Surprisingly, not a lot of people have actually heard about the phenomena of our oceans’ garbage patches, yet on an ecological basis, the patches are likely harbingers of some seriously bad times. Similar to many of the changes that are starting to become known in our global environment (and when I say “starting”, I mean that the garbage patches were predicted as far back as the 80’s and evidence of them began appearing in the late 90’s), the exact ramifications of these ecological disturbances are not yet fully realized.
What is abundantly clear, however, is that they are already having negative impacts on our oceans and the signs don’t point to a happy outcome as the situations in the garbage patches worsen. Personally, it’s a crying shame that our absolute recklessness and willful blindness as to the fate of our non-recyclable products has resulted in such a massive ecological impact. The situation is one that is only going to get worse unless people can be truly educated about it. It really saddens me to think that there are so many cascading effects that continue to compound the issue. With a continued ignorance in the developing world and a blasé attitude in the developed world, not enough people really care that we are simply destroying entire habitats, ecosystems and species.
(Courtesy: Coastal Care)
What then are these Great Garbage Patches sitting in the middle of our oceans? So far, only two major garbage patches have been ostensibly identified. The more infamous of the two is the Great Pacific Garbage Patch (also known as the “Pacific Trash Vortex”), while the other is the Northern Atlantic Garbage Patch. That’s not to say there are not more garbage patches, it is quite feasible that there are, except they haven’t as yet been identified. The Great Pacific Garbage Patch is actually two separate garbage patches (the Western and Eastern Garbage Patches), connected by a thin current called the Subtropical Convergence Zone. Some scientists have estimated the Eastern patch is approximately two times the size of Texas whereas the Western Patch forms east of Japan and stretches to just west of Hawaii.
Great Pacific Garbage Patch
(Courtesy: Mercury News)
North Atlantic Garbage Patch
Garbage patches form as a result of oceanic “gyres” (of which there are five major ones: the North and South Atlantic gyres, the North and South Pacific gyres and the Indian Ocean gyre).
Gyres are formed due to the effects of gravity, wind and the Coriolis Effect. Let’s break that all down a little.
Gyres tend to form primarily in the upper water column in our oceans (the first 3-400 metres of water in the ocean, including surface waters and thus the most visible water system we can relate to). The upper water column makes up 10% of all the water movement in our oceans. Given the rotation of the planet, water at the equator is approximately 8 or so centimeters higher at the equator than elsewhere. Being higher, it is closer to the sun and so expands. Also, due to the increased height the water globally then flows down from the equator (somewhat sped up by surface winds and natural gravitational pull) and basically “piles” up.
This is where the Coriolis Effect then kicks in. Without getting into the complicated physics of it, effectively the Coriolis Effect causes water to veer to the right (clockwise) in the northern hemisphere and to the left (anti-clockwise) in the southern hemisphere. You have probably seen this Effect if you have traveled both sides of the equator and watched water go down a drain.
With the water veering because of the Coriolis Effect, it essentially creates “mounds” as the equatorial waters flow and swirl around the globe. Due to the continuous movement of oceanic waters, these currents then rotate around the mounds, keeping the piled-up water in one place. Think of it like large whirlpools (without the draining effect in the middle, of course) out in the middle of the oceans.
As water continues to move into these gyres it draws in garbage from all over the world (both from land-based dumping and from marine dumping by ocean vessels – cruise ships create over 8 tons of waste a day). That garbage then gets pulled into the “mounds” and gets “stuck” there for extended periods, thus forming the garbage patches in our oceans.
So what kind of “garbage” are we talking about? There are many forms, but the major culprit is plastic. In fact, plastic constitutes approximately 90% of all trash floating in the world’s waters. According to the United Nations Environment Program, in 2006 for every square mile of ocean there were 46,000 pieces of plastic. So dense in places, in fact, that the plastic outweighs the plankton in the some areas six to one. Greenpeace has identified that of the nearly 91 million tons of plastic produced globally each year, 10% ends up in the oceans, with 70% of that sinking to the ocean floor. The remaining 30% stays in surface waters and either ends up on shores worldwide or in the oceanic gyres. This next graphic shows the average concentration of plastics in just the North Atlantic Garbage Patch alone:
As I mentioned, two major garbage patches have been identified, but it is suspected that there may be more. Why is it so difficult to determine whether there are more garbage patches? Probably for the same reason why it is incredibly difficult to determine exactly how big the garbage patches are that we already know of.
