Amino Acids.

They come in a wide range of shapes, including, rods, spheres and spirals.

Biology

Bacteria can produce energy from a wide range of sources, which enables them to thrive in even extreme conditions. Many are Autotrophs and make energy directly from Carbon Dioxide, in a similar way to plants. Others are Heterotrophs, consuming other matter like an animal does. There are even some Autotrophs that can produce energy using chemicals in the absence of light! It was previously thought that light was a necessity of life, but we now know that this is not the case, with some bacteria producing energy in the depths of the oceans where no light reaches.

Reproduction

Bacteria generally reproduce through Binary Fission. This is where the DNA is replicated and the cell increases in size, doubling all of its components. This cell then split in two,giving two genetically identical organisms. They may also reproduce through budding, or fragmentation. Another trait that separates Bacteria and Archaea, is the ability to produce spores that may lie dormant for long periods.

Importance

Bacteria play a vital role in our oceans, much like they do on land. They are responsible for the decomposition of organic mater, allowing it to re-enter the food web and be recycled. The Autotrophs directly produce energy and play a significant role in primary production.^1,2