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#1 2007-07-07 17:39:28

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,763
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Re: Building soil

A key part of terraforming a dead world is to make soil. Without soil, crops don't grow. In nature on Earth, transforming an igneous flow into rich soil takes millions of years. Mars has an advantage because it's pulverized by meteorite strikes and partially hydrated. However, growing a fertile soil will take time.

When I was a kid I read a book called "Farmer in the Sky" by Robert A. Heinlein. It was about an immigrant to Ganymede starting a homestead. The character was shocked when he saw the plot of land he was assigned, it was nothing but bedrock; but a neighbour picked up a stone and licked it, then said "this is good land". The first thing they did was use dynamite to blow up large boulders, then a machine as large as a combine used an ultrasonic saw blade to cut the bedrock into pieces. Another machine had rakes of ultrasonic blades that cut the rocks into smaller rocks. He made multiple passes, each time spacing the blades closer together to cut the stones smaller. Once he was down to the size of gravel (or crushed rock) he set the blades shallower with each pass as he spaced the closer. That layered the stones, large ones deep and progressing to smaller ones close to the surface. It continued through sand all the way to rock flour on top. They imported soil concentrate from Earth, containing soil bacteria and worms. His neighbour brought over a welcoming gift: a truck load of kitchen scraps. The immigrant farmer thought it really strange that this guy would haul his kitchen garbage over, but he explained that you don't use the expensive imported concentrate straight. You mix the concentrate with rotting kitchen scraps to expand it to several times it's mass, then lay stripes on the field. The first crop he grew on that land was soil.

This is an interesting story, but the details are a bit off. First, rotting kitchen scraps are used today; it's called compost, so that's Ok. But straight rock flour isn't the best soil; it doesn't give up it's nutrients too quickly. Rock flour is a technical term, and it is used as a source of micro-nutrients. It is literally rock ground to the consistency of flour. However, sand and gravel won't decompose into soil, at least not within a single person's lifetime. So you want to pulverize the ground bedrock to rock flour all the way down to the cut bedrock surface. Second, you want a more aggressive means of decomposing that rock flour into soil.

Feldspar will dissolve in hydrochloric acid; quickly in strong hot acid, slowly in mild warm acid. In fact, this is the basis for my paper on smelting aluminum from feldspar. Bauxite is the result of a tropical rainforest leaching all the nutrients from soil, what's left is silica, alumina, and rust. Strong alkali is used to dissolve alumina and silica, rust is left behind. Then a gas that becomes acid when dissolved is added to neutralize the pH; the aluminum hydroxide precipitates but silica stays in solution. Aluminum hydroxide is then dried and heated with oxygen from the air to become alumina. My process is the reverse: strong acid dissolves silica and alumina but leaves rust, a gas that becomes alkali when dissolved is added to neutralize the pH; aluminum hydroxide precipitates but silica stays in solution. From there it's the same. It works great with feldspar high in aluminum, anorthite and bytownite, but feldspar low in aluminum tends to dissolve the calcium, sodium, and/or potassium as well as aluminum leaving silica on the granules. Silica from high aluminum feldspar dissolves, but silica from low aluminum feldspar forms quartz. Once a layer of quartz as thin as a soap bubble forms on a granule, it stops dissolving. Luckily, the predominant form of feldspar on the surface of Mars is bytownite. So, how can we use this to make soil?

Over just a few million years, flowing water will convert feldspar to clay. Which clay depends on which feldspar you start with:
Albite with iron becomes iron smectite
NaAlSi3O8 + Fe2O3 + H2O -> NaFe2(Si3Al)O10(OH)2

Microcline becomes illite
KAlSi3O8 + 1/2 Al2O3 + 1/2 (Mg2O3 or Fe2O3) + H2O -> KAl(Mg,Fe)(Si3Al)O10(OH)2
Note: illite has 2 aluminum atoms, it tends to weather from smectite and microcline.

Illite weathers to become kaolinite
KAl(Mg,Fe)(Si3Al)O10(OH)2 + 2 H2O -> 3 Al2Si2O5(OH)4 + SiO2 + 1/2 (Mg2O3 or Fe2O3) + 1/2 K2O

Several of the intermediates are ions in solution. So the trick to decomposing feldspar into clay is to leave all the decomposed ions in one big soup. So we need a strong acid and something to make that acid, all in a pool of water. That means some sort of swamp. Growing sphagnum moss produces acid with pH in the range 3 to 4.5, a strong acid. So the ideal is a peat bog; sphagnum moss is growing peat.

I had thought how to apply this to Manitoba (where I live) to produce more farm land. The south has extensive agriculture, but the arable zone extends in a diagonal north-west. There is rain and rivers to the east, but Canada Shield is bare exposed bedrock mixed with patches of soil only a few inches deep. There is boreal forest growing on that Canadian shield, the terrestrial ecozone is called Boreal Shield. The east side of lake Winnipeg, from the lake to the border with Ontario has no road. There are a few isolated communities, but the only way there is bush plane or boat, or drive on the frozen lake in winter. They do drive semi-trucks in the depths of winter, but have to carefully prepare the ice to ensure it's thick enough to carry the weight of a truck. Last winter it never got cold enough to form ice thick enough for a truck, they had to fly in vegetables. We could terraform large patches of that, if the people there want to. I was thinking of an entire township at a time; in the western provinces a section of land is a square one mile by one mile, and a township is six miles by six miles. Since Canada has gone metric and the east side of the lake doesn't have roads, we could round that off to an even number in metric. One kilometre is 0.621 miles so a township is roughly 10km by 10km.

Procedure: start by clear cutting all the trees. I know, environmentalists will cringe at this point, but the objective is to convert it to an entirely different ecozone: from boreal shield to prairie. Next scrape off all the soil and sift to remove rocks and stones. Chip the trees and chop weeds and bushes, but keep grass and twigs separate. Mix the soil with wood chips and chopped weeds, that's your rich soil starter. Next use dynamite to shatter any boulders, and road building techniques (more explosives) to level rock outcrops and rises. When it's roughly flat, use rock cutting equipment to cut a flat level floor. It doesn't have to be polished, rough to the touch is Ok, bumps a few millimetres high are acceptable but it does have to be relatively smooth. Cut the edges to form the sides of a bowl, this will make the entire township one giant flat bottom bowl to hold water. Cut it 2 metres deep. Then take all the rocks you cut out of bedrock, together with all the blasted boulders, and all the rocks, stones and gravel you collected; crush all that to rock flour. Fill the bowl with that rock flour, using road building roller vehicles to compress it. It doesn't have to be tamped, just compressed. The top layer will be more rock flour mixed with the compost you kept: top soil mixed with wood chips and chopped weeds and bushes. Lay that mix loosely over the surface. Cover with the twigs and grass to keep the soil from blowing away. If you did it right you should have 2 metre depth of soil with bowl sides half a metre above the soil top. Do this where there's a near by river or stream, flood the whole thing with water. There should be a couple inches of water above the soil. Seed with sphagnum moss; that creates a peat bog.

