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Lecture 26
Human Presence in the Ocean

"By acquiescing in an act that can cause suffering to a living creature, who among us is not diminished as a human being?"
-- Rachel Carson, The Silent Spring

"By acquiescing in an act that can disrupt and destroy delicate ecological balances, who among us is not diminished as a human being?"
-- textbook paraphrase

Why We Should Care

Over half our population lives within 50 miles of the coast

We eat at least 15 lbs. of seafood per person each year

Just about everything bought & sold goes thru ports in cargo ships

15 million species in oceans & wetlands, each one vital to balance of nature

17% of our oil and 25% of our natural gas comes from offshore

peanut butter is spreadable because of an ingredient found the ocean!

Most of the worlds weather patterns...

The oceans are fun to be near or in...

Pollution - U.N. Definition, 1982

"Pollution is the introduction by humans, directly or indirectly, of substances or energy into the marine environment (including estuaries) 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."

Pollution - Pinet, 1998

"Pollution is the introduction OR extraction by humans, of material and energy from the environment, such that concentrations of these substances are raised or lowered below 'natural' levels to such a degree that environmental conditions change. This contamination by direct or indirect human activity is pollution whether the impact happens to be the living or to the nonliving parts of ecosystems."

Pollutants tend to be concentrated in three parts of the ocean.

-- The sea bottom because they chemically attach to silt and clay sized particles.

-- Along pycnoclines, especially in estuaries because the particles are trapped by the density discontinuity.

-- At the air-sea interface where conditions promote particle aggregation.

Hydrocarbons in the Sea

Petroleum is oil that occurs in sedimentary deposits.

-- It is a complex mixture of hydrocarbons, molecules that contain hydrogen, carbon, and minor amounts of nitrogen and metal.

-- Its composition varies depending on its geological history.

Oil can be light or dense depending on its size. The different types have different boiling properties.

In the process of distillation crude oil is heated and the different fractions are separated out to give rise to kerosene, diesel fuel, gasoline, and other petroleum products.

Much of the oil pollution in the ocean occurs when petroleum is transported from where it is pumped out of the ground to where it is refined and consumed. This is mostly due to "standard operational discharge" related to pumping bilges and ballasting ships.

Relatively little pollution occurs due to tanker accidents.

A substantial amount of oil is supplied by rivers which carry untreated domestic and industrial wastes to the sea.

Natural inputs of oil originate with phytoplankton and sea bed seeps.

Figure

The Wreck of the New Carissa

Exxon Valdez Oil Spill

SECOND biggest oil spill in U.S. waters

32,000 metric tons or 53 million barrels!

total death toll will never be known

1000 miles of shoreline damaged


Oil Spill Cleanup

The "Pac Man" solution:
- oil munching bacteria (bioremediation)

skimming oil off surface

high pressure hosing

burning

floating booms

chemical dispersants

Municipal and Industrial Effluent

Human activity creates an enormous amount of waste each year

-- 20,000,000,000 tons!!

much of it ends up in the ocean.

including toxic chemicals and pathogens (disease-producing organisms).

Human wastes fall into 3 major categories:

-- Sewage

-- Metals

-- Artificial biocides

The human population tends to be concentrated along rivers. As a result rivers contain a large proportion of contaminants and this material is transported to the coastal ocean.

Other material is discharged from underwater pipes.

Figure

Municipal and Industrial Effluent
(Cont.)

The area close to an outfall pipe may consist of few infauna. With increasing distance from the pipe depleted populations gradually reach normal densities. The responses of organisms to chemical contaminants occur at the cellular, organismal, population, and community levels.

Major Types of Waste

Sewage

Metals

Biocides

Sewage

Sewage consists of a messy sludge, a heterogeneous mixture of organic and inorganic chemicals.

-- A major component is human waste which contains organic matter, inorganic nutrients such as nitrogen and phosphorus, bacteria and viruses. The introduction of nutrients can promote phytoplankton blooms, especially in estuaries. Eventually the bloom dies, sinks and is degraded by bacteria. The decomposition process uses up oxygen and may cause the water column and sediments to become hypoxic or even anoxic. This sequence of events is referred to as eutrophication.

Fish and invertebrate kills often occur as a result of eutrophication because they cannot survive without oxygen.

The effects of sewage dumping also extend to the continental shelf where zones of hypoxic bottom water are becoming more and more common. Chemical poisoning that damages fish (e.g., fin rot) is also evident.

Figure

Metals

Most metals occur naturally in seawater at very low concentrations. They enter in river water and via volcanic eruptions. Many organisms require trace amounts of metals for the proper functioning of various physiological processes.

As a result of human activity, many metals enter the ocean, increasing the normal concentrations to such high levels that they become toxic.

Figure

Metals (cont.)

Mercury is a by-product of the chlorine-alkali and paper-pulp industries, is released from anti-fouling paints used to paint the hulls of ships, and is an ingredient of pesticides.

Once in the ocean it is adsorbed onto particles and settles out to the sediment. In this form it is very stable and resists bio-degradation.

Mercury is subject to bioaccumulation by organisms which consume the contaminated particles. Very high concentrations can build up in the tissues.

Consumption of mercury contaminated shellfish and finfish can lead to neurological damage, kidney malfunction and death in humans.

