Examples of Surface Tension

We talked about surface tension in class today, one example given was the water strider walking on water. Here are some other interesting ones taken from http://hyperphysics.phy-astr.gsu.edu/hbase/surten.html :

1. Floating a needle: If carefully placed on the surface, a small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink.
2. Don't touch the tent!: Common tent materials are somewhat rainproof in that the surface tension of water will bridge the pores in the finely woven material. But if you touch the tent material with your finger, you break the surface tension and the rain will drip through.
3. Clinical test for jaundice: Normal urine has a surface tension of about 66 dynes/cm but if bile is present (a test for jaundice), it drops to about 55. In the Hay test, powdered sulfur is sprinkled on the urine surface. It will float on normal urine, but sink if the S.T. is lowered by the bile.
4. Soaps and detergents help the cleaning of clothes by lowering the surface tension of the water so that it more readily soaks into pores and soiled areas.
5. Surface tension disinfectants: Disinfectants are usually solutions of low surface tension. This allow them to spread out on the cell walls of bacteria and disrupt them. One such disinfectant, S.T.37, has a name which points to its low surface tension compared to the 72 dynes/cm for water.
6. Washing with cold water: The major reason for using hot water for washing is that its surface tension is lower and it is a better wetting agent. But if the detergent lowers the surface tension, the heating may be unneccessary.

Man-made sandbar might save disappearing Ocean Beach

Saw this on mercurynews.com:

Man-made sandbar might save disappearing Ocean Beach

Associated Press

SAN FRANCISCO - Engineers believe they have solved the problem of Ocean Beach's disappearing coastline, which has vexed engineers for decades while creating millions of dollars in damage.
The Pacific Ocean takes more sand than is replaced, which has resulted in disappearing sand dunes south of Sloat Boulevard and damage to beach parking lots and the Great Highway.
The Army Corps of Engineers believes the solution lies in the creation of a sandbar a half-mile offshore using 300,000 cubic yards of sand it dredges each year from the shipping channel outside the Golden Gate.
The sandbar will lessen the wave energy and provide sand to replenish what is washed off the beach, engineers believe.
The corps has tested the idea, and dropped about 275,000 cubic yards of sand in June 2005. It dumped another 300,000 cubic yards in May.
Patrick Barnard, a coastal geologist with the U.S. Geological Survey, said tests show that the 1,000-meter stretch of coastline targeted in the tests has grown by three feet.
Even if the experiment is behind the beach's three-foot growth, engineers say it may take 10 or 20 years to restore the beach. There are still issues outstanding, such as the ideal shape and location for the sandbar.

Taken from: http://www.mercurynews.com/mld/mercurynews/news/local/states/california/northern_california/16563632.htm

Corals at risk as Caribbean waters warm again

Scientists are worried that as the Caribbean waters get warmer, there may be a repeat of the widespread coral death as a result of bleaching, that took place in 2005. As U.S. Geological Survey biologist Caroline Rogers told The Associated Press "about 40 percent of coral died around parts of the U.S. Virgin Islands last year, and the coral that survived likely isn't healthy enough to survive another hot summer". Rogers has studied Coral reefs in the U.S Virgin Islands for 22 years and is worried that the warming situation is looking a lot like that which occured in 2005. She also states that it is almost impossible to stress how important this is. Coral in Puerto Rico and the U.S Virgin Islands that are disease infested and bleached by warm waters, was especially hard hit last year.

Tyler Smith, a marine researcher at the University of the Virgin Islands states that "the rising temperatures appeared to be something new that the corals aren't used to" and he has "seen some very large colonies — 100-year-old colonies — in the Virgin Islands that have completely died".

The U.S. National Oceanic and Atmospheric Administration said waters were also warmer than usual in the South Pacific, mid-Atlantic and Indian oceans this month.

Coral reefs form a part of the Caribbean's multi-billion dollar tourism industry, as it is visited by tourist who are diving or snorkelling in the water. Read more at http://www.msnbc.msn.com/id/12475917/

Ocean Sediments

Just a little more information on ocean sediments.
Organic or inorganic matter originating from erosion or weathering of rocks, chemical processes involving sea water and the oceanic crust, volcanic eruptions and tghe activity of living organisms etc. that accumulates in unconsolidated, loose form is defined as sediment.
Sediments record the past, so sediments on the ocean floor will tell history of ocean basin development, tells when the ocean floor was formed (by studying age of the sediments and magnetic reversals), and will contain fossils that indicate ancient life in the sea.
There is biogenous sediments which is made up of 48% for calcareous ooze and 14% for siliceous ooze of the deep sea floor sediments, which is formed from the remains of living organisms (plants and animals). Sediments derived from rock are called lithogenous/terrigenous sediments, there is also authigenic (formed on or in the sediments on the sea floor), volcanogenic (particles from volcanic eruptions) and cosmogenous (particles from outer space). Read more at http://maritime.haifa.ac.il/departm/lessons/ocean/lect09.htm

