It then finds its way back to the oceans. Salinity is vital for animals that live in the ocean. Most marine organisms in the open ocean have body fluids whose salinity closely approximates that of the water around them. However, problems arise for marine organisms who live in the coastal environment. In the intertidal zones and estuaries, wide fluctuations demand mechanisms that will increase water uptake or remove salt.
Some animals protect their internal salinity with shells or scales.
Perhaps this adaptation has permitted it to thrive in these stressful habitats. Particularly susceptible to salinity fluctuations are the eggs of many vertebrates and invertebrates. Myths have arisen about salt. To spill salt at the table requires throwing a pinch over the left shoulder for good luck. There are some examples of art that celebrates salt.