The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The molecules at the surface of a glass of water do not have other water molecules on all sides of them and consequently they cohere more strongly to those directly associated with them (in this case, next to and below them, but not above). It is not really true that a "skin" forms on the water surface; the stronger cohesion between the water molecules as opposed to the attraction of the water molecules to the air makes it more difficult to move an object through the surface than to move it when it is completely submersed.
Cohesion and Surface Tension: The cohesive forces between molecules in a liquid are shared with all neighboring molecules. Those on the surface have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their nearest neighbors on and below the surface. Surface tension could be defined as the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of the water molecules.
River basins:
North Carolinas 17 River Basins:
Hiwassee
Savannah
Little Tennessee
French Broad
Watauga
Broad
New
Catawba
Yadki-PeeDee
Roanoke
Lumber
Cape Fear
Neuse
White Oak
Tar-Pamlico
Chowan
Pasquotank
Marine food web:
upwelling : up welling is necessary because upwelling brings cold nutrient-rich waters to the surface which helps seaweed growth and suppo upwelling brings cold, nutrient-rich waters to the surface, which helps seaweed growth and supports plankton to grow.