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| p.1 #8 · Galapagos- #6 Equatorial desert? |
Amazing how vegetation just grows from rock...guess it just goes to show how fertile lava is. Throw a little seed and some water and poof! Nice series Charlie.
Thanks Eric and Ken.
Based on the few things I've observed and read about regarding plants growing on lava fields, it seems as though most (all?) lava is made up of minerals that benefit plant growth. The main question is how long it takes the lava to break down enough to be useful for plants to utilize:
Thick, slow-cooling lava takes much longer to become usable than volcanic ash- for example.
Plants took root on Mt St Helens within a year of it exploding and sending ash flows and plumes to cover large sections of land.
But it's more than just lava breaking down into its component minerals.
To have good soil, vegetation also has to be part of the equation.
Plus water to dissolve nutrients and get them into the new plants.
In the case of Mt St Helens after the blowup- all the ingredients were there. Add water and voila! Except for the absence of tall trees, within 10 years of the explosion, the ash fields were jammed with new plant life, including new and small trees by the thousands.
But the Galapagos are different. They came straight up out of the ocean, several miles off the S. American coast. Most likely, for the first few million years there was just the lava and rain. Plant seeds no doubt blew there occasionally, but there was no soil for them for a very long time, so they tried to grow, but probably lived very short lives (at least their death and decay helped build some soil). Eventually a small variety of plant communities got started on the islands. Enough for some plant-eating animals to feed on. But how did the animals get there? Some birds were probably blown off course. Some non-flying animals floated there on clumps of vegetation that washed out to sea. Etc.
Many millions of years later, people happened upon this unique group of islands out in the eastern Pacific. A perfect natural classroom for the likes of Charles Darwin.
And a pretty cool place for you and me to visit also.