Thursday, May 10, 2012

Promulgation of Plastic Pollution

On May 9th, biology letters published an article entitled "Increased oceanic microplastic debris enhances oviposition for an endemic pelagic insect".  Translated to regular English, this means that very small bits of plastic pollution have increased the ability of ocean water striders to lay more eggs in the north east Pacific.

What does this mean to us land dwellers?  First, we need a little more explanation as to what is happening. 

The largest collection of pollution, known as the "Great Pacific Garbage Patch", lays just north of  Hawaii, extending across the ocean in an area called the North Pacific Subtropical Gyre (NPSG), shown in red on the map.  The actions of ocean current and eddies aggregate solid pollutants here regularly.  As an aside, while this is the largest collection in the Pacific, other garbage patches exist due to ocean eddies and other currents.  

Before the 1970s, the floating substrata of this region mostly consisted of wood, pumice, and seashells.  Now,  plastic reigns as the largest inhabitant to the floating substrata.  

The North Pacific Subtropical Gyre
The levels of microplastic (less that 5mm in size) pollution has grown over 100% in the past 40 years.  That's two orders of magnitude.

The plastic is not dumped into the ocean that size; the sun and wave action breaks up most floating pieces of plastic to microplastic size.  In the end, one plastic 20oz. bottle may transform into tens or hundreds of microplastic pieces.

Oceanic water striders, officially named Halobates sericeus, always lived here.  They eat plankton and are eaten by larger animals, such as turtles, birds, and fish.  But these insects need a hard surface on which to lay their eggs (oviposition).  In the past, the lack of available surface space naturally limited their population. Now, though, scientists found a "positive association" between the number of eggs, juvenile, and adult H. sericeus and the level of microplastic debris.
I believe that messing around with your own food chain is cause for trouble - and messing around we are.  On top of this pollution, we've fished several species of fish either to extinction or near extinction.  And we tend to want the big fish to eat.  So we've effectively created a situation where the smaller fish have more food to eat and less predators eating them.

But will the changes in the ocean stop here?  How will the larger population of water striders and potentially smaller fish effect the balance in the ocean environment?  What other animals will start to use the plastic pollution to create new floating communities?  Have we just accidentally created a new biome in the ocean through inadvertent pollution?


  1. Interesting question to ponder. That reminds me, have you seen the documentary "Bag It"?

  2. I heard the Pacific is even worse :(


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