This is because of photodegradation. While larger pieces of debris are frequently seen in the gyres, the process of photodegradation of plastic causes the individual pieces to constantly break down into continually smaller pieces. Unlike biodegradable garbage breakdown, however, the disintegration of plastic is never-ending and it remains a polymer even when it gets down to the molecular level. Some of these pieces are so microscopic that they simply become part of the water column, invisible to the naked eye.
The only way to gauge the size of the patches is by water sampling – using nets and boats. This is a time-consuming, difficult and relatively inaccurate way of verifying the size and spread of the pollutants.
Ok. So there are big patches of tiny plastic particles in the oceans. Is that detrimental? You’d think the statement that there are large plastic debris fields in the oceans would be enough to raise concern, but the likely environmental impact is probably a lot worse. We’ve already pointed out one alarming fact … in some parts of the oceans, plastic outweighs plankton six to one!! Considering that plankton is the base of the entire marine food web, it’s pretty obvious that dense plastic zones of water will be bad for the entire marine ecosystem.
Additionally, the photodegradation poses some titanic problems. One of these is the ingestion of plastic by marine life and by marine birds as the pieces degrade to microscopic sizes. This, in turn, introduces both indigestible product to the creature’s digestive system, as well as some serious toxins. Clearly bad news for the respective creatures! In some instances, even beyond the fact that harmful toxins are being ingested; there have even been documented cases of the plastics causing hormonal disruption in certain animals/fish. Here’s an example of an albatross chick that was fed plastic by its parents out at sea:
Even the most uncaring out there will recognize that this ingestion of plastic by marine life is problematic. Especially if, for no other reason, you further realize that the probabilities are that those creatures, or the creatures that eat those creatures, will at some point be caught in the fisher’s net and that those ingested plastics and toxins will circuitously be introduced to dinner plates worldwide.
Greenpeace has determined that at least 267 species of marine life have been affected by plastic marine debris worldwide. Further, invasive species have been found in non-traditional locations as a result of hitching a ride on floating debris.
But let’s not be so selfish as to only care about how dangerous toxins can end up on our plates. Let’s think about this in a slightly more global perspective. Of greater concern is that these plastics are changing the ocean’s ecosystems, which in turn is likely to impact the whole world’s ecosystem too. Hormonal disruptions of marine life, depopulation of various fish and other marine species because of plastic density/toxin ingestion, or evolutionary adaptations due to the increase of pollutants will dramatically impact ecosystems that have take millennia to evolve. What will be the effects and how can we tell if the effects will be negative? Well, that’s the problem …. we can’t!! Once such massive changes start to take effect, whatever results will simply have to be dealt with. We cannot accurately predict the outcome. I’d hazard a guess: it will not be good.
So, what can be don e to reverse the tide? Unfortunately, one of the biggest obstacles lies in anyone taking responsibility. To date, no country has specifically claimed any measure of responsibility, so there is no major international effort being undertaken to actively prevent and/or treat the current problem.
Instead, there have been some independent groups that have begun to research the full extent of the patches and their impact on marine life, infrastructure and ecosystems. A few have also commenced feasibility studies on how best to effect a clean-up of the garbage patches. The majority of these studies started only as recently as 2008/9, so they are still underway. And because of photodegradation, that clean-up is likely to be immensely difficult.
Without major philanthropic endeavour and international support, however, it is unclear how much can be done. On a personal basis, I know that I try my best to live as much of a plastic-free lifestyle and strive to recycle, recycle, recycle. I suggest you also try and adopt a similar view. On top of that, I know it doesn’t do much to help, but every time I dive, I make sure to pick up any trash I see along the way. It will only make a small dent in a huge problem, but every little helps. That and educating the masses as to the extent of the problem will hopefully create a little more pressure for wealthier nations and corporations to take a more proactive approach.