What is equilibrium?

Question

What is equilibrium relating to the natural environment and coastal environments?

Answer 1

A state of Nirvana...or something, I didn't understand the question TBH!

Answer 2

it's not one thing or another

Answer 3

A perfect balance

Answer 4

When things are in balance.

The numbers of animals and plants stay the same.

The coastal habitat with the numbers for the amount of plants and animals stay the same thus there is a balance.

Answer 5

Wow! Great question!

Equilibrium is a word that you can break down into its word parts: "equi" and "libra". The first part, "equi," means equal. The second part, "libra," means balance. Thus, the term literally means "equal balance."

Equilibrium refers to the tendency of things in nature to want to be the same, or in balance. You have probably experienced what happens when things get OUT of balance numerous times in your life. Have you even opened a door to a building and felt air rush out? This happens all the time where I live here in Florida. We keep our buildings cool with air conditioning that runs almost non-stop. In contrast, outside it is hot, hot, hot! As the air conditioning runs, the air inside the building can build up (think of what its like in a really crowded room). All that cool, incoming air creates high air pressure inside the building compared to the normal air pressure outside the building ( the warm air particles outside are more spread out).  Obviously things are NOT in balance. As soon as you open the door, the air is going to rush out the door -- there is more "space" for air particles outside than inside. I always remind my students that air likes to flow from high to low, meaning from high pressure to low pressure. The air will continue to flow out through the open door until the air pressure inside is in balance with the air pressure outside. We can then say that the air in both places has reached equilibrium.

The same happens if you hold an ice cube in your hand. Your hand has a lot more heat than the ice cube -- they are NOT in equilibrium. Your hand will give up heat to the ice cube, allowing the ice to warm and melt into a liquid. Again, the heat flows from high to low, in this case from your hot hand to the cold ice cube. As your hand gives up some of its heat, it will begin to feel cooler. The ice is obviously getting warmer. The ice cube doesn't give your hand coldness, it steals away the heat! However, your hand will never get any colder than the ice cube, because as soon as your hand and the water (formerly the ice cube) reach the same temperature, then they have reached equilibrium and the heat transfer basically stops.

When you talk about coastal equilibrium, you’re getting into a much more complex issue. Beaches and coastlines are, by their very nature, in constant change or flux; a geologist would say they are dynamic. There are daily changes caused by high and low tides, monthly changes due to spring and neap tides, seasonal changes related to changes in currents, river flow, and sediment loads, and extraordinary changes due to storm events, earthquakes, tsunamis, etc.

Still, despite all of this change, beaches and coastlines tend to be amazingly stable over long periods of time. Even though a beach may experience significant erosion during a spring storm, if that sand only gets carried a little way offshore, subsequent wave action may return the lost sand back to the beach face over the next few years.

Coastal equilibrium refers to the state in which the sand and sediment that moves into a coastal zone seems to be balanced with the sand/sediment that gets carried away. Beaches and coastlines that are in coastal equilibrium may experience short-term changes, but over the long haul, sediment levels and beach profiles tend to remain relatively constant.

Beaches that are not in equilibrium are usually migrating – either retreating (eroding) or advancing. Geologists try to pinpoint what factors may have disrupted the equilibrium. The usual culprit is related changes in sediment loads and sediment flow related to human causes (dredging a channel, reducing river flow, building a groin, etc) and occasionally natural causes (such as landslide offshore that causes a change in near-shore currents). There are significant regional and global factors disrupt equilibrium as well, such as rising or falling sea level and subsidence and uplift.