Biocides

Many artificial biocides are manufactured to control the growth of organisms e.g. insect pests. Others have biocidal properties, but they are used in manufacturing. Unfortunately, many of these compounds have entered the sea via run-off and have had devastating effects on sea life. Several halogenated hydrocarbons or organochlorines, in particular DDT and PCBs are potent biocides.

-- Unlike other hydrocarbons they are not readily degraded by bacteria. Thus, they persist for a long time in the environment.

-- Animals which ingest them have difficulty excreting them resulting in bioaccumulation.

DDT Biocide

The use of DDT was banned in the United States in the late 1960s, but it is still being manufactured and used in other parts of the world. It is typically applied by aerial spraying and much of it ends up being dispersed great distances by winds. It has been found in deep sea muds and in the ice of Antarctica.

PCB Biocides

PCBs are used to manufacture plastics, paints, electrical equipment and other products. They enter the ocean as fine particles following the incineration of discarded products. Their use was banned in the United States in 1979. Nevertheless, they are widespread in the oceans because they are not easily degraded.

Figure

Toxic Effects

Toxic effects of DDT and PCBs include:

-- The incomplete development of copepods and oysters.

-- The death of shrimp and a variety of fish.

-- The death of fish-eating birds.

Boston Harbor: one of the most polluted in the country
Sewage dumped from 48 communities




Boston Harbor Outfall Tunnel


Discharge of Treated Effluent by Way of an Engineering Masterpiece

Under the Sea Salad
(Serves 6)

3 cups rice, cooked & cooled
1/4 onion, chopped
1 green pepper, chopped
1/4 tsp. pepper 1/2 c. may or Miracle Whip
1 tsp mustard
1 6-oz. can dolphin-safe tuna, drained

Combine all ingredients in a large bowl, mix well, and refrigerate until ready to serve.

Coastal Development

Most of the worlds population lives close to waterways including the oceans. In most cases this presence is having a detrimental affect on coastal systems.

Coastal development interferes with the normal processes that affect coastlines. Remember the shoreline is a naturally changing system.

Coastal engineers build groins, seawalls, and dredge navigable channels to try to slow the rate and pattern of inevitable change.

Regional planning is needed to balance human needs and sustain the environment.

Ocean Dredging and Mining

In addition to using the oceans as a sink for the wastes produced by human activity, we are also removing materials from the oceans.

These activities include:
-- Dredging

-- Ocean Mining

Ocean Dredging

Dredging by the U.S. Army Corps of Engineers removes approximately 230 million cubic meters of sediment every years from navigable channels and coastal waterways.

Dumping

Generally ocean disposal of uncontaminated materials does not have major long-term adverse effects on the fauna.

Uncontaminated sand may be used for beach nourishment projects.

Ocean disposal of contaminated sediments poses a problem for animals when they recolonize the site, and some materials may be dispersed by coastal currents.

Ocean Mining

The oceans contain a vast array of valuable resources.

Shallow nearshore areas have been exploited for gravel, sand, phosphorite, and tin.

Deep sea regions harbor valuable resources, but this part of the ocean is more difficult to mine.

-- Manganese nodules containing manganese, copper, cobalt, and nickel blanket parts of the deep sea floor. The mining of nodules creates large sediment plumes which may have detrimental affects on benthic and water column organisms.

The Oceans' Future

A commonly held belief is that the oceans capacity for accepting human refuse and for self-cleansing is limitless. It is not.

The coastal ocean has a finite, natural capacity that in many cases has already been exceeded.

The most seriously polluted region is the coastal zone that borders large urban centers.

However, even the open ocean is showing signs of pollution. Areas that coincide with the major shipping channels are showing signs of contamination.

Since the ocean is a dynamic system and water is exchanged regularly no part of the ocean and for that matter the Earth is truly free of human influence.

All nations must work together to develop regulations to protect the environment.

The human population already at ~6 billion people is expanding at an exponential rate. This growth rate will place increasing pressure on the environment. It is essential to protect the Earth system from unnecessary degradation. As individuals we can make a difference if we choose a lifestyle that mitigates harm of the Earth's ecosystems.

Simple Living Collective
of San Francisco, 1977

  1. Does what I own or buy promote activity, self-reliance, and involvement, or does it induce passivity and dependence?

  2. Are my consumptive patterns basically satisfying, or do I buy much that serves no real need?

  3. How tied is my present job and lifestyle to installment payments, maintenance & repair costs, and the expectation of others?

  4. Do I consider the impact of my consumptive patterns on other people and on the Earth?

What will YOU do to help?
Ten Things YOU Can do to Save the Ocean!

- if this is the last science course you ever take, so be it, but you should continue to increase your knowledge of science - this is important if you are to be a good citizen of the country, a good citizen of the world

- it is fairly easy to keep up with science - go beyond watching the "X Files" and check out the good shows such as "Bill Nye, the Science Guy," "Nova," and the many programs on the Discovery Channel.

- Michael Jordan was passionate about how to execute the perfect jump shot, Robert Redford is passionate about acting and movie direction - scientists are no different - they have a passion to understand how the world works - this is an extension of something that we ALL do (wonder about how the world works)

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Origin: June 1, 2000, Last update: May 28, 2010
http://dusk.geo.orst.edu/oceans/lec26.html