When you lay the rock flour, also lay water pumps with hoses leading to distant parts of the bog. This creates water circulation; you want acid water moving through the rock flour, especially deep, right down to the bedrock floor. A simple intake is a slow sand filter. That is formed by cutting a sump pit in the rock bottom, place a submersible sump pump at the bottom with a water proof electrical cord leading out, cover the pump with a stainless steel wire mesh. Then cover in gravel or crushed rock. The wire mesh has to be small enough that the gravel or rocks won't go through. Then cover the gravel with sand, the gravel and sand are approximately 1 meter deep. The top of the sand should be level with the bedrock floor of the field. A slow sand filter 130cm diameter has a flow rate of 10 litres per minute. The output hose can lead to the surface elsewhere in the bog, the point is to create ground water movement throughout all the rock flour. The sand filter prevents the pump from getting clogged with rock flour, and prevents disturbing the growing peat. The pumps can be powered by solar panels.

A water pipe or large diameter hose can bring water from the nearby stream. You don't want a lot of fresh water in the bog, it's supposed develop a strong acid, but you need to ensure it doesn't dry out. A simple device like the float in a toilet tank can control a pump to draw water from the stream, or if the stream inlet is up hill from the bog just a valve will do. Once the bog is covered in peat, no open water exposed, evaporation will dramatically slow; rain may be enough to replenish the bog.

Sphagnum grows in association with blue-green alga Nostoc muscorum (Cyanobacterium). This fixes nitrogen as well as carbon.

It'll take years for the rock flour to release its sodium, potassium, and calcium, and hydrate into clay. When done you can drain it, then focus on building top soil using more traditional agriculture techniques. During that time you don't want the land sitting idle, if you bought the land you want it to work for you, produce revenue. Several berries grow in peat bogs: blueberry, raspberry, saskatoon berry (aka Juneberry), cranberry, huckleberry, sarsaparilla (for root beer), lingonberry (aka cowberry, partridgeberry, mountain cranberry or foxberry), and cloudberry.
Cloudberry is also known as bakeapple or baie qu'appelle in Newfoundland and Cape Breton Island, and plaquebiere or chicoutai in Quebec. It's rich in vitamin C. Cloudberry is popular in Finland, Sweeden, and Norway; an export opportunity. They are used fresh or as jam, juice, tarts, and liqueur: Lakkalikööri and Aquavit. Dogfish Head Brewery has made an Arctic Cloudberry Imperial Wheat beer. Rodrigues Winery in Newfoundland has made an award-winning wine and liqueur from these berries.

Black spruce trees can grow in peat bog. Peat grows with a pH of 3.0 to 4.5, black spruce can grow in pH 3.5 to 7.0. Fastest conversion of rock flour to clay is with strongest acid, so optimal is 3.0 to 3.5, but if you want trees you can neutralize the acid a bit. Another agriculture option is ranching the constructed peat bog. Depending how firm the bog is, you can raise Wood Bison. This species of bison is slightly larger than Plains Bison, an adult male measures 3.04 to 3.8m in length and 1.67 to 1.82m in height at the shoulders, weighing between 350 and 1,000kg. Wood bison have their hump slightly forward of their front legs and the hair on their front legs isn't as long. They live in open boreal and aspen forests where there are large wet meadows and slight depressions caused by ancient lakes. Sound like a constructed peat bog? Some forest with large wet meadows. Notice all the berry, tree, and animal species are native to boreal forest. Using native species is key to success. There are natural bogs in the Boreal Shield ecozone; this constructed procedure uses natural processes but builds deep soil. Naturally boreal forest has a couple inches of soil with large, exposed patches of bedrock.

From: Government of the Northwest Territories
"In summer, they can be found in small willow pastures and uplands where they feed on sedges, forbes and willows.  In winter, they move to frozen wet sedge meadows and lakeshores where they feed on sedges.  In the fall, they can be found in the forest where they feed on lichens."

Wood Bison is the largest land animal in North America. It has red meat, almost indistinguishable from beef but more lean. I bought a pound of ground bison from a grocery store once, cooked into burgers. It tasted slightly better than lean ground beef. I believe it was Plains Bison. Oh, the common American term for Bison is Buffalo.

It may take a while to build an oxygen atmosphere on Mars, but a peat bog can grow with very little atmospheric oxygen. Once there is an oxygen atmosphere, we can ranch Bison. I don't know how deep Mars soil is, but this procedure will create arable soil from even hard exposed bedrock.

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#2 2007-07-07 20:59:44

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,763
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Re: Building soil

The above post gives some grand ideas without numbers. Numbers for dissolving feldspar in acid can be found in the paper "Experimental study of anorthite dissolution and the relative mechanism of feldspar hydrolysis" by ERIC H. OELKERS and JACQUES SCHOTT, published in Geochimica et Cosmochimica Acta, Vol. 59, No. 24, pp. 5039-5053, 1995.

Table 5 on page 5048 of this paper lists dissolution rates for various pH and temperature. At 25°C and 3.5 pH you get -12.57 expressed as a logarithm in mol/cm^2/sec. That means 1/10^12.57 moles per square centimetre per second. Rock flour has a particle size such that 75% passes through a mesh of 0.075mm or larger. Solid basalt has a density of 3011 kg/m^3, the particle size has a volume 0.00022 cubic millimetres or 0.22 * 10^-12 cubic metres. Therefore each particle mass is 665 * 10^-12 kg or 665 * 10^-9 grams. Anorthite has a chemical formula of CaAl2Si2O8 which has a molecular weight of 278.2072772 grams per mole. That means 2.39 * 10^-9 moles. Assuming spherical particles (they won't be that neat), the surface area is 0.0001767 cm^2. That means 50267598 seconds, or 581.8 days. So a little under 2 years if you maintain temperature at +25°C and pH at 3.5. It won't be that neat, so a few years.

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#3 2007-07-08 02:40:28

noosfractal
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From: Biosphere 1
Registered: 2005-10-04
Posts: 824
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Re: Building soil

Sounds fantastic to be able to produce usable soil in just a few years.

Some people have worried, for example, that iron concentrations might be too high, so that we might have to go through a rather more involved process to create topsoil.  Have you read anything about that?


