Wild Blue Oceans

Water covers seventy percent of the earth's surface.  We've explored less than a tenth of that space, and are finding previously unknown species every year.

Although so much of the ocean remains a mystery, we do know that humankind is dependent on it for survival.  Over half our world's oxygen is produced by tiny plants that live in the ocean, called phytoplankton.  The ocean also provides fish, seaweed, and shellfish, which are important sources of food for many people.

Kelp Forest at Birch Aquarium
Kelp Forest - picture by Natalia

Human Impact on Earth's Waters

The National Oceanic and Atmospheric Association (NOAA) states that 80% of ocean pollution begins on land.  That's a lot!  But what is it, where does it come from, and how does it affect the world?

Marine Debris

Marine Debris is a fancy way of saying Ocean Garbage.  Between 60% and 80% of all trash we dump in the ocean is plastic, making it the biggest contributor.  Every year, it's estimated that 8 million metric tons of plastic get dumped into the sea.  Turtles get entangled in plastic quite frequently.  Corals entangled in plastic are 20 times more likely to be infected than plastic-free reefs.  Turtles and corals aren't the only ocean life affected; plastic bags have been found in the bellies of ocean creatures.


Plastic pieces smaller than 5 millimeters (the size of a sesame seed) are called microplastics.  They most commonly form when larger chunks of plastic are both immersed in an ocean environment, and exposed to UV rays.  Under those conditions, plastic continues breaking into smaller and smaller fragments, some of which reach micro size.  Microbeads are a form of microplastic that are so small they can pass through water filtration systems.  They are added as an exfoliant to health and beauty products, though not in the United States, where they have been banned since 2015.  Microplastics get eaten by birds, and can damage their insides.

Toxins and heavy metals

Toxins and heavy metals make their way from factories, mines and sewage treatment plants to the ocean.  These poisons get eaten by fish that get eaten by other fish that get eaten by humans.  Sometimes those poisoned fish are eaten in enough quantities to make humans sick.

Nonpoint Source Pollution

Nonpoint Source Pollution means pollution that results from many sources.  It includes oil from cars, farm waste, septic tanks, vehicles, air pollution that settles, and forestry.  Oil and other vehicular fluids and emissions collect on roadways.  When it rains, groundwater seeks streams and rivers, carrying the pollutants along with it.  This form of pollution is called runoff, and is not exclusive to vehicles.  Different types of oil have different effects on creatures, none of it good.  Oil is toxic, can block sunlight when it floats on the water, and can smother creatures.

Pesticides and fertilizers

Pesticides and fertilizers are also carried by runoff.  Excess nitrogen and phosphorus cause overgrowth of algae (algal blooms).  When those die, part of their decomposition process depletes oxygen, creating areas that can't support marine life.  Those oxygen-dead areas are called dead zones.


Not all the oil in the ocean comes from man.  According to NOAA, 46% of it comes from natural seeps.  Mankind is responsible for the other 54%:  37% comes from using or consuming oil, 12% from transporting it (spills), and 3% from extraction.