Seston - The Particles In The Water 

Episode I - Seston:
In this episode we look at seston, the particles in the water column. We discuss how they are made and used, and their role in the marine environment.
Script:
Have you ever wondered how the circle of life operates in the ocean? Where does food come from and how do the organisms that live there use it?
4. Particles in the water
The particles that exist in the water column are essentially the building blocks of life for those animals that make their home in the ocean. These particles, both living and non-living, can provide food to the animals that eat them, construction materials out of which some animals make their homes or, they can represent homes to a vast number of micro-organisms that live on their surfaces. Collectively, these particles are known as seston.
5. How are they created
The particles in the ocean are created through a combination of physical and biological processes. On the physical side, many smaller particles may be created from larger ones through the turbulence caused by the crashing of a wave or by the mixing of water currents as they are forced through narrow passages. Others are produced by the slow disintegration of larger particles over time.
On the biological side, particles are created by small plants called phytoplankton as they capture energy from the sun and create more and more through their reproductive activities. When the particles die, either naturally or by being eaten, they enter the food chain where the basic feeding, reproductive and dying processes produce even more particles of different sizes.
6. Why are they important
One of the most important functions of particles is that they are the main method for transferring food energy from one organism to another. Whether they are microscopically small or large enough that you could see one sitting on the end of your finger, there are many living things that have adapted to utilize particles.
7. What are they made of?
Most seston in the water is made up of a combination of both organic and inorganic components.
The inorganic components are from mineral origin and are essentially any small particles of silt or mud that are suspended in the water column.
The organic components are from a biological origin and can be either living or dead. Live particles may be phytoplankton microbes, larvae, phytoplankton or fungi. The dead components are the remains of other organisms or their digestive waste. Sometimes, many of these components are bundled together with organic glue produced by phytoplankton into structures known as marine snow or flocs.
8. Who uses them [scallops, mussels, tunicates, corals, cukes]
Seston is used by many species in their day-to-day activities. The many organisms that use seston can be extremely varied and beautiful. You may have seen many of these while walking along the shore, at the grocery store or visiting an aquarium. Some examples include barnacles, mussels, scallops, corals, sea anemones, sea squirts or tunicates, and sea cucumbers. Many different kinds of fish and even some of the largest animals on earth, whales, feed on relatively small particles in the ocean.
9. What effects do they have
Each particle of seston can be a tiny meal. Food energy is tied up in the organic portion of these particles; the higher the organic content, the richer the meal. After all there's not much nutritional value in sand. When any organism has an abundance of high quality food, there are much fewer restrictions to growth and reproduction. As a result, an abundance of rich particles can promote high species densities which can contribute significantly to the local ecosystem.
10. Why are too many particles bad
But you can have too much of a good thing! When humans influence the aquatic environment with their activities such as fishing, farming, land inputs and energy development; particle concentrations may increase dramatically. If the local habitat cannot support enough organisms to consume this large influx of organic particles, then the local ecosystem can become destabilized and impacted. Particulates can then accumulate and create conditions that are physically and chemically unattractive to many of the natural organisms that would normally live there.
One solution to dealing with any excess food production has already been invented by Mother Nature with the creation of food webs for the recycling of this energy. Understanding how to create these situations is the goal of ecological engineering.
11. Conclusion
Seston is one of the foundations for all life in the marine environment and its existence is critical to healthy operation of ecosystems. By understanding the role of seston in natural food production, we can learn how to imitate natural ecosystems and to foster more sustainable food production for humans.