Underwater construction teams are groups of people who build things underwater, like structures and buildings. Just like how builders on land use tools and machines to build stuff, underwater construction teams have special tools and equipment for building things underwater.
Sometimes, these teams work in shallow waters where they can still breathe with special breathing apparatuses that allow them to stay underwater for extended periods. In deeper waters, however, they have to use pressurized submersibles - this is like a special kind of underwater vehicle that people can get into and stay pressurized in order to breathe properly and work efficiently.
The tools they use to build underwater structures include things like drills, hammers, and welding equipment - but these tools are specially designed to work underwater. And when they build underwater, they use a special kind of cement that can harden and set even when it's submerged in water.
Underwater construction teams are sometimes hired by different organizations that need to build things underwater - for example, if a hotel wants to build a restaurant underwater, they will hire an underwater construction team to help them build it. The teams work together to design the structure, build it, and make sure it's safe and secure underwater.
It's a really fascinating job that requires a lot of skill and bravery - and it's amazing to think that people can even build things underwater!