| View previous topic :: View next topic |
Chad
In: Ramsbottom
|
|
 |
|
For any phenomenon, we aim to look for a single cause.
For the presence of deserts we have that... the absence of substantial vegetation directly west of said desert.
For the absence of desert, on the other hand, we currently have three:
1) The western effect (the presence of substantial vegetation directly west of said desert).
2) The eastern effect (presently mechanism unconfirmed).
3) The hidden behind a north-south mountain range effect (stops sand and diverts dry air).
If we can accept three causes for the absence of desert, surely a fourth is not going to break the camel's back (or is it...?). I would thus like to nominate the Polar Effect (because I'm not convinced the polar regions are affected by the eastern effect in anything like the same way as the narrow vegetated bits of other landmasses).
If the eastern effect is caused by seaweed, it can only be as a catalyst causing very localized precipitation, which in turn leads to adjacent vegetation growth with consequent increased precipitation... This cycle could not even get started in the polar climate.
|
|
 |
|
 |
|
Grant
|
|
|
|
So the sea-weed conditions on the eastern coast are the same as the conditions on the western coast. Therefore, seaweed can't explain anything.
|
|
| |
|
|
|
Mick Harper
Site Admin
In: London
|
|
|
|
|
Oh, OK. Always give up at the first setback, that's the clue to intellectual advance.
|
|
| |
|
|
|
Grant
|
|
|
|
|
All right. Suppose there is less seaweed in the west because the western shores tend to have bigger waves? I can't find evidence for this yet but I'll keep looking.
|
|
| |
|
|
|
Hatty
Site Admin
In: Berkshire
|
|
|
|
|
Seaweed is found on western shores like Cornwall and Ireland. It clings to rocks even in rough seas. There wouldn't be anything to cling to in rough seas where there's only sand but if, as you say, the eastern leeward shore is calmer presumably it could gain a foothold even where there's nought but sand.
|
|
| |
|
|
|
Grant
|
|
|
|
On the other hand, did you know that Chile is one of the world's main sources of seaweed?
Sorry, death of a beautiful theory by an ugly fact and all that business!
http://www.algaspardas.cl/VASQUEZ%202008%20JAP.pdf
Also, the earliest inhabitants of the Atacama used seaweed as firewood.
|
|
| |
|
|
|
Mick Harper
Site Admin
In: London
|
|
|
|
|
Well done, Grant, you've discovered what everyone over the age of six knows which is that seaweed is as much present on the west coast as on the east. So now you have to work out why seaweed on the east coast has a markedly different effect than it does on the west coast. If you had bothered to read Hatty's posts you would at least have got a starting point. Oh, but I was forgetting, you are always looking for a reason to give up.
|
|
| |
|
|
|
Ishmael
In: Toronto
|
|
|
|
| Chad wrote: | | For any phenomenon, we aim to look for a single cause. |
Good, good.
| For the absence of desert, on the other hand, we currently have three: |
There can be only one.
| If we can accept three causes for the absence of desert, surely a fourth is not going to break the camel's back (or is it...?). |
We cannot accept three causes. Mick's theory, with respect to the Eastern Effect, has violated the AE principle of "Same effect, same cause."
| If the eastern effect is caused by seaweed, |
I say the reason plants grow where they grow is universal. However, seaweeds are plants so they may be counted as part of the ecology as much as are land-based plants.
Oh. And my answer is very simple. So much so, you will likely find it disappointing.
|
|
| |
|
|
|
Ishtar
|
|
|
|
I was starting to wonder about Algae for a little while, it's just like sea weed and the Arctic goes though an Algal bloom every summer. 6 months of sun might help with that.
Krill feed on algae that grow on sea ice and penguins eat Krill - where do we find penguins? In the Antarctic. (hmm.. wonder if there is a link to months of sun, algae population, krill, and whale migration)
While this may help in the polar regions, I can't find anything that is particularly eastern about its growth - but I think Hatty is onto something. I'll keep looking for more info.
|
|
| |
|
|
|
Chad
In: Ramsbottom
|
|
|
|
As Mick told us (and Hatty's post confirmed) the big thing about seaweed is its ability to seed clouds through the production of iodine. But this iodine can't produce rain out of thin air (or more correctly dry air) it needs to act on airborne moisture.
