Humans have a large impact on estuaries.
Humans like living near estuaries which is why they are so threatened by us. Estuaries are the final impact of human activities throughout the catchment. This means that the estuaries use the surrounding environment such hills and rivers drain into them. Pollution runs down into the estuaries, damaging their cleanliness and ability to home some creatures including cockles which are indicators of the water because they can only live in clean water.
Another effect that humans have on estuaries is erosion. Erosion is when the banks of the estuary disintegrate, causing the shorelines to creep further and further into the mainland and making the water muddier. Humans impact the rate of erosion by chopping down trees which hold the banks together and stop the mud from flooding away. When humans chop down trees and plant grass in its place as they have done to many areas around estuaries, the land isn't held together as securely and strongly by the grass as it was by trees. This increased erosion increases the turbidity of the water as well affecting plant and animal communities. Although humans have many visible effects on estuaries, there are many effects that humans have on estuaries that are not immediately apparent. By this, I mean when organisms are no longer in the estuary because they cannot survive there. This may be due to a change in habitat or any other environmental change caused by humans. For example cockles are what is known as an indicator because they indicate how clean the water is. The cockles filter our the water, removing minute particles of live and dead organic material from the water to keep the estuaries as clean as possible. When the estuaries become too polluted, the cockles are unable to filter the water properly as they get too blocked up with the pollution. If all the cockles die out, they are unavailable for the other creatures in the ecology to eat, therefore impacting their ability to survive. This shows how important every trophic level is and without even a single type of one species, the whole food web is impacted. Humans disrupt the natural ecology of the estuaries, therefore endangering the estuaries. |