Sand and young rays.
- Thread starter andersp90
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csx4236;2449525; said:
Quartz and silica is the same thing.
"The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO2), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is resistant to weathering."
http://en.wikipedia.org/wiki/Sand
There is Quartz and silica in all aquarium sand. And in the amzon itself.
Wow- what a thread!
I think everyone is generalizing way too much here. The word sand refers to the size of the particles. It has nothing to do with what the sand is composed of, or it's angularity (or how sharp it is). In my opinion, if sand is at times harmful it is more related to the angular edges of the sand. If you look at the microscope pictures, you can see particles that are rounded and smooth and some that are pretty sharp looking.
Different minerals have different hardness. Geologists have a scale to measure hardness- called the Mohs scale of hardness where the hardest mineral (diamond) is a 10, the softess is a 1. Some, like quartz (which is also silica or what glass is made of) has a pretty high hardness. Because of that, it is more resistant to weathering and will tend to retain those sharper angles more than a softer mineral. Talc is one of the minerals with the lowest hardness. If you've ever rubbed talc between you're fingers you know it is very soft.
If sand is causing a problem, it is more likely (in my opinion) to be due to the particle shape than it's size.
I knew that geology degree would be useful eventually!
I think everyone is generalizing way too much here. The word sand refers to the size of the particles. It has nothing to do with what the sand is composed of, or it's angularity (or how sharp it is). In my opinion, if sand is at times harmful it is more related to the angular edges of the sand. If you look at the microscope pictures, you can see particles that are rounded and smooth and some that are pretty sharp looking.
Different minerals have different hardness. Geologists have a scale to measure hardness- called the Mohs scale of hardness where the hardest mineral (diamond) is a 10, the softess is a 1. Some, like quartz (which is also silica or what glass is made of) has a pretty high hardness. Because of that, it is more resistant to weathering and will tend to retain those sharper angles more than a softer mineral. Talc is one of the minerals with the lowest hardness. If you've ever rubbed talc between you're fingers you know it is very soft.
If sand is causing a problem, it is more likely (in my opinion) to be due to the particle shape than it's size.
I knew that geology degree would be useful eventually!
andersp90;2449655; said:Quartz and silica is the same thing.
"The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO2), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is resistant to weathering."
http://en.wikipedia.org/wiki/Sand
There is Quartz and silica in all aquarium sand. And in the amzon itself.
all quartz is silica, but not all silica is quartz....it is part of a large group of minerals that come under the heading of silicates
http://en.wikipedia.org/wiki/Silicate_minerals
andersp90;2450000; said:
Since the Amazon basin is huge, I would imagine it is pretty varied. Much of the sediment load of the river must come from the erosion of the Andes Mountains.
So, while I can't comment on the specifics of the Amazon River basin, here is some info that might be helpful.
The substrate type is going to depend on where on the river you are. In the areas where the river is flowing faster- there is going to be larger sediment, in general less eroded (more angular, not as rounded). Where the river slows down, the river does not have enough energy to carry the larger sediment, so it gets buried. Probably more mud in these areas. By the time particles get this small they have been weathered a long time, so in general it should be pretty rounded in all but the hardest mineral types.
Now throw into the mix seasonal changes in water flow and thus the energy of the river and it's ability to carry sediment, add in the huge areas of the amazon river that these animals inhabit and I don't think it is possible to make generalizations about something as big as 'The Amazon River Basin'.
Also, keep in mind that in any river, there are areas where the water is flowing faster and where it flows slower. These different areas will have different types of sediments in them. In a river, if a fish prefers a more rapidly flowing area, or an area with a different type of substrate it moves. In our captive environments, this is not possible.
It all get's quite complicated the more you think about it. That's why it's so cool though!
You may be able to find articles on the sediment types within the amazon river basin.
