I just got a request to talk about this and it sounds very interesting to study, so here goes!!
We know that Noah was told to take samples of all the land animals that have to breathe air, but what about the animals that couldn’t live on the ark?
First we’ll look at what fish (and other water creatures) need to stay alive. They need oxygen, a way to balance the salt and water levels in their bodies, clean enough water that their gills don’t clog up, and a steady temperature. We all know a world-wide Flood would mess all of these things up, so how did the fish we see around the world survive it?
If you’ve ever found a fossil in your garden or on a walk, you know that there are billions of sea creatures that did die. The whole earth is covered with them (more on that soon!!). Just like most of the land animals didn’t make it through the Flood year, most of the water creatures were killed and many turned to stone as a memorial to God’s judgment of people’s sin.
OK, here are some of the ways we know of that God could protect some of these creatures during the Flood.
Water doesn’t always work the same way
It is sorted into layers depending on what is in it and how warm it is. Cold water sinks (until it freezes), and so does saltier water. So, if a section of water is warmer, or lower-salt it floats in layers above the rest of the water. Wind also will pull this warmer, less salty water out of the way allowing deeper, cooler water to rise. There is a deep layer of water that flows off of the Antarctic coast that is less salty than the water above it, but sinks because it is cooler.
Today there are some very interesting areas where salt and fresh, cool and warm waters mix (or rather don’t mix) and make a very complex layering, swirling water system. The Amazon River is one of these places. There is so much fresh water flowing out of the Amazon that the surface of the ocean beyond its mouth is fresh for about 250 miles [400km]! Trapped areas of water can be quite different from the open ocean as well. The Black Sea is very unusual with the water near the surface being only about half as salty as regular sea water, but with deep water areas that are cooler and saltier. They have just found a river running along the bottom of the Black Sea from the Mediterranean that is so much denser that is flows down like a waterfall at one point!
Something people almost never consider is how salty the original ocean would have been. There is some exciting science showing how much of the salt on earth came from deep underground like magma. The first ocean might have been a lot less salty until the run off from the land started to collect.
We also know that during the Flood there were pockets of water that didn’t get swirled around so badly. I’m going to do a post on the land formations that show us that this is true. For example, Ayer’s Rock in Australia is at the bottom of one of these basins. This area would have protected some water animals from being swirled away.
We can’t know exactly how God protected the kinds of sea creatures that are still alive today because we weren’t there and He didn’t tell us. But we know this, God cares for His creation. He is sad when our sin makes the world a painful and deadly place for His creatures. The fossil record shows us that most of the varieties of all animals God originally created are not alive today. We also know that when Jesus comes back to earth as King, He is going to restore the waters to great fruitfulness. What a glorious time that will be!
Here’s an experiment you can do to see how this all works: Home School Science Press: Saltwater and Heat Convection
Lear more about the creatures themselves in How did Freshwater Creatures survive the Flood? Part 2
Then said he unto me, These waters issue out toward the east country, and go down into the desert, and go into the sea: which being brought forth into the sea, the waters shall be healed. And it shall come to pass, that every thing that lives, which moves, where ever the rivers shall come, shall live: and there shall be a very great multitude of fish, because these waters shall come thither: for they shall be healed; and every thing shall live where the river comes. And it shall come to pass, that the fishers shall stand upon it from Engedi even unto Eneglaim; they shall be a place to spread forth nets; their fish shall be according to their kinds, as the fish of the great sea, exceeding many. Ezekiel 47:8-10
Site I used to build this post:
Water Encyclopedia Ocean Currents (very cool, long page for you voracious readers!)