Discovery Guides Areas


Deep Sea Oil Spill Cleanup Techniques: Applicability, Trade-offs and Advantages
(Released August 2010)

  by Pam Graham  


Key Citations





algal bloom: a relatively rapid increase in the population of (usually) phytoplankton algae in an aquatic system. Typically only one or a few species are involved and the bloom is recognized by discoloration of the water resulting from the high density of pigmented cells. Although there is no officially recognized threshold level, algae are unlikely to be considered to be blooming unless more than 10,000 cells per milliliter occur.

bioremediation: use of biological agents, such as bacteria, fungi, or green plants, to remove or neutralize contaminants, as in polluted soil or water. Bacteria and fungi generally work by breaking down contaminants such as petroleum into less harmful substances. Plants can be used to aerate polluted soil and stimulate microbial action. They can also absorb contaminants such as salts and metals into their tissues, which are then harvested and disposed of. The use of green plants to decontaminate polluted soil or water is called phytoremediation.

bottom pressure: the pressure at the bottom of a column, solved by the equation: Pbottom = Ptop + pgh , where p = fluid density, g = acceleration due to gravity, and h = column height or depth.

capillary wave: a small, free, surface-water wave with such a short wavelength that its restoring force (force in the direction of equilibrium) is the water's surface tension, which causes the wave to have a rounded crest and a V-shaped trough. The maximum wavelength of a capillary wave is 1.73 cm.

Case-Based Reasoning (CBR): is a problem-solving paradigm that utilizes the specific knowledge of previously experienced, concrete problem situations (cases). A new problem is solved by finding a similar past case, and reusing it in the new problem situation. CBR is an incremental, sustained learning approach, since a new experience is retained each time a problem has been solved, making it immediately available for future problems.

centripetal force: the force necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation.

containment boom: large floating barriers that round up oil and lift the oil off the water.

convergence zones: an area of two converging strong ocean currents. According to NASA, oceanic convergence zones usually produce sharp changes in temperature and water mass characteristics and a lot of biological activity.

ecosystem: an area that contains organisms (e.g., plants, animals, bacteria) interacting with one another and their non-living environment. Ecosystems can be of any size (e.g., forest, meadow, and log).

enzyme: a specialized substance that acts as a catalyst to regulate the speed of the many chemical reactions involved in the metabolism of living organisms.

food web: a complex of interrelated food chains in an ecological community. Also called a food cycle.

hatchling: newly hatched bird, amphibian, fish, or reptile. For sea turtles, leaving the nest is a group activity that can take several days. The first turtles to hatch wait quietly until more nestmates are free of their eggshells. This creates a small air pocket that gives the hatchlings room to thrash around. The hatchlings do not instinctively dig upward but instead respond to the movement of nestmates in such a way that the turtles are brought to the surface. The activity of one turtle triggers the movement of others so that with sporadic outbursts the hatchlings move as a group toward the surface. As the ceiling and walls of the chamber collapse from the thrashing turtles, the floor rises until the hatchlings are near the surface. Turtles hatching alone or a few at a time have little chance of escaping from the nest.

in-situ burn: a controlled burn-off of oil on the surface of water. The "in situ burn" technique is a method approved by the Coast Guard and National Oceanic and Atmospheric Administration. The burns are conducted within fire resistant containment rings.The oil is either ignited from a helicopter or a boat.

marine environment: bodies of salt water and any plants, animals and other objects that exist in the bodies. Marine environments are diverse and can change rapidly depending on tidewaters and currents. They include many unique animals and plants, such as corals and bi-valves, and many unique habitats, such as underwater volcanoes.

micron: a metric unit of length equal to one millionth (10-6) of a meter.

microorganism: an organism of microscopic or submicroscopic size that typically consists of only a single cell. Microorganisms include bacteria, protozoans, and certain algae and fungi.

microwaves: electromagnetic radiation in the frequency range from 1 to 40 GHz or from 1 to 300 GHz, depending on the rating system. Numerous transmission systems use microwaves, including line-of-sight between buildings and across vast distances, as well as communications satellites, cellular systems and wireless LANs.

oiled wildlife: wildlife that has been exposed to oil. "Oiled animal" is actually fairly complex, as it can encompass a number of different presentations. First, animals can have apparent external exposure, as is typically seen with birds contaminated with a crude oil on their feathers. Wildlife can also show non-apparent external exposure, which is when birds or other animals do not have dark oil visible on their fur, feathers or scales, but oil can be detected by smell, feather matting, or other sensory clues. Third, animals can have apparent internal exposure, typically seen in live animals through oil in their feces, and in dead animals by visually assessing their gastrointestinal tracts on post-mortem evaluation. Fourth, an animal can have sub-apparent internal exposure, often determined by microscopically examining organ tissues, looking for damage that could be associated with toxin exposure. Last, oiling can also be determined through chemical analysis of different samples, be they feathers, swabs of skin, or tissue samples.

optical spectral region: the inexact range of wavelengths in the electromagnetic spectrum that is visible to the human eye. Typically, the human eye responds to wavelengths from 400 to 700 nanometers (nm), with a small percentage of people capable of perceiving wavelengths as short as 380 nm or as long as 780 nm.

polypropylene: a versatile polymer that serves double duty, both as a plastic and as a fiber. As a polymer, it is used to make things like dishwasher-safe containers. As a fiber, propylene is used to make indoor-outdoor carpeting, the kind found around swimming pools and miniature golf courses. Properties that make polypropylene a good boom material are that it is easy to make colored and it does not absorb water.

pre-dive inhalation: the intake of large volumes of air before diving. Sea turtles are almost always submerged in water, and, therefore, have developed an anaerobic system of respiration. Although all sea turtles breathe air, under dire circumstances they may divert to anaerobic respiration for long periods of time. When surfacing to breathe, a sea turtle can quickly refill its lungs with a single explosive exhalation and rapid inhalation. Their large lungs have adapted to permit rapid exchange of oxygen and to avoid trapping gases during deep dives. However, turtles must emerge while breeding, given the extra level of activity.

protozoans: any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.

salinity: the dissolved salt content of a substance like soil or water.

sea turtle: any of various large turtles with limbs modified into flippers, widely distributed in warm seas. Species include Caretta caretta (loggerhead turtle), Chelonia mydas (green turtle), and Dermochelys coriacea (leatherback turtle), using beaches as a nesting habitat.

solvent: substance that can dissolve another substance, or in which another substance is dissolved, forming a solution. Water is the most common solvent.

specific gravity: the ratio of the mass of a solid or liquid to the mass of an equal volume of distilled water at 4oC (39oF) or of a gas to an equal volume of air or hydrogen under prescribed conditions of temperature and pressure. Also called relative density.

surface tension: property of a liquid surface displayed by its acting as if it were a stretched elastic membrane. This phenomenon can be observed in the nearly spherical shape of small drops of liquids and of soap bubbles.

surfactant: (shortened form of "surface-active agent") a chemical that stabilizes mixtures of oil and water by reducing the surface tension at the interface between the oil and water molecules.

symbiotic relationship: a relationship between two entities that is mutually beneficial. Thus there is a positive-sum gain from cooperation. This is a term commonly used in biology to explain the relationship between two entities that need each other to survive and prosper.

water column: the open water of the ocean between the surface and the sea bed.

X-band radar: radars operating on a wavelength of 2.5-4 centimeters (cm) and a frequency of 8-12 gigahertz (GHz).