Things That Affect Photosynthesis in the Ocean

Sunlight

• Sunlight is the energy source for the process of photosynthesis. As long as the solar energy isn't so intense that it kills the phytoplankton, more sunlight equals more photosynthesis, according to a paper by John H. Ryther for the American Society of Limnology and Oceanograpy. Equatorial oceans are the sites of more photosynthesis than oceans located far to the north or south because they receive more intense sunlight all year long. Most photosynthesis occurs in the top few feet of the ocean, because sunlight is quickly filtered out in the briny ocean water, and is absent at the lower depths.

Temperature

• Along with sunlight, temperature is a factor in photosynthetic production, horticulturalist Erv Evans wrote for the North Carolina State University. Plants become less active as the temperature drops, and below a certain temperature will become dormant and die. Conversely, if temperatures rise too high, this will have an adverse effect on plant photosynthesis. An optimum temperature needs to be maintained for the needs of the particular plants and phytoplankton that have evolved to function in certain ecosystems.

Species

• Some species process more sunlight than others. The vast majority of photosynthesis in oceans is undertaken by microscopic plant species known as phytoplankton, the Live Science website states. In the absence of these organisms, there are few species in the oceans that will fulfill their function.

Pollution

• Ocean pollution exists in many forms, some of them toxic and localized, others spread across entire oceans, but all of them degrading the functions of the ocean on which all life depends, according to the website Marine Insight. Oil spills, toxic emissions, plastic waste and agricultural runoff all combine to have an impact on the levels of photosynthesis that are occurring in the oceans. In some cases, such as emissions of sewage into coastal ocean ecosystems, nutrients for phytoplankton become excessive, causing algal blooms that block sunlight from lower depths and disrupt food chains. In other cases, toxins kill everything in a particular area, leaving dead zones in the ocean where no photosynthesis or other life functions occur.