Gibbs himself considered the following problem that arises if the ideal gas entropy is not extensive. Two identical containers of an ideal gas sit side-by-side. There is a certain amount of entropy S associated with each container of gas, and this depends on the volume of each container.
The intertidal zone is the area of the ocean between the high tide and low tide lines, usually on the beach at the water's edge. If you think of the line created at high tide as the upper limit and the line created at low tide as the lower limit, the intertidal zone is everything between those lines.
The splash zone is commonly covered in encrusting algae and dark lichens that are tolerant of sea spray. Few other marine organisms can tolerate the almost terrestrial conditions found in the splash zone. Below the splash zone is the high intertidal zone, which is exposed to air for a large part of the day.