Our oceans are our planet’s life support system. They provide us with oxygen, food and fresh water and control our weather. One teaspoon of sea water contains as many as a million one-celled algae which produce oxygen during photosynthesis. These algae are at the bottom of the food chain that leads to whales, the largest of mammals. We depend on the oceans for our seafood. The evaporation of ocean water forms clouds which bring us rain and snow, a vital source of fresh water on land. Lastly, the flow of ocean currents heats and cools the earth’s atmosphere and creates different weather patterns.
Our oceans cover about 70 percent of the earth’s surface and contain roughly 97 percent of Earth’s water supply. The increasing amount of carbon dioxide on earth produced by burning of fossil fuels has had two effects on the sea water. First, it has increased sea temperatures to produce unpredictable weather and more storms whose intensity have harmed life on sea and land. Second, sea water is becoming more acidic, killing sea creatures by weakening their ability to produce calcium bearing shells. The possible cumulative impact of these changes are sobering. Recent analysis of the massive volcanic release of carbon 250 million years ago showed the resultant ocean acidification led to the destruction of 90 percent of life on earth, mostly in the ocean.
The algae in the oceans make 50 percent of the oxygen on our planet. During photosynthesis algae also make sugar from carbon dioxide and water. In order for algae to make proteins, fats and carbohydrates they also require inorganic nutrients such as nitrates, phosphates and sulfur, naturally available in deeper parts of the ocean and brought up to the surface by ocean currents. When too many nutrients are available, some algae may grow out of control and form harmful algal blooms (HABs). HABs have occurred regularly along coastal areas where fertilizer from rivers and from sewage merge with sea water. While many blooms provide more food for living things higher up in the food chain, some blooms are harmful due to possible toxicity, or interference with the balance of basic ingredients needed for all marine health. The economic impact of HABs on harvesting seafood and tourism is estimated to be at least $82 million per year in the United States.
We need healthy oceans to sustain a balanced environment for our own well-being. Our modern lifestyle has produced a more turbulent sea that is becoming more acidic and polluted with run-offs and plastic products that kill sea lives. However, we can make use of improved technologies to diminish the effects of our lifestyle. Foremost, we can reduce our carbon emission by using more efficient means of transportation and heating, cooling and lighting of homes and buildings. And more careful use of plastics and chemicals should be mandated to eliminate unnecessary pollution of our environment.