What three characteristics must organisms in the intertidal zone have to overcome?

1. Resistance to desiccation (drying out): Intertidal organisms are periodically exposed to the air during low tides, so resistance to desiccation is critical for their survival. Many intertidal organisms have thick or impermeable body coverings, such as shells, exoskeletons, or waxy cuticles, that help minimize water loss. Some intertidal organisms also produce specialized proteins or mucus that can retain water and prevent dehydration.

2. Tolerance of salinity fluctuations: Intertidal organisms are exposed to varying levels of salinity due to tidal cycles and freshwater inputs from rivers and streams. They must be able to tolerate fluctuating salinities and osmoregulate to maintain their internal water balance. Some intertidal organisms can actively regulate their internal salinity levels, while others rely on passive mechanisms, such as the accumulation of compatible solutes, to withstand salinity changes.

3. Ability to withstand mechanical stress: Intertidal organisms are exposed to strong currents, waves, and tides which can generate high levels of mechanical stress. They must have robust body structures and attachment mechanisms to resist being swept away or damaged by the physical forces of the intertidal environment. Many intertidal organisms have strong holdfasts, claws, or other adaptations that help them adhere to rocks, substrates, or each other.