Consider the Carbon: Marine Snow and Microfibres
Cordelia Roberts
This week as part of our 'Plastic Not Fantastic' series, we hear about the plastics found in the microfibres from clothes from Cordelia, a masters student from the University of Plymouth.
Since the first paper’s in the early 2000s highlighting microplastic pollution, the issue has become well known globally. A rallying for change has transcended into national policies, banning microbeads in cosmetics and a sudden surge of popular books that hone in on changing our lifestyles to stop the plastic tide…
Through all of this raised awareness, we know that once in the ocean, microplastics can affect marine life directly through ingestion. But, do they have the capacity to influence the way the oceans cycle carbon?
It all starts at the ocean surface. Microscopic algae, known as phytoplankton, take up carbon dioxide (CO2) dissolved in the seawater, allowing them to grow and generate big blooms spanning many kilometres wide.
Phytoplankton. Photo: Pixabay
As phytoplankton use up the nutrients at the surface of the ocean, the cells of the bloom begin to die and fall as marine snow. When the cells fall, they collide with each other and other material (faecal pellets from fish or microscopic animals called zooplankton) and form little parcels of organic material.
Marine snow gets its name from its snow like falling and tumbling as it fades from a bright green chlorophyll containing cell to a dark murky white as the light fades into the deep dark sea. Larger cells sink faster and smaller cells sink slower. As there is no primary production in the deep sea, this marine snow is crucial for feeding the deep sea and when it reaches the sediment, it can be confirmed that this carbon is locked away out of the atmosphere.
Synthetic clothes release microfibres when washed. Photo: Friends of the Earth
But also at the ocean’s surface, where phytoplankton grows and blooms and begins this crucial part of the carbon cycle, is the input of plastic microfibres from our plastic based clothing.
These fibres can enter the oceans when a few thousand of them are rubbed off your clothes during your weekly wash. The contents of your washing machine’s outflow pipe then journeys down the drains and straight past the filter at the waste water treatment plant; too tiny to be caught by filters. Quite easily these plastic fibres, thinner than a human hair, make their way into a river, an estuary and out into the big blue ocean’s surface waters and eventually become intertwined with our magnificent phytoplankton bloom.
Microfibres. Photo: Friends of the Earth
As the cells of the phytoplankton bloom fall down to the depths of the ocean abyss, there is the unfortunate chance that they may collide with the plastic microfibres, which have the potential to slow the speed at which marine snow sinks to an extent that may even lead them to float and never reach the deep sea. There is also the potential for the quality of the marine snow (i.e. how much carbon it contains), to be reduced. The introduction of microplastics into marine snow could therefore impact both the rate at which carbon dioxide can be removed from the atmosphere and locked down in the sediment– something we should all be concerned about, and the amount and quality of nutrients that the deep sea is getting.
Marine snow falling on a coral garden. Photo: Megan Cook http://scientistsatsea.blogspot.com/2016/06/submarine-canyons-ecosystem-services.html
Unfortunately we know now, that microplastics have reached all places in the oceans, including the deep sea, with marine snow a potential vector for this. BUT… trying to avoid any addition to your possible January blues, we must muster some cheer and good willed spirit (or a little bit of Christmas spending money) to consider these few things that can help prevent the problem from worsening.
Think about the clothes you’re buying – think second hand store or good quality clothes. The latter might be a little more expensive but actually in the long run you’re saving money, doing yourself and the oceans a favour.
Think about how often you actually need to wash your clothes – naturally if its dirty its dirty! If it’s just a case that you’ve worn it a couple of times, could a quick spritz with some smelly stuff do the job?
You can minimise the amount of fibres coming out of your washing machines!!! Check out products the range of products coming out that can capture the fibres your clothes produce – great to see what’s producing fibres (helps make action number 1 a little easier) and also a little scary to see what could be ending up in the ocean!