Fan of Red Oasis

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#4 2007-07-08 06:18:12

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Building soil

On the old message board we had an individual who was a farmer with a bachelor degree in agronomy with a specialty in soil analysis. I showed her (posted a message) the result from Sojourner, the little rover on Mars Pathfinder. This was before Spirit or Opportunity launched. She pointed out the soil is low in K (potassium) and rich in Fe (iron). That's where the concern came from. I miss that message board, we actually had Martyn J. Fogg himself join our terraforming discussion once briefly. Anyway, the lady with the agronomy degree said the high iron content might be Ok, an excess soil nutrient might not harm the plants, but she didn't know. At that time we discussed building soil for a greenhouse. This was for the first Mars base. I suggested we process some soil to extract potassium, keep the potassium as fertilizer and throw the rest away in a pile outside. Then takes some fresh soil and enrich with that potassium.

Technically Mars doesn't have soil, it has regolith. However, some regolith is bedrock, some is boulders, rocks, sand, and some is loose material with the consistency of soil. It can't be called soil until it has organic matter, but how do you distinguish between bedrock, boulders, rocks, and loose material? Even NASA geologists have now taken to calling rocks rocks, boulders boulders, and the loose material with the consistency of soil is called soil.

The process would involve taking Mars soil, bring it into a greenhouse pressurized with Mars atmosphere and soak it in water. This will release oxygen, superoxides break down into normal oxides. Several chemical reactions will occur, the result will be normal compounds. We can also take the Mars atmosphere, freeze out CO2 as dry ice and keep the rest. This "diluent gas" will be mostly argon and nitrogen, add that to the greenhouse. I presented a paper at a Mars Society conference on atmosphere harvesting; I worked out how much CO2 would be left in the diluent gas. It would concentrate carbon monoxide so add a platinum catalyst with an electric warming element to the gas concentration canister to combine CO with oxygen. There isn't much oxygen in Mars atmosphere, but once you remove almost all of the 95.32% CO2 you will significantly concentrate everything else, including oxygen. There's more O2 than CO so the catalyst will combine them to form more CO2. One point of doing this in the canister that removes CO2 is that produced gas will be removed as well. There's also some ozone, but the same catalyst will break down O3 into O2. These steps alone will generate a 5.0 psi atmosphere in the greenhouse suitable for plants. The oxygen generated by soaking soil in water won't be enough for humans to breathe, but will be enough for plants.

If you want to get really fancy you can further separate the diluent gas. Freezing CO2 into dry ice is easy; the temperature is just a few degrees colder than Mars at night. However, you could freeze it to cryogenic temperatures to fractionate the gasses. Or add hydrogen and no oxygen, burn to produce anhydrous ammonia. That ammonia can be frozen at moderate cold to a solid, separating it from other gasses. If you carefully balance the hydrogen, the left over is 99.9% argon. Use that argon to fill the gap between layers of a double wall greenhouse. That means argon filled sealed windows. Ammonia can be used as refrigerant or fertilizer. You may not want a sealed greenhouse with dramatic levels of anhydrous ammonia, but you can further process to make nitrogen oxides, then combine nitrogen oxide with ammonia to form ammonium nitrate fertilizer, the white fertilizer pellets. The trickiest part there is forming neat pellets.

Before adding nitrogen fertilizer, though, is further processing Mars soil. After soaking in water the soil will be alkali. There's a reason plagioclase feldspar is called alkali feldspar. Take a batch of soil in a pressure container and bubble CO2 to create the same pressure as a pop bottle. Use pure Mars atmosphere for this, it's readily available and already over 95% CO2. Dissolved CO2 forms carbonic acid, a mild acid. Acid will neutralize the alkali. Vent the gas back outside to Mars. You'll loose some water as humidity, but most will freeze as frost inside the canister.

You also have to watch salt content. If there's too much salt you can soak and then draw off water. Filter the water to keep soil particulates, but dissolved materials like salt will go through the filter. Boil dry to retain water, throw away the salt. You'll loose some nutrients that way, hopefully it isn't necessary.

I once did a calculation from Sojourner sample A-2. Each kilogram of soil would generate:
11.5 grams salt
113.1 grams baking soda
12.7 grams gypsum
1.8 grams calcium oxide
11.0 grams phosphoric acid
1.6 grams oxygen

That assumes enough acid is generated to consume calcite and dolomite. Hydrochloric acid will break them down, but an acid solution with salt will form some HCl. Note calcite and dolomite release CO2 when they decompose. That'll be released when you vent the CO2 to Mars. Is that salt concentration Ok? We don't want to loose the phosphoric acid, that's your phosphate fertilizer.

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#5 2007-07-08 13:41:06

RobS
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From: South Bend, IN
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Re: Building soil

When building soil for a greenhouse, you will want to select your geological materials carefully because Mars will not be covered by "average Mars" everywhere. Catastrophic flood deposits will be sorted in some places, sand in some spots, gravel in others, clay in others, boulders in others. Some flood deposits may be salty; others may not be if the water volume was large and the water source was atmospheric. The other interesting source of material for greenhouses would be eolian deposits. They will be the equivalent of rock flour in terms of particle size. They might not be "average Mars" either: in areas where the ground is mostly exposed fresh lava flows, much of the eolian material may be wind-eroded basalt flour. It may be that "average Mars" eolian dust won't have too much salt and other undesirable elements, too; I don't know. But thorough rinsing of the dust may remove the undesirables.

Iron is not a problem. It dissolves in water when the pH is low. Add carbon dioxide to water to make carbonic acid, run it through the material, pour off the water, then depressurize the water to vaporize the water and CO2, precipitating the iron. The rovers have found lots of iron carbonate salts and ancient Earth had lots of iron carbonate (taconite is the mineral) and I suspect they are a product of low-oxygen, high CO2 water.

                    -- RobS

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#6 2007-07-08 13:46:53

RickSmith
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From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Building soil

Hi RobS,
  Great posts!  Thanks for all the work.

  Some questions, the plants you mention, do they require insects to fertilize them?  (The moss would not, but what about the berry bushes you mentioned?)

  Do any of those plant species have minimum requirements for O2 or N2?

  Warm regards, Rick

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#7 2007-07-08 15:08:29

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,763
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Re: Building soil

Rick Smith: RobS is Robert Stockman, I'm Rob Dyck, different person.

