Many of the challenges the Blue Movement faces are easy to see or grasp. It’s relatively easy to grasp what overfishing looks like, what dirty water smells like, and what shark-finning feels like. But oceans are still affected by problems that are much more difficult for us to conceptualize—and which may, ultimately, have a more drastic effect on life as we know it.

Ocean acidification is one such challenge. As more carbon dioxide is released into the atmosphere, much of the excess is absorbed by the oceans.The excess CO2 changes the pH level of the water, and even slight variations from the delicately-tuned balance can topple underwater ecosystems. These out-of-whack ecosystems, along with a dearth of oxygen, can cause many fish populations to collapse.  At this point, though, we still don’t know what the ultimate outcome of ocean acidification will be. The current increases and fluctuations in ocean acidity are happening at a rate 100 times faster than ever before, and only time will tell what kind of damage will be done.

Not only has climate change caused the oceans’ acidity to change, it’s also caused the temperature to rise. Over the past century, waters have warmed by about . 0.18°F. Small though this number may be, it can have drastic impacts on fragile sea creatures such as reef-building coral and krill, both of which are essential to many other marine species.  Another more visible impact of warmer oceans has been a rising sea level.  As water heats, it expands, leading to flooding of coastal habitats and escalating severe tropical storms.  

And then there are parts of the ocean that are completely devoid of life. In these so-called Dead Zones, no life can sustain due to a complete lack of oxygen in the water. Although zones can “die” naturally, most of the recently discovered dead zones are the result of human activity.  Chemical fertilizers from crops are the biggest drivers of algal blooms that deplete these areas of their oxygen.  The process can suffocate even large ecosystems, leaving them without adequate levels of to support life.  Organisms that are unable to relocate cannot survive and those that are able to swim must find new homes.  There are currently over 400 dead zones worldwide ranging in size from one to seventy thousand square kilometers.  

But as is the case for many underwater issues, responsible action and reform can restore some of the damage that’s already been done. It’s not yet too late to reverse course.

[Dead Zones of Coral Reefs Credit: http://www.co2science.org/data/acidification/acidification.php]