Off the west coast of any desert the air is too dry for the seaweed to do its seeding job, whereas over on the less dry east coast it can seed clouds to produce precipitation (just as it can on the west coast... north and south of the deserts).
The seaweed which produces the greatest quantity of iodine is kelp... and kelp is big (in every sense of the word) down Antarctica way.
So what we are looking at is not so much an eastern effect.. as a damp coast effect... and in that respect it could indeed account for Antarctic precipitation.. it can work with or without plant transpiration... all it needs is airborne moisture (from whatever source).
|
|
| |
|
|
|
Hatty
Site Admin
In: Berkshire
|
|
|
|
| Ishtar wrote: | I was starting to wonder about Algae for a little while, it's just like sea weed ...
While this may help in the polar regions, I can't find anything that is particularly eastern about its growth |
Seaweed presumably has to go with the flow, or rather currents. Looking at a map of kelp distribution it appears to be at home almost anywhere. Large brown algae, kelp-like though not apparently kelps, can grow on coasts even around Antarctica. It's certain that kelp forests provide shelter and food for an assortment of sea creatures much as trees do.
An article by a Chilean scientist talks about kelp beds and coral reefs under the heading of marine ecosystems, the latter being in tropical rather than temperate zones. Whether kelp and coral have the same role is not clear; the organisms that live off coral contain microscopic quantities of algal matter which in turn contains iodine; perhaps this comes to be embedded in the reef as part of the creatures' skeletons.
|
|
| |
|
|
|
Hatty
Site Admin
In: Berkshire
|
|
|
|
|
Just a thought. Are coral reefs the reason why "there's no such thing as a desert island"? Could they 'seed clouds' too? In tropical seas that is.
|
|
| |
|
|
|
|
|
Mick Harper
Site Admin
In: London
|
|
|
|
| Off the west coast of any desert the air is too dry for the seaweed to do its seeding job, whereas over on the less dry east coast it can seed clouds to produce precipitation (just as it can on the west coast.... north and south of the deserts). |
I cannot agree with this. Since we are dealing with the Eastern Effect and the Eastern Effect is the only reason we have for increased precipitation, then the conclusion is being used in the argument to reach the conclusion.
Read Hatty's posts again.
| It's possible that on east coasts it merely rots and releases something which ultimately causes precipitation. Is that the idea? |
Grant, a good wheeze and something I'd not thought of. Develop.
|
|
| |
|
|
|
Chad
In: Ramsbottom
|
|
|
|
| Mick Harper wrote: | | Off the west coast of any desert the air is too dry for the seaweed to do its seeding job, whereas over on the less dry east coast it can seed clouds to produce precipitation (just as it can on the west coast... north and south of the deserts). |
I cannot agree with this. Since we are dealing with the Eastern Effect and the Eastern Effect is the only reason we have for increased precipitation, then the conclusion is being used in the argument to reach the conclusion. |
There may, at first, appear to be some circularity involved... but that very much depends upon what you take as your default starting position.
I was simply being consistent by applying exactly the same reasoning and logic that I used to explain why there was vegetation east of the Andes (adjacent to the Atacama). The eastern margin is green simply because there is vegetation growing there (and transpiring)... as before, there is no need to explain how the vegetation got there... we just need to explain how it is preventing desert from taking hold.
And that is because the east coast seaweed is seeding clouds from the moisture caused (in most cases) by transpiration from vegetation directly to its west.
(Notice how, if you take this argument, the eastern effect suddenly converges with the western effect... overcoming Ishmael's multiple source objection.)
As we said previously, the actual width of the eastern green strip depends on local conditions... and as I said, it is very much a balancing act between drying forces from the west and easterly precipitation... In the Sahara the western forces reign supreme... in South America (south of the Atacama) the eastern force wins out almost entirely... in Australia the battle is being played out, for all to see, west of the Great Dividing Range.
Ishmael is probably right (an annoying habit of his) about it being a function of relative wind velocities... but I haven't seen the data yet.
|
|
| |
|
|
|
|
The Library Index 
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in 