RobS: Thanks for the iron removing procedure. I had hoped there was one but didn't know. And thanks for "taconite", I was wondering why there weren't carbonate minerals for all metals found in plagioclase feldspar. Early Earth formed carbonates inorganically, all the positive ions should dissolve and combine with carbonate ions from the high pressure CO2 atmosphere. Earth started with an atmosphere similar to Venus, our oceans combined CO2 with ions leached from rock to form sedimentary rock; primarily limestone. That's how CO2 was sequestered. I checked webmineral.com but it isn't listed; however Siderite is: Fe(CO3). It's listed as Fe++CO3, which implies it's an iron/carbonate salt, exactly how you describe taconite. An alternate name, or an alternate crystal structure? They also list an entire calcite group of minerals, all salts of carbonate:
Calcite CaCO3
Magnesite MgCO3
Siderite FeCO3
Rhodochrosite MnCO3
Sphaerocobaltite CoCO3
Smithsonite ZnCO3
Otavite CdCO3
Gaspeite (Ni,Mg,Fe)CO3

All these minerals explain where the ancient CO2 went.

RickSmith: You asked about pollinators. Good question, I missed that. Embarrassing, I had checked for a pollinator when Cindy asked about desserts. I suggested growing cocoa trees in a large greenhouse for chocolate. It turns out the pollinator is midges, also known as no-see-ums. Biting midges, and they require a variety of plants with rotting vegetation on the ground.

Algae and sphagnum moss do not use pollinators. They can grow without insects. Blueberry pollinators are bumble bees, honey bees, and wild bees. Cranberries are pollinated by bumble bees and wild bees; honey bees will work as well but "do not eagerly work them". Honey bees are the "best" pollinators of raspberries. Saskatoon berry (Juneberry): honey bees. All the berries are pollinated by one bee or another. Black Spruce trees pollinate by insects or wind.

Google found an interesting article: "Effect of Low Oxygen Partial Pressure to the Bumblebee Respiration"
Vol.65, No.634(19990625) pp. 2056-2062
The Japan Society of Mechanical Engineers ISSN:03875016

Quoting the abstract: "Insects augment oxygen supply using convective transport during flight in two ways: with deforming tracheae by surrounding muscles movement (muscle pumping) and with contracting air sacs by exoskeleton movement (abdominal or thoracic pumping). However, because induced flow inside tracheae is difficult to measure, it is not known how the convective transport actually contributes. By comparison between direct measurement of oxygen partial pressure in a flight muscle based on electrochemical method and flight/ventilation activities in a bumblebee, Bumbus hypocrita hypocruta, a method was developed for estimating gas transport efficiency. Oxygen partial pressure, P_<O2>, in the bee periodically fluctuated with discontinuous abdominal movement in normal air. While the P_<O2> strongly varied among individuals in normal air, the P_<O2> took a unique value in oxygen poor air (&le;8%). By enhancing ventilation, the bee could respire in an oxygen poor atmosphere up to 2%. Furthermore, the bee could fly in an atmosphere of 6%, in which the P_<O2> decreased to 0.7%. Estimated efficiency of the gas transport increases with atmospheric oxygen concentration decreases."

Normal air on Earth is 20.946% oxygen, this abstract says bumble bees can fly in 6% oxygen. Very encouraging for a partially terraformed Mars.

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#8 2007-07-08 21:02:59

RickSmith
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From: Vancouver B.C.
Registered: 2007-02-17
Posts: 244

Re: Building soil

Hi Rob Dyck.

Oops!  Sorry about that.  Yes you are right, I meant thank you to you.

Thanks for the information on bees & pollination.

Warm regards, Rick

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#9 2007-07-09 02:54:42

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,763
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Re: Building soil

Odd; very few comments. The point of the long posts is that we can grow peat bogs on Mars. Sphagnum moss and cyanobacteria of peat will grow in an atmosphere with no oxygen. They will require nitrogen to form protein, ideally as atmospheric nitrogen. These organisms will produce oxygen, at the same time they'll convert rock flour to clay and produce a lot of rich organic matter for top soil in the top layer. Once a minimum oxygen atmosphere is built sedges, forbs, willows, and black spruce trees can be planted in the peat bog. Once there's enough oxygen for bees, berries can be planted as well. Large bogs could be grown for a few years to build soil, then drained to grow other environments. An easy transition is to convert bog to boreal forest, since boreal forest has bogs in it naturally. However, once soil is built more than 2 metres deep you can grow almost anything. Wheat grows roots 1.0 to 1.8 metres deep, depending on variety. Peat moss is used to improve top soil, so a drained peat bog will be great. If you start with 2.0 metres of rock flour, hydration into clay will add water making it expand a bit, and sphagnum moss and cyanobacteria will convert water and CO2 gas into carbohydrates, and water/CO2/N2 into protein, also adding volume. Final soil will be deeper than the rock flour you start with. Grinding rock, placing circulation pumps and controlling water level will take effort but the result is rapid conversion to arable soil.

Bog world.

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#10 2007-07-09 04:12:52

noosfractal
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From: Biosphere 1
Registered: 2005-10-04
Posts: 824
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Re: Building soil

I haven't seen much discussion on this next stage of terraforming, so people are probably just still thinking about it.

Let me try to put together a terraforming timeline, and see where bogification fits in ...

Year 0: decision to terraform
Year 10: insolation mirrors go online
Year 15: PFC factories go online
Year 35: polar CO2 sublimates
Year 45: 300 mbars of CO2
Year 50: liquid water on Mars (mean global temp. > 0C)
Year 55-70: oceans form
Year 75: first ammonia asteroid outgas
Year 80: first Dyckian bogs (N2/O2 pressure ~0.2 mbars)
Year 90: first blue-sky harvest

what do you think?


Fan of Red Oasis

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#11 2007-07-09 12:45:14

nickname
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From: Ontario, Canada
Registered: 2006-05-15
Posts: 354

Re: Building soil

Or

Year 0: decision to terraform
Year 1-5: Carbon collected from Phobos, sent on pole impact with Mars 
Year 6: 300 mbars co2 atmosphere
Year 7: polar CO2 sublimates adding additional 300 mbars.
Year 7: liquid water on Mars (mean global temp. > 0C)
Year 7: oceans form
Year 8-20 gas imports from Titan
Year 21: first Dyckian bogs)
Year 25: first blue-sky harvest or pink sky. smile


Science facts are only as good as knowledge.
Knowledge is only as good as the facts.
New knowledge is only as good as the ones that don't respect the first two.

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#12 2007-07-09 21:51:03

X
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From: Alabama
Registered: 2007-02-02
Posts: 134

Re: Building soil

Are the berries you listed restricted to bogs or just acidic soils?  I know I've seen blueberries in permanently dry land before.

Are there still wood bison out there?  I thought the last few were interbred with plains bison at a Canadian Park back in the day when the only bison left anywhere were there and Yellowstone.  Not a problem either way since we could always just select for smaller bison to begin with.

