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Oil Spills and Aquatic Plants

Aquatic plants are a variety of vegetation that requires fully water-saturated soil. While they have adapted to flourish either fully or partially submerged underwater, their health depends on that of their environment, and thus they are highly sensitive to the chemical exposures introduced by oil spills. Oil spills occur with alarming frequency and pose varying degrees of hazard to aquatic plants depending on the magnitude of the spill and the nature of the oil.

  1. Oil Classification

    • Oil types exist along a spectrum from light to heavy, depending on their density and distinct chemical properties, and each type poses different harms to aquatic plants. According to the Environmental Protection Agency, heavier oils tend to sink to the bottom of the water and there contaminate the sand and sediment, in which many aquatic plants are rooted. Light oils generally spread over a greater surface area, forming a layer on top of the water that can impede the flow of light and oxygen and cause subaquatic dead zones.

    Spill Magnitude

    • Just as different oil types will affect aquatic life in different ways, the size of an oil spill has a different impact on underwater vegetation. Data presented in 2001 by the Environmental Research Consulting Group shows that throughout the 1990s, U.S. vessels alone were responsible for 134 million gallons of oil spillage. While the number of oil spills per year is on average decreasing worldwide, the increase in international shipping often means that the spills that do occur are of a greater volume. The larger the spill, the more difficult it is to clean up, the wider its areas of impact and the more harm it causes to aquatic plant life.

    Chemical Effects

    • Oil contains a number of substances that are highly toxic to aquatic life. In addition to harming plant species, oil spills also endanger the fish and mammals that feed on aquatic vegetation. As noted by the U.S. Fish and Wildlife Service, the toxic chemicals present in oil spills can cause the die-off of plant species in large areas. Furthermore, the chemical components of oil can hinder or accelerate the growth of algae in certain areas. Algae is a necessary part of many aquatic ecosystems, but when it grows out of proportion it can cut off needed flows of oxygen to underwater areas and endanger the life of other plant varieties.

    Cleanup

    • Clean-up efforts in the wake of oil spills tend to suffer from delays, and are often not conducted in time to prevent severe damage to sensitive aquatic plant species. While most aquatic ecosystems have inbuilt mechanisms to regain their healthy functioning, the high toxicity of chemicals found in oil limits the ability of a body of water to regenerate. However, ecologists have recently begun to experiment with bioremediation, a process that uses microorganisms to break down oil residues, and which is hoped will accelerate cleanup and save aquatic life.

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