Gulf Oil Spill What happens to oil in salt water? What happens to oil in fresh water? How can an oil spill from an oil tanker affect the Mississippi River off the shoreline of New Madrid, Missouri? Oil spill from an oil rig along the shore of Gulf Shores, Alabama?
Example Know Need To Know What is the composition of the Mississippi River? What is the composition of the Gulf Coast? How will oil interact with these two different types of water? • Oil is…….. • Water is made up of…… • Oil behaves to water….
The Characteristics Of Oil • Crude oil is made up of complex hydrocarbon compounds that range from light gasses to heavier tars and waxes. Oil is composed of thousands of compounds in varying quantities. No two crude oils are exactly alike because of the many different compositions. • The different physical and chemical properties of crude and refined oils are very important - they influence the physical and biological effects of an oil spill, the behavior of a slick and the effectiveness of clean-up operations. Some oils are far more harmful to the environment and more toxic than others
Why Don’t Oil and Water Mix? • Water molecules are polar – they have a small positive charge at one end and a small negative charge at the other end, and they stick to each other. Oil molecules are non-polar – they have no charge. Because of this, oil molecules are more attracted to each other than to water molecules, and water molecules are more attracted to each other than to oil molecules.
Salinity of the Ocean • The salinity of ocean water varies. It is affected by such factors as melting of ice, inflow of river water, evaporation, rain, snowfall, wind, wave motion, and ocean currents that cause horizontal and vertical mixing of the saltwater. • But in the latitudes bordering the Equator the opposite condition prevails -- evaporation exceeds rainfall because high temperatures plus increased winds accelerate evaporation losses • Composition of Ocean Water • Element Percent of Ocean Water Oxygen 85.7000 Hydrogen 10.8000 Chlorine 1.9000 Sodium 1.0500 Magnesium 0.1350 Sulfur 0.0885 Calcium 0.0400 Potassium 0.0380 Bromine 0.0065 Carbon 0.0026
Chemical Character of the Mississippi River • Dissolved Solids in River Waters • Minnesota River glacial gravel and sand deposits in the northeast to sandstone and limestone hills • Illinois, and Missouri Rivers relatively soluble sedimentary rocks • The Ohio River drains mostly hilly and mountainous terranes composed of predominantly insoluble rocks
Hardness of River Waters • Both natural and human-influenced sources contribute chemicals to the dissolved solids of the Mississippi River. The chemicals can be separated into two groups based upon their electrical charge. The major positively charged chemical ions (cations) are calcium, magnesium, sodium, and potassium, and the major negatively charged chemical ions (anions) are bicarbonate, chloride, sulfate, and nitrate. The hardness of water increases as more calcium and magnesium ions are dissolved by tributary water flowing over naturally occurring rock sources in each river basin. Hardness is reported as the equivalent concentration of calcium carbonate in milligrams per liter. The value of hardness shown in the map for each basin is the median value in water samples collected at the gaging station closest to the mouth of the tributary. The graph on the left side of the figure shows the variation of the median hardness along the length of the Mississippi River for the period from 1970 through 1991.
Nitrate in River Waters • Figure 14. -- A wide range of human activities adds chemicals to rivers. The use of common salt, sodium chloride, to deice highways has contributed to the chloride concentration in rivers. Burning fossil fuels creates sulfur compounds that are major sources of sulfate for river water (Hem and others, 1990). In fact, the contribution of sulfur to rivers from anthropogenic sources may now be about one-half as much as from natural sources (Berner, 1971). Spreading fertilizers consisting of phosphate, nitrite, and nitrate compounds on cropland eventually adds to the total concentration of these chemicals in rivers as do other human activities such as the disposal of sewage effluents from metropolitan areas. Wastes from livestock production also add nitrogen compounds.
What happens to oil in the ocean? • The combination of biological, physical, and chemical processes is usually referred to as weathering. These weathering reactions have different rates depending on the chemical structure of the oil, habitat conditions (such as water temperature or oxygen and nutrient supply), and mixing of the water by wind, waves, and currents. In some spills, oil does not last much beyond weeks to months
No Two Spills Are Exactly Alike • Oil spills are a problem in part because we never know when or where they will occur. Many factors affect the seriousness of a spill - the type and quantity of oil spilled; where oil is spilled (on land, near shore, in a river or lake, on the open sea); weather conditions; surrounding environment; etc. This is why prevention and preparedness are crucial.
What Causes Spills? • An accidental spill is only one of several ways that oil ends up in Canadian waters. Naturally-occurring oil seeps, offshore oil and gas production, marine transportation, atmospheric fallout, waste discharges and runoff are other ways. In fact, the two major sources of oil input into the environment are municipal waste and routine tanker operations such as bilge washing. • Most accidental spills - at sea, in the Great Lakes and on land - are a combination of human error and circumstances. Weather can make navigation treacherous, heavy icing can disable a ship, equipment can fail, cold or hot weather can snap pipes, and offshore blowouts can occur at drilling sites.