I like the idea about getting the iron out of the soil.  Use it as a building material or something.

Raising and caring for honeybees is well known and public.  Plus there are a few varieties to choose from like Italian, African, or Japanese.  Maybe you could get some funding from animal lovers if you use Japanese honeybees as they're losing ground to invasive species.  Plus the workers are either entirely stingless or have mild stings.  Honeybee honey also has a very long shelf life.  Raising bumblebees is currently proprietary knowledge so you'd either have to figure it out yourself or pay for it.  It might be patented or copywritten though so by the time it is needed maybe it'd be common knowledge.  The downside is their honey becomes rancid in a few months.  Not a problem really except that'd limit it use as a human food source.

Why not start building a few manmade domed islands when we first get to Mars with the bogs inside?  We'd probably just want to go with plants and bees so it can be left to its own devices.  The advantage is first the soil is being prepared for when the outside atmosphere is ready so those areas could be a bit ahead of the rest.  Also it'd supplement the food supplies of anyone out exploring the surface as well as giving them a base of operations away from home.  Hop out of your rover, pick some berries, go camping, and stretch your oxygen supply a bit by sleeping inside the dome.

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#13 2007-07-09 21:57:07

RobertDyck
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From: Winnipeg, Canada
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Re: Building soil

Transporting gas from a planet with substantial gravity isn't practical. An asteroid can be moved entirely to Mars, though a large asteroid has to skim the atmosphere to give up its material slowly. You don't want to blow off the precious atmosphere in a massive impact. But ships?

When I was a teenager I thought of using the Moon to transport gas from Venus to Mars. Build an automated factory that builds factories. Every month it would build another full-size factory. Each of these second generation factories would harvest lunar resources, refine to construction material, and build gas transport ships. Each ship would be reusable, transporting as much liquefied Venus atmosphere as a modern jumbo oil tanker in Earth's oceans. It would skim the atmosphere of Venus to collect it's load, chill down and pressurize to liquefied gas, and repeat the process until it's tanks are full. Then head off to Mars to deliver the gasses. Each ship would be reused, returning to Venus for another load. Fuel would come from asteroids and the moons of Mars. Constructing one giant ship per week from each second tier factory, and the first tier factory building one second tier factory per month, you have an exponential rate of gas transport. There's a problem: how the hell do you do that!? That's a hell of a lot of automation! Furthermore, you have an exponentially increasing demand for fuel, how do you harvest enough fuel? You would need nuclear power to ensure those ships don't run out, but even a nuclear engine requires propellant.

I gave up on the idea. Yes, you can transport an ice asteroid from the Kuiper belt or a trans-Neptunian object, but forget about transporting gas between planets. A planetary atmosphere is just too much. Work with what you've got on Mars. Besides, I already said the numbers show we can produce a shirt-sleeve environment on Mars with only resources currently on Mars. You may need nitrogen from an asteroid depending on whether we find significant soil nitrate deposits. You probably will orbital mirrors (insolation mirrors), but we could play with PFC and SF6 numbers to see if we can minimize that. That's all.

Another point is that we don't need a 300 mbar atmosphere. It would be nice, but not required. Martyn Fogg's book talks about a 2.5 bar atmosphere, Earth has 1.01325 bar so that's about 2.5 times Earth. Not at all necessary. He also quotes CO2 adsorbed in regolith at <190 mbar according to "Zent et al" or <280 mbar according to "Fanale et al". He cites current atmosphere is ~7 mbar and claims polar caps contain <a few mbar (quoting "Fanale et al"). I always thought the poles contained more than that, but using Fanale figures we get ~287 mbar of almost pure CO2 atmosphere. Current atmosphere is 2.7% N2 and 1.6% Ar but that's with 7.5 mbar pressure (measured by Viking 2). That would be swamped in a CO2 atmosphere after releasing from regolith. So a 290-300 mbar CO2 atmosphere is quite possible. I also calculated humans require 170 mbar of pure O2 to breathe, after 6-12 weeks of high altitude training. That's minimum, the lungs tend to dehydrate requiring a breathing mask that recycles breath moisture. Apollo used 5 psi pressure with 60% O2 and 40% N2. That provides 3.0 psi partial pressure O2, the same as on Earth at sea level. (Kennedy launch site is at sea level.) Skylab used the same gasses. In metric, 5.0 psi is 344.74 mbar. So a 300 mbar atmosphere with 170 mbar (2.465 psi) partial pressure of O2 and the rest N2 is prefect. But if you start with 290-300 mbar CO2 then you have to remove some CO2. Plants convert hydrogen and oxygen from water plus carbon from CO2 into carbohydrates. The oxygen from CO2 is released. So a 300 mbar CO2 atmosphere could be toxic for quite a while. Earth has 20.946% O2 with 1013.25 mbar pressure, so that's 212.24 mbar partial pressure O2. If you increase oxygen above that it increases forest fires. The weight of O2 is less than CO2 so the atmosphere will spread out becoming deeper, which will reduce surface pressure some, but I don't think to 212.24 mbar. It may require some oxydation to remove atmospheric oxygen. Ironic that a balanced atmosphere may require removing O2, but the alternative is to leave CO2 at toxic concentration. We'll need some really agressive plants.

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#14 2007-07-09 22:07:24

RobertDyck
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Re: Building soil

Are the berries you listed restricted to bogs or just acidic soils?  I know I've seen blueberries in permanently dry land before.

Any acidic soil.

Are there still wood bison out there?  I thought the last few were interbred with plains bison at a Canadian Park back in the day when the only bison left anywhere were there and Yellowstone.

I've read conflicting reports. Yes, Wikipedia reports what you said. The CBC reported that Russia bought some wood bison in 2006 as breading stock, they claimed there was enough available to sell. Although you want to minimize transport cost to Mars, and space in pressurized greenhouses is at a premium, outside in the open you want large animals that produce lots of meat with minimum work.

I suppose we could roof over a peat bog once we have 300 mbar pressure. That would help keep heat in as well as oxygen. The result could increase oxygen to support bees. Once we have bees we can grow berries. All this is great once the transparent plastic film roof doesn't have to contain pressure, just O2.

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#15 2007-07-09 23:21:20

RickSmith
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Re: Building soil

... Sphagnum moss and cyanobacteria of peat will grow in an atmosphere with no oxygen. They will require nitrogen to form protein, ideally as atmospheric nitrogen. ...

Again great posts Rob.

