The Sea Base is a floating sea colony that will be used on both earth and mars. It is built out of materials congealed from the sea. Mainly, in a process I yet do not understand, a charged anode and cathode are put in water, and after about a half a year, with a current of around 1 milliamp, you will have a metal that is much stronger than steel, and 1/4 the weight of aluminum. That metal is magnesium. Magnesium is a water-soluble compound that can be a salt, a solution, or a metal, or many other things. Combining elemental magnesium with the material known as manganese, we can make a water-resistant, hard, and easy to get metal. Only problem is, if you want a lot of it, make orders a year in advance. (note: the actual congealing time can be much shorter than a half a year, it's just that I prefer extremely safe and tough structures that are garunteed to last a tempest or two)The entire base can be congealed in a month with a toughness of something like concrete. I think that we could make the whole thing in a week, but a single torpedo would sink the structure. One major advantage of magnesium congealment is that although it does use power, it uses a teeny-weensy amount, and you could build a brick sized piece of magnesium (in a half a year, of course) with a double-a battery. All we have to do to shape something is to simply change the shape of the wires.
The actual colony is not going to look anything like what you think it will. It is going to be a highly efficient colony, that produces excess power, and has no need for imports, gets the food at the base of the food chain with no fear of exterminating it. And that food is algae. In a process outlined in the page, we create edible ( and palatable) food out of algae grown in nitrogen ponds. The colony will be modular, we can grow the pods out on the sea, with no fear of having to import. It's basically a one-way trip there, and then we get down to business.
Ocean Thermal Energy Converters. "This is the pulsing heart of the Sea Base. It works in a simple, yet efficient way. The OTECs of the Sea Base will operate on an open cycle, using sea water as the working fluid. The secret to making the open cycle work is a low pressure chamber. Since the boiling point of any liquis is dependant on the ambient air pressure, you can lower a liquid's boiling point by lowering the pressure around it. In the open cycle, the warm sea water is admitted into a vacuum chamber where the pressure has been reduced; at this lower pressure, .43 psi, the boiling temperature of seawater is onle 80 farenheit. The OTEC consumes 700 calories of power for every 1000 it produces. We can do this by locating our colony on the equator. Wecan pump up warm water in to the pressure chamber, and the warm water will evaporate, turning a turbine, which turns a generator. This is nearly twice the efficiency of a nuclear power plant. Cold water is brought up from a depth of 3300 feet through a pipe 40 feet in diameter, and is pumped through a condenser at a rate of 9400 cubic feet per second. Since water has nearly neutral bouyancy, the cold water pump must overcome only the density differance between the cold water and the warm surface water, plus the friction losses in the pipe. Even though the water is being raised over 3300 feet, it requires only the energy needed to pump up an equivelant volume 18 feet on the surface.
Nevertheless, an enourmous propellor-type pump, mounted inside the cold water pipe, is needed to supply this motive force. There are other power useres on an OTEC as well. A 100 megawatt OTEC absorbs 41 megawatts for its own operation. These are also efficient by discharging nitrogen-rich cold water through a filter that then carts the nitrates of to the algae, which feeds us. We also cool down the equatorial waters, slowing the greenhouse effect. Water vapor is far and away the most powerful greenhouse gas. Absorbing infrared radiation over a wide spectrum, it will be the death of us if we continue our industrial operations. When the equatorial water temperature reaches a critical temperature, steam that comes off will aid the greenhouse effect by causing it to heat some more. This will cause a "runaway greenhouse effect". It will be armagaddeon. Aside from doom and death, OTEC components are large, highly specialized and sophisticated peices of machinery, which, at least initially, must be purchased from outside suppliers. The costs of a 100 megawatt OTEC break down as follows:
Item Cost$/KW
Flash Evaporator $53.16
Surface Condenser 354.11
Retubing 113.41
Air Removal Vent Condenser 27.01
Turbine 220.90
Generator Exciter 40.42
Sea Water Pumps 132.73
Conensate Pump 2.21
Air Removal Equipment 181.43
Fouling Control System 57.71
Auxiliaries, Power Conditioning 50.89
Hydrogen Production 340.00
Total Capital Cost Per Kilowatt $1,573.98
At this price, the components for a 100 megawatt OTEC module will cost $157,000,000--installed. The Sea Base will house seven 100 megawatt OTEC modules, at a cost of $1,100,000,000.
Each module will produce 59 megawatts of net electrical power. Of this power, 113 megawatts--most of the production of two modules--will be dedicated to internal purposes. The 100,000 colonists living on the Sea Base will require 1 kilowatt per capita, 100 megawatts; the remaining 13 megawatts will be used in various industrial operations in the Sea Base. This will leave a balance of 300 megawatts for export, at a production cost of 1/2 cent/kwh.
Well, away from the doomsday predictions and cost charts, the colony has no solid wastes. It uses Super-Critical Water Oxidizers to completely burn-off (no pun intended) the "undesirables". This base will be the launching point of many space missions, and with a little tinkering, we could rig a drill that was built from a discarded deep-water pump.
Nitrogen is vital to plant metabolism. It is the basic building blocks of all amino acids--the backbone of proteins. Nitrogen availability is usually the limiting factor in plant growth, both on land and at sea. Available nitrogen in the surface in the surface waters of the tropical seas is very quickly absorbed by phytoplankton--single celled plants like diatoms and other algas. If there is an abundance of nitrogen available, algae reproduce exponentially and the nitrogen is quickly absorbed.
Food production is essentially a nitrogen supply problem. If there is enough nitrogen available, then ample food can be produced. Most plants can't use elemental nitrogen, N2, directly from air or water because it is chemically unreactive and therefore difficult to metabolize. Plants require 'fixed' forms of nitrogen: nitrite(NO2), nitrate (NO3), or ammonia (NH3). On land, agriculture depends o producing nitrogen in fixed forms so plants can use them for growth. This is accomplished by recycling nutrients in the soil in the form of humus ot manure, by planting nitrogen fixing crops like legumes, or by using man-made fertilizers.
Fortunately, the oceans contain a virtually limitless pool of nitrogen in fixed nutrient forms. Because plants and animals take their nutrients into the depths with them when they die, the concentration of nitrates increases rapidly with depth, reaching a peak around 3300 feet down under. Below 3000 feet, nitrate concentrations remain relatively constant throughout the worlds oceans--around .4 grams per cubic meter, or .00005 ounces per gallon.
Less than half of a gram may seem to be a little too diluted to be effective, at least by our standards. To think about how small this amount is, let's think that you are preparing a gallon of deep sea water. To this gallon you would add about nine tablespoons of sea slat. Then, you would add two ten-thousandths of a teaspoon of nitrate. This would be nothing larger than a grain of salt.
How can such a tiny amount of nitrogen be attributed to the explosive growth of phytoplankton? The answer lies in size. Compared to their land equivelants--grass--phytoplankton are extremely great potential of absorbing these nutrients. This is not biochemistry, this is geometry. A single plant, a blade of grass, would have a volume of 10 cubic millimeters. An equivelant volume in algae would require 10,000 plants, each with a volume of .001 cubic millimeters. The algae--depite having the same volume as the blade of grass--will have 100 times the surface area of the grass, and 100 times the grasses' ability to absord nutrients. The effective concentration of nitrate in sea water is, therefore, more like 0.5 ounces per gallon, enough to create a lightly concentrated plant food. To the micro-organisms, it nourishes, deep sea water is like fertilizer.
Links
Back to the Main Page
Marshall Savage's Webpage, the First Millennial Foundation, if you're interested. Funny. Maybe Tarchanna's the Second Millennial Foundation, in light of Savage's page.
IceFoX's Sea Base Page. His page is pretty much a version of this page grounded in reality.