What happens when there is an oil spill in slat and fresh water? • About 380 million gallons of oil enter the world's oceans and coastal waterways each year from natural and human sources. This illustration shows the approximate worldwide percentages arriving from each source. The relative inputs of oil can vary significantly in different parts of the world. The percentages for transportation include oil lost specifically in oil/petroleum commerce (tankers, pipelines, etc.), as well as the normal operation of all other sea-going vessels.
What happens to oil in the Mississippi River? • When oil pours into shallow waters with muddy sediments—such as marshes or lagoons—and conditions allow the oil to become mixed into the mud, it will generally persist for a long time. This is a result of the fundamental chemistry of oil compounds. Since they don’t dissolve in water, oil compounds tend to adhere to particles in the water or get incorporated into biological debris, such as fecal matter or dead organisms. These oiled particles and debris settle from the water column and become part of the sediments on the bottoOil spills in fresh or inland waters, and especially in rivers, are more likely to contaminate shorelines. Fresh water is consumed by people, making it important to minimize contamination of drinking water sources.m.
Predict: • What are some other factors that could arise if the oil spill is not contained?
Are Local Conditions Important? • Very. Local environmental conditions such as weather, tides and currents, wind speed and direction, the difference between air and sea temperature, and the presence of ice flows, affect the behavior of spilled oil, as well as our ability to clean up spills quickly. Severe weather conditions can make navigation and routine maneuvers difficult, and cause an oil spill.
DEPTH • The Gulf of Mexico basin resembles a large pit with a broad shallow rim. Approximately 38% of the Gulf is comprised by shallow and intertidal areas (< 20 m deep). The area of the continental shelf (< 180 m) and continental slope (180 - 3,000 m) represent 22% and 20% respectively, and abyssal areas deeper than 3,000 m comprise the final 20% (Gore, 1992). The Sigsbee Deep, located in the southwestern quadrant, is the deepest region of the Gulf of Mexico. Its exact maximum depth is controversial, and reports by different authors state maximum depths ranging from 3,750 m to 4,384 m. Mean (average) water depth of the
Currents in the Gulf • The Loop Current commonly bulges out in the northern Gulf of Mexico and sometimes will shed a clockwise rotating ring of warm water that separates from the main current (Figure 1). This ring of warm water slowly drifts west-southwestward towards Texas or Mexico at about 3-5 km per day. This feature is called a "Loop Current Ring", "Loop Current Eddy", or "Warm Core Ring", and can provide a key source of energy to fuel rapid intensification of hurricanes that cross the Gulf, in addition to the Loop Current itself. The Loop Current pulsates in a quasi-regular fashion and sheds rings every 6 to 11 months. When a Loop Current Eddy breaks off in the Gulf of Mexico at the height of hurricane season, it can lead to a dangerous situation where a vast reservoir of energy is available to any hurricane that might cross over. This occurred in 2005, when a Loop Current Eddy separated in July, just before Hurricane Katrina passed over and "bombed" into a Category 5 hurricane
How will hurricane season affect the oil spill? How the oil spill in the Gulf of Mexico will affect the development of tropical storms this year is a question that scientists are still trying to figure out. The oil on the ocean surface can diminish the amount of surface evaporation, which would lead to local increased ocean temperatures near the surface
Hurricane season 2010 • Meteorologists predict there will be an average of 17 named storms with 10 of those storms developing into hurricanes in the Atlantic this season, which began on June 1 and runs through Nov.30.
The Effect of a Hurricane on the Oil Spill • The oil slick itself will be dispersed and degraded by its contact with the hurricane. The churning and mixing of the oil into the sea water causes the process of biodegradation to accelerate. In addition, the dispersal of the oil by the hurricane may cause it to spread over a larger area. The parts of the oil spill close to the coastline may be driven inland by the storm surge, creating additional problems with the clean up of debris. • Due to the counter-clockwise rotation of the hurricane, one passing to the west of a slick in the Gulf of Mexico can push the oil toward the coast whereas if it passes to the east it is more likely to push the slick back out to sea and away from the coastline
Picking up speed • Oil has been pouring into the Gulf of Mexico since April 20 from a blown-out undersea well, the result of an explosion and fire on an oil rig. The spill is located in a relatively stagnant area of the Gulf, and the oil so far has remained relatively confined near the Louisiana and Alabama coastlines, although there have been reports of small amounts in the Loop Current. • The model simulations show that a liquid released in the surface ocean at the spill site is likely to slowly spread as it is mixed by the ocean currents until it is entrained in the Loop Current. At that point, speeds pick up to about 40 miles per day, and when the liquid enters the Atlantic’s Gulf Stream it can travel at speeds up to about 100 miles per day, or 3,000 miles per month. The simulations all bring the oil to south Florida and then up the East Coast. However, the timing of the oil’s movement
What are some possibilities for the future?What will happen when the oil leaves the loop current?