I don't think it is quite as easy as you think.  I've done some digging and you need 0.5 kPa of Nitrogen before nitrogen fixing plants will work.  You need 0.1 kPa of Oxygen before higher plants will grow. (About half that for mosses, liverworts, hornworts and the like, tho I've not been able to find numbers as hard as I would like.)  I am pretty sure the first 'plants' colonists will be some variety of cyanobacteria, aka bluegreen algae.

Currently Mars has 0.0175 kPa of N2 and 0.001 kPa of O2 (rounding a bit).  However an early greenhouse could have your bog to act as a soil factory for other greenhouses.

I got to thinking about bees in low O2 environments.  Our lungs work because the pressure of CO2 in the air is so low that the CO2 in our blood leaves because of the "Gibbs Free Energy".  (Basically this says that the CO2 goes both ways, but the pressure of CO2 in the air is so low, that almost no CO2 goes across the membrain into our blood; it is effectively one way.)  However, if you increase the CO2 partial pressure, then even tho there is plenty of O2, the CO2 can't leave our blood and we smother.

I expect that insects would have the same problem in a CO2 atmosphere as we do.  We need a lot of buffer gas on Mars that is not CO2.

Have you seen, "Planetary Ecosynthesis as Ecological Succession" by James M. Graham from the university of Wisconsin-Madison?  This lists a variety of plants that might be of use, but it does not give many details on how they could be best used.

Would you mind making a post in my "Plants that are useful for colonization & terraforming" thread suggesting Sphagnum moss and give a link to your initial post in this thread?  I'm hoping that thread can be a clearing point for plants of use.  (I knew about Sphagnum moss, but never realized how perfect it is for Mars.)

Very Warm Regards, Rick.

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#16 2007-07-10 09:26:17

RobertDyck
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Re: Building soil

Don't jump to odd conclusions. We don't need very much buffer gas. Humans can breathe pure oxygen as long as the partial pressure is the same as on Earth. As I've said in other posts, a member of the old message board posted an article from the U.S. Air Force about pilots breathing low pressure. They found strong pilots who were acclimated to low pressure could breathe 2.5 psi pure oxygen indefinitely, and 2.0 psi pure oxygen for up to 30 minutes before passing out. Pilots could breathe 2.0 psi partial pressure of oxygen if it was mixed with nitrogen for significant pressure. Another problem was drying of lung tissue at extreme low pressure.

Guelph University did greenhouse experiments in hypobaric chambers. They found plants could grow just fine in pressure as low as 10 kPa (100 mbar). The lower the pressure the more water transpired through their leaves, but  as long as there was plenty of water they were fine. Growth rate as measured in carbon uptake was constant at all pressures. In a sealed greenhouse any water transpired will condense on greenhouse ceiling and walls, running back into soil trays. Since water is recycled, they're fine. In the open you have to ensure plenty of water, but it demonstrates low pressure is Ok. In fact, they reduced one full-grown spinach plant to Mars ambient pressure and left it for an hour. It immediately wilted, but as soon as they restored pressure it perked up and continued growing. This simulated greenhouse total pressure loss; so in such a case you only have to fix the enclosure, the plants survive.

Some people claim atmosphere without buffer gas is a fire hazard, but reality is flammability is directly related to partial pressure of oxygen. Buffer gas has very little effect on flame rate. The Apollo 1 fire was caused because they pressurized to 3 psi above ambient using pure oxygen. The Cape is at sea level so ambient is 14.69 psi, so they pressurized to 17.69 psi. At that pressure pure oxygen is dangerous. The contractor asked them not to do that, but the memo was lost. They changed from 3.0 psi pure oxygen to 5.0 psi with 60%/40% O2/N2 mix. One excuse was "buffer gas", but in reality the real problem was ignoring the memo that said not to use pure O2 at 17.69 psi. A side effect was higher pressure prevented drying lung tissue.

Oh, you can decompress to spacesuit pressure (3.2 or 3.3 psi pure oxygen) with zero prebreathe time from 5.0 psi. The Shuttle's current problem with prebreathe time is due to operating at 14.69 psi cabin pressure.

This thread is about building soil. Your points about sphagnum requiring 0.1 kPa (1 mbar) of oxygen, and cyanobacteria requiring 0.5 kPa (5 mbar) of nitrogen are well taken. That demonstrates we will have to increase these gasses, but we don't need to approximate Earth.

Again, the other issue for atmosphere guys is radiation protection. As I've said before, an oxygen atmosphere with sufficient partial pressure for humans to breathe will respond to UV light. UV will convert O2 into ozone (3 O2 -> 2 O3). UV will also break down ozone back into O2. Expect an equilibrium with surface UV equalling that of Earth. As long as you don't do something stupid to destory ozone, like releasing CFCs. Martyn J. Fogg's book says a CO2 atmosphere will cause CFC to break down much more quickly than on Earth, and when it does it releases chlorine gas. It's actually chlorine that destroys ozone. That's why PFC is so good, it doesn't have any chlorine. Nitrogen absorbs X-ray, so nitrogen is good too. However you don't need as much as Earth.

Let's not commit ourselves to something that isn't required and can't be achieved. Instead let's set a reasonable goal, something we can achieve with resources available. For any ambitious endeavour I take the approach of assuming it can be achieved, don't flinch from grandiose schemes that appear completely unreasonable, then trim down to something that is practical. This approach has proven successful, I've found practical solutions for many problems others thought unachievable. Instead of whining about how hard something is, just get to work. But you can't obsess over a detail that is impractical. Mars is a smaller planet with lower gravity and currently has no magnetosphere, therefore expect it will always have lower atmospheric pressure. We don't need to copy Earth; we just need something we can live on.

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#17 2007-07-10 21:18:24

RickSmith
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Re: Building soil

Hi RobertDyck.
  I think that Terraforming Mars is possible, however, I do think it will be a huge job taking a long time. I think that your idea of using bogs as a soil factory is brilliant.

  My point about bees and the Partial Pressure of CO2 is that we can have bees in domes, but it will be a long time before we have free range bees.  Not only do we have to raise the oxygen partial pressure (O2 p.p.) but we have to drop the CO2 p.p. tremendously.  (Which gets rid of a much needed green house gas.)

  My understanding is that a buffer gas in an oxygen atmosphere acts to reduce the flame temperature.  This means that some substances will burn in pure O2 that won't burn in our oxy-nitrogen atmosphere.  Of course this would be given constant pressure and you are suggesting a lower overall pressure.  Do you have a link or book that gives more detail on this?


  By the way, a Science Fiction world that has a high O2 p.p. atmosphere can be found in Spider Robinson's and Robert Heinlein's "Variable Star".  In this the world Brasil Nava (created by Guy Immega) there is a 30% O2 p.p. and wood will burn while wet (which drives how the world was planned to be colonized.)  The air pressure is close to Earth's.

