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Buoyancy - Whatever floats your boat
Publié par Corbridge Middle School, United Kingdom le 3 juillet 2018

We studied the buoyancy of different objects in different concentrations of salt water for a CREST Award. Buoyancy and salinity are linked to some major environmental issues:

1. Ballast water: fresh or salt water, sometimes containing sediments, held in tanks and cargo holds of ships to increase stability and manoeuvrability during transit. When ships dock their cargo at a port, they have to take on vast amounts of sea water to maintain their stability, which is then dumped at the next destination. Historically, ships used to take on ballast in the form of sand, but this is likely to have transported many non-native plants over here in the past. The potential of sea water ballast to carry non-native organisms from far away countries poses a very real threat and the control measures that have been put in place to date are not adequate.

Apparently a container can carry 100,000 m2 ballast water, which can contain a shocking 10,000 species, from bacteria and viruses to crabs and fish. This was responsible for an outbreak of cholera in Peru in the 1990s. Known invasive non-native species carried by ballast water include the carpet sea squirt, forming a physical barrier on the sea floor to native grazing fish, and the comb jelly, a voracious predator. With new ports and trade routes being created, this is becoming an increasing problem not just for its capacity to spread invasive species but also for the effect it can have on the gene pool and adaptability of populations.

  1. The Buoyancy of Ice

You may already know that there is a huge problem in the atmosphere and this problem is caused by greenhouse gases that are being produced daily. This causes global warming, which can damage the environment in Antarctica since the ice caps are being melted. This can cause rise in sea level and damages animal habitat. If Sea levels continue to rise in this way, then it will have a major impact on coastal homes, and will end up flooded. As ice melts the water becomes less salty and the remaining ice sheets may sink lower in the water which could cause sea levels to rise - even a couple of millimeters of additional sea-level rise couse make global sea-level rises even more serious.


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