Marine Ecosystem

The Marine Ecosystem

Standing on the beach, looking out over the Pacific Ocean, most of us imagine we are looking at a big, uniform body of water that stretches all the way to Japan. In fact, the ocean is far from uniform and the waters near the coast are constantly shifting, mixing, and changing. Winds set currents flowing and the rotation of the Earth starts these currents spinning. Jets of water, like huge rivers, extend hundreds of miles offshore, sucking up cold rich water from the depths where it nourishes vast areas of algae, plankton, and fishes. Ultimately, the ocean waters off the West Coast of North America are some of the most dynamic and productive in the world.

Because it is so dynamic, the Pacific Ocean is ever-changing. Currents change with the seasons. The jet stream snakes back and forth through the atmosphere sending storms North to Canada, then South to California. Winds at the equator help pull cold, Arctic water South to California, then shift to send huge volumes of warm water up the coast, influencing temperature and rainfall patterns around the globe. Distinctive communities of plankton and fish move with the water.

Salmon are among the hundreds of fish species found in the Pacific Ocean. They are finely attuned to these ocean changes because their lives depend on it. Young fish entering the ocean are extremely vulnerable, and their fate depends on what they find in the first few weeks of their ocean lives. If food is plentiful and predators few many will survive, but some years warm water carries huge schools of hungry fish up the coast, and young salmon are eaten like popcorn. Some salmon migrate in the ocean for thousands of miles, from California to Alaska and back, living in the ocean for five years or more, always following ocean currents to find the best conditions. Others spend their lives closer to home, but all depend on the dynamic ocean to feed and protect them so they can grow large and return to lay eggs in the rivers where they were born.

Sea Surface Temperature

Represented here in blue and green, rivers of cold water extend outward from the coastline, providing the nutrients that sustain life in the Oregon salmon and albacore fisheries.
(Image source: NOAA CoastWatch)

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