  Warm regards, Rick

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#18 2007-07-11 12:51:19

noosfractal
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From: Biosphere 1
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Re: Building soil

Seashore mallow seen as biodiesel source
http://news.yahoo.com/s/ap/20070710/ap_ … e_mallow_2

Here is a crop for the bogs if they are salty


Fan of Red Oasis

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#19 2007-07-11 20:19:16

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,328

Re: Building soil

Another issue is that the higher the co2 is in the greenhouse the lower the nutricianal food value is.

What I am wondering is how many square feet of greenhouse will be needed for a crew of 6 knowing that the crops such that you have continous food growth of a variety of crops.

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#20 2007-07-11 23:59:29

RickSmith
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Posts: 244

Re: Building soil

Another issue is that the higher the co2 is in the greenhouse the lower the nutricianal food value is. ...

Hi SpaceNut, everyone.
I never knew that.  Do you have a reference to the study?

Warm regards, Rick

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#21 2007-07-12 07:32:37

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,328

Re: Building soil

Here is what was found and will copy this to the greenhouse thread in Human so as to keep soil creation on topic.


Article section in quote is what I am bring to the attention of all.

Achieving Solar Space Energy - An Interview With the Space Solar Power Institute's Darel Preble

2.   During your presentation you spoke about the decline in nutritional value of the world’s agricultural products, could you please explain that dynamic.

Preble:  Sure.  Let's examine wheat and rice - the worlds top two grains. At doubled carbon dioxide levels, plant-available nitrogen decreases 40 to 50 %, resulting in reduced nutrition from forage and grasses grown under doubled CO2. Wheat grown at doubled CO2 declines in protein content by 9-13% and produces poorer dough of lower extensibility and decreased loaf volume. 

Hence flour, produced from wheat grain developed at high temperatures and in elevated CO2, degrades. “The nutritive value of rice was also changed at high CO2 due to a reduction in grain nitrogen and, therefore, protein concentration.”  The protein content of rice declines under combined increases of temperature and CO2. Iron and zinc concentrations in rice, important for human nutrition, would be lower.

(By not eating whole grain products and eating "junk food" we have voluntarily reduced our nutritional intake by even more, so this is cumulative. We are becoming increasingly overfed, but undernourished.)  Ruminants, including cattle, sheep, oxen, buffalo, deer, - the source of nearly all the milk and half the meat the world eats - will  gain weight much more slowly grazing on forage growing under doubled CO2. CO2 is expected to reach doubled levels by mid century, under business as usual assumptions.

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#22 2007-07-14 21:14:36

Midoshi
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From: Colorado
Registered: 2007-07-14
Posts: 157

Re: Building soil

Well this is really cool for me. First post on New Mars, by the way. Short story is that I'm a fresh physics bachelor's graduate with a taste for hard sci-fi.

I happened to come up with the same idea of using a peat bog to terraform Mars a week or two ago. Lo and behold, when I poke around the internet I find a recent thread here on New Mars that confirms my hunches and really make a plausible case for the method. Awesome!

Unlike RobertDyck, I didn't come up with the idea through trying to figure out how to transform the soil (which was exceedingly clever, by the way). My thoughts were more along the line of characterizing what would happen once the temperature and pressure of Mars were raised and rain could develop (I've thought about how to do that too, but nevermind for the moment). I realized that the >611 Pa, >0 C conditions that would allow the first rains to fall (during some distant Martian summer, most likely) the average annual temperature of the regolith would still be far below 0C. [Note: Everything I talk about here refers to local environment parameters] The rain would permeate the ground until it hit the isotherm at which it froze (the depth of which would depend on local temperature, regolith thermal diffusivity, and the salinity of the water as it passed through the regolith) and would basically start forming permafrost. As the planet warmed more and more, the bottom of the permafrost layer would sink deeper and deeper, and whenever the temperature of the top was warm enough during the summers it would form an unfrozen active layer above the permafrost. This would continue until the average annual surface temperature was above the groundwater's freezing point, at which point you'd have no more permafrost caused by the annual cycle. You would still find it if you went down far enough that the ground hadn't yet felt the full effects of terraformation. But this level too would slowly recede deeper into the ground if average temperatures above freezing point were maintained at the surface. I'm interested mostly in the sub-freezing point surface average period, during which the permafrost layer would be near the surface.

What does this have to do with bogs? Well, it's not hard to realize that the permafrost would cap the depth to which rain could seep, just like in the arctic on Earth. As mentioned before, this limit varies according to the local average surface temperature, the water's salinity and the thermal diffusivity of the regolith, but would be on the order of centimeters to meters using typical regolith parameters and freezing points of fairly dilute salt solutions, meaning that a relatively small amount of groundwater would actually be needed to saturate the regolith up to the surface (I have numbers for much of this, if anyone is interested...). Once the soil was saturated, the temperatures and soil type (as so beautifully explicated by RobertDyck) would combine to produce an environment very similar to a tundra bog here on Earth. With vegetation this type of system is capable of producing peat, which could be used not only for fertilizer but as an economic crude fuel for colonists as well.

Things might get a bit tricky once you increase the average surface temperature above the water's freezing point. In some places bedrock would be close enough to the surface that it would sustain the bogs, in others you might have pre-existing ancient permafrost that would provide ready-made groundwater as things warmed up. Unlucky areas would simply drain out and become cool deserts with an ever deepening watertable. I've been looking at some radiograms of the subsurface by MARSIS to get an idea of where you'd want to avoid farming because of excessively deep bedrock or permafrost, but not much has been released and the images aren't very illuminating. I'd like to add that information to a map I'm constructing of suitible settlement locations, so if anyone's knows of any data/images on that sort of thing I'd be much obliged.

My apologies if that was excessively long for a first post.


"Everything should be made as simple as possible, but no simpler." - Albert Einstein

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#23 2007-07-14 21:30:24

RickSmith
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Re: Building soil

Hi Midoshi,
  Welcome to the terraforming forums!  Don't worry about the length of the posts, especially if you have interesting information to share.

  The numbers you were talking about...  were they discussing the amount of water needed?  In any case feel free to share them, the more hard data the better!  With all the craters, there should be plenty of places where we could have the poor drainage needed for bogs.

  If we have beg enough mirrors warming the poles, we should get increasing amounts of water running south to north during southern summer.

  Does anyone know how salty it can get before Sphagnum Moss is inhibited?

Glad to hear from you Midoshi,
Warm regards, Rick.

