speed. Aircraft Ballast tanks are also used in some types of aircraft: Aerostats (balloons and airships) Gliders Environmental concerns Ballast water taken into a tank from one body of water and discharged in another body of water can introduce invasive species of aquatic life. The taking in of water from ballast tanks has been responsible for the introduction of species that cause environmental and economic damage like zebra mussels in the Great Lakes of Canada and the United States, for example. Non native macroinvertebrates can find their way into a ballast tank. This can cause problems ecologically and economically. Macro-invertebrates are transported by transoceanic and coastal vessels arriving in ports all over the world. Researchers from Switzerland sampled 67 ballast tanks from 62 different vessels operating along geographic pathways, and tested for mid ocean exchange or voyage length that had a high chance of macro-invertebrate relocating to a different part of the world. An assessment was done between the relationship of macro-invertebrate presence, and the amount of sediment in ballast tanks. They discovered a presence of a highly invasive European green crab, mud crab, common periwinkle, soft-shell clam, and blue mussel in the ballast tanks of the sampled ships. Although the densities of macro-invertebrate were low, invasion of non-native macro-invertebrates can be worrisome during their mating season. The most serious effect is observed when a female macro-invertebrate is carrying millions of eggs per animal. Migration of living animals and settling particle-attached organisms can lead to changed distributions of biota at different locations of the world. When small organisms escape from a ballast tank, the foreign organism can upset the ecological balance of the local habitat and potentially damage the existing life. Vessel workers check the ballast tank for living organisms ≥50 μm in discrete segments of the drain, it also represents the level of sedimentary of different rock or soil in the tank. Throughout the sample collection, concentrations of organisms varied in result in the drain segments, patterns also varied in level of stratification in other trials. The best sampling strategy for stratified tanks is to collect various time-integrated samples spaced evenly throughout each discharge. All transoceanic vessels that enter the Great Lakes are required to manage ballast water and ballast tank residuals with ballast water to clear out and exchange for tank flushing. Management and procedures reduce the density and richness of biota effectively in ballast waters and thus