Lobsters Are Osmoregulators Essay

1309 Words Jan 28th, 2006 6 Pages

To determine the principals of osmoregulation, we sampled two lobsters from each tank and there were three different tanks which the water ranged in salinity. The experiment is to determine whether the six lobsters tested are osmoregulators or osmoconformers, this is done by obtaining a sample of hemolymph. The first step of the lab is to prepare the needle and syringe that will be taking the hemolymph. The syringe size was 1 ml, and the intention is to collect between 0.5 and 1.0 ml of hemolymph. The needle size was 20 gauge, because anything smaller would destroy the hemolymph cells. Then the lobster was picked up with a firm grim around the dorsal celphao-thorax region and flipped over to expose the ventral side. The
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The first being the refractometer, which measures the light refraction though water. The amount of light ray refracted though the water determines the salinity. The refractometer required correct readings of temperature for it to be accurate. The other instrument is called hydrometer that measures the specific gravity of salinity in water. This was accomplished by the height at which the hydrometer floated in water. The amount of salt in the water affects its density; therefore the hydrometer gave an accurate reading of salinity. The water was also tested for the amounts of ammonium within the three tanks. The ammonium analysis began with a water sample from each tank. This was taken to the lab and diluted 1/10 with deionized water in a test tube. Three test tubs were used with 2.5 ml from the three different tanks and then the test tube was then filled with 22.5 ml of deionized water. Thirty drops of Mineral Reagent had to be placed in the test tubes, then 3 drops of poly-vinal alcohol. The last step was adding 1 ml of Nesslers Reagent, which had to be inverted before being placed in the spectrophotometer, which had a digital screen that produced the ammonium value. Oxygen levels were also taken, by a dissolved oxygen meter that measures the amount of oxygen dissolved in a unit volume of water.


It has been previously shown that lobsters are osmoconformres, which implies that their blood osmolarity is

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