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#24 2007-07-15 06:23:06

noosfractal
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From: Biosphere 1
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Re: Building soil

Hi Midoshi, great first post  smile  I'll second Rick's welcome and I'd also love to see what numbers you've come up with for permafrost dynamics. 

Maybe you also have some comments in the context of microterraforming where we would try to create plant-friendly conditions in just one (say 10 km diameter) domed crater.


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#25 2007-07-17 00:35:41

Midoshi
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From: Colorado
Registered: 2007-07-14
Posts: 157

Re: Building soil

Thanks RickSmith and noosfractal! I appreciate your welcome. :3

So, I guess I should start with some background theory on how shallow subsurface temperatures work. Couple of assumptions here..

#1) That we're close enough to the surface that the radiation from the Sun absorbed by the surface dominates the subsurface temperature and that heating by the planet's internal sources is negligible. This is a pretty good approximation down to a couple hundred meters on Mars in places without geothermal hotspots.

#2) That the density and thermodynamic nature of the regolith is the same underground as it is on the surface. This one really depends on the local geography, since you might have bedrock a few centimeters beneath the surface in some places and perhaps almost a kilometer in others. Based on analysis of craters, there's evidence that the regolith goes down a few tens of meters on much of Mars (inside a crater I'm not so sure).

#3) We're talking about a one dimensional model here. Just temperature versus depth. Pretty good assumption if the regolith is fairly homogenous horizontally, which it is in most open places. Areas near the edges of crater walls or at the interface of a sandy and rocky area would be exceptions.

Okay, now that those are out of the way, it's time to introduce the idea of 'thermal skin depth'. This is basically a first order approximation to how deep a change in temperature on the surface effects the subsurface temperature. It turns out that relatively fast changes (like daily temperature cycles) don't penetrate very deep into the ground; that is, they have a shallow skin depth. Annual changes, on the other hand, penetrate much deeper, and long term trends on a geological scale can effect the temperature of the ground very deep indeed.

And so, given the assumptions above, the skin depth of a temperature change occuring over a period of time t effects down to a depth:

d = I/(p*C)*sqrt(t/pi)

where I is the thermal inertia of the ground, p is the density of the ground, and C is the heat capacity of the ground. There are many ways to express this equation, but I find this the most convenient for this application since we have maps of Mars' thermal inertia, as well as measurements of regolith density from several surface probes and decent estimates of heat capacity based on our knowledge of the regolith composition.

Okay, on to the numbers I promised! Pretend, if you will, that we have jacked up the average annual surface temperature of some part of the Martian surface to 0C. It turns out that the underground temperature at the skin depth is equal to the integrated average of the surface temperature over the period of time t. This means that the temperature at the annual skin depth will be 0C. Since (fairly pure) water freezes at 0C, the annual skin depth will give us a first order estimate to the active layer depth, that is, how far down the ground will ever thaw and allow liquid water to persist in the summer. For various 'surface' parameters:

pure liquid water @ 0C: 2.8 meters
pure water ice@ 0C: 8.4 meters
high thermal inertia regolith: 2.6 meters
low thermal inertia regolith: 0.11 meters

One thing I have to say right away is that the water and ice calculations do NOT in any way take into account the heat of fusion, that is, the energy it takes to melt ice into water. To do that would require more complex modeling involving a function describing the surface temperature at any point in the year...even including day/night cycles if they were violent enough to cross the 0C point routinely! While this wouldn't be incredibly hard to do, we can extract a lot of info without going to all that trouble. Suffice it to say that 8.4 meters is an upper limit and 2.8 meters is something of a more realistic estimate for a thin water 'crust'. Don't take this too seriously though. It's not like we're accouting for convection or anything, since we're really talking about regolith saturated with water where convection is retarded to the point of negligibility.

It's interesting how close the liquid water and high inertia regolith are, and without doing explicit calculations for groundwater saturated regolith we can guess that the skin depth is going to be ~3 meters for much of Mars. The ice and low inertia regolith represent the extremes of the Martian skin depths, varying by nearly an order of magnitude! Note that like with electrical conductivity, the characteristics of the material presenting the 'path of least resistance' dominates when present in significant amounts. Thus, low inertia regolith (60% porosity) saturated with pore ice would have a skin depth much closer to that of pure ice than pure regolith.

So what good does all this do us? Well, most importantly we can make some estimates of the maximum amount of water needed to saturate Mars' regolith on a global scale. Assuming the 'worse case scenario' of having to fill down to 8.4 meters with liquid water over the entire globe at 60% porosity, we get an equivalent ice volume of 1.3 million cubic kilometers, which is slightly less than the amount estimated to be in a Martian single ice cap (1.6 million for each, as I understand). This is very comforting, and it gets better. Assuming a slightly more realistic warming by filling only up to ±30° lat and estimating a skin depth of 3 meters, we obtain a required ice volume only 150,000 cubic kilometers, or less than 5% of the total estimated cap inventory. Note that this does NOT account for the mass of the water required to be in the atmosphere for rain to fall on Mars...I've made other models for that. ;3  Suffice it to say that the amount (at least for the atmospheric parameters I've been using lately) is close to negligible compared to the total amount of groundwater needed for regolith saturation between the surface and permafrost limits.

While these calculations give some idea of how much water would be needed to create a significant bog-like environment on Mars, they've got some issues. Notice, for example, that I didn't take salinity into account. The easy way to account for this is to just say the average surface temperature is equal to the freezing point of the salty water, e.g. if an area of Mars with groundwater salinity equal to that of the ocean (too high for moss...?) and an average annual surface temperature of -2°C (the freezing point of said water), the skin depth results would be pretty much the same as the ones derived for pure water and an average temperature of 0C. A really complete analysis would include the fact that the first water that rained down would pull salts underground with it...making the upper levels less salty (as has happened on Earth) and the deeper levels more so. This would mean that there could be a layer of liquid salty groundwater above salty ice but below fresher permafrost...and it'd mean you'd need slightly more water to fully saturate the ground.

Another (probably more obvious) thing I didn't account for was the topography of the Martian surface and the tendency for the groundwater to pool and form rivers and lakes (possibly seas) in depressions. In fact, bogs could probably form in isolated craters long before widespread surface bogs became possible. Another benefit of craters (some moreso than others) is that you are dug in closer to the bedrock, meaning that once average annual temperatures break the freezing point of your groundwater it won't take much extra water (if any) to fill in down to the bedrock than it did to fill down to the permafrost. In these locations noosfractal's domed craters could possibly begin terraformation before outside pressure levels would otherwise allow, thus accelerating the oxygenation process and ozone formation (which I also have a model of).


"Everything should be made as simple as possible, but no simpler." - Albert Einstein

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