Earth Day 2012: The Top 5 Threats to Our Oceans, Part Two

Apr 22 2012

Continued from Part One, focused on Overfishing and Marine Pollution. Read part one here.

Climate Change

Several studies have shown that in the past century our planet has seen climate change and warming unlike any other time in recent history. While this has many effects on land, such as more erratic weather patterns, it effects the oceans in two main ways: sea temperature and sea level rise.

In the past century, the temperature of the ocean has raised 0.18°F (0.1°C). Factors such as ozone depletion and increased solar activity contribute to this rise. As the surface of the water absorbs heat and the temperature rises. Some sub-tropical seas have shown a 1 degree surface temperature rise in the past half-century.

Warmer than usual marine environments also give way to marine invasive species. That is, species that do not typically inhabit a given area but with abnormal temperatures can survive in the new environment. These species can deplete a once healthy ecosystem by introducing disease and competing for food.

As ocean water warms, it expands. Due to increased sea temperature, the sea level is rising. Ice melting on land also contributes to the rise in sea level. Sea levels are expected to rise between 2.5 and 6.5 feet by 2100, a level that would swamp many cities along the East Coast of the U.S. There are other more dire scenarios some environmental scientists believe to be possible. Such as, if the Greenland ice sheet were to completely melt, the sea level could rise up to 23 feet, enough to submerge London and Los Angeles.

Ocean Acidification

Above-normal sea temperature is a contributing factor to coral bleaching. Ocean acidification also plays a major part. Over the last 250 years, the ocean has absorbed 530 billion tons of CO2 which has increased ocean acidity by 30%. Under these harmful circumstances, once healthy coral loses its algae pigmentation and expels zooxanthellae, causing it to turn white.

Acidity reduces carbonate- the mineral used to form the shells of many species such as lobster and mussels as well as smaller species which the food chain heavily depends on.

Due to ocean acidification, coral reefs are depleting twice as fast as rainforests.

Marine Habitat Loss and Destruction

70% of the world is covered by the ocean, yet only .6% of our worlds oceans are protected.

Factors such as overfishing, coral bleaching, boating, oil spills and other industrial pollution all cause serious damage to our oceans. Coral reefs bare most the brunt of marine habitat loss. Over 15% of the worlds coral reefs have already been lost. 30% of those still existing are directly threatened by human impacts.

Costal development can lead to runoff and erosion that is harmful to the surrounding marine area. This occurs all along our coastlines, small island developments and coastal swamps and marshes.

Marine Protected Areas (MPAs) are similar to National Parks on land. While they are not closed off completely to human activity, they only allow a certain minimal and regulated presence.

Hope everyone has a great Earth Day and celebrates it in their own way. We encourage you to share our Earth Day 2012 page. For every share, we at Seathos will collect 1 lb of trash from our local beach in Venice, CA.

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