They excrete their ammonia waste in the form of urea in water hence they are ureotelic in water.

Aquatic reptiles, such as turtles, alligators, and crocodiles, have evolved certain adaptations to live in water. One of these adaptations is their ability to excrete waste products, specifically nitrogenous waste, in the aquatic environment. Aquatic reptiles are ureotelic in water, which means they excrete urea as their main nitrogenous waste product.

Ureotelism in water refers to the ability of aquatic reptiles to convert ammonia, which is highly toxic, into a less toxic form, urea, for excretion. This adaptation allows them to live in an aquatic environment without the risk of ammonia toxicity. Let's delve deeper into this concept:

1. Nitrogenous waste in reptiles:
- Reptiles, like all animals, produce nitrogenous waste as a byproduct of protein metabolism. This waste mainly consists of ammonia, which is highly toxic to cells.

2. Terrestrial reptiles and uricotelism:
- Most terrestrial reptiles, such as snakes and lizards, excrete their nitrogenous waste in the form of uric acid. Uric acid is a relatively insoluble compound, which allows reptiles to conserve water in their dry habitats.

3. Ureotelism in aquatic reptiles:
- Aquatic reptiles face a different set of challenges compared to terrestrial reptiles. In water, the excretion of uric acid would require a large amount of water, which is not desirable.
- Instead, aquatic reptiles have evolved the ability to convert ammonia into urea, a more soluble nitrogenous waste product. Urea can be excreted in a relatively dilute form, conserving water.

4. Adaptations for ureotelism in water:
- Aquatic reptiles possess specialized renal structures, such as well-developed kidneys and ureters, that aid in the excretion of urea.
- They also have a high tolerance for urea accumulation in their tissues and blood, allowing them to maintain osmotic balance in the water.

In conclusion, aquatic reptiles are ureotelic in water, meaning they excrete urea as their primary nitrogenous waste product. This adaptation allows them to survive in an aquatic environment by efficiently eliminating toxic ammonia while conserving water.