by E.R. Cross

Water is a chemical compound of hydrogen and oxygen, having the well known formula of H2O. It is abundant and widely distributed. It is also essential to animal and plant nutrition. Its many uses have led to an equal number of abuses. Ten years ago, only three small rivers, all in the western United States, were pristine. There are probably none now.

The oceans of the world are huge chemical systems containing nearly 100 geochemical parameters. Their most abundant elements are hydrogen and oxygen in the chemical combination H2O (water). The amount of oxygen found in solution in water at different times and locations will vary considerably for many reasons. It is generally accepted that the concentration of free oxygen in the water at the seas surface is determined by the solubility of the gas when in equilibrium with the surrounding atmosphere. The solubility is influenced greatly by temperature, less by the degree of salinity. As might be expected, the oxygen concentration in sea water also varies seasonally. Variations also exist at different depths.


Recently, R. Smith, who lives in Florida, wrote asking, Is there a possibility that the ships sunk in Florida waters as artificial reefs are now or can become pollutants? I suspect that anything that is not natural to the body of water in which it is placed is or can become a pollutant, including an apparently inert steel vessel and its many other possible pollutants, particularly paints, varnishes and other metal finishes.

As recreational divers we are more likely to be aware of our underwater environment than most other people. We also have an opportunity to be aware of the extent of the various kinds of pollution in the water. Before getting into the specifics of the environment and the several kinds of pollution, I would like to define some of the words we will use in this brief discussion.

Environment stems from the word environ; that is, something that encircles, surrounds or envelops. It could mean existing conditions, situations or even circumstances. Ideally, environment would mean the sum or total effect of surrounding conditions, influences or forces that affect or modify conditions in a habitat (a word with a closely related meaning). Think about this when you read about an environment being destroyed or ruined or polluted beyond repair. It is obvious that an environment cannot be destroyed. However, the fitness of the environment can be changed; possibly so drastically that the original life forms cannot survive. These areas may be sick but the environment is still there and some forms of life will find the new environment suitable.

Habitat represents all conditions of a particular site occupied by a specific form or forms of life. A habitat is not an environment but it is surrounded and affected by it. Along with the environment, a habitat is also affected by the whole complex of biotic, geologic, oceanographic and geographic conditions of the site.

Pollution is the contamination of a habitat and its surrounding environment by matter or material that make the site less favorable for the biota. Fresh water emptying into the ocean is a deadly pollutant to many forms of marine life. Silt, effluent discharges from chemical plants, refineries and metal processing plants can also be lethal pollutants. More insidious forms of pollutants may be the metallic ions formed by the corrosion process of rusting vessels. Mine tailing and processing waters are frequently dumped into coastal waters. Loading and discharging mineral products, such as coal, oil and freight, may have an adverse impact on habitat and environment.

I once made several dives on a steel vessel sunk on a coral reef. The shells of many mollusks had a rusty layer of material overlaying the normal shell color patterns. The shiny, rusty coatings on the Cypraea were so thick the natural color patterns were completely obscured. Other shells were coated with a rusty film but not to the extent of the Cypraea. More alarming than the melanism (pigmentation) was that most of the affected shells were also in some way rostrate. Alga forms attached to the hull of the vessel appeared stunted.

It is not only steel structures that may cause harmful pollution. Several years ago in Japan, earthquake rubble was dumped at sea to form an artificial reef. Quite quickly alga forms settled on the concrete. Browser type fish began eating the alga but soon developed fatal sicknesses. Apparently something in the concrete was poisonous to several forms of marinelife.

In personal communication with a malacologist in Fiji I learned that in some Fijian coastal areas mine tailing and processing water was discharged into the ocean. Most mollusks, but especially the shells of the Cypraea family, were affected by both melanism and rostrate forms.

Some pollution causing material seems to concentrate in areas of poor water circulation. For example, if a large, relatively flat object, such as a waterlogged board or a flat rock, is overturned, a thick layer of silty material may be discovered. Bubbles emitted from this material as it was uncovered would probably be hydrogen sulfide generated by rotting material. Oxygen is scarce under these objects but a few forms of life may be present; mainly worms.

In Alaska, studies have been made in areas of the discharge of mine tailings and of ship-loading berths. Primarily, the mine tailings tended to smother the marinelife in the area of the dumps. However, there was some low level toxicity. At the loading terminal where coal, zinc and asbestos were transshipped, elevated lead, zinc, copper, mercury and cadmium were measured. Since the coal had a low toxicity level, most damage to the habitat and environment by the coal spills was owing to the smothering action of the spilled cargo.

At outfall sewers and other freshwater waste discharges, fish in the area were occasionally observed with blisters and open sores on their sides. Possibly these were tumors of some kind.

Fresh water, particularly silt laden fresh water, can be devastating to marinelife in coastal areas. I suspect at least some, perhaps most, of the problem with coastal corals is owing to the excessive runoff of silt laden fresh water. Thousands of photographs from space show this form of pollution is common and deadly on a worldwide basis.

Technifacts readers are asked to carefully read the water and be very observant for any forms of pollution; whether in lakes, rivers, estuaries or the oceans. Note your findings of pollution in its many forms. Send your thoughts on any sort of degradation of habitats or the surrounding environment to E. R. Cross, c/o Technifacts, SKIN DIVER Magazine, 6420 Wilshire Boulevard, Los Angeles, CA 90048-5515. Together we can make a difference.