Why Are Phytoplankton Important to the Health of Oceans?

Phytoplankton is extremely important to the health of the Earth's oceans. Driving the marine food chain, these organisms are affected by environmental factors, many of which can be traced to human civilization and industrialization. The health of the ocean's phytoplankton is essential to the overall health of the planet and consequently to the long-term viability of all life on Earth.

Facts

Phytoplankton is a type of marine plant, consisting mainly of microscopic algae such as diatoms and dinoflagellates that live mainly near the ocean's surface. They are usually rounded and single-celled. There are fresh and salt water species of phytoplankton. At the surface, the density of marine phytoplankton can be many millions of organisms per square meter.

Benefits

The ocean's phytoplankton is responsible for nearly half of the Earth's photosynthesis. Each day, more than 200 million tons of carbon dioxide is absorbed by phytoplankton. This process is vital to producing oxygen, maintaining global temperatures and for the ocean's ability to handle climate change. The basis of the ocean's food chain is also dependent on phytoplankton. These organisms provide more than 200 billion metric tons of food per year for many marine creatures, ranging from the smallest floating animals called zooplankton to the largest fish, the whale shark, and certain species of whales. Shellfish are also nourished by phytoplankton sinking to the ocean floor. The commercial fishing industry is directly affected by the health of the ocean's phytoplankton.

Problems

The phytoplankton population is very susceptible to global warming and climate change. Concerns have been raised by scientists that harmful rays from the sun, passing through the hole in the ozone layer, could kill phytoplankton. They are also harmed by pollutants in the ocean, such as agricultural runoff, and are often absent in areas of high pollution concentrations. Phytoplankton is nourished by nutrients welling up from the ocean floor and iron deposited on the ocean's surface by the wind. Changes in global climate are likely to affect wind patterns, which drive currents and carry required minerals to the ocean.

Research

Research is being conducted on a global scale to assess the impact of global warming, climate change and pollution on the phytoplankton population. Using instruments on NASA's Aqua satellite, scientists can track the amount of fluorescent red light emitted by the ocean's phytoplankton. This measures how well the organisms are functioning. Used in conjunction with analysis of the green pigment of chlorophyll, which measures the amount of phytoplankton, researchers are developing a better picture of the ocean plants' overall health. This picture will enable them to suggest new policies for society to adopt to protect the oceans--and by extension all life on the planet.

Warning

The collapse of the oceans' phytoplankton population would be a critical blow the the world's environment. Governments should heed the scientific data and enact policies that curb global warming, restrict pollution and guard the health of our planet. In the interconnected web of life, we may all be affected by the survival of one of its microscopic inhabitants.

References

• Researchers investigate ocean health

Resources

• Definition and further reading