Much like our landscape, the ocean floor has topography—hills, valleys, plains, and even mountains—which provide habitat for marine life forms. Most deep-sea marine life does not live in the desert-like open ocean, but congregates along the edges of continents and around seamounts and ridges. These physical structures deflect deep currents and create “upwelling” (the upward movement of oceanic water), which in turn brings nutrients to sea levels where fish congregate.
Ocean currents are rivers of hot or cold water within the ocean that can flow for thousands of miles. They are created by a wide variety of influences, including the Earth’s rotation, wind currents, air temperature, and the topography of the ocean floor. These currents have an impact on the life cycles of marine creatures and also affect the temperature of nearby land masses.
One well-known example is the Gulf Stream, a surface current that is commonly said to flow clockwise. This means the Gulf Stream flows around the Atlantic ocean in something close to a giant circle. It heads southward in the Atlantic Ocean in a route that parallels Europe's coastline, then rounds west through the Gulf of Mexico, then flows northward along America's coastline to Newfoundland before crossing the Atlantic to warm Northern Europe.
Deep ocean currents are driven by cold dense water formed at the Earth’s poles, which sinks and flows toward the equator.
It’s estimated that millions of tons of garbage enter the ocean each year. Over half of the trash arrives from land, finding its way to the ocean via streams, rivers and storm water discharge. Most of this garbage is generated by people who do not dispose or recycle their garbage properly. The remainder is created by ocean-based operations—fishing gear, illegal dumping, and shipping containers lost at sea.
This garbage tends to accumulate rather than disperse in the ocean. One such “Garbage Patch” rests between California and Hawaii—and is estimated to be twice the size of Texas. Why does it collect in one area? It’s at the center of the North Pacific Subtropical Gyre, a swirling vortex which accumulates debris as huge rotating currents of wind and air move in a clockwise direction.
This growing patch of garbage consists largely of plastic debris that does not biodegrade and that now outweighs plankton per cubic meter of sea water. Countless seabirds, fish, and marine mammals die each year from eating or getting tangled in the plastic debris.