The reason why lakes and wetlands can adjust the temperature is because the specific heat capacity of water is the temperature when a certain mass of water absorbs (or releases) the same heat.

Under the same sunlight, the heat absorbed by sand, lakes and wetlands per unit area is the same at the same time.

According to the heat calculation formula Q=cm△t, it can be known that the specific heat capacity is inversely proportional to the change value of temperature when the absorbed heat and mass are the same, so the specific heat capacity of water is large when the mass is the same and the absorbed (or released) heat is the same. Its temperature changes very little.

So, the answer is: big; Small.