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8 votes
Accepted

Is it true that "All life on earth gets its energy from the sun"? How much biomass is not derived from photosynthesis?

As you say, the existence of organism that live out of chemical compounds expelled by hydrothermal vents (Chemoautotrophs), immediately render the sentence "All life on earth gets its energy from the ...
Camilo Rada's user avatar
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7 votes

How can half a degree of average temperature result in such devastating impact on coral reefs?

Coral die because of coral bleaching, a process in which the symbiotic algae living in the coral (which give the coral its colour), leave the coral host. Bleaching can occur for a variety of reasons, ...
Gimelist's user avatar
  • 23.2k
5 votes

Why don't most organisms use magnesium in their shells and bones if it is lighter and more common than calcium?

First off, magnesium is not more common than calcium where it counts for Earth organisms, namely the crust. By mass calcium is more common in the crust, by atoms they are about equal (the enrichment ...
Oscar Lanzi's user avatar
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5 votes
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Can the sealed bottle garden be called a perpetual motion machine?

There are no perpetual motion machines. So when you think you've found one, you need to ask a couple of questions, because there will always be an answer to at least one of them. How is the ...
410 gone's user avatar
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4 votes
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Why are there places where trees don't grow?

A non-conclusive list: frequent wildfires not enough water too much water bad soil conditions average temperatures too high or low not enough sunlight animals human intervention other vegetation is ...
Erik's user avatar
  • 756
4 votes
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How quickly can coral fossilize?

First thing is that the sea-level wasn't necessarily that high when the reef was growing, Hondurus is on the edge of the Caymen Trough Fault Zone and experiences quite high rates of uplift, (...
Ash's user avatar
  • 4,550
3 votes
Accepted

Are any New Guinea snakes invasive?

No. None of the species we currently consider invasive on Papua New Guinea are reptiles. A web site here has a dataset which lists 51 invasive species for that location. Of the 3 species in the phylum ...
justCal's user avatar
  • 1,186
3 votes
Accepted

What is the connection (if any) between jarosite and subsoil biological activity near Spain's Río Tinto?

From what I've read so far, it appears jarosite may not be a prerequisite for the formation of certain life forms, instead that it is produced by certain organisms. Río Tinto (Huelva, southwestern ...
Fred's user avatar
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3 votes

Saharian calima dust, apart of Fe2O3 does contain FeO?

I think you are correct. Typical sand is silica (white) with a little Fe2O3 (red) to give a "sand" color. FeO is black and over geological time in air, oxidizes further to Fe3O4 with hydroxides and ...
blacksmith37's user avatar
  • 1,043
2 votes

Why does Earth have abundant oxygen in the atmosphere?

My answer goes a little beyond the evidence -- there isn't much evidence. The question There's a lot of free oxygen now. This oxygen did not suddenly come from underground or from space. So it used ...
J Thomas's user avatar
  • 281
2 votes
Accepted

Pre-Phanerozoic CO2 levels and pluricell life influence in C Earth's cycle

It changes, there is no one overwhelming effect. At some times plants have dominated at others ocean sediments have dominated. Position of continents, global temperature, sea level, and evolution of ...
John's user avatar
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1 vote

What would be effects if sun was smaller, but had same mass?

The power output of the sun is given by the Stefan-Boltzman equation: $$P = \sigma T^4 A$$ where $\sigma$ is Stefan-Boltzman constant, T is the temperature, and A is the surface area. The surface area ...
Stevan V. Saban's user avatar
1 vote

What kind of fossil or creature is this from? Found in the ocean

Thanks for your help everyone--after your tips I did some sleuthing, and in the included picture/top right in black and white, that looks EXACTLY like what i found, the 'arm' of some kind of starfish.
James's user avatar
  • 31
1 vote
Accepted

Phosphate in the oceans, does it tend to bond with sodium?

The pH of ocean water is currently about 8.1, which lies between the second and third dissociation constants (7.20 and 12.37, respectively). So most of the phosphate inthe ocean in its twice-...
Oscar Lanzi's user avatar
  • 3,936
1 vote
Accepted

Does crustal thickness have anything to do with how life existed and sustained on Earth?

If the crust were the thickest layer or Earth, several things would happen: It wouldn't be a "crust" any more, by definition. Because this is what a "crust" is: a thin layer on the exterior of ...
Gimelist's user avatar
  • 23.2k

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