HOW’S THE WATER?

As you gaze out over the usually still waters in our sector of Puget Sound’s vast marine labyrinth, you may take them for granted. You might think that salt water is pretty pedestrian stuff: just liquid with a lot of salt dissolved in it. Actually, it’s more complicated than that.

Scientists routinely take measurements of various aspects of the waters around Puget Sound. The factors being measured are those that experts watch closely in waters throughout the world. Things like salinity, oxygen content, and pH sound pretty uninteresting on the surface, but if you’re a crab, an octopus, a clam or a fish, these elements of salt water are crucial to your ability to make a living and reproduce successfully.

Dissolved oxygen is one important indicator of our waters’ overall health. Lowered levels of oxygen put marine life under stress, demonstrated tragically by summer events in Hood Canal. What depletes oxygen? It’s lowered when substances such as animal waste, improperly treated sewage and fertilizers wash into the water. This increases algal growth, and its ultimate decomposition, when it dies and falls to the bottom, uses up the oxygen that marine animals need.


All life in all the world's oceans rely on just the right chemical balance in the waters around them.

Another measurement is salinity, which refers to the amount of salts dissolved in the water. Too little or too much also affects marine life. The sea’s natural salt comes from the mountains, washed down by rivers. But humans can increase oceanic salt through agricultural runoff, wastewater from industry, and sewage plant effluent.

Temperature is also measured religiously; scientists are alert for big changes. Most marine creatures cannot tolerate a wide range of temperatures. Many fish, for example, have migrated up to northwest waters from the south because the southern reaches of the Pacific simply became too warm, particularly during those infamous “El Nino” events, and more important, gradually through global warming.

Another factor to measure is pH. This refers to the acidity or alkalinity of the water. If pH levels are too low or too high, fish may not be able to produce healthy young. Acidity is increased by the same human activities that alter salinity.

So there’s more to salt water than just the salt. Fortunately, scientists take these and other measurements continuously, all over the world, to determine how healthy the waters are, for the creatures that live in them, and we human creatures that live along their edges and interact with them on a daily basis.