Bacteria

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Q 1.
	Where in the sea is the greatest concentration of bacteria found?
Q 2.
	What types of bacteria act as the biological filter in gravel bottoms of marine aquariums? Also, are commercial cultures of these bacteria available for reducing the breaking in time of new aquariums?
Q 3.
	I have a diesel engine boat in which the primary fuel filter is loaded with what looks like a by-product of an oil-eating microbe. Is there any chemical or treatment that will kill the microbes and stop the clogging?
Q 4.
	How fast do bacteria grow on unrefrigerated seafoods?
Q 5.
	I have read that homing pigeons have a substance in their heads that allows them to detect the earth's magnetic field and navigate by it. Do any aquatic organisms have this material?
Q 6.
	Bacteria that could help clean up oil spills were described in the March-April 1977 and November-December 1978 issues of Sea Frontiers. Would these bacteria work well in a septic tank as a cleaning additive?
Q 7.
	The unusual bacteria discovered in the vicinity of deep-ocean vents along the East Pacific Rise were discussed in the September-October 1983 Sea Secrets on page 14. Do these bacteria survive at very hot temperatures, or are they only at the perimeter of the hot vents, where the water temperature is more moderate?
Q 8.
	Is it true that the frequency of left-right coiling in marine foraminifers reflects changes in seawater temperature?


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	Q&A 1.	Where in the sea is the greatest concentration of bacteria found?
	Although countless kinds of bacteria are found throughout the sea, they occur in the greatest concentration at the surface and at the bottom, with the mid-waters having the lowest concentration. The reason for this is that the distribution of decomposing organic matter, on which the bacteria thrive, is most concentrated at these depths. Oceanic bacteria are extremely important insofar as they reduce dead matter to water-soluble materials which serve as basic food materials for the sea plants, which in turn form the food basis for marine animals.
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	Q&A 2.	What types of bacteria act as the biological filter in gravel bottoms of marine aquariums? Also, are commercial cultures of these bacteria available for reducing the breaking in time of new aquariums? Fort Lauderdale, Florida
	The filtering bacteria in the gravel of marine aquariums are mostly of the genera Nistrosomonas and Nitrobacter. To the best of our knowledge, there are no cultures available commercially. The best way of reducing the breaking in time for a tank is to seed the newly laid gravel with a cup or two of gravel from the upper inch of an already established aquarium. The length of time for conditioning the new tank will, of course, depend on its size and the health and density of the seeding culture.
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	Q&A 3.	I have a diesel engine boat in which the primary fuel filter is loaded with what looks like a by-product of an oil-eating microbe. Is there any chemical or treatment that will kill the microbes and stop the clogging? Washington, D.C.
	Microbes, mainly fungi and bacteria, are a common problem in the diesel fuel systems of boats, especially in the tropics. Their presence suspended in the oil results in clogged fuel filters and fuel injectors. Three factors contribute to their growth and aggravate the problem: free water in the fuel, warm temperatures, and a long period during which to grow. Several approaches may be used to attempt to control the growth. The amount of free water in the fuel can be minimized by adding to the fuel isopropyl alcohol in a ratio of 1:1,000 (one pint per every 125 gallons of fuel). The microbes can be killed through the use of any one of several biocides commercially available (check with a local marine supplies dealer for a brand that has proven effective in your area). Finally, fuel should be used and replaced regularly. If a boat is to sit unused for a long period, its fuel tanks should be treated according to the manufacturer's instructions.
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	Q&A 4.	How fast do bacteria grow on unrefrigerated seafoods? Salem, North Carolina
	One bacterium on a piece of seafood will duplicate itself by dividing, in less than 20 minutes under ideal growth conditions (food, water, and proper temperature). These two bacteria will divide in the next 20minutes, resulting in four bacteria, and so on. Thus, if ideal growth conditions continued for eight hours, for example, one bacterium has the potential of growing into more than 16 million bacteria. All raw seafoods contain an initial amount of bacteria, but growth of these bacteria can be retarded. As recommended in Marine Advisory Bulletin MAP-22, Bacteria and Seafoods by Otwell and Koburger, the containers, utensils, and surfaces used to process raw seafoods should be thoroughly cleaned and sanitized before being used for cooked products. Seafoods should be refrigerated at between 32 degrees Fahrenheit and 40 degrees Fahrenheit. Frozen foods are typically stored at 0degrees Fahrenheit but, for seafoods, the author recommend -20 degrees Fahrenheit or below. Although it is written primarily for workers in the seafood-processing industry, Bulletin MAP-22 describes precautions that should be taken in the home kitchen as well. One copy is free upon request from the Marine Advisory Program, University of Florida, G022 McCarty Hall, Gainesville, Florida 32611.
