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Throughout our existence, human beings have taken advantage of
the resources that the ocean provides. As a result of global industrialization
and a boom in population size, this once seemingly inexhaustible
resource has become threatened by human activity. Oil spills and
pollution, careless commercial fishing practices, and general disregard
for delicate marine ecosystems has given rise to several serious
problems.
When people picture an oil spill in their mind, they see an enormous
ship crashed upon the rocks, oozing thousands of gallons of crude
oil into the surrounding water. Unfortunately, as our demand for
energy rapidly increases and more oil is transported across our
oceans, this scenario is becoming all too common. Accidents during
shipping are inevitable. The number of oil spills will continue
to increase with our demand for fossil fuels. When these oil spills
occur they have devastating effects on marine organisms nearby.
Also, due to inadequate methods for containment, spills tend to
have far reaching effects, as the contaminants spread. Organisms
that have been in contact with the oil suffer greatly. Sea birds,
for example, become matted in the oily water, and cannot maintain
body warmth or buoyancy. Those that do not drown or freeze to death
often die from ingestion of oil as they desperately attempt to clean
the goo from their feathers; marine mammals such as sea otters and
seals experience similar problems. Though whales and dolphins are
not effected in this manner, they are often poisoned by ingesting
contaminated fish. The entire food web is damaged as oil builds
up at different trophic levels.
Fortunately recent technological improvements have allowed us
to respond to oil spills relatively quickly, and perform a clean
up with modest success. The methods we use today for oil spills
in the water include booms, burning, dispersants, and skimming.
For beach cleanups, bioremediation, chemical cleaning, hot water/high
pressure, manual treatment, and mechanical treatment are the methods
used.
Boom: long links used to surround and collect oil
Burning: ignites gaseous oil slicks to reduce to tarry
residue
Dispersants: Chemicals that breakup oil into small concentrations,
even
Individual molecules
Skimming: skims oil off the surface
Bioremediation: fertilizers stimulate the growth of
microbes that eat the oil
Chemical cleaning: chemicals used to clean oil from
the beach (detergents)
Hot water: high pressure blasts oil off beach for skimming
Manual Treatment: Shovels, rakes, and manpower to remove
oil
Mechanical: Heavy machinery used to "scoop"
oil off the beach
*These methods are not perfect, and are considered by many
environmentalists to be inadequate.
Another problem facing marine animal populations is bycatch from
the commercial fishing industry. While seeking a target species,
untargeted species of marine life are caught and killed. While these
species pose no loss to the fishermen, they are very valuable to
the ecosystem. Drift netting, seine netting, and trawling are several
of the methods that contribute to the large amounts of bycatch.
Shrimp trawling is probably the most destructive method, claiming
ten pounds of bycatch for every pound of shrimp. Drift netting and
seine netting entrap air-breathing animals such as dolphins and
turtles that drown before they are discovered in the nets. In addition,
drift netting entangles animals such as sharks that must continue
swimming in order to breathe. These organisms suffocate when they
become entrapped in the net. Such indiscriminate fishing techniques
are rapidly depleting many marine organisms including the highly
endangered Vaquita, whose numbers are thought to have dwindled to
several hundred animals.
Pollution is an obvious problem faced by ocean ecosystems as large
quantities of garbage and waste continue to be dumped into the sea.
Many pollutants such as broken glass, plastic bags and six-pack
rings cause the untimely death of animals that mistake them for
food or become entangled in them. Runoff is a specific form of pollution
that is often in the form of industrial and agricultural waste.
These toxic substances leech into the sea through storm drains,
sewer systems, rivers, and the water table. Such substances include
chemicals such as lead, mercury, cadmium, chromium, soaps, detergents,
pesticides, herbicides, fertilizers, and other inorganic byproducts
of industry. They can also include living matter such as viruses,
bacteria, and other microbes. Needless to say, these compounds disturb
the ecosystem once they reach the ocean. With the coastal populations
growing larger every year, larger amounts of runoff are causing
serious problems for marine biota.
There are many different ways to measure the amounts of these destructive
chemicals in the ocean. Excessively high levels of certain elements
can lead to an unhealthy marine environment. The marine environment
has a range of levels of different chemicals that are acceptable
for living organisms. One good method to test the chemical health
of the ocean water is pH testing. While this does not pin point
the exact chemical or chemicals (cause) that may be polluting
the water, it does offer a mechanism by which we can quantify their
effects.
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