The Extinction of Oysters

oysters filter water

Oysters are filter feeders that filter water naturally as they feed.

Yes, you read that right. According to a recent study of oyster habitats around the world, these mollusks are disappearing, and 85 percent of their reefs have been lost due to over-harvesting and disease. Most of the remaining oysters in the world can be found in five locations in North America.

The study involved an international team of researchers led by Michael Beck of the Nature Conservancy and the University of California, Santa Cruz. They examined the condition of oyster reefs in 40 ecoregions and found that they are at less than 10 percent of their prior abundance in most places.

While they are not officially extinct, the researchers claim that they are “functionally extinct”, meaning they lack any significant ecosystem role. What does that mean for us? Well, besides the fact that they provide food and employment to people living in coastal areas, oysters are important to ecosystems because they are some of nature’s best water filters. Known as “filter feeders”, they consume harmful pollutants while feeding. As we have mentioned before, an adult oyster can filter up to 60 gallons of water a day, which is more than most reverse osmosis filters can do. In addition to the mollusks, themselves, oyster reefs are also constructed to naturally purify contaminated waters.

In order to avoid complete extinction, any reefs with less than 10 percent of former abundance should close to further harvesting until the numbers rise again.

Banana Sushi – An Edible Solution to Dirty Water

Banana SushiWe’ve written quite a few posts on natural water filters. Here are two more of nature’s best water filtration methods, more recently implemented by researchers:

Seaweed Water Purification

Stamford professor of ecology and evolutionary biology, Charles Yarish, believes that seaweed could be the next revolutionary trend in water purification technology. His method, termed ‘extractive aquaculture’ or ‘bioextraction’, uses seaweed as its main component, and may effectively clean up pollution in waterways from both natural waste and human sources. How does it work? The same way that shellfish do: by extracting organic and inorganic nutrients from from seawater. Although nutrients are generally regarded as beneficial to organisms, too many of them may contribute to the growth of harmful algal blooms, which deplete oxygen in water. Although bioextraction itself ¬†is not new (it has been used before by ancient cultures in Egypt and China) Yarish’s method of bringing together plants and animals on different levels of the food chain into one place, in order to achieve purification in specific areas, is quite innovative, and will allow aquaculture to function more like a natural ecosystem.

Banana Peels Filter Water

All this time, we thought banana peels were useless… well except in the game of Mario Kart. Not anymore, thanks to the discovery of Milena Boniolo, a chemist from the Federal University of Sao Carlos, near Sao Paulo, Brazil. When dried and ground into a powder, banana peels have the ability to decontaminate polluted water by at least 60 percent. The process may be repeated until the water is purified almost completely. Banana peels are rich in negatively-charged molecules, which attract the heavy, positively-charged metals present in contaminated water. Considering that restaurants alone may discard tons of banana peels on a daily basis, this natural method could introduce a much-less expensive alternative to current water filtration technologies.

Put these two methods together, and what do you end up with? Banana Sushi – an edible solution to dirty water.

Over the course of one year alone, we have discovered quite a few natural ways to purify water. I’m sure there will be more to come, so stay tuned, and bookmark this tag in your browser for updates.