The designated uses of each water body then determine which parameter that a standard will be based on. Think of a parameter as a characteristic of a waterbody. A waterbody contains all sorts of things including dissolved oxygen, dissolved salts, nutrients, organic matter, algae, sediment, and fecal coliform bacteria (bacteria from the intestines of animals and birds). This is not necessarily bad and each water body characteristic or parameter can be important part of fueling the larger ecosystem. However, an excess or imbalance of certain parameters can be bad for the waterbody and the ecosystem. For instance, dissolved oxygen will have the most significant impact, compared to other parameters, on the health of fish and aquatic organisms. So, if a waterbody has low dissolved oxygen, it will probably lead to low fisheries productivity or fish kills. This is why standards have single parameters that relate back to the designated use.