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	Q&A 5.	I have read that homing pigeons have a substance in their heads that allows them to detect the earth's magnetic field and navigate by it. Do any aquatic organisms have this material? Fort Worth, Texas
	The green turtle, common Pacific dolphin, and Cuvier's beaked whale, as well as some bacteria, algae, chitons, and tunas, have been found to possess quantities of magnetite in their bodies. The iron-rich particles act like tiny compass needles, orienting to magnetic field lines. Certain aquatic bacteria and algae with magnetite tend to maintain a particular geographic heading. If the magnetic field is artificially altered, they change their direction of motion accordingly. Northern hemisphere bacteria orient toward the north, while southern hemisphere bacteria typically orient toward the south. Such behavior ensures that, at either location, the bacteria move down into the sediment. Magnetite in yellowfin tuna occurs in tissues in the snout. Through conditioning experiments at the National Marine Fisheries Service, Honolulu, four yellowfins have been trained to distinguish the natural magnetic field in Hawaii from a stronger one. Their ability to use magnetic fields in their extensive migrations, however, has not been proven. Likewise, the importance of magnetite to sea turtles and marine mammals can only be speculated at this stage. Researchers studying this fascinating "sixth sense" hope to further explain how a wide variety of animals navigate during their remarkable migrations.
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	Q&A 6.	Bacteria that could help clean up oil spills were described in the March-April 1977 and November- December 1978 issues of Sea Frontiers. Would these bacteria work well in a septic tank as a cleaning additive? Deer Park, New York
	Bacteria designed to digest oil would probably not work well in a septic tank. The sludge in a septic tank is chemically much different from petroleum. Furthermore, most current work on oil degradation uses marine aerobic bacteria. While these bacteria might survive in a septic tank, there definitely is not enough oxygen available for them to work well. Generally, drainage contractors utilize soil microbes as a cleaning additive in septic tanks or cesspools.
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	Q&A 7.	The unusual bacteria discovered in the vicinity of deep-ocean vents along the East Pacific Rise were discussed in the September-October 1983 Sea Secrets on page 14. Do these bacteria survive at very hot temperatures, or are they only at the perimeter of the hot vents, where the water temperature is more moderate? Pittsburgh, Pennsylvania
	Bacteria have been isolated directly from the very hot water of the deep-ocean vents during research submersible Alvin dives. Microbial growth, as we know it, is apparently not limited by high temperature but rather by the absence of liquid water. At the high pressures found in the deep ocean, water can exist in liquid form at very hot temperatures and, thus, vent bacteria are able to exist in what might otherwise be considered a highly improbable environment. In laboratory experiments, John A. Baross of Oregon State University discovered that, at atmosphere pressure, some of the bacteria from vent seawater samples did not grow at all below 149 degrees Fahrenheit and remained viable up to 210 degrees Fahrenheit, close to the ordinary boiling point of water. He and his colleagues also found that, at simulated pressures of 265 atmospheres, bacteria collected from the inside of a "blacksmoker" vent-the hottest type-did not grow at temperatures less than 176degrees Fahrenheit, and they continued to grow at temperatures at least as hot as 482 degrees Fahrenheit. For example, at 482 degrees Fahrenheit and 265atmospheres, the number of bacteria doubled every 40 minutes (See "Growth of 'Black Smoker' Bacteria at Temperatures of at Least 250 degrees Celsius, Nature, 303: 423-426, June 2, 1983).
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	Q&A 8.	Is it true that the frequency of left-right coiling in marine foraminifers reflects changes in seawater temperature? Belleville, New Jersey
	A complete range of temperature effects is seen in planktonic foraminifers. The direction of coiling in some species is sensitive to temperature, while other species always coil one way or another, and still other species display random direction of coiling at all temperatures. For those species with a distinct temperature response, the proportion of left-to-right-coiling tests, or shells, has been used in determining ancient temperatures on Earth. The direction of coiling is a function of growth rate, the density of the calcium carbonate skeleton, and the differential effects of biological and physical factors on chamber formation. Temperature directly affects metabolic rates and sinking rates. The exact mechanisms by which temperature changes the direction of coiling in certain foraminifers are not known.
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