The Blue Planet- Deep Sea

Check out these really amazing video clips:
http://www.youtube.com/watch?v=W9Er4dpUfrM

http://www.youtube.com/watch?v=00YJIyoZ56U

http://www.youtube.com/watch?v=DaEHbBV4IGg

Salt-Water Fish Extinction Seen By 2048

Came across this article, thought it was a bit shocking and depressing, but interesting.
An international team of economists and ecologists think that pollution, climate change, habitat loss and over fishing resulting in the disappearance of numerous species will cause the worlds ocean to be empty by 2048.
Boris Worm, PhD, of Dalhousie University in Halifax, Nova Scotia, with colleagues in the U.K., U.S., Sweden, and Panama, conducted a study in an effort to understand what this loss of ocean species might mean to the world.
These researchers analyzed several different kinds of data, data from 32 experiments on different marine environments. They found that already 29% of edible fish and seafood species have declined by 90% -- a drop that means the collapse of these fisheries. The researchers note that "the issue isn't just having seafood on our plates. Ocean species filter toxins from the water. They protect shorelines. And they reduce the risks of algae blooms such as the red tide". They also state that "the loss of species isn't gradual. It's happening fast -- and getting faster. Worm and colleagues call for sustainable fisheries management, pollution control, habitat maintenance, and the creation of more ocean reserves". Read more at http://www.cbsnews.com/stories/2006/11/02/health/webmd/main2147223.shtml

Greenhouse gas turning oceans acid

Researchers believe that the large amount of carbon dioxide (CO2), that is being produced by transportation and other manufactoring industries is posing a new and potentially devastating danger to the world. British scientist believe that large amounts of CO2 that already greatly contribute to global warming is now posing a serious threat to marine life such as coral reefs and fish. It is now thought that CO2 "is also rapidly turning the world's oceans acid as it is dissolved in sea water, and putting an enormous array of marine life at risk.
Ocean acidification may wipe out much of the microscopic plankton at the base of the marine food web, and have a knock-on fatal effect right up the chain, through shellfish to major human food species such as cod. It is already known to be having a serious impact on some organisms such as coral, and putting a question mark against the whole future of coral reefs". Read more at http://www.nzherald.co.nz/section/story.cfm?c_id=5&objectid=10009477

Underwater Jamaica

http://www.youtube.com/watch?v=4Xc1EeMJa1I

NB: Cathy when I was going through these i realised that the other two videos had been removed from youtube, so i deleted them from the blog post.

The Ocean

Some Quick facts about the Ocean:

• The deepest known point on Earth is at the bottom of the Mariana Trench, a depression in the floor of the western Pacific Ocean, just east of the Mariana Islands. The Mariana Trench is 1,554 miles long and 44 miles wide. Near its southwestern extremity, 210 miles southwest of Guam, lies the deepest point on Earth. This point — referred to as the “Challenger Deep”— plunges to a depth of nearly 7 miles.
• The ocean bottom is divided into three major areas: the continental shelf, the continental slope, and the deep ocean basin.
• The Earth’s longest mountain range lies under the sea. Over 56,000 kilometers (35,000 mi) long, this mountain range, called the Mid-Ocean Ridge system, snakes its way around the globe.

Read more at http://www.ocean.udel.edu/deepsea/level-2/geology/deepsea.html

Impacts of bottom trawling

Bottom trawling plays a major role in disrupting or destroying life on the ocean floor. Here is a video that shows some of the impacts of bottom trawling http://www.youtube.com/watch?v=kRME2Sfqsnk

Global warming threatens basis of marine life in the world's ocean

Came across this interesting article on usatoday.com. According to Seth Borenstein (AP, Science Writer), new NASA satellite data show that as the world's oceans get warmer the critical base of the ocean food web is now shrinking. "The discovery has scientists worried about how much food will grow in the future for the world's marine life.
The data show a significant link between warmer water — either from the El Nino climate phenomenon or global warming — and reduced production of phytoplankton of the world's oceans, according to a study in Thursday's journal Nature". Read more at http://www.usatoday.com/weather/climate/2006-12-06-marine-life-threatened_x.htm

Where in the Bahamas did Columbus first land?

I found it interesting and fascinating that people have spent so much time and effort trying to figure out exactly where in the Bahamas Columbus first landed. I googled this and found that they have concluded after much debate and interpretation of Columbus' journal that "in 1492, Christopher Columbus made his first landfall in the New World on the island of San Salvador in the eastern Bahamas. After observing the shallow sea around the islands, he said "baja mar" (shallow water or sea), and effectively named the area The Bahamas, or The Islands of the Shallow Sea". http://www.bahamas.com/bahamas/about/general.aspx?sectionid=1597&level=1 For further reading or to find out how they came to the conclusion that San Salvador was infact the island that Columbus first landed see http://www.newworldexplorersinc.org/ColumbusNav%20&%20Landfall.pdfsNav%20&%20Landfall.pdf

Here is a picture of Columbus Isle, San Salvador, Bahamas.