The Human Presence in the Ocean

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The Human Presence in the Ocean
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Pollution is the introduction by man, directly or
indirectly, of substances or energy into the
environment resulting in deleterious effects such
as harm to living resources, hazards to human
health, hindrance of marine activities, including
fishing, impairing quality for use of sea water
and reduction of amenities.
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Pollution What is it?

• In studying pollution it is important to have a
  baseline from which to measure mans impact upon
  the environment because some of what is
  considered to be pollution may be occurring
  naturally and not caused by man.

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Pollution What is it?

• Pollution tends to be concentrated in three parts
  of the ocean environment the sea floor, the
  pycnocline, and the neuston layer.
• Pollutants are eventually broken down by various
  oceanographic and biological processes.

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Petroleum is a complex mixture of hydrocarbons,
combinations of hydrogen and carbon with various
amounts of nitrogen and metals.
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Hydrocarbons in the Sea

• Oil as it comes from the ground is called crude
  oil or petroleum.
• Only a small fraction of the oil in the sea comes
  from major oil tanker accidents.
• Once in the environment, an oil spill begins to
  be altered.
• The rate at which the oil is dispersed and
  dissipated depends upon the weather, composition
  of the crude and the waves and currents.

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Hydrocarbons in the Sea

• All oil is toxic at all levels of the food chain,
  but degree of damage depends upon the type of
  petroleum and upon the specific habitat and
  ecosystem.
• There are several methods employed in attempting
  to clean a spill Floating booms, Chemical
  dispersants, burning the oil at the surface,
  skimming, and bioremediation

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Each year humans produce over 20 billion tons of
wastes, much of which is disposed of in the
ocean.
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Municipal and Industrial Effluent

• Most of the wastes come from farmland, cities and
  industrial areas and enter the sea by way of
  rivers.
• Wastes tend to be concentrated in harbors, bays
  and estuaries.
• All bodies of water have a natural capacity to
  clean themselves of a certain amount of
  pollution, but dense populations can produce so
  much pollution that the self-cleaning capacity is
  exceeded.
• As pollution enters the sea, it can be greatly
  diluted depending upon the waves and currents.

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Municipal and Industrial Effluent

• Various pollutants behave differently depending
  upon their temperature, density and solubility.
• As effluents are released, they form a
  contaminant plume which increases in size with
  distance as the pollutant is diluted by
  surrounding water.

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Municipal and industrial wastes in the ocean can
be divided into three general categories sewage,
metals and artificial biocides.
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Municipal and Industrial Effluent

• Sewage consists of mostly human waste sludge or
  organic and inorganic chemicals.
• Heavy metal is a term loosely applied to a
  collection of elements such as lead, mercury,
  cadmium, arsenic and copper that normally occur
  in trace amounts in the ocean, but become toxic
  in larger dosages.
• Artificial biocides are man-made toxic chemical
  compounds that do not occur naturally.

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Hypoxia on Louisiana Shelf
1. Areal extent Largest oxygen-depleted waters
in west Atlantic Ocean (up to 16,000 km2 to
18,000 km2 of hypoxic water recorded, Rabalais,
1998) 2. Seasonality From late Feb. to early
Oct., and peaks in middle Summer when
stratification is most severe 3. Severity and
duration of hypoxia depends on the amplitude and
phasing of discharge from the Mississippi/Atchafal
aya rivers (Justic et al, 1993 Rabalais, 1996,
1998)
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ltgt Epidemiologic Notes and Reports Toxigenic
Vibrio cholerae 01 Infections -- Louisiana and
Florida
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• What is cholera?
• Cholera is an acute, diarrheal illness caused by
  infection of the intestine with the bacterium
  Vibrio cholerae. The infection is often mild or
  without symptoms, but sometimes it can be severe.
  Approximately one in 20 infected persons has
  severe disease characterized by profuse watery
  diarrhea, vomiting, and leg cramps. In these
  persons, rapid loss of body fluids leads to
  dehydration and shock. Without treatment, death
  can occur within hours.

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• How does a person get cholera?
• A person may get cholera by drinking water or
  eating food contaminated with the cholera
  bacterium. In an epidemic, the source of the
  contamination is usually the feces of an infected
  person. The disease can spread rapidly in areas
  with inadequate treatment of sewage and drinking
  water. The cholera bacterium may also live in the
  environment in brackish rivers and coastal
  waters.
• Shellfish eaten raw have been a source of
  cholera, and a few persons in the United States
  have contracted cholera after eating raw or
  undercooked shellfish from the Gulf of Mexico.
• The disease is not likely to spread directly from
  one person to another therefore, casual contact
  with an infected person is not a risk for
  becoming ill.

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Gymnodinium
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Noctiluca
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Pseudo-nitzschia sp.
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Pfiesteria
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Municipal and Industrial Effluent

• Bioaccumulation is the process whereby organisms
  retain and concentrate a toxic material within
  their body.
• Biomagnification is the process whereby a toxic
  material increases in concentration with each
  trophic level of a food chain.
• It results from bioaccumulation at each trophic
  level.

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Dredging accounts for 80 to 90 of the material
dumped at sea each year.
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Ocean Dredging and Mining

• If the dredged material is clean, dumped slowly
  enough, and is the same material as the original
  substrate, it presents no long-term environmental
  problem.
• Contaminated sediment represents an initial and
  long-term source of pollution.

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Mining of deep ocean deposits will most likely be
accomplished with a hydraulic pumping system that
will vacuum water, sediment and organisms from
the sea floor and bring them to the surface.
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Ocean Dredging and Mining

• The majority of the organisms drawn into the
  system will be killed.
• Large areas of the sea floor each day will be
  disrupted and stripped of life.
• Sediment released at the surface will create a
  massive sediment plume as it sinks to the bottom.

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All Earth systems, geologic, atmospheric and
hydrospheric, are interconnected and alteration
of one will impact the others.
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Climate Change

• Oceans store heat and transfer it poleward in the
  ocean gyres.
• Currents and upwelling can have a direct impact
  on local and regional climate.
• Carbon dioxide (CO2) in the atmosphere allows
  light to pass, but traps heat.
• Burning fossil fuel is increasing the amount of
  CO2 in the atmosphere and together with
  deforestation is causing the greenhouse effect or
  global warming.

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Climate Change

• Possible consequences of global warming include
• Melting of glaciers in Greenland and Antarctica.
• Rising sea level and flooding of most coastal
  cities.
• Smaller temperature differences between the
  equatorial and polar regions resulting in changes
  in wind and rain patterns.

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Based upon a study by the U.N., the current state
of the marine environment is
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The Oceans Future

• Most of the water of the open ocean is clean,
  except for heavily traveled shipping lanes.
• Coastal waters and shelf waters are contaminated
  to varying degrees everywhere and the amount of
  contamination depends upon population density,
  degree of urbanization, agricultural practices
  and shipping activity.
• Coastal habitats are being severely affected and
  destroyed at an increasing rate.
• Major pollutants in the ocean should be the
  immediate concern, but the long-term presence of
  minor pollutants is uncertain.

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The Oceans Future

• Too little is being done to reduce human activity
  on land that impacts the ocean.