Water ecosystems, specifically freshwater ecosystems, are some of the most important resources in the replenishment and purification of water sources used by humans. Unfortunately, the sustainability of a large amount of these ecosystems is being negatively affected by land development. Increased use of underground aquifers, creation of water-diversion systems, industrial and household waste water contamination, and the eradication of wetlands and marsh areas all pose a threat to these ecosystems that help to provide us with fresh water.
So how exactly do these freshwater ecosystems purify our water? Well many pollutants including metals, sediments, nitrogenous compounds, oils, and viruses are all able to enter freshwater sources in one way or another. As this (now polluted) fresh water flows through natural wetlands, woodlands (also called Riparian Forests), and manmade wetlands, many of these pollutants are filtered out by the organisms in each of these environments.
Wetlands have the highest degree of species diversity of any ecosystem comprised of a wide variety of flora and other hydrophytic fauna. One of the main functions of wetlands is to remove metals and sediments that make their way into water. In fact, natural wetlands are able to eliminate 20-60% of metal, 70-90% of nitrogenous compounds, and around 90% of sediment from freshwater sources. Coastal wetlands, such as saltmarsh and mangroves, are likely to have the highest rates of greenhouse gas capture and containment, and the drainage of these wetlands would turn them from carbon containers into carbon sources, further harming the ozone layer and speeding up the global warming process. Wetlands also reduce the risk of flooding greatly by retarding the movement of floodwaters towards nearby residential areas. These ecosystems are also extremely important sources of biodiversity in terms of the microbes, flora, and fauna living in them. Imitation (or manmade) wetlands essentially serve the same purpose, although they do so on a much smaller scale and can not serve as a replacement for natural wetlands by any means. Back in the 1600s, before extensive population and development of the land occurred, the U.S. housed over 220 million acres of wetlands. Unfortunately, many natural wetlands are disappearing at an alarming rate due to commercial land development and today less than half of the nation’s wetlands are still around.
This photo depicts how wetlands purify the water that flows through them.
Another freshwater ecosystem that is extremely important in helping to purify sources of water is that of Riparian forests or, more specifically, Riparian forest buffers. These buffers are actually woodlands surrounding bodies of water that consist of trees, shrubs, and grass plantings that provide protection of aquatic resources from adverse impacts from things such as land development. These buffers are also able to filter out large quantities of sediment, pesticides, nitrogen, phosphorous, and other potentially harmful materials from the shallow subsurface of the water which they surround. Temperature regulation in cold water rivers and streams, prevention of bank erosion by holding soil in place and absorbing the shocks from flow action, and an increase in species biodiversity are just several of the additional benefits provided by the forest buffers.
This photo depicts the various zones of a Riparian forest buffer, and generally shows what the buffer should look like.
In conclusion, there are lots of important freshwater ecosystems out there that provide us with a majority of the drinking water that we use in day to day life and these valuable resources are very quickly being depleted not only in the U.S., but worldwide. Unfortunately, not many people are aware of the importance of things such as marshes or Riparian buffers and as a result, not much is being done to protect these ecosystems and the species that live there.
While I am talking about deforestation and the wide variety of forests, I have not touched not he topic of Riparian forests. They are interesting and unique systems in themselves. I did not realize the severe depletion wetlands in addition to forests that was occurring. It is an understatement to say that an ecosystem will fail without plants; it will be desiccated and non existent. The animals, insects, plants, and nutrients in the world around us used tone in perfect balance and thrive. Over the past several decades, we have ruined many beautiful habitats and species. I agree with Erica in saying that we need to be reactive…we have no other option at the point. To end with a favorite quote of mine: “If all the insects were to disappear from the Earth, within fifty years all life on Earth would end. If all human beings disappeared from the Earth, within fifty years all forms of life would flourish.” — Jonas Salk
I’ll be quite honest in saying that I had no idea that wetlands and the forests surrounding bodies of water played such a big role. With that in mind, its a shame that not much is being done to protect them. It is a little saddening that we take everything beneficial wetlands do for us for granted while we continue to deplete them at an alarming rate. Its clear that the benefits of these systems is substantial and if people were aware of that, I’m certain more efforts would be taken to preserve them. I think its amazing that nature has organisms and ecosystems that filter out contaminants in our fresh water supply. The fact that they also double in slowing down flooding is even more fascinating. Hopefully more efforts will be taken in the future to preserve these wonderful ecosystems.
It’s remarkable as to how Earth can filter such pollutants in a natural manner. From wetlands to Riparian buffers (using this phrase allows me to sound more intelligent), the processes for purifying elements that contaminate our water supply. However, you raise an accurate point in that many people (like me) have not even come across these effects prior to reading about this. If we raise awareness soon, there’s a very good likelihood that our future with fresh water supply will be in a better state. These multifaceted systems are essential for our living, but work diligently without us knowing.
This was a very interesting post. I have long been interested in ecology and have always recognized the benefit of water sheds and their related ecosystems. It is amazing without plants how much of a toll erosion can take and destroy an environment (like Haiti). I liked that you talked about fertilizers and heavy metals being filtered through freshwater ecosystems. The efficacy of such systems are such that they are now used as a primary and secondary filter for sensitive habitats. In Singapore, for example, they use both fresh and salt water systems to filter and diagnose runoff from landfill areas. I think what is most amazing about these ecosystems are their roles as sponges, absorbing and slowly releasing excess water in times of flooding. I think this post is a great example of the ecological niches we ignore daily, but heavily rely upon.
I had never heard of Riparian forests! Very interesting. The depletion of wetlands is a huge issue in current society and you captured it beautifully. For the past several years, I have been a counselor at a natural resource conservation summer camp, and the rapidly declining number of wetlands is always a huge topic of discussion. I guess that, unfortunately, by this point, we are forced to be reactive rather than proactive with the issue.