One of the most important natural resources is water. It acts as a source of hydration for all living things and it can serve as a habitat for many. Oceans, rivers, lakes, ponds, and many other bodies of water are some examples. However, what microscopic life lives in the water? Are there miniature beasts that inspired tales of sea monsters? Or is it all just fantasy? Well, bodies of water ranging from still puddles to raging oceans all contain some form of microscopic life. The microscopic life can range from simple single-celled organisms to complex multicellular life forms. Either way, they are all essential parts of a natural ecosystem. Some examples of microorganisms include diatoms, ciliates, and rotifers. These creatures and their fellow microorganisms are many times smaller than a grain of sand, but they are an interesting part of the world.
Microorganism 1: Diatoms
The three organisms pictured here are all a microorganism called a “diatom”. These aquatic creatures have a clear silica shell. Silica (or “Silicon Dioxide”/SiO2) is a translucent, hard, and colorless compound. For comparison, the material is somewhat similar to glass. Diatoms are photosynthetic, meaning they can create chemical energy through a process as photosynthesis. By combining CO2 (carbon dioxide), H2O (water), and sunlight, they are able to create a sustainable source of energy for themselves. The diatoms pictured in A1 and A3 were both taken from Vasona Lake in Los Gatos, California. Their greenish-yellow pigment is caused by the chlorophyll encased within their shell. Both of the diatoms also have little oil bubbles within them, which are used to store energy for later use. Not only can they be found in freshwater environments, but they can also be found in saltwater areas. The diatom from picture A2 was taken from a saltwater environment in Sausalito, California. It’s anchored to a piece of seaweed, possibly so it does not get swept up by the ocean’s currents. Diatoms within Earth’s oceans are responsible for producing about 40% of all oxygen within them, which helps the ocean support the amount of creatures it has. Another thing to mention is that they are responsible for producing 50% of the oxygen humans breathe. Also, diatoms are sources of food for various forms of marine life. Needless to say, diatoms are a valuable part of any water-related ecosystem.
Microorganism 2: Ciliates
The creatures in the above pictures belong to a group known as “ciliates”, which are microorganisms that possess an organelle known as a “cilia”. These organelles look like little strands of hair and are similar to that of a flagellum. They can be used to move around within the water, or to gather food. Pictures B1, B2, and B3 feature some freshwater ciliates that were found in Vasona Lake. The ciliate in B1 moved slowly, meaning it most likely used its cilia for collecting food and feeling the surrounding environment. However, the ciliate in B2 is almost the exact opposite, since it moved by spinning its cilia rather than using them to gather food. Picture B3’s microorganism does something completely different all together. It spun its cilia in a circular motion to suck in its prey into its food vacuole. Also, the ciliate in Picture B1 has some algae within itself. They share a mutualistic relationship since the ciliate provides a safespace for the algae and the algae provides the ciliate with some products of photosynthesis. Most ciliates are not harmful, but a very small amount of them have a parasitic nature towards other organisms. Another thing to note is that they are protozoans, meaning they are single-celled organisms. They may have a singular cell, but they’re somewhat complex even when compared to some multicellular organisms. The ciliates are another essential part of the aquatic microscopic world.
Microorganism 3: Rotifers
The picture above displays a micro-animal called a “Rotifer”. Rotifers are filter-feeders that can be found in lakes, ponds, rivers, or virtually any body of water. Most dwell in freshwater environments, but some species have been seen in saltwater areas since they are primarily an aquatic species. They’ve also been seen in films of water on mosses, lichens, and even some detritus. In order to filter feed, the rotifers spin a cilia-covered organelle called a “corona”. Parts of their diet include deceased microorganisms, bacteria, and algae. They have a tail-like structure on the end of their body with two toes sticking out at the bottom. The toes act as anchors so that the rotifer can stay in one place without being moved. The rotifer in C1 was found within a sediment sample taken from Vasona Lake. It moved quickly from one spot to another on the slide, hinting at the idea that it was searching for food. However, some rotifer species swim differently than others. For example, the Macrotrachela Quadricornifera moves by inching itself places whereas Brachionus Calyciflorus glides through the water. Despite their small size, these creatures are actually complex, multicellular organisms. The name “rotifer” comes from the latin word meaning “wheel-bearer”, which relates to the aforementioned crown of cilia on it. About 2,200 different species of rotifers have been described, most being 0.1 millimeters to 0.5 millimeters long. However, the species known as Rotaria neptunia could grow a little longer than a millimeter. Without them, bacteria populations would explode out of control and bodies of deceased microorganisms would plague an environment. Rotifers are valuable predators and scavengers needed in any micro-ecosystem.
Diatoms, ciliates, and rotifers are only a couple types of microorganisms that can be found within an aquatic ecosystem. In a mere couple drops of water, a small world could unfold before one’s eyes. Despite their sizes, they help support entire ecosystems by playing their role in nature. Needless to say, the microscopic world is incredibly diverse with its numerous amounts of species helping the world.