Top Three Threats to Oceans and More Than Three Ways To Help

In honor of Earth Day, here's a look at how we can help the largest living space on the planet: the oceans.

Why care about the oceans? Here are just a few reasons:

Half the oxygen we breathe comes from marine plants.

Ocean currents distribute the heat that allows northern locations like Spain to be "Mediterranean," and grow all that food.

The oceans have absorbed one-quarter of our CO2 emissions: It'd be whole lot hotter without them.

And, about one billion people, mostly in developing countries, depend upon seafood as their main source of protein.

So the oceans matter. A lot.

But you wouldn't know it given how we've treated them. Millennia of pressure from us landlubbers has left emptier, more polluted oceans. But many of us don't even notice the change. Kids today aren't surprised at beach closures due to high toxins following a rainstorm and the average angler is jazzed at hooking a hundred-pounder—for a species that used to reach over a thousand.

Whether we realize it or not, this wet and salty footprint of ours threatens the life-support systems that all of us—air and water-breathes alike—depend upon for survival.

Good news is, it's not all bad news. Below I list the three most pressing threats to oceans and the many ways we can help turn the tide. So dive in, share your thoughts, and support the innovative and often simple solutions for a greener Blue Planet.

Overfishing: taking too much out

As mighty and massive as the oceans are, they are no match for industrial trawlers with nets big enough to swallow a dozen jumbo jets at a time. Outrageous subsidies, technology, and our insatiable appetite for seafood have fueled a fleet capable of fishing out the ocean 2.5 times over.

And we are well on the way.

Seventy-five percent of major fisheries are over-fished or at their limit. Large animals—tuna, sharks, cod—are down by 90 percent. Aquaculture offers some hope, but as a fledgling industry, there are still lots of wrinkles—in some cases major creases—to iron out.

The most important step we can take is to reduce demand for unsustainable fisheries. Eat less seafood, and buy only locally, sustainably caught species. You can find out which ones are good choices here and here.

Second, marine life needs somewhere to hide. Join efforts to create marine reserves so that 99 percent of the ocean doesn't stay open for slaughter.

Pollution: putting too much in

There are two kinds of pollution: garbage dumped or washed into the sea and chemicals, such as hormones and pesticides, that run-off from land.

Plastics are the worst kind of trash: Toys and bottles break down into small fragments easily ingested by everything from fish to seabirds. Animals eventually starve—no room for food in a belly packed with plastic—or die from internal bleeding. Plastics also accumulate toxins; these poison pellets pass the toxins into flesh of fish we eat.

As for chemicals, everyday run-off is the biggest offender. Every eight months, as much oil as the Exxon Valdez spilled is washed into the ocean from U.S. streets. Fertilizers from farmlands fuel algal blooms that suck oxygen out of the water, leaving enormous dead zones: There are more than 400 worldwide, affecting more than 95,00 square miles of ocean.

Cutting back on bottles and packaging in your purchases helps keep plastic out of the ocean. To tackle the smaller stuff, invest in low impact development (LID), which helps collect storm water before it sweeps up pollutants and pours them into the sea. Wash your car with biodegradable soap, and make sure it doesn't leak oil. Supporting local, organic farms will reduce fertilizer loads on land and ultimately, in the ocean.

Acidification

This may be the scariest threat of all. Besides the well-known effect of potentially dissolving coral reefs and loss of shelled species like clams and oysters, ocean acidification disrupts growth and reproduction in multiple species, disables the sense of smell in some fish, changes how critical nutrients like iron can be absorbed by marine plankton, and alters how sound travels through water—something marine mammals rely on for communication, courtship, and hunting. The effects of acidification are pervasive and happening fast, while we've only just scratched the surface of understanding the consequences. One thing is certain: Species at the base of the food chain are suffering and the ripple effect will likely cause some serious waves—for food security, industry, coastline protection, and tourism.

It will take centuries for natural systems to restore ocean pH, but reducing emissions now will help blunt the impacts. In addition to curbing your own carbon footprint, you can help the EPA use the Clean Water Act to regulate pH. The public comment period is now open so show your support here.

The consequences of centuries of abuse are not easy to reverse, but they are not impossible to change. Oceans are remarkably resilient systems.  We know what needs to be done. Through individual action, pledges, and petitions, you can join in the growing movement to better care for the ocean that everyday takes care of us.

Photo credit: Simon MAX Bannister