There are 6 main ecosystems: ocean, desert, tundra, forest, grasslands, and wetlands. The ocean covers 72% of the Earth's surface and contains deep sea and kelp forest areas. Deserts cover over 1/5 of the Earth and have little rain, making them extremely hot in summer and warm otherwise. Tundras are located in the northernmost parts of the Earth and are cold, vast, and treeless. Forests include tropical and temperate rainforests found near the equator and coastal areas. Grasslands have different types depending on rainfall and grass height. Wetlands include marshes, swamps, and peatlands with varying amounts of open